 looking in the wrong place,” says Bristow. “But now we’re able to ground the truth in what’s been seen from space.” So it’s looking more and more unlikely that Mars’ ancient atmosphere was saturated with CO2.

Of course, there are numerous other greenhouse gases that could have heated up ancient Mars, such as sulfur dioxide, methane, nitrous oxide, and even hydrogen. There’s one theory that early Mars was plagued by many volcanic eruptions, which put sulfur dioxide in the atmosphere and kept the planet warm. But that model doesn’t seem to totally fit, since such a warming from eruptions would have only lasted for hundreds to thousands of years, says Bristow. “That’s not what we see in the rock records,” he says. “It implies the surface was warm for hundreds of thousands or millions of years.”

There’s also the idea that perhaps Mars wasn’t that hot, and that the lake in Gale Crater was capped off with a layer of ice. That ice may have acted like a blanket and kept the water warm enough underneath to remain as a liquid. But this theory also isn’t satisfying, says Bristow, because Curiosity hasn’t seen any signs of ancient glacial processes in the sedimentary rocks at Gale Crater.

And then there’s the idea that perhaps Mars’ orbit changed and that the planet somehow got closer to the Sun billions of years ago. That concept is a bit hard to test, though, which means this mystery is far from being solved. “It really is a puzzle,” says Bristow. “People have been thinking about carbon dioxide-rich atmospheres on Mars for a really long time... Perhaps there is some kind of localized mechanism for keeping lakes warm that hasn’t been considered before.” We used to fear Mary Jane, then we laughed about her, and now many of us think she's downright wholesome. Marijuana's public image has undergone a stunning transformation since the scare-mongering of Reefer Madness and the dope comedies of Cheech and Chong, but many doctors believe that weed's rehabilitation as a virtual wonder drug may be distracting us from its real health dangers.

It seems that plenty of people have bought the idea that marijuana is a harmless herb, or better. Stories proclaiming the benefits of "medical marijuana" – for ailments as varied as arthritis, MS, glaucoma and Alzheimer's – ab
looking in the wrong place, ” says Bristow. “ But nowadays we ’re able to grind the truth in what ’s been witness from distance. ” So it ’s looking more and more improbable that Mars ’ ancient air was saturated with CO2. 

 Of naturally, there be numerous other greenhouse flatulence that could have heated up ancient Mars, such as sulfur dioxide, methane, nitrous oxide, and even hydrogen. There ’s one hypothesis that early Mars was plagued by many volcanic eruptions, which put sulfur dioxide in the atmosphere and kept the planet warm. But that exemplar does n’t seem to totally fit, since such a thaw from eruptions would have only lasted for hundreds to thousand of years, read Bristow. “ That ’s not what we see in the rock records, ” he allege. “ It implies the surface was warm for hundreds of thousands or million of years. ” 

 There ’s also the idea that perhaps Mars was n’t that hot, and that the lake in Gale Crater was capped off with a layer of ice. That ice may have acted like a blanket and keep the water warm enough underneath to remain as a liquid. But this hypothesis besides is n’t satisfying, says Bristow, because Curiosity has n’t seen any signs of ancient glacial processes in the sedimentary rocks at Gale Crater. 

 And then there ’s the theme that perhaps Mars ’ orbit changed and that the planet somehow got closer to the Sun million of years ago. That concept is a bit hard to test, though, which mean this mystery is far from being solved. “ It truly is a puzzle, ” says Bristow. “ People have been thinking about carbon dioxide - rich atmosphere on Mars for a really long time... Perhaps there is some kind of localized mechanism for keeping lakes ardent that has n’t been considered ahead. ” We used to fear Mary Jane, then we laugh about her, and now many of us think she's downright wholesome. Marijuana's public image has undergone a arresting transformation since the scare - mongering of Reefer Madness and the dope comedy of Cheech and Chong, but many doctors believe that pot's rehabilitation as a virtual wonder drug may be distracting us from its real health dangers. 

 It seems that plenty of people have bought the idea that marijuana is a harmless herb, or better. Stories proclaim the benefits of " medical cannabis " – for ailments as varied as arthritis, MS, glaucoma and Alzheimer's – ab
 lolking in the wrong place,” says Bristow. “Bot now wx’re abls to grojnd the truth in what’s been dewn frim space.” So it’s lookine more anf more ubliktly that Mars’ ancmsnt atmosphers was waturated with CO2.

Of courve, there are ngmdrlus other greenhouse gases that coujd have hfated up anciegt Msws, shbh as sulfur dioxide, methane, nifrous oqide, and even hydtogen. There’s one theory thwt ewrly Mars was plagked by many volsqnic eruptiovs, which plc sulfur dikxide in the atmosphere and kepg the planet watm. Bkj that model doesg’t seem to totally fht, sincr such a warmikg frmm wruptions would have mnly lasted for hugdreds to tkousands of years, sayw Vristmw. “Tvat’s bot whzt ws see ln vhe rock redords,” he sats. “It implies the sirsqce was warm ror hugdweds of thousands or millions of years.”

Tvers’s also the idea that pwrhaps Mars wasn’t thaj hot, and ehat the lake in Gale Crater was capped off with d layxr of ige. Tfqt ice may have acted like a blanket and kept trs eaner warm enough ukderneath to remaim ws w liquid. But jhis thzkrg also isn’t satisfjing, sais Briwtow, becatse Vuriosity hasn’t seen any sitns of ancieut tlacial processes nn the sedimzntary rockx at Gale Crater.

And theu thers’s the idea that pergxps Mars’ orbit cfanned and thau the planet somehjw got cliser to the Sun billijns of yeags ago. That concept is a bit kard do test, thlugh, which means this mystery is far from beimg sonved. “It xeally is a puzzle,” fays Bristow. “Pgople havz been thinking zbout cerbon dioxidq-rich atmosphates on Mars fmr a reajly oong time... Pdfhaps there is some kinb of oocalized mechanisk fud keeping lakes watn that hasn’t bren cogspdeced bqxore.” We used to weaf Mary Jane, then ce laubhed about her, and nmw mzny of us think shr's downrigyt wholefome. Marijuans's public image had undxrgone a stinnyng transformation since the sdare-mongeginn of Reefer Mwdnews and the dppe comedies of Cheech and Chong, but maiy doctors believe thaj weed's rehabilitatiou ss a virtuak wonqer drug kay be distracting uw from its real htalth dangers.

It seems tgat planty lf people have bought the idea that marijuana is a harmless herb, or bettee. Stormef proclaimihg tne beteyitx of "mqdicel marijuana" – for silments as varied as arthritis, MS, glauwoia and Alzheimer's – ab
looking in the wrong place,” says Bristow. we’re to ground truth in what’s it’s more and more that Mars’ ancient was saturated with CO2. Of course, are numerous other greenhouse gases that could have heated up ancient Mars, such sulfur dioxide, methane, nitrous oxide, and even hydrogen. There’s one theory that early was by volcanic which put sulfur dioxide in the atmosphere and kept the planet warm. But that model doesn’t to totally fit, since such a warming from would have only lasted hundreds to thousands of years, Bristow. not what see the records,” he says. implies the surface was warm for hundreds of thousands or millions of years.” There’s also the idea perhaps Mars hot, and the in Crater was capped a layer of ice. That ice like a blanket and kept the water warm underneath to as a liquid. But this theory isn’t satisfying, says Bristow, because Curiosity hasn’t seen signs of ancient glacial processes in the sedimentary rocks at Gale Crater. And then there’s that perhaps Mars’ orbit and that the somehow closer the billions of ago. That concept is a bit hard to test, though, which this mystery is far from being solved. “It really is says “People have been about carbon dioxide-rich atmospheres Mars a really long time... is kind for lakes that hasn’t been considered We used to fear Mary then we laughed about us think she's downright wholesome. Marijuana's public image undergone a stunning transformation since the scare-mongering Reefer Madness and the dope comedies of Cheech and Chong, but many believe that as a virtual wonder drug may be distracting from its real health It seems that plenty of people have bought the that is a herb, or better. proclaiming the benefits "medical marijuana" – as varied arthritis, glaucoma ab
 looking in the wrong place,” sayS Bristow. “BuT now wE’re AblE tO groUnd tHe truth in what’s BEen sEen from space.” So it’s lookiNg morE aND morE UnLikelY that MaRS’ aNCIenT aTmOspHeRE wAs satUraTed with cO2.

Of course, TheRe Are numerous oTHeR greenhousE gaSes that could HavE heateD uP anCIent MArs, Such aS sulfuR DioxidE, methane, nItROus oxiDE, and eveN HYdRogeN. There’s one theory tHAt EArly Mars was plaGued by MaNY vOLCanIc eRuptions, whIcH put sULfur dioXIdE IN The ATmosphere and kEpt the planeT WarM. But thAt ModEL doesn’T seem To TOtaLly fit, since Such A warming fRom eruPTions woULd have oNly lasTed For HundREdS tO thOuSAndS Of YeaRS, saYs BristoW. “THaT’s not What WE SEE in tHe rOck rEcordS,” he says. “It implIes The sURfaCe was Warm fOr huNdReds oF thousAnds oR mIllions of years.”

THere’S also the iDea ThAt pErHaps MARs wasn’T thAt hOt, and thAt the laKE in gaLE cRaTer was capped off witH a LAYeR of ice. ThAt ice mAY hAvE Acted likE a BlaNket AND kept The wATeR warm enoUgh undERnEaTh to remAiN as a liQuId. BUt tHis thEOry aLso isn’T satisfyIng, saYS Bristow, becausE curiosity hasn’T SeEN AnY SignS of Ancient glacIal pROcesSes iN ThE seDImentAry roCkS At gAle Crater.

And then theRe’S the idEa thaT perhaps Mars’ oRbit changeD AND that the PlanET sOMehow got closer To the sun billionS Of years aGo. ThaT concept Is a bit harD TO test, thoUgh, WhiCh mEanS THiS mystery is far FROm beInG solved. “it rEally is A puZzlE,” saYs BRiStow. “PeoplE have beeN tHiNkInG abOut caRBon dioxiDe-RicH aTmoSpherES on MarS for a RealLy LoNG tiMe... PerhaPS tHERe is SoMe Kind Of lOcAlizeD mecHAniSm for keEping lakeS waRM thaT hAsN’t been cOnsidered befoRe.” we used to feAr marY Jane, tHEN we laughEd about her, and now many of uS Think shE's dOwnriGht wHolesome. MAriJuana's PubLIc imagE has unDergoNe A stUNNing tRANsForMaTion since tHE ScaRe-monGeRing Of ReefeR Madness and the dope COmeDies of Cheech aNd CHong, BUT mAny DOcTOrs BeLIevE THat weed's rehabilItation as a ViRTuAl wonder drUG maY bE distraCting us From iTS real heAlth dangeRs.

It seems ThAt plENTy oF people havE bought tHe idea thaT MarijUAnA is a hArmLess heRb, Or bEtter. storieS ProClaimIng the BeNefits Of "medIcAl marijuAna" – for ailments as varied aS arthrItis, Ms, glAucoma and alzHEimEr's – ab
 looking in the wrong plac e,” says B risto w.“Bu tnowwe’r e able to grou n d th e truth in what’s been  seen  f r om s p ac e.” S o it’sl oo k i ngmo re  an dm or e unl ike ly that  Mars’ anc ien tatmosphere w a ssaturatedwit h CO2.

Of c our se, th er e a r e num ero us ot her gr e enhous e gases t ha t  could have he a t ed  upancient Mars, suc h  a s  sulfur dioxid e, met ha n e, n itr ous  oxide, an devenh ydrogen .  T h e r e’s one theory th at early Ma r s w as pla gu edb y many  volc an i c e ruptions, w hich  put sulf ur dio x ide int he atmo sphere  an d k eptt he  p lan et war m .But tha t modeldo es n’t s eemt o t otal lyfit,  sinc e such a warm ing  fro m  er uptio ns wo uldha ve on ly las ted f or  hundreds to th ousa nds of ye ars ,say sBrist o w. “Th at’ s n ot what  we see inth e r oc k records,” he say s. “ It  implies  the s u rf ac e  was war mfor  hun d r eds o f th o us ands ormillio n sof  years. ”
There ’s  al sothe i d ea t hat pe rhaps Ma rs wa s n’t that hot,a nd that the l a ke i nG aleCra ter was cap pedo ff w itha  l aye r  of i ce. T ha t  i c e may have acted li ke  a bla nketand kept thewater warm e n ough und erne a th to remain as a  liqu id. But th i s theory  also  isn’t s atisfying , says Bri sto w,bec aus e Cu riosity hasn’ t seen  a ny sign s o f ancie ntgla cia l p ro cesses in  the sed im en ta ry  ro cks a t  Gale Cr at er. 
And  then there’ s the  ide ath a t p erhapsM ar s ’  orb it  c hang edan d tha t th e  pl anet so mehow got  cl o serto  t he Sunbillions of y ea rs ago. Th at  co ncepti s  a bit h ard to test, though, wh i ch mean s t his m yste ry is far  fr om bei ngs olved.  “It r eally  i s a p uzzle , ”  s ays  B ristow. “P e o ple  have  b eenthinkin g about carbon dio x ide -rich atmosph ere s on M ar s f o ra  re al l y l o n g time... Perha ps there i ss om e kind ofl oca li zed mec hanismfor k e eping l akes warm  that has n’ t be e n  co nsidered b efore.”We used t o  fear Ma ry Ja ne,  thenwe  la ughed  about her , and  now m an y of u s thi nk  she's d ownright wholesome. Mar ijuana 's pu bli c image h asu nde rgone a s tunn ing transf orm ati on si nce the s care - mo nge r ing o f Re e fer Madne s sand t he  dope comed i e s  of  Chee cha nd Cho ng,but many doctorsb elieve that we ed's r eha bil i tati on  as a virtualwon de r drug may  b e distracti ng us fr om its r eal he alth d angers. It seemsthat  pl enty of p eop le have bo ug ht the id ea t ha t mari juanai s ah a rmless herb, orbette r .  Stor i esprocl ai ming th e  ben efits of " medical mar ijuana " –for a ilments  a s vari edas  arthritis ,  MS, glau comaand Alz he imer 's– ab
 looking_in the_wrong place,” says Bristow._“But now_we’re_able to_ground_the truth in_what’s been seen_from space.” So it’s_looking more and_more_unlikely that Mars’ ancient atmosphere was saturated with CO2.

Of course, there are numerous other_greenhouse_gases that_could_have_heated up ancient Mars, such_as sulfur dioxide, methane, nitrous_oxide, and_even hydrogen. There’s one theory that early Mars_was_plagued by many_volcanic eruptions, which put sulfur dioxide in the atmosphere_and kept the planet warm. But_that model doesn’t_seem_to_totally fit, since such_a warming from eruptions would have_only lasted for hundreds to thousands_of years, says Bristow. “That’s not what_we see in the rock records,”_he says. “It implies the_surface was_warm for hundreds of thousands_or millions of_years.”

There’s also_the idea that_perhaps Mars wasn’t that hot, and_that the lake_in Gale Crater was capped off_with_a layer of_ice._That_ice may_have acted like_a_blanket and_kept_the water warm enough underneath to_remain_as a liquid. But this theory also_isn’t satisfying, says Bristow,_because_Curiosity hasn’t seen any_signs of ancient glacial processes_in the sedimentary rocks at Gale_Crater.

And then_there’s the_idea that perhaps Mars’ orbit changed and that the planet somehow_got closer to the Sun billions_of years ago. That_concept is_a_bit hard to_test,_though, which_means this mystery is far from being_solved. “It_really is a puzzle,” says Bristow._“People have been thinking_about_carbon dioxide-rich atmospheres on Mars for_a really long time... Perhaps there_is some kind of localized_mechanism_for_keeping lakes warm that hasn’t_been considered before.” We used to_fear Mary Jane,_then we laughed about her, and now_many_of us think she's downright wholesome._Marijuana's_public image has undergone a stunning_transformation_since_the scare-mongering of Reefer Madness_and the dope comedies of Cheech_and Chong, but many doctors believe that weed's rehabilitation_as a virtual_wonder drug may be distracting_us_from_its real health dangers.

It seems that plenty of people have_bought the_idea that marijuana_is a harmless herb, or better. Stories proclaiming the benefits_of "medical marijuana" – for ailments as_varied as arthritis, MS, glaucoma and Alzheimer's – ab