Acoustically transparent speaker fabric

Question: I would like to find an acoustically transparent material for speakers  and am looking for something with an interesting elegant texture.  I am wondering if raw silk is acoustically transparent?  Or does anyone have another source or idea?  Linen? Just  I am looking for an eggshell color or vanilla. A little stretch would be desired as well.
Answer: If you're asking whether there are any naturally occurring acoustically transparent fabrics, I think the answer is no.
There are plenty of synthetic fabrics that are manufactured to have acoustically transparent properties.  Here's a good start.

Acoustically transparent speaker fabric


What happened to cities in the Western Roman empire after the fall of Rome?

Question: What were the transitions, How long did each transitional period last.
Comment: The question seems very general and vague. Could you narrow the focus a bit? Which cities are you most interested in, what time frame exactly, and what transitions you're referring to?
Comment: [Henri Pirenne – Medieval Cities: Their Origins and the Revival of Trade](http://www.amazon.com/Medieval-Cities-Their-Origins-Revival/dp/0691007608)
Comment: _I came here to write the above comment, but I already did :O_
Answer: The western Empire was totally overrun, and very little Roman culture was left. Many families fled abandoning estates, especially the aristocracy. It was quite a sudden transition, but many buildings survived and were used by the occupiers. The technology and knowledge that the Romans had left in each province was lost, and you can imagine how throughout the dark ages and well into the middle ages, people must have marvelled at the skill apparently needed to have left the elegant villas, bridges, aqueducts behind. Stone building was a rare skill for centuries afterwards, and concrete had to be rediscovered. In England for example, the main Roman towns became the main cities of the Anglo Saxons. Wintanceaster (Winchester) was the court of Alfred the Great, previously Venta Belgarum. Lundenwic (London), used to be Londinium. York, Eboracum. The crumbling fortifications were supplemented with simple palisades and utilized as 'burhs'.
I could certainly tell you much more about this time, but please be more specific, in case I end up writing a book. And I would too.
Comment: I know this is a closed post but.. "you can imagine how throughout the dark ages... " While in Augsburg West Germany, in the '80's, I stood on a stone bridge in disrepair, while gazing up at a portion of Roman Aqueduct. I didn't live in the times, but rather more than a thousand years later....
Comment: I'm quite interested by this! For example, where did all the skilled artisans and aristocrats go? Did the invading barbarians not think to reacquire these skills they wonder so much about? Also re: roads in europe, here in Britain I can tell you that yes, they actually are, but most roads have been paved over because even the Romans couldn't have foreseen the modern day 10-ton container lorry :). The fact that they are usually the best routes to connect 2 cities also doesn't help their surival rates. You can still find them though, and they're certainly still usable for bicycles and such.
Comment: It must be amazing. In Italy especially, and in several places in Europe, I hear that roman roads are still actually used by traffic. If we marvel at them now in our so-called 'advanced' age, imagine what it looked like to a fellow with a flock of sheep and a wattle and daub hut!
Comment: @Evil Washing Machine we should think up a question or two about those matters. There's some terrific mystery in that post roman/dark ages period that I'd love to see explored on here!
Comment: I read a book by the historian Peter S Wells, Barbarians to angels. According to him, they stopped writing about their time. That's the reason we don't know much about the dark ages. Most likely, the romans left the cities in the previous western roman empire. But if we look at archeological evidence, it seems like the cities were never depopulated. They still functioned as cities, but now with inhabitants that weren't roman. The dark ages don't have to be as dark as they seem without written records.


Can companies add their own age restrictions to sales?

Question: In recent days, two very large companies have decided to require that gun buyers be at least 21 years of age [Reuters]. I understand that the government can add age restrictions to sale of certain items. However, can an individual company elect to do so if it is not legally required? Doesn't that amount to age discrimination?
Answer: Discrimination is legal, so long as there is not based on a protected category or class(e.g. race, sex, religion).
Age is generally not a protected category. Some states do treat age as a protected category, but:
1) It is generally only in employment, so, for example charging someone differing amounts based on their age is legal (e.g. senior discounts, kids under X are free, etc.).
2) It is generally only protecting higher ages (i.e. discriminating against someone in employment because their age is higher than what you'd like would be illegal, but discriminating against someone because their age is lower than you'd like is not; and in some cases the later is mandatory).
Comment: That is *why* I chose alcohol and the age range I did.  Asda is a UK supermarket chain owned by Walmart.  Alcohol is legal in the UK for anyone over 18.  Discrimination on the base of age *is* prohibited by law in the UK (for all reasons with specified exceptions).  And I agree with your point.
Comment: This would be much more interesting in England and Wales, where age *is* a protected characteristic in both directions, and the protection applies outside employment.  Of course, the particular example that raised the question doesn't apply in England and Wales because supermarkets can't sell guns *at all*.  On the other hand, if Walmart wanted to stop Asda selling alcohol to people aged 18-21, they couldn't.
Comment: @MartinBonner: Alcohol may not be the best example, because it's banned by law for anyone under 21 in the US. Knives maybe? But the point remains, it's legal to discriminate, except for discrimination for a reason that is prohibited by law.


What filter should I buy if I wanted to do 5 min shutter speed in daylight?

Question: What type of filter would I need to create an image such as the following: http://500px.com/photo/10158205
Comment: you'll need about 13-14 stops ND for a 5 minute exposure in direct sunlight!
Comment: @longneck Exactly as they would be because the dock is stationary whilst the water and clouds are moving.
Comment: Amazing photo. I've been wanting to pick up a 10 stop filter which I think is as dark as they come. Right now I stack a 3 stop filter with a CP filter (probably just over 4 stops total) but although it helps in the evening and early in the morning it doesn't really slow things enough in the daylight. As Matt said 13 - 14 but probably even 20 stops (2 10 stop filters) You will not see anything trough that so you have to focus and compose and then put the filters on.
Comment: Funny, to me that photo looks photoshopped, are you sure it's a long exposure?
Comment: @ClaraOnager agreed re:photoshop, the edges of the dock are perfect lines.
Comment: @MarkWhitaker: I wouldn't expect motion-blur on the dock, but the lines just look too perfect to be real. I get the impression that the water has been smoothed out in photoshop and that the edges of the dock were straightened out in the process.
Answer: We can actually work this out using the information given to us by the metadata and the photo itself. This is going to be a rough science, but good enough to help choose a filter.
Firstly, we have the exposure information in the photo's metadata. This tells us it was taken at f/22 for 105 seconds at ISO 100. Secondly, what does the photo itself tell us about the prevailing light conditions? The sky clearly shows it was cloudy, but the soft shadow under the bench indicates there was some sunshine too (as do the streaks in the sky, in fact). So let's call it partly overcast.
The Sunny 16 rule tells us that on a partly overcast day, at ISO 100, we'd use an exposure of 1/100s at f/11. But the photographer has used f/22, so we need to adjust the shutter speed accordingly to 1/25s (we've lost two stops on the aperture so need to add two to the shutter speed).
So, without a filter we think this scene could have been captured with something like f/22 at 1/25s and ISO 100. We're already making lots of assumptions here - it might have been a much brighter or cloudier day than we're assuming, and of course the image may have been substantially post-processed - but let's assume we're near enough, say within a stop or two. To convert that into a long exposure you'll need a neutral density (ND) filter.
So, the question now becomes: what strength of ND filter is needed to convert a shutter speed of 1/25s into one of 105s? That's somewhere around 11 stops of difference (11 stops is equivalent to multiplying the shutter speed by 2048: here it's multiplied by nearer 2600, but only according to our back-of-an-envelope calculations). If our figures are more or less correct, 11 stops of filtering would produce roughly an 80s exposure. A 10-stop filter would produce a 40-second exposure. Both of those would produce a very similar looking result to the photo you've linked to. Plus I always find very dark ND filters will take quite a bit of extra exposure: those shutter speeds may end up nearer to 100s and 50s respectively.
I'm not sure you can actually buy an 11-stop filter but 10-stop filters are common. So my answer is: you'd need a 10-stop (aka NDx1000) neutral density filter. You may want to stack this with a lighter filter (e.g. a 2 or 3-stop ND) if you really want to get extreme long exposure times.
Comment: Bear in mind all of the above is very rough. Other ways to increase the shutter speed would be to lower the ISO even further (e.g. if your camera supports ISO 50) or reduce the aperture if possible (although beware this may lead to distortion).

Super-short answer: **get a 10-stop filter and experiment!**
Answer: That is an exposure of less than 2 mins. You need an ND filter to be able to expose that long in daylight without overexposing.
An ND400 will be sufficient for this, given a low enough ISO and small enough aperture. That is the darkest filter I own and I have used it for similar exposures in broad daylight.
Comment: this helped me alot thanks, been looking ages of an answer for ages.
Answer: You would need a variable neutral density filter, or a really dark neutral density filter.
You can also use two polarising filters to get the same effect as a variable neutral density filter, only that the light gets polarised also.
Comment: The variable-ND filter *is* two polarizing filters. It's also worth noting that you may get color-shifts with stacked ND filters (I know I did, and I wasn't using ultra-cheap filters either).
Answer: Look for a LEE Big Stopper or a B+W #110 10 stop ND.
Comment: +1 -- I have the B+W 10 stop, and it is utterly brilliant!


そう in "あなたはどうしてそう私を心配させるの"

Question: I understand そう normally means "seems that way", "I think so", etc. In this case, そう comes after どうして and before 私. Which word before or after should be paid attention to in this case to derive the meaning of そう? And if those words don't matter, than what does そう mean in this sentence?
Answer: そう is an adverb and is linked to the verb 心配させる. It basically is a less formal way of saying そのように (like that). You can translate it as "so much" if you want a natural English, but IMO it is not the best way to interpret it.

あなたはどうしてそう私を心配させるの : Why do you make me worry like that/so much?
Answer: Newbie's answer, so I might be completely wrong...
どうして is adverb and can't be modified by そう.
Also, そう can't modify 私, it should be そうな at least to do so, even if we only look from grammar point of view.
So, the only possibility is that そう here used in different sense (it has many), e.g. as adverb modifying final verb: (adv) (1) so; really
Resulting in translation: Why did you make me worry so (much)?

そう in "あなたはどうしてそう私を心配させるの"


Is CT-Art better for tactic training than chesstempo tactics?

Question: What are some major differences of doing tactics training using chesstempo or CT-Art?
Answer: The answer to the title question is "No, they're both excellent for tactics training and are good at different things."
Chess Tempo:

problems are a random selection of positions taken from actual games (chosen by computer to be good chess problems)
over 100,000 problems and growing
problems are served to you based on your rating
no extra didactic material, but you can read other users' comments and discussions on the problems, and look at computer-evaluated variations
free for basic usage, costs money for some extra features
online only (it's a website)

CT-ART:

a specifically designed course with many composed problems (and some based on real games), so it is explicitly trying to teach you certain subjects
a fixed number of problems (thousands)
you just go through the courses in order
occasional didactic feedback asking you to demonstrate simpler patterns that can be put together to form the desired combinations, but no English discussion
costs money
can be used offline (it's an app)
Answer: http://www.apronus.com/chess/trainingtactics.htm
This article outlines the various possibilities for training tactics that are offered by the ChessTempo.com website. For all I know, this is unique in the world. The full richness of the features described there requires a paid membership.


What's a good way to taste a variety of alcoholic beverages?

Question: I've never been too keen on alcoholic beverages since trying things growing up and not liking them. However, I try to keep an open mind and would like to taste more. My problem is I'm hesitant to buy my own packs of beer or bottles of wine or drinks when I'm out, as that might get expensive. Is there a way to taste a variety of beverages without breaking the bank or sampling off friends' drinks all the time?
Comment: The question is pretty inherently open-ended, so there probably isn't a good way to modify it to fit the Q&A format.  I'd suggest taking it to the The Frying Pan (chat room) since it's more of a discussion-type thing than a specific question.
Comment: The cheapest way to try lots of alcoholic stuff is to be a lush and have a lot of friends that are lushes. Or, work in an establishment with a bar. Wooo for trying lots of random stuff!
Comment: Someone care to elaborate on the closure? I don't understand how this is not constructive.
Comment: The question is closed because it does not lend itself to a Q&A format; there is no way to give a single, canonical answer to the question.  It bespeaks a poll-type answer, with many good answers, and isn't easy to rate ones better or worse.
Comment: Is there a way you can think of fixing it to open it again?
Answer: As far as beer goes: Many brewpubs will offer a sampler (or flight) of beer that includes small (few oz) glasses of many of their beers from IPA to stouts and wheat beers. You get a few sips of each beer for the price of a pint (or so) and you can determine what you like or don't like. Also, sometimes brewpubs offer samples of their beers if you ask. I went to a place offering habanero beer, and definitely wanted  a sip before buying a pint. It's not always advertised but worth asking if you have an interested in something in particular.
For wine: Many places that sell wine also offer tastings on occasion, also wineries generally have tastings if there are any in your area. Wine stores usually will have a red and a white available during tastings and the person in charge of the tasting can recommend what kind of food to pair it with. Tastings are a great way to get to know what kind of  wine you like!
For liquors: Finding a local distillery can be tricky if there are none where you live, but I'm lucky to know of a few near me that have tastings for a small fee. A caveat, though, liquor can be hard to drink for some without being mixed with some sort of mixer (juice, soda, etc). So just keep that in mind, when you sip some gin, you may enjoy it mixed with tonic even though you dislike it on its own.
Answer: If you are not keen on the taste of alcohol, I would start with cocktails.
Go to a good cocktail bar (ask for recommendations from friends or websearch), take the list and pick drinks that are mixed with things you like.  Make a night of it! Try and go with a few friends and all order different things.  If the bar tender is good he will help you out with good selections etc.
As for beer - Lemontwist has a good idea.  Any good Ale pub here in the UK will offer you a sample before you buy.  Also many brewers also produce a "variety box" which contains 1 or 2 bottles of approx 6 different beers (usually 9-12 bottles total).
Wine - Lemontwists idea is again a good one.  But wine is probably the toughest thing to try, trying the same wine with certain foods, at certain temperatures or having breathed a different amount will greatly affect it.  I'd either try the systematic (pick a price point, buy a glass of wine, note its details and your rating, lather rinse repeat (Im sure there is an app for that)), or just go for luck - pick at random and try and remember the ones you like.
Answer: Find a local bar with a cheap happy hour and get friendly with the bartender. If they're any good, they should be well-equipped to help you find a drink you'll love.
Side note: I was going to suggest myopenbar on the off chance you lived in NYC, but it looks like they just recently closed up shop :/


Is this wall load bearing based on the attached blueprints?

Question: I would like to remove a wall in my walk-out basement but I don't know how to interpret this architectural blueprint.  Based on this blueprint, is the wall bearing load or not?  I have highlighted the wall in question in the pictures below.

Click for larger view

Click for larger view
Comment: Can you take pictures of the area?  Also what is the age of the house and area?
Answer: EDIT: On second look, the drawing actually tells us.  There's a note box to the right: TYP BEARING WALL 2x4 stud 16" O.C. on Continuous footing.  The dashed line around the wall indicates the footing.
ORIGINAL:
If I'm reading the drawing correctly, IT DEFINITELY IS.
For the sake of this discussion, north is the top of the drawing.
There appears to be a beam running E-W from the post to the East wall.  There are no notes on the west wall talking about a beam pocket.  This leads me to believe that the dark line following the same path as the beam is simply a dimension line, not a continuation of the beam.  So the beam does not extend westward towards the area you want to deal with.
This makes the total span in the area you're looking at 36 feet.  Far too long for 2 x 12's,
which means the wall you want to remove is definitely supporting the joists.
Even if the beam does continue, I would take great care. 20 feet is about the max for a joist span.  This job calls for a professional engineer to assess the situation.
The solution is probably to dig a footer where the doorway is now, and put up a steel post and raise another short steel or paralam beam where the wall is.
This involves building temporary stud walls on either side of the existing wall to support the load while you're working.  You'll need to find a contractor who has done this type of work before.
Comment: Good catch.  The "header by supplier" notation above the wall is the second dead give-away.
Comment: If this is the case, why is there a 3" post a little north of the marked "beam"? That also says "Beam By Supplier".
Comment: @alt That was a bit confusing for me too.  The dimension line obscures the beam end.  The best I can tell, it appears to be a short beam running from the post to the east wall.   If it ran all the way across, we'd see a "Beam Pocket" note on the west wall.
Comment: I changed my mind, after reading this answer again it included enough detail to rationalize the answer that it IS a load bearing wall.  I provided a separate answer which provides additional (perhaps more specific) details and is helpful for posterity sake.  Thank you @Chris Cudmore
Answer: According to the response from Shannon @ house-improvements.com (he's the pro who owns the site):

Yes that is for sure [the wall is load bearing]. Three things tell me
  that:

there is a concrete footing (dotted lines) under that wall.
there is a note about a header in that door opening.
the span of those joists over to the main beam is to long to be supported by the size of joists indicated with out some support
  along the way.

There are some options for you though:

That wall looks to be approx 20' long It is possible that a steel beam could possibly be designed to carry that load but more than
  likely you would need a post in the middle as well. .
You could open just a portion of that wall and use a wood or steel beam that can span the chosen distance. Either way you should consult
  a pro because this is load bearing. And this will require a permit.

Thank you everyone for your comments and answers, it is much appreciated!
Answer: Everything Chris said is true...but I'm not sure if the note box gives us information about mentioned wall or different one.It't hard to tell from the drawing, at least for me...I don't know the standards in your country, and if house is built according to regulations, but bearing walls should be either vertical or horizontal (I mean one or another direction on the drawing) so maybe you can compare these two "types" and see which is bearing.Also,keep in mind that maybe it is not the wall which is bearing weight, but only his upper part, beam and the rest of the wall isn't load bearing. I would like to provide you with more helpful information but just from the drawing I can't.
Comment: If you can't provide an answer, then why did you provide an answer?
Comment: @Tester101 Well not sure I haven't, but not a final one I agree. Anyway I gave OP some hints what to look for in order to find the answer for himself.
Comment: I'd have thought the "Typ" was shorthand for "Typical" and all the walls where the foundation is shown would be considered load bearing, following the typical spec given.
Comment: @Rowland Typ most likely does stand for "typical" but I'm not sure if that is description of the wall our OP is interested in.And the fact that it does have a foundation doesn't necessarily means that it is load bearing. Many designs I have worked with had foundations under every wall on the ground level, which I think is good thing.


What's the easiest way to look up a transaction on the blockchain?

Question: If I want to check if my transaction has made it to the blockchain, where can I look it up and by what data can I search/filter? Of course there is the transaction id and possibly a payment id, but is there other data I could use to find my transaction?
Comment: What you are asking is not clear. "is there other data I could use to find my transaction?" - well, whatever data you happen to have is what you could use. You should rephrase that to be clearer.
Comment: Is there something unsatisfactory with my answer? It's been several weeks and it's helpful to either receive feedback or have it marked as correct.
Comment: nope, there isn't anything unsatifactory :) not sure how I missed this one.
Answer: The best general tool for this is http://moneroblocks.info/.  It is somewhat comparable to the Bitcoin site https://blockchain.info/, and you can conduct searches using a number of different identifiers.
However, if you are focusing on a specific transaction, I think your best bet might actually be a very useful tool developed by one of our community members: http://xmrtests.llcoins.net/checktx.html
By using the transaction hash, viewkey or private transaction key, and the recipient's public address you can prove that a transaction made it to its intended destination.


Why is the magnetic field inside a solenoid constant?

Question: Why is the magnetic field along the length of a solenoid constant? (preferably in relatively simple terms)
Thanks!
Comment: It's a perfectly sensible question. It's essentially a question of the form, "Is this regular pattern due to a simple, deeper principle, and if so what principle?" If you don't like questions like that, then you don't like a lot of science!
Answer: First, remember that the magnetic field is only uniform for a long solenoid, and even then only if you restrict your attention to regions far away from the ends.
The fundamental reason the field doesn't depend on position along the length of the solenoid is that, when you're far from the ends, the magnetic field of a long solenoid looks almost the same as that of an infinite solenoid. The field is "mostly" caused by the current relatively near you, so it doesn't matter much if the solenoid extends forever or just for a very long way. For an infinite solenoid, the field has to be uniform as a function of position along the axis, since every point along the length is the same as every other point (if you prefer, the system is translation-invariant along the axis).
I think the more surprising thing about the magnetic field inside a solenoid is not that it's uniform along the length, but that it's uniform in the perpendicular directions -- that is, that the field doesn't depend on whether you're close to the axis or far from it (as long as you're inside it). It'd be easy to imagine the field would either drop off or get stronger as you move perpendicular to the axis, but it doesn't (again, for a long solenoid when you're not near the ends).
The deep principle here is Ampere's Law. If you draw any closed loop in space, and "add up" (integrate) the tangential ("forward-pointing") component of the magnetic field around the loop, the total equals a constant times the amount of current passing through the interior of the loop. Now choose your loop to be a rectangle like, for instance, the red rectangle in the image in this website. If you move the upper side of this rectangle up and down (keeping it inside the solenoid), the enclosed current doesn't change, which means the magnetic field strength can't change.
Answer: Remember, if we assume that the solenoid is long compared to the radius of turns, the field is approximately uniform and inside the solenoid it is parallel to its axis, while it is zero outside.
This approach applies then the Ampère's law:
$$
\int B. dl = \mu_0 i
$$
By integrating around the solenoid we obtain:
$$
B = \mu_0 N/L i
$$
Answer: So to simplify, in a solenoid you have a long straight wire bent into coils that are nearly parallel and close together. The force of a magnetic field is maximized when the current moves perpendicularly to the field lines, but is zero when it moves parallel to it; therefore, we can assume that in a solenoid the magnetic field is essentially uniform or constant because the wires are nearly parallel.
Answer: The field lines inside the solenoid are  in the form of straight parallel lines. This indicates that the magnetic field is the same at all points inside the solenoid. That is, the field is uniform inside the solenoid.
Answer: The turns of the solenoid ar nearly parallel to each other.The force acting on each turn would be the maximum only when the field lines are perpendicular to the turns .But,it will be zero when field lines are parallel to the current carrying turns.so contrasting this ,we can conclude that inside a solenoid,there is zero force applied on the turns which in turn helps us conclude that the magnetic field lines are parallel or uniform in a long solenoid.!!


Do historians agree that most wars are caused by religion?

Question: I'm not a historian, but this is a very common claim that crops up in debates over God's existence and religious scripture. What is the opinion of the community of professional historians?
Comment: Most wars are caused by a conflict of interest, whether that interest has a veneer of belief (religious, philosophical, ideological) or not.
Comment: While it might motivate the commoners to fight a war they don't otherwise care about, religion is generally a cover for some other more pragmatic reason to go to war.
Comment: Marxist historians agree that wars are caused by property & exploitation of the proletariat.  Liberal historians agree that wars are caused by conservatives.  Conservative historians agree war is caused by liberals and everyone agrees to hate Tom Lehrer.  Any statement that begins, "All X agree... " Ilia rhetorical, not academic.  The only response to such statements is to order another pint & change the topic.
Comment: @Bregalad Agreed - the "primarily opinion based" close reason doesn't make sense; its perfectly possible to objectively survey historians for a consensus. Or, for the underlying question, to go through the wars of history one by one and tally up their causes by categories. Several studies did just that.
Comment: @Scrontch that is a hopelessly naive view, I would say that almost all of the worst genocides in the existence of this world has happened in the 20th century
Comment: The late Robert Heinlein, a graduate of the United States Naval Academy once opined that all wars were, at root, caused by population pressure.  He added that this was true even for religious wars, but you had to dig into trade routes and resources to see it.  I once queried the head of the History department at his alma mater about it, did not really get an answer.  I observe that the Naval Academy is a very good school, and understanding the causes of war is very much part of the education of an officer.
Comment: War is fought over resources.  Religion is used to convince people who will less materially benefit from its spoils to fight.
Comment: @Kai: "Never in history has the world been less religious, never in history has mankind had more potential for destruction". The question is about real wars fought, not potential for destruction. Arguably, despite contrary belief, never in history we have lived in more peaceful times (see e.g. Steven Pinker).
Comment: Which historians? How many have to agree before the answer is yes?
Comment: @Bregalad Agreed about the close vote (and that the reason doesn't make sense). However, downvotes might be for other reasons (e.g. lack of evidence of prior research).
Comment: Why only historians?  It seems similar as asking if doctors agree if death happens to all of us
Comment: often times Religion is used to justify acts of war or to pretty much convince people to go to war, however the underlying cause of those wars are actually to gain territory, resources or simply to exterminate competition.

You'd be surprised how enthusiastic people get just by yelling "God demands it!" or "God wills it"
So more accurately religion is a tool. But not the actual cause.
Comment: Many if not most wars are started over resource conflicts, whether it be water, raw materials, land, or people (workers, slaves, etc.). Quite often religion is used to stir up sentiment against the enemy in the population, but that's using religion as an excuse rather than the root cause.
Comment: is it a coincidence that this kind of question appears just some decades after atheist regimes (commies) killed +100M people?
Comment: Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/86416/discussion-on-question-by-tomislav-ostojich-do-historians-agree-that-most-wars-a).
Comment: @Semaphore - counting wars one-by-one might not be that easy anyway: Later in Thirty years war, that started with religious pretexts about the freedom of religion here in Bohemia, catholic France supported protestant countries to weaken Hapsburg monarchies. Though you could argue, that 30YW were actually several separate conflicts, further muddling your counts.
Comment: I'm also curious about wars for multiple reasons (or with multiple stated reasons) -- does the Reconquista count as a religious war? A war for territory growth? A war for a strategic location? (possibly a bad example because it wasn't really a single war, but you see my point)
Comment: @Luis no.......
Answer: The idea that "most wars are caused by religion" is trivially false. From what I can see, this is a rhetoric rooted in a critique of theism, rather than serious historical analysis. Even a casual survey of history shows most wars had little to nothing to do with religious differences - according to quasi-original research on Wikipedia, only 6.98% of known conflicts were religious.
To my knowledge, there has been no formal polling of academics on the subject. Nonetheless, we may infer a prevailing opinion of historians from their research. While existing works only examine the modern period, they all point to the same conclusion: Territory, not religion, is the most common cause of war.

Territorial disputes is the leading cause of war throughout the centuries. Source: Holsti, Kalevi J. Peace and War: Armed Conflicts and International Order, 1648-1989. Cambridge University Press, 1991.
(Although the works cited below are time-limited, there is no obvious reason to believe the underlying patterns of wars would be significantly different in the pre-modern world. Even the Muslim Conquests or the Christian Crusades were isolated and punctuated by many non-religious conflicts. The European Wars of Religion were a historical aberration, not the norm.)

First, let's consider the analysis of modern wars by Evan Luard. He divided post-1400 history into five periods and noted that the primary causes of war shifted over time. To briefly summarise, his findings were:

Age of Dynasties (1400-1559): conflicts over territory were linked to dynastic claims.
Age of Religion (1559-1648): religious conflicts triggered conflicts over territory, but non-religious wars of opportunity also took place.
Age of Reason (1648-1789): religion vanished as a cause of war, to be replaced by conflicts over strategic territories and dynastic succession.
Age of Nationalism (1789-1917): wars became increasingly linked to identity and national independence - territories were a common cause of war in colonial empires, Latin America as well as the Far East.
Age of Ideology (1917-1986): political ideology dominated the causes of war.

However, other historians have noted that:

[W]hile Luard declines to nominate territory as the dominant factor throughout the centuries, nevertheless, territorial issues keep cropping up in his analysis - in connection with issues of succession, dynastic disputes, or state creation. Thus, Luard probably underestimates the importance of territorial issues in fomenting wars.
Cashman, Greg. What Causes War?: an introduction to theories of international conflict. Rowman & Littlefield Publishers, 2013.

Luard's analysis is evaluative rather than qualitative. For the latter, consider the survey by Kalevi Holsti in 1991. He divided the post-Westphalia history of conflict into five periods and attempted to classify their causes into rather narrow categories. The results were as follows:

As you can see,

"Territorial issues" are the only ones that have been among the dominant issues in each of the periods [1648-1714, 1715-1814, 1815-1914, 1914-41, and 1945-89]. In four of the five periods, more wars have involved territorial issues than any other kind of issue, exceeded only in 1815-1914 by the "maintain the integrity of state/empire" issue, which is an issue obviously related to territorial concerns.
Vasquez, John A. The War Puzzle Revisited. Cambridge University Press, 2009.

In contrast, as you can see from the table, religion began at only 6% and has steadily declined since then. This is dwarfed by the number of wars over control of land or resources, even in our current period when territorial conflicts are at a historical low. As the following table demonstrates that territorial disputes constitute the vast majority of all wars since Westphalia:

Source: Vasquez, John A. The War Puzzle Revisited. Cambridge University Press, 2009.

Of course, Holsti's analysis began only after the European Wars of Religion, identified by Luard as the same period religious differences were a leading cause of war. Nonetheless, the fact that religion all but disappeared as a cause for war in the centuries since is strong prima facie evidence against the claim that it could have caused "most wars".
Fundamentally speaking, wars are nearly always driven by some kind of self-interest. Land, historically near synonymous with wealth, was of prime interest to most polities. Consequently - without discounting the genuine effects faith may have on true believers - religious (as well as ideological, nationalistic, etc) reasons are just as likely a source of legitimacy for using force, as it is a motivation in and of itself.
Comment: Great answer! Do you have any insight on how many of the non-religious wars used religion to sell the war to the people of the countries involved? I mean, while the actual reason for the conflict may not have been religious, religion may have been used to popularise and/or justify the war. If we count such cases as religious wars, would that change the answer in any significant way? (Also, you have a typo and I don't have the rep to fix it: _The European Wars of Religion were a **historian** aberration_, should be _historical_.)
Comment: And even in those 7% of wars "caused by religion", I would bet many of them were in reality caused by territorial or financial disputes, and religion was just a good pretext to declare war or to motivate the soldiers (but the war would have started regardless).
Comment: Seconding @vsz here. For instance, the 30 Years War (touched on in this answer) was clearly religious, right? Well, what made it truly long and bloody was the involvement of Catholic France *against* the Catholic Hapsburg Empire. At first by subsidizing other parties, but eventually directly. That was pretty obviously not religiously motivated.
Comment: @terdon Thanks for the catch, fixed. As for your question, I do not believe that would significantly affect the conclusion, no. For the most part, religious wars *already are* wars sold to the populace / armies / foreign states using religious justifications, rather than being genuinely motivated by religion. That's the point being hinted at regarding Laud - if the wars really weren't about territory, why did religious conflict fight over territories? Without being unduly cynical, the line between religious wars, and non-religious wars justified by religion is very thin.
Comment: Indeed; in fact I'd be surprised if we could find _any_ war that was actually and wholly fought for religious reasons. Fair enough.
Comment: @T.E.D. Yeah, that's what I'm trying to communicate. As I said in the conclusion and the comments above, religion is an ideological mechanism for *legitimising violence*, but the motivations for resorting to violence in the first place is nearly always rooted in some kind of self-interest. That said, while the French highjacked the war for geopolitical reasons, the first half of the 30 YW was clearly religious in nature. Dismissing religion as a factor in all wars is as untenable as blaming it for most wars.
Comment: @JAD The Russian Revolution created the world's first Communist state that year, and allowed the remaining Allies to be reframed as democracy fighting autocracy.
Comment: @UKMonkey Yeah no, this proves you obviously didn't read the answer. The very first paragraph suggests 7% of known wars have religious causes. The second section reports that religion triggered many wars between 1559 and 1648. The second figure lists religion as accounting for 6%, 3% and 4% of war causes in three different periods. And religion is discussed again in the conclusion. **Again, just because religious wars may involve territory, does not change the fact that the vast majority of wars did not involve religion at all.**
Comment: The Crusades are generally considered "religious wars", but remember the bit about the 4th Crusade, where the Crusaders decided their fellow Christians in Constantinople were easier pickings?   Dig into a lot of the actions of the actual crusaders and it looks a lot more like people looking for power and glory than people driven by religious conviction.
Comment: @Edheldil ... and you'd be right.  However, you'd also be right to point out that the European wars of religion had much more to do with money and politics than they did with religion.
Comment: Is this study relevant or useful: http://news.bbc.co.uk/2/shared/spl/hi/world/04/war_audit_pdf/pdf/war_audit.pdf
Comment: I'm going to use that phrase, "quasi-original research," so I can get by the folks who shutdown immediately after the word Wikipedia.
Comment: @Semaphore gotcha, thanks for the clarification!
Comment: Shitty TL;DR: People like to have stuff. Often, people are willing to use force to get stuff. Sometimes they are willing for religious reasons. Sometimes they use religious reasons as a justification when they were already willing. The bottom-line is having a unifying ideology (whether that was part of your original motivation or not) helps convince a broader audience to use force to get stuff. In a few cases (percentage-wise), that ideology is religious.
Comment: Even crusader wars were plunders. On their way back, they plundered orthodox monasteries.
Comment: @SYS_V Good find. Although they only reviewed a handful of wars, these findings reinforces other studies about how religion is mostly not the cause of wars - I see only 7 wars where they scored religion's involvement at 3/5 or more.
Comment: The second table is interesting, but I would like to have the total number of wars considered in each period. For instance, there was '-' (aka 0%, or at least less than 1% I suppose) *secession/state creation* wars in 1815-1917, but I find it hard to believe considering the desintegration of the Ottoman Empire and the US civil war. Also, it might be interesting to weight the wars by their intensity (mesured e.g. by the casualties).
Comment: Thank you for this answer.
Comment: @Semaphore re: your second comment. My personal opinion would be that the lines between most allegedly separate causes of war are in practice highly blurry.  The only reason two countries may be separate in the first place (and proceeding to engage in territorial wars) might have been long-ago religious divisions. Which are/were in turn tied up with cultural/ethnic/ideological identities etc etc...
Comment: Not to downplay the substantial research done here, but I feel like "territory" is a bit of a non-answer when it comes to war and its motivations, given that war is an armed struggle over territory almost by definition. The Mexican-American war is about as close to a war fought over pure territorial issues as you'll find, but even that is caught up in weird messianic state populism notions. The almost-war we had over Crimea looks like a territorial dispute, but there you'll find economic and ethnic undertones too. Everybody wants to rule the world, but you need a good reason to send tanks.
Comment: Is there a specific reason that the transition from Age of Nationalism to Age of  Ideology falls in the middle of WWI?
Comment: The answer fails to take into account that territorial disputes may very well be religious based.  For example "This holy land named Jerusalem is ours".
Nor does it take into account that a war may be caused by multiple issues, any one of which removed may result in no war; but only one issue is recorded as the cause.
Comment: @T.E.D. you could argue that 30YW was actually a series of interrelated conflicts.
Comment: @Evargalo The Ottoman independence wars most likely fell under "National liberation/state creation"; the consensus is that the American Civil War was fought over slavery, so that probably got put under "ideological liberation". It would be interesting to see the result by casualties **if** calibrated to the level of casualties for conflicts of the era (so you're not just measuring how much more deadly wars were in different centuries), but that's an immense work way out of scope for an answer imo.
Comment: @Smeaphore But how does Kalevi Holsti make a distinction between "National liberation/state creation" and "secession/state creation" ? I am afraid this might be just about the outcome of the war, not its causes: e.g., *if* the Confederate States had gained independance, wouldn't they be considered a 'nation' today ? Or Timur got its independance, so Timur's war might be called 'National liberation', while Ajeh hasn't, so Ajeh's war might be called 'Secession' ?
Comment: @Evargalo That's just nonsense. The Ottoman minorities have national identities and a history of statehood for centuries. Greeks, for instance, has existed for millennia before any Turks set foot in Greece. Meanwhile the Confederates didn't even speak a different language to the Union. There are always going to be fringe cases, but there is an intuitive and obvious distinction between these categories. Anyway, what's the point of quibbling over this? As noted he was intentionally being pedantic; the finer points of his analysis on what drove state creation has got nothing to do with religion.
Answer:
Do historians agree that most wars are caused by religion?

No, historians have not formed such a consensus.  There are numerous scholarly works reaching back 5 millennia demonstrating that this belief is apocryphal.  This work demonstrates religion historically has played a small role in wars either as a major or minor cause.

Is Religion the Cause of Most Wars?
  History simply does not support the hypothesis that religion is the major cause of conflict. The wars of the ancient world were rarely if ever, based on religion.
...an objective look at history reveals that those killed in the name of religion have, in fact, been a tiny fraction in the bloody history of human conflict. In their recently published book, "Encyclopedia of Wars," authors Charles Phillips and Alan Axelrod document the history of recorded warfare, and from their list of 1763 wars only 123 have been classified to involve a religious cause, accounting for less than 7 percent of all wars and less than 2 percent of all people killed in warfare.

A Different source: The Encyclopedia of War edited by Gordon Martel says if one excludes 40 little understood internal wars fought by the Islamic Caliphate religious wars drop to only 3% of all wars in its pages.
Institute for Economics and Peace issued a report in 2014 which further supports these numbers.
So Historians, reviewing 5 millennia worth of war, have reached the opposite conclusion.  Religion is a reason for war, but not the reason for most wars.
Wars are often blamed on a single reason but typically caused by a combination of reasons.  Yes Religion is among the reasons historically countries go to war, it is even a primary cause of some conflicts like the Crusades, Thirty Years' War, and the Lebanese War 1975-1990  Religion is not the primary reason historically speaking for most wars.
Common (major and minor) Reasons for War:

Economic gain: (oil, natural gas, nickel, etc ).

Anglo-Indian Wars (1766-1849)
A series of wars fought by  British East India Company leading to the colonization of India.
The Winter War (1939-1940)
The Soviet Union invaded Finland in order to control the nickel mines.
The American Revolution
For America a revolutionary war, for the French who allied with the United States against Britain it was fought over trade routes and commerce.  The French involvement began first with a trade agreement with the Colonies and only after that was signed a declaration for French military assistance against Britain.
WWII, in the Pacific
The Japanese attacked Pearl Harbor in order to seize commodities in Asia.
Iraq's invasion of Kuwait.
Iraq invaded Kuwait to seize the oil and alleviate their war debt with the Kingdom.
South China Sea
The ongoing dispute with China over the South China Sea,  It's about 11 billion barrels of untapped oil and 190 trillion cubic feet of natural gas estimated to exist in the disputed territory.

Territorial Gain

Mexican-American War (1846-1848).  It was a land grab.  The slogan manifest destiny spoke to the United States desire to become a two Ocean country. (Atlantic and Pacific).   The War facilitated the United States purchase of what is now the American South West as well as California.
Arab-Israeli War or "Six Day War" (1967-1988)
After years of small-scale conflict when Egypt blockaded the straight of Tiran, Israel attacked gaining the Sinai Peninsula, the West Bank, and Golan Heights effectively tripling the size of the Israeli state.
Russia's invasion of the Crimea (2014)

Nationalism

World War I

Revenge

World War II (invasion of France by Germany)
One of Hitler's stated reasons for invading France was to reverse the Treaty of Paris which ended WWII which he felt treated Germany unfairly and was a factor in Germany's impoverishment in the interwar period.  He met with French representatives in the same train car which hosted the WWI summit which ended the Great War and even had the memorial in Paris to the historic treaty blown up.

Civil Wars and or Revolutions
  Fought over disputes which arise internally to countries or over a change of leadership.

American Civil War (1861-1865)
Russian Civil War (1917-1923)
Spanish Civil War (1936-1939)
Korean War (1950-1953)
French Revolution (1789-1799)
Haitian Revolution (1791-1804)

Addressing the Comments

Steven Burnap
  "Lebensraum" was an explicit aim of Germany in WWII. The Japanese actions that lead to WWII in China, as well as their invasion of the Philippines, was also very much about gaining territory. Though this really just goes to show that history usually doesn't fit into neat categories. "Religious war" being a neat category.

@Steven Burnap,  Hitler's book Mein Kampf, was written in two volumes, The first volume, entitled Die Abrechnung ("The Settlement [of Accounts]," or "Revenge"), calls for revenge against France for its destruction of Germany's first and second Reichs.
Specifically, Hitler discusses the 30 Years War in which Germany's first Reich (Holy Roman Empire) was eviscerated by the French in 1648, with the Peace of Westphalia.  Secondly and famously the treatment of Germany in the surrender documents ending WWI which both impoverished Germany in the interwar period and ended Germany's second Reich, Imperial Germany ()1871–1918 ending Kaiser Wilhelm and the end of WWI.
In Hitler's first volume he dedicates the title to the major theme of his foreign policy.   Revenge against France.   To your point Hitler also discusses "Lebensraum" in his first volume,  the need for "Living Space" for Germany and says Germany will gain this in the east at the expense of the Slavs:  Czechoslovakia, Poland,  Belarus, Ukraine, and Russia.
A major stated goal of Hitler's Third Reich was to address the downfall of the first and second German Reichs at the hands of the French.  In June of 1940, Hitler drove this point home with what National Geographic calls his Revenge Treaty in which France surrenders to Germany June of 1940.  Hitler held the surrender ceremony in the same boxcar in which France had hosted Germany's surrender in WWI.  Designed the entire venue to embarrass the French referencing Germany's previous treatment by the then victorious French in WWI.   Just after this ceremony Hitler personally ordered Frances Rethondes Clearing memorial to WWI's German surrender blown up with dynamite.
As for Japan's war in China, I don't dispute what you say.  What I said was Japan attacked the United States, Dec 7, 1941, over oil.  The attack was to clear obstacles to Japan's real target of that offensive, the Dutch East Indies -- now Indonesia.
On July 26, 1941, the American President Franklin D. Roosevelt signed an executive order which froze Japan's assets in the United States and cut Japan off from 93% of their Oil all of which was imported.  Japan had about a year and a half of oil in their strategic reserve and after that, they would not be able to continue their war in China.  Japan attacked Pearl Harbor on Dec 7, 1941; and invaded Dutch East Indies Dec 8th to secure what was then the 4th largest oil exporter in the world behind the U.S., Iran, and Romania and guarantee Japan would be energy independent.
Japan also gained access to rubber production facilities and iron mines both of which were important, but oil was the most important material they seized in the days after Pearl Harbor.

Japan's Dutch East India Campaign
  Access to oil was one of the linchpins of the Japanese war effort, as Japan has no native source of oil;15 it could not even produce enough to meet even 10% of its needs,13 even with the extraction of oil shale in Manchuria using the Fushun process.16 Japan quickly lost 93 percent of its oil supply after President Franklin D. Roosevelt issued an executive order on 26 July 1941 which froze all of Japan's U.S. assets and embargoed all oil exports to Japan.17 In addition, the Dutch government in exile, at the urging of the Allies and with the support of Queen Wilhelmina, broke its economic treaty with Japan and joined the embargo in August.15 Japan's military and economic reserves included only a year and a half's worth of oil.13 As a U.S. declaration of war against Japan was feared if the latter took the East Indies, the Japanese planned to eliminate the U.S. Pacific Fleet, allowing them to overtake the islands; this led to the attack on Pearl Harbor.
Comment: Some of these are rather disputable. For example, wwii and invasion of France by Germany happened after the war already started. It was a logical pre-emptive strike after the war has already started. While Germany may had motivation to revenge, the actual conflict is clearly territorial and triggered by invasion of Poland. East was the main target, fighting UK and France was just a necessity after the Strange War.
Comment: There's good reason to believe though that the Nazis would have been happy if England (and by extension France) would have stayed out of the war with Poland, so while it's fair to say that war with France was obviously something Hitler was preparing for, and which ultimately he was working towards, it's not that clear that the actual war aorse simply because the Nazis wanted revenge. After all, France declared war on Germany (in response to the invasion of Poland), not the other way round.
Comment: "Lebensraum" was an explicit aim of Germany in WWII.  The Japanese actions that lead to WWII in China as well as their invasion of the Philippines was also very much about gaining territory.  Though this really just goes to show that history usually doesn't fit into neat categories.  "Religious war" being a neat category.
Comment: @Greg I think that you are refering to what in English is named the [Phoney War](https://en.wikipedia.org/wiki/Phoney_War)
Comment: @Greg To expand... Germany and France have been at loggerheads since at least the Franco-Prussian War with recidivism and revanchism for past losses. Now it was Germany's turn. Germany (or at least the party in power) wanted revenge for WWI. It also wanted the territory it lost to Poland and France for economic and nationalistic reasons. And it needed to knock out its hostile neighbor to the west: security. The invasion of France was nationalism, revenge, territory, economic gain, and security.
Comment: @StevenBurnap I responded to your comments at the end of my answer.    Greg, I would just say that territorial gains in the East and revenge goals in the West are not mutually exclusive.   Hitler expressed decades long interest in both.
Comment: Saying  a war has a religious cause or revenge cause as the above answer states doesn't imply it's the only cause.
Comment: Small quibble over the Winter War: the USSR wanted more than just nickel, but also power plants and a strategic buffer around Leningrad. Ultimately it was also an attempt to expand the Soviet sphere of influence by subjugation (same as with the Baltic republics and the partition of Poland with Germany).
Comment: @SPavel,  You are right.   I changed my answer to make it more clear. I wasn't trying to suggest the various examples of conflicts were motivated only by economic, territorial, nationalism, or revenge; but that in these Wars there was some of that type of cause. Just like the sited material found 123 examples were religion played some cause in 1763 wars.. not 123 wars exclusively caused by religion.
Comment: "No historians have not formed such a consensus." There should be a comma between "no" and "historians".
Answer: In addition to the good answers given already, I'd like to point out that wars are typically not mono-causal. Very often, several reasons as well as causes (i.e. sparks that light the fire) come together for a war to start.
In addition, the reasons given in public are often not the actual reasons. There are a number of explicitly religious wars (the Islamic conquests of Europe, the European answer aka The Crusades). In many other wars, religion played a role in the "us vs. them" sense - religion is one of the factors that bind people together and separates them from other people, just like language, skin colour, etc. It is easier to start a war against "others" than against "like us".
And finally, there are many parties involved in wars. The head of state might declare the war, but there are so many different people with interests involved and for some of them a financial profit might be important, for some of them territorial gains, and for some of the religion. These goals also change during the course of a war or in parts of the war. For example, JMS gave "revenge" as the reason for WW2, but the attack on Russia had other reasons, and the war in North Africa was purely for resources. Meanwhile, WW2 also had the Asian part with Japan as the aggressor, which again had different reasons to start their part.
Identifying one reason for a specific war is most likely an oversimplification. So the question as phrased doesn't even make sense because it asks to identify a mono-causal relationship which in reality does not exist.
Religion certainly played a role in most pre-modern-times wars, though it was more often used as a cover for more simple desires (taking land, resources, disputes over hierarchy or succession, etc.) than the other way around.
I'm not a professional historian, just interested in history. From what I've found in books and other resources, historians would not, in general, agree that anything is the #1 source of wars, simply because wars are not so easy. That begins with the difference between reason and cause - between what the background of the conflict is and what often small spark caused the conflict to finally erupt. WW1 is a good example for that, it was caused by the assassination of Archduke Franz Ferdinand, but if that hadn't happened, something else would have most likely caused the war that everyone was pretty much waiting for.
That makes it difficult to ascertain if religion contributes to that background. For the king or whoever, it is certainly easier to start a war if he can also add religious reasons to the motivation. The 30 years war is an example where religion played a major role, but many other often regional causes added to the mix until the whole thing exploded.
Comment: @Hosch250 - land grab or not, religion was not only a thinly veiled excuse in these cases. Especially the islamic expansion was part of the religion from the very start, Mohammed himself started this and the European wars were just the conclusion of that process. The Crusades wanted to liberate the holy lands, which by purely economical reasoning was a questionable motive, you need at least a combination with religion to make the whole thing make sense. In more simple terms: In other conflicts you can remove religion and apart from some propaganda nothing goes missing. In these two cases, not.
Comment: The Islamic Conquests and Christian Crusades were still just a disguise for an (attempted) land grab.
Comment: @user151841 - the silk road never went through the holy land. Its southernmost terminator was Damascus, well north of Jerusalem. But neither were chokepoints, you'd have to go into the interior, at least to Palmyra, to get a chokepoint. Crusaders never went that far. The to me most likely non-religious interpretation of the Crusades is a counter-attack against muslim invasion, as the orthodox head of Constantinople had plead for help from the pope - his religious enemy, so the situation must have been dire indeed. But that is a different discussion.
Comment: @Hosch250 Depends on the participants. Certainly there were many who had no prospects of inheritance at home, and went on the Crusades hoping to become a lord in the East. At the same time, many kings and lords financed, organised, or participated in the Crusades without a realistic hope of gaining possessions so far from their own lands. Some were probably making political calculations, but it's dubious you can wholly discount genuine religious motivations for everyone.
Comment: @Tom By purely economic reasoning, whoever controlled the "holy lands" controlled European land-based trade with Asia.
Comment: @user151841, the Silk Road route varied over the years, but it generally entered the Mediterranean either through Constantinople or through Egypt, not through the Holy Land.
Comment: Agreed. But then you can't discount genuine religious motives for everyone in *any* war.
Comment: @Hosch250 - I'd say you need to control a couple more places for that to work.
Comment: @Mark Having trade skip over the Byzantines/Ottomans was a long sought-after goal of various European nations...
Comment: @Hosch250 well, the Islamic Conquest **was** a land grab, not even disguised. It was all about conquering the entire world for Islam - but that's the point: **For Islam**, not for any ruler or people, but explicitly for religious purposes.
Answer:
Q Do historians agree that most wars are caused by religion?

Most historians agree that most wars cannot be described with a monocausal reason.
There is a big bunch of problems associated with asking the question in this way. Definitions, conceptualisations, perspective, timeframe and grammar are all undetermined or off. Is this about whether the claim as such is true or about an assumed majority opinion of historians; now or previously?
Just a thought: Who started the Global War on Terrorism? The Americans? Al-Qaeda? For what reasons (aka "cause")? Is religion the main causative motivator for the American led forces? Is it for "the other side"? Perhaps a minority might answer yes to religion as a motivator for American forces, but surely most will accept the narrative that bin-Laden and his followers were primarily religion motivated? Or do they emphasise his apology that he became offended when American troops were stationed on Saudi-Arabian soil, making this again about land and territory, 'holy' or not? But perhaps it is different yet?

Bush's war openly remains a cosmic battle between nothing less than the transcendent forces of good and evil. Such a battle is necessarily unlimited and open-ended, and so justifies radical actions–the abandonment, for example, of established notions of civic justice at home and of traditional alliances abroad.
James Carrol: "The Bush Crusade. Sacred violence, again unleashed in 2001, could prove as destructive as in 1096.", The Nation, September 2, 2004

Historians do not always agree on a subject matter of the past. Historians diverge very widely if it is about how to apply those insights from the past to the present day. If you want to know historians view on what the reasons for war are, then a number of people will say this or that.
Samuel Huntington, for example, views that civilisations or cultures are clashing –– and were for some time now. The main differentiator of a culture by this definition is its religion. Therefore, those sympathising with the Huntington school assume that most wars are caused ultimately by religion.
But leaving aside the semantics over grammar and resultant meaning of "are caused", it seems that there still is an anachronistic and eurocentric vision dominating the way this question was to be answered here.
This question is about religion in general, not about Christianity, Islam or any form of monotheistic religion? Then religion is a prime motivator for ingroup-outgroup behaviour. It represents the core of order for any civilisation against the chaos. And therefore for war in general. We do not have to reduce "religion" to "any form of some belief" to approach the problem. Otherwise, it gets trivial: "we believe that this strip of land belongs to us, we believe to need that etc"; we believe capitalism to be so much better for mankind".
Going into a structuralist or functionalist mindset we might say that sure, religion needs a base from which to perform. So a religious motive is in reality about power, and that is about power over the inhabitants, and that is over the lands on which those inhabitants live. Muslim expansion is then nothing about any form of to invent or develop a form of Islam, just land grabbing of Arab conquistadors who happened to eventually provide an ideological superstructure to justify the new rule and system of power distribution and organise a changed set of alliances between rulers and ruled.
If we ask the propagandists for war from the past, then we have to first reflect on the nature of state and religion in general. It was indistinguishable. Romans fought a bellum sacrum, Christians had Crusades against Muslims, Albigensers, Prussians; earlier Charlemagne brought Christianity by sword to the Saxons, native Americans; Muslims conquer India, Hindus fight the Muslims, English Christians wanted to mission the world with tea, opium and Christianity for the betterment of humanity. Muslims have their jihad to this day. The Incas were weakened when Christian Spanish arrived to conquer those pagans because of a civil war to determine who really was the legitimate descendant of Inti, the sun.
Mayans had their star wars, Aztecs flower wars. The latter from a modern perspective for no particular reason, other than to capture people to be used in human sacrifice. That looks as if there is nothing else but a religious motivation in those kinds of wars. Romans inquired the auspices before going to war than performed a religious ritual on the mars field, performed evocatio deorum before the enemy's city gate, then captured the city god and added it to their own pantheon. The Hittites performed exactly likewise.
Is there any war or warlike conflict in the Bible or the early Jewish history that is not entirely about religion? The taking of the promised land, the wars against Jericho, Ai, Israel & Judah, the Maccabean Revolt, the at least three full Jewish Wars against Rome?
It can very well be argued that it is universally true, that before the 'modern state' and the ideas of separation of church and state, religion was one prime cause for all the wars.
Or it is true that rulers and generals always lie. That what really was or is the cause is always something else. All marxist historians would agree to that. And Clintonistas as well. It's the economy, stupid.
The prime motivation as stated by instigators might then be "religion", although it really is about something else: the means to rule; in form of land, labour means of production. Those who follow Claude Levi-Strauss will of cause know it even better than that: all human conflict can be broken down to disagreements over the exchange of women. Let's not forget reductionist explanations like those from an offshoot of psychoanalysis. War is an illness in society and all of society's illnesses can be cured by achieving a proper orgasm. –– If that sounds ridiculous, then looking for mono-causality of war, for any war, in the thousands of years for its history is likely as well.

Religion is one of the most powerful forces in human history, and its power makes itself known in ways both dramatic and intimate in our world today; unfortunately, the impact of religion is often divisive and violent. If we want to truly understand religion's ability to influence human events, we need to grasp its psychological bases, and to take a scientific approach to religious psychology means using our best theories of how the mind works.
John Teehan: "In the Name of God. The Evolutionary Origins of Religious Ethics and Violence", Wiley-Blackwell, 2010.
Martha T Nussbaum: "Democracy, Religious Violence, and
  India's Future",
This is one of history's ironies, that although religion has been used to justify violence, violence can also empower religion. Perhaps understandably. therefore. in the wake of secularism, and after years of wait· ing in history's wings, religion has made its reappearance as an ideology of social order in a dramatic fashion: violently. In time the violence will end, but the point will remain. Religion gives spirit to public life and provides a beacon for moral order. At the same time, it needs the temper of rationality and fair play that Enlightenment values give to civil society. Thus religious violence cannot end until some accommodation can be forged between the two-some assertion of moderation in religion's passion and some acknowledgement of religion in elevating the spiritual and moral values of public life.
Mark Juergensmeyer: "Terror in the Mind of God: The Global Rise of Religious Violence", University of California Press: Berkeley, London, 2000.
To understand the role of religion in the emergence of American empire, we need to look beyond any simple opposition or interaction between "church" and "state" and see instead how the construction and corrosion of power and authority have operated across sectors of society, especially around apparently "secular" categories in which the displacements of religious logic have most
  effectively operated under assertions of innocence, purity, or transcendence.  ose categories through which the material origins of desire have most consistently been compressed and displaced in America are age, race, and gender, as expressed in the culture in various identities associated with collectives like the nation or, now, an empire.
Jon Pahl: "Empire of Sacrifice. The Religious Origins of American Violence", New York University Press: New York, London, 2010.
Violence served to uphold the Egyptian concept of correct order, known as Ma'at. Some violence, such as sacrificial servant burial, did so by ensuring that correct social order continued in the next life. Most violence in the service of the order was aimed at the destruction of chaos, or Isfet.
Kerry Miles Muhlenstein: "Violence in the Service of Order: The Religious Framework for Sanctioned Killing in Ancient Egypt", Dissertation, University of California: Los Angeles, 2003.
Much has been written about the relationship between religion and violence, and much of what has been written is aimed at determining whether, how, and why religion causes violence.  This book has a different goal. Followers of many different religions who commit violent acts seek to justify these by appealing to religion. I aim to understand how such justifications proceed; and how they do, or do not, differ from ordinary secular justifications for violence. I will show that religious justifications for violence generally exemplify the same logical forms as ordinary secular justifications for violence. I will also show that many religiously based justifications for violence are as acceptable as rigorous secular justifications for violence, provided that crucial premises, which religion supplies, are accepted. Religious believers are able to incorporate premises, grounded in the metaphysics of religious worldviews, in arguments for the conclusion that this or that violent act is justified. I examine three widely employed types of premises that appear in such arguments. These are: appeals to a state of "cosmic war," appeals to the afterlife, and appeals to sacred values.
Steve Clarke: "The Justification of Religious Violence", Blackwell: Chichester, 2014.
The Enduring Relationship of Religion and Violence / Violence and Nonviolence at the Heart of Hindu Ethics / Buddhist Traditions and Violence / Sikh Traditions and Violence /  Religion and Violence in the Jewish Traditions / Religion and Violence in Christian Traditions /  Muslim Engagement with Injustice and Violence / African Traditional Religion and Violence / Religion and Violence in Pacific Island Societies /  Violence in Chinese Religious Traditions
Mark  Juergensmeyer & Margo Kitts & Michael K. Jerryson: "Violence and the World's Religious Traditions. An Introduction", Oxford University Press, 2017.
Answer: Other answers are justifying a straight "no", but what else is going on in the "critique of theism" mentioned by Semaphore?
The atheist philosopher Tim Crane addresses, in his book "The Meaning of Belief" (2017, Harvard University Press) claims of this kind that are made by certain atheist critics of religion (so, his subject is not any supposed consensus among historians). Spoiler alert: his view of attempts by famous atheists like Dawkins or Hitchens to analyse religion is not broadly approving. What does he say about claims that religion is wholly or mainly responsible for war and other violence? p120-122:

The violence and destruction imposed in the name of Christianity has a long history: the medieval Crusades ... [4 further examples]; and we could go on, of course. Put like this, you can see why people say that the history of Europe in the second millennium AD was a history of religious violence.
Against this has to be placed the equally terrible history of large-scale nonreligious violence and cruelty. Examples easily spring to mind: the killing of the Central American natives by the conquistadors, the slave trade, ... [4 further examples]. And then of course there are the other monstrous crimes of the twentieth century: the Nazi Holocaust and the mass killings by the communist regimes in China and the Soviet Union. As with religious violence, it seems all too easy to find examples.
Some writers more sympathetic to religion attempt to argue that those examples show that religion is not really the source of the world's problems, and that even so-called religious conflicts are not really religious underneath. ... Karen Armstrong traces the origin of human violence to the beginnings of agrarian societies and the accumulation of wealth...
The account I sketched of identification in Chapter 3 of this book indicates one other place where an explanation of of religious violence that is not specifically religous might begin. The tendency of human beings to form groups explicitly defined in opposition to others, which then seek the destruction and subordination of the other groups, is one of the characteristic features of many recognizably human societies. But facts like these do not mean that religion has no special, distinctively religious role in explaining episodes of violence. ... The question is rather, what is this role.

He goes on to point out that even wars that some attribute to religion are not necessarily caused by any theological content of the religion. p132:

It would be entirely incorrect, even frivolous, to suggest that the filoque clause is one of the factors that influenced the war between the Serbs and the Croats in the 1990s. And yet, if we are to look at the theological origin of the separation of the Roman and the Orthodox Churches, this would have to be mentioned (among many other details) ... yet it is plain that this doctrine has nothing more to do with the war than the fact that the Serbs use the Cyrillic alphabet and the Croats use the Latin alphabet.

So, what is there to religion other than theology? Well, that's the major part of the book, and his view is that religion consists of group identification, together with the "religious impulse" toward something that transcends normal life, connected by a shared notion of what specific things are sacred. Hence, there are other ways that religion could be a factor than just theology. p134 returns to the causes of religious violence:

I mentioned three further conjectures about the sources of religious violence and conflict: (2) nontheological but distinctively religious aspects of religions; (3) the element of identification; (4) other nonreligous aspects of human psychology, society and culture.

p143:

Religion is one factor, without doubt. But is it the most fundamental or important factor? How can we go about answering this question? Is there even any need to answer it? ... The extreme violence in these cases is often explicable in terms of the tendency of identification (religious or not) to exclude and discriminate against others; the violent content of some religious texts; or the struggle for power, supremacy, or autonomy among competing religious groups--in addition to human motivations and desires (for example, revenge) that are intelligible independently of anything to do with religion.

There's plenty more detail, but his gist is that what constitutes religion "causing" violence (or a war in particular) is by no means a simple or settled issue. That being the case you can't really have a simple, settled view of whether religion is uniquely culpable among other factors.
So the claim that "most wars are caused by religion" may not even be intelligible. Do most wars have religion among their causes? Are most wars caused solely by religion? What aspects of religion can be included or excluded in the assessment of whether religion caused something? You're going to do a very different analysis according to how you interpret the basic structure of the question, never mind your actual historical opinion about the causes of every war.
Answer: Historians, by and large, agree that most wars fought for resources  and thus are caused by the greed for worldly or physical gain, be it land, women or money. See: "Encyclopedia of Wars," by Charles Phillips and Alan Axelrod.
However, in order to motivate the masses, they used religion as a motivational tool. This still works today, given how many use Christianity as a motivation to be a conservative. This is ironic, given that that religion was essentially a rebel movement, against the Roman Empire and decidedly not a conservative cause.
Therefore, while religion itself might not cause wars, it does acerbate them because religion is used as a justification. Joan of Arc, the Civil War, Colonial wars would not have had this effect had it not been for the religious motivation. And it's doubtful that Joan of Arc would have gone to Germany or Africa to fight perfidious Albion.
As a side effect of triumphantly decrying that religion is NOT a cause of wars, some play the fake victim card: "Oh, us poor Christians, who are oppressed by the evil atheist hordes."
Comment: @Michael: not necessarily a "cause", but you're only asking for an argument. There were theologial debates over slavery, and Franklin proposed in 1776 "Rebellion to Tyrants is Obedience to God" as the motto for the US Seal, but they went with "E pluribus unem". That would seem to be a religious point (albeit that's not a fully-developed form of it) in favour of the revolutionary war. It would be astonishing if *literally no* religious argument was used by *anybody* in favour of (and against) anything important.
Comment: I am unaware of *any* religious arguments used to gain support for or provide justification of  the American Civil War or the American Revolution.
Comment: @ GwenKillerby, you made a rather gratuitous assertion that "religion" was used to justify the American Revolutionary War and the American Civil War. I challenge you to prove that assertion, otherwise, your assertion is nothing other than your own personal opinion
Comment: @MichaelJ. Eeehm, your reasoning is fallacious, therefor invalid. It has no value. Consider that I didn't claim religion was a **NECESSITY** to start a war. And further: Did no-one claim in either of those wars that "God was on their side" ? I'm gonna take a wild guess  and say that both sides in both wars claimed exactly that.
2,1 seconds of googling will find you Southern claims that slavery was A-OK because of the "Curse of Ham".  In typical southern conservative fashion, even THAT was a lie: Ham wasn't black, and his descendants weren't Africans.
Answer: I have never read such a theory, by any historian.  This is likely because few real historians have ever made the claim.
I think we can easily see why that is: To be "most" it must be over 50%.
But not all religions are warlike.  And not all warlike religions can be used to justify/launch wars.
Buddhism, Hinduism, Taoism are non-warlike religions.  And they can most certainly not be used to justify wars (the god of those religions can't be owned by a group of followers.  And those gods never made any promises, and never demanded the followers to find new followers)
Shintoism is warlike religion but it can't be used to start wars.  because it isn't a god-owning religion.
Mesoamerican religions are not overly well understood, but given they didn't launch a holy war against the foreign invaders it seems pretty clear that holy war wasn't their thing.  Native americans also don't have a war like religion.
Right there, that's more than 1/2 the world, and probably more than 1/2 the wars ever fought.
Then there are a few religions that are both warlike and war justifying.  This is made possible by a custom made god that institutionalizes racism, makes land grant, and gives a religious mandate to spread the truth of 'love', 'peace', 'hope', 'chosen' and 'faith' to anyone lacking in 'love', 'peace', 'hope', 'chosen' and 'faith'.  And if the infidels, heathens, nonbelievers, etc. refuse to accept the truth, the followers are encouraged to convert them, by force if necessary.
But even then, not too many of the wars by the adherents were actually fought in the name of those religions.  And most of the biggest ones were all religion free.  Napoleonic War, Franco-Prussian War, WWI, WWII, the 100 years war, the 30 years war, the crimean war, etc.  That doesn't mean each side didn't bring their holy men with them to war, to ask their god to smite down those other guys in the opposing army.
So I would say a tiny percentage of wars are caused by religion, the rest are caused by kings playing the game of thrones.
Comment: +1 but there's actually been some wars with religious characteristics involving Buddhists, for example Ikko-Ikki; also Shintoism isn't inherently more warlike than other paganistic faiths, you're probably thinking of State Shintoism which actually considered itself distinct from "Religious Shintoism".
Comment: In Mesoamerica there were [flower wars](https://en.wikipedia.org/wiki/Flower_war) - in which religious motives might have been one of the reasons.
Comment: To say "Buddhism, Hinduism, Taoism are non-warlike religions ... Shintoism is warlike religion ..." is a myth all by itself. References?
Comment: @sofageneral, the debate among historians is whether religion was the dominant / only cause for flower wars.  Historians do not doubt that religion was a component of the flower wars.
Comment: it is a myth?  why?  because you say it is?  Do you have any references to support your theory?   (too can play this silly game)  Everyone knows Bushido is a warrior code steeped in the tradition of Shintoism (itself a mix of zen-Buddhism, chinese Confucianism and Japanese traditions, which is where the warlike elements came from)
Comment: flower wars?  that sounds a lot like american football meet gladiator...  or something...   And since they aren't here to explain themselves (thanks to religious people from Europe), I guess we will never really know what they were about, or whether religion was a part of it...
Comment: Given that the worst ethnic-religious cleansing since Yugoslavia is now being perpetrated by the Buddhist Burmese, makes claiming that Buddhism is non-warlike pretty nauseating. It was instigated by a Buddist MONK! A good example of Buddhism being used as a motivator to slaughter Rohinga. (Cue "No True Scotsman" fallacy in 5, 4, 3...).
ANY group identification will be used to justify slaughter, religion is no exception. In this case, the usual "Muslims raped a girl" lie was used. That the veracity was questionable isn't even the point. The point was that Muslims were blamed AS MUSLIMS.
Comment: GwenKillerby   have you considered the possibility that what you are staitng is fake news by god owners invented to make other god owners feel better about their god owning religions
Comment: And how are the Rohingyas getting genocided?  https://www.washingtonpost.com/news/worldviews/wp/2018/01/10/in-a-first-burmese-military-admits-soldiers-killed-rohingya-found-in-mass-grave/?utm_term=.bea20ed0a7f4    may be 10 in a mass grave.. and people want to call it genocide, ethnic cleansing, or what have you?  that's not even a bad weekend in tijuana.  (It would be a bad weekend in chicago. but not unheard of)
Comment: The approximately quarter of  million Japanese Christians exterminated by a movement led by Buddhist monks might disagree with the proposition that Buddhism is any less warlike than Christianity. Neither religion is warlike at all taken on its own. That you can call Christianity warlike and think Buddhism or Hinduism isn't reveals a severe Eurocentrism in your education.


Is there a web image gallery generator that will run on Ubuntu?

Question: Is there a web image gallery generator that will run on Ubuntu?
What I'm looking for is something that will take a set of images, create a Javascript image gallery that I can then upload and embed on a web site I run. Ideally embed onto a Google Blogger blog as well. I can place the pictures on a folder on my own web server, or elswhere.
There are online services that do this, but they require that I host the pictures on other sites, and it gets to be a bit of a hassle having so many sites and logins and hosting services involved. It would be nice if I could just bundle everything up and put it on my web site, completely self contained.
I came across this, but it requires Adobe Air, and, not only do I not really want to get involved with Adobe, they stopped supporting Air for Linux after version 2.6.
I'm hoping for something fairly user friendly. It's not just me who will potentially build galleries.
I found an old post from 2005 on Ubuntu Forums mentiong gThumb, but, unless I'm missing something, it doesn't create a slideshow style presentation, just creates a grid of pictures. Or at the least, the options for customizing the look and feel of the gallery is very limited, and not in keeping with modern looks and feels.
Does such a thing exist?
Answer: I use gThumb. It's in the default Ubuntu installation.
Just select the folder of photos you want to use and go to File --> Export To --> Web Album


Removing Evolution password under KDE?

Question: I'm using Evolution mail client under KDE. I want to get rid of entering my password each time I use it. How can I do that ?
Answer: Evolution keeps it's passwords in gnome-keyring
Applications > Accessories > Passwords and Encryption Keys
From here, goto the passwords tab, find the correct password entry, double click on it, expand the password section, then click "show password" and change your password here.
Enter the old password (the one you've been prompted for when you start Evolution), but leave the new password fields blank.
It will prompt you with: Store Passwords Unencrypted?. Click on Use Unsafe Storage.
Log-out / Log-in

Removing Evolution password under KDE?


Does the block size of a symmetric cipher impact the security of the cipher itself?

Question: Will a 128 bit block have some security implication in post-quantum cryptography?
Comment: @otus I'm pretty sure that the blocksize won't have any implications with regards to QC, but that's the part I would not be able to argue successfully. I'm pretty sure with regards to Grover's attack because of the nature of it. But that would come down to an educated guess.
Comment: I'm not sure that this is a duplicate, since OP is specifically asking about security against quantum computers, and the linked duplicate answer does not explain that.
Answer:
Does the block size of a symmetric cipher impact the security of the cipher itself?

Yes, absolutely. A small block size limits the amount of data that can be encrypted with a given key, and some block modes are more badly affected by this than others. Additionally, some cryptographic attacks against weak ciphers can be made more practical against a block cipher with a small block size, such as the slide attack, which becomes very difficult to implement when the block sizes are large.
The classical issues with small block sizes are well documented, and other questions on this site on that topic have been answered. Generally, a small block size opens up a can of cryptographic worms regardless of whether or not your adversary is quantum-capable. A 32-bit block size is silly. A 64-bit block size is worrying and can be insecure in certain situations. A 128-bit block size is okay. A 256-bit block size is better. A 512-bit block size is generally excessive. This holds true, quantum or not.

Will a 128 bit block have some security implication in post-quantum cryptography?

No, a small block size will not generally be affected by quantum computers. The quantum algorithm that would be responsible is Grover's algorithm, which is a search algorithm. All the attacks against block ciphers that rely on a small block size are limited by the amount of ciphertext the attacker has, not by the number of operations an attacker is able to perform. Sweet32, slide attacks, etc. depend on nothing more than being able to collect a lot of ciphertext that has been encrypted under a single key. Once sufficient data has been collected, the number of computations required to break the guarantees of the cipher are not great enough to benefit substantially from Grover's algorithm.
It's important to note, however, that a block cipher used for authentication, e.g. with CBC-MAC, is more vulnerable against a cryptanalytic quantum computer. The reason for this is that a small block size results in a small authentication tag size, and Grover's algorithm can be used to brute force the small tag with more ease. The same is true if the block cipher is used as the core of a hash function, which would result in smaller digests that are easier for a quantum computer to attack.
Comment: The CBC-MAC security theorem, which is affected by the block size, is independent of the _adversary's_ computational limits.  When instantiated, only the AES security conjecture depends on the adversary's computational limits, and then it is essentially just the key size that affects the cost, not the block size.  (The situation is exactly the same for the one-time pad security theorem and its instantiation with AES-CTR; this is why the conceptual structure is worth highlighting rather than obscuring by dogmatically imposing a barrier to connecting the terminology!)
Comment: I…don't know what mikeazo is getting at there.  If there is something there, it warrants elaboration.
Comment: @SqueamishOssifrage The security theorem remains fine, but the small tag size is bad.
Comment: The security theorem—that the advantage distinguishing $\operatorname{CBC}_\pi\colon \{0,1\}^{mb} \to \{0,1\}^b$ for uniform random $\pi$, from uniform random $f\colon \{0,1\}^{mb} \to \{0,1\}^b$, is bounded by $\binom{mq}{2} 2^{-b}$—is the main half of what justifies using $\operatorname{CBC}_\pi$ as a MAC; the other half is the obvious fact that a uniform random function is (strongly) unforgeable.  Neither of these is affected by Grover, because the adversary can't tell _offline_ whether a candidate authentication tag is correct or not.
Comment: Why do you say the small tag size is bad?
Comment: @SqueamishOssifrage Ah I see what you mean. Should I remove my mention of CBC-MAC?
Comment: I am not sure offtalon whether CBC-MAC and Grover have any interesting connection, except insofar as Grover can be used for key recovery. (There are, of course, plenty of interesting things that can be done in the completely asinine model where you hand the adversary a quantum superposition of MACs on a platter, for an adversary-specified quantum superposition of messages; many academics have averted perishing by publishing on this topic. But it is of no practical consequences whatsoever except to the most inconceivably incompetently engineered cryptography, in the quantum future.)
Comment: @SqueamishOssifrage The reason I added that was because of [this answer](https://crypto.stackexchange.com/a/5904/54184), but I admittedly didn't look into it deeply. Key recovery is what I was thinking of, and I was under the impression that a small block size would make that worse in the case of CBC-MAC.


Changing volume of alarm on Nokia Lumia 800

Question: I have a Nokia Lumia 800 with Windows Phone 7.8 on it and I am unable to control the volume of the alarms for the alarm clock on the phone.  I used to have an LG Optimus with Windows Phone 7 on it and I was able to adjust the volume, so I think it might have something to do with the phone rather than the OS, but I'm not sure.  Does anyone know if it's an issue with the Nokia Lumia 800 specifically, and if there is a way to fix it so that I can adjust the alarm volume?
Answer: From Windows Phone Help:

Alarm volume is separate from the overall phone volume and can't be
changed. As long as your phone is on, your alarms will still ring out
  nice and loud even if you turn down or silence the phone volume.

The above applies to any Windows Phone out there. I used to have an LG Optimus too and I can't remember being allowed to set the volume for built-in alarms.


References for implicit [intrinsic - I remembered wrongly] co-ordinates

Question: When I was at school I learned about "implicit coordinates" for curves in a plane. Essentially these mapped the path in terms of arc length $s$ from a fixed point, and direction of travel $\psi$ measured against a fixed line (so the curve has to be sufficiently smooth). The point was that these data could be measured by a person travelling along the path. They were handy for computing curvature, and solving chase problems, I recall.
A question was posed about curves parameterised by arc length, which put me in mind of this. I did a search online, as I wanted to mention it in a comment, and came up with nothing resembling what I remembered.
I may have the name wrong, of course, or such co-ordinates may now be called something else. But a good reference would be helpful.
EDIT
As noted in comments below, the term is intrinsic coordinates. Good references still welcome, though the correct terminology does open up various online resources. I learned about these at school, and afterwards they went nowhere, or so it seemed. Yet they always seemed interesting. I suppose the way that Riemann Surfaces are made up from local bits (the direction gives you a piece which is locally nearly straight) - and generalisations of the same in various manifolds and geometries are where it went. Yet the particular expression here, which is effectively how to map a curve using a car with a milometer and a compass always seemed very real.
Comment: I've heard of the term *intrinsic coordinates*, which is the term used in A Level Further Mathematics.
Comment: @Zhen Lin: solved it in one - my memory is going.
Answer: Here are some resources, but there must be some others out there.
Some notes and examples in the plane
Lecture notes on aeronautics covering three dimensions


How to do GRUB editing?

Question: How to do grub editing in ubuntu version 11.04 and 11.10? What is the purpose of grub editing? If anyone knows the solution please answer it..
Comment: Grub settings are in this folder /etc/grub.d now
Answer: Grub is the bootloader - so the purpose of editing it is to change parameters during boot.
The files you can edit are /etc/default/grub and the scripts in /etc/grub.d.
Changing the grub.cfg in /boot/grub is not recommended as any changes you make manually will be overwritten the next time an update to grub is called.
If there is a specific reason that you want to edit the file please update your question.
https://help.ubuntu.com/community/Grub2
Answer: GRUB:= GRand Unified Boot-loader
It is a common boot loader that can boot the system, weather Linux or windows or others
Grub Editing= play with the boot configuration or customize the boot configurations.
How to edit : as said in forestpiskie's post you can manually edit those files.. or use a GUI for that...
Grub customizer is a good one ( look :Grub Customizer installation)
Startup manager is also fine (check : community website )
BUT IF YOU MANAGE TO MESS UP WITH BOOT, You can't boot into the system... don't worry a lot of methods are there to fix the boot loader.....
The recommended one is Boot Repair....Boot repair installation it can fix the problem even if the boot loader is deleted or corrupted...... Also keep the copy of boot repairer disk (check:Boot-repair disk Source forge page) before you attempt some thing that may corrupt the loader...
If you wanted to customize the GRUB too badly... read this manual
If you want to theme grub your own reading the book listed in this post may help you :grub guide by Towheed Mohammed
All the best with grub editing and customizing... if for info hope that this provides necessary information.. if not ask :)

How to do GRUB editing?