Emperor Nero's "planetarium" - reality or a myth?
A report on Nero exhibitions in Germany this year made me aware of the claim that the octogonal dining room - coenatio principalis - of his palace Domus Aurea in Rome had either one rotating dome or several nested ones in order to display celestial motions 1),2),3). Or - since there is no archaeological evidence for such mechanisms - that there was a fixed dome with moving lanterns instead 4).
The only contemporary source seems to be one line in a text by Gaius Suetonius Tranquillus - and Ref. 5 says that scholars "have long debated whether this planetarium-like aspect of the room was a marvel of Roman engineering or simply a figment of Suetonius' often whimsical imagination." Is there a consensus by now about what clever astronomy display system was or wasn't installed in the Domus Aurea? And what about an even better 'planetarium' in Domitian's Domus Augustana Ref. 1 mentions?
Reality check: page 12 of the 2016 Meteor Shower Calendar of the International Meteor Organization. The key sentence there: "Results from Mikhail Maslov and Esko Lyytinen indicate that we will cross a part of the stream which was shifted closer to the Earth’s orbit by Jupiter in 2016. As a consequence, the background ZHR may reach a level of 150–160." Which would be 1/5 to 1/4 more meteors at the peak than an typical year with a ZHR (zenith hourly rate) of 120 or so - this is not a dramatic increase, on a par with some recent years and well below e.g. the 1993 Perseids show which reached a maximum ZHR over 400.
Maslov's current calculation can be found in more detail here: He sees the - somewhat - higher than usual peak at 12:40 UTC on August 12 which for Europe means that the nights Aug. 11/12 and 12/13 should be comparable. Taking into account the radiant altitude and the bright Moon - which sets only after midnight, meteor party planners beware! - one can hope for actual maxmimum hourly rates under otherwise excellent conditions in the 70s, i.e. on average one meteor per minute: see the first and third diagram at the bottom of this Dutch website, blue = what you would see.
There is, however, a minority view based on a NASA model mentioned in this presentation from 2015 which sees a somewhat higher maximum ZHR (around 200) half a day earlier (around 0:30 UTC on August 12): should that happen European observers would be in a sweet spot an see twice as many meteors per hour in the wee hours of August 12 (middle diagram on the Dutch page). It is this vague possibility that much of the (extra) hype this year is based upon, but be warned that NASA's model has had a worse track record that what goes into the IMO Calendar.
So far I've seen only this one article strongly arguing against the PER 2016 hype and pointing out (some of) its problems, though it still uses exaggerated ZHR numbers and doesn't discuss the competing models. Some further information pages and articles of widely varying quality and in several languages about the 2016 Perseids can be found here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here and here - but from the preceding paragraphs you now know what to believe and where to be skeptical. And what really happens can be followed here, with a few hours delay while visual reports from experienced observers are being ingested.
Just another quick - and sad - notice about the state of science reporting these days. Each and every major science news website in the Anglo-Saxon world is reporting that "a weasel" had attacked an electrical system of the Large Hadron collider, causing a shutdown. But there was no weasel: as everyone can read on page 10 of the Daily Summary for April 29 of the LHC machine status, the culprit was a fouine, and you have just to go to the respective French Wikipedia page to find out that this refers to one species of carnivore, known - use the sidebar with the 'Autres langues', always a good idea to translate animal names precisely - as the beech marten in English or the Steinmarder in German.
It's so simple: martens are the genus Martes while weasels and some close relatives form the genus Mustela. Both belong to the same subfamily Mustelinae and are thus related (although recent genetic research seems to remove the Martes and others from that subfamily) - but they are neither the same nor is one a subset of the other. (In German confusion might arise as the genus Martes is known as 'Echte Marder' while the family Mustelidae that includes the martens, weasels and much more is called 'Marder', so Wiesel are Marder but no Echter Marder can be a Wiesel. In English the term 'weasel' usually refers to one Mustela species while the Mustelidae may be called "weasel family".) A little digging would also unveil that the beech marten is the only Mustelid known to bite into cables (the reason for which is a subject of interesting research all by itself) - weasels don't do that.