[HN Gopher] JWST: Identification of carbon dioxide in an exoplan...
___________________________________________________________________
JWST: Identification of carbon dioxide in an exoplanet atmosphere
Author : sanketpatrikar
Score : 127 points
Date : 2022-08-27 09:36 UTC (13 hours ago)
(HTM) web link (arxiv.org)
(TXT) w3m dump (arxiv.org)
| FL33TW00D wrote:
| For everyone imagining an industrial revolution 700 light years
| away - unfortunately WASP-39b isn't well suited:
|
| "WASP-39 b is a hot, puffy gas-giant planet with a mass 0.28
| times Jupiter (0.94 times Saturn) and a diameter 1.3 times
| greater than Jupiter, orbiting just 0.0486 astronomical units
| (4,500,000 miles) from its star"
| jcims wrote:
| It's diameter is ~112k miles, or roughly 2% of the distance to
| its star. It's hard to imagine the amount of chaos in that
| atmosphere. I would think all of the churn from the
| gravitational gradient would end up effectively tidally locking
| it?
| jacquesm wrote:
| That could work both for and against life.
| jcims wrote:
| Totally agree. Particularly if it becomes tidally locked
| and you end up with a ring-shaped habitable zone that's out
| of the direct heating/radiation of the sun and fed by
| convective currents coming from the cold side.
| anonporridge wrote:
| Why would the presence of CO2 in the atmosphere ever be used to
| assume an industrial revolution in any scenario?
|
| The atmosphere of both Mars and Venus are 95% CO2. Earth had
| plenty of CO2 before humans even existed. In fact, there were
| periods hundreds of millions of years ago where Earth had
| drastically more CO2 (up to 9000ppm vs 420ppm today) than it
| does today.
| addaon wrote:
| "Assume" is a strong word, but if we observed an exoplanet
| with free oxygen in the atmosphere and stable levels of
| bioindicators (methane etc) for a period, and then saw CO2
| spike from nearly zero to significantly higher levels...
| well, it's evidence of something.
| anonporridge wrote:
| Sure, but that's not related to this study.
|
| _Maybe_ that 's something we'll detect over the course of
| hundreds of years of observing, but the shear scale of the
| time of the universe makes the chances that some other
| alien species just happens to be going through an
| industrial revolution while we're around to observe it, are
| so astronomically small as to barely be worth considering.
|
| In your example, an intelligent species in an industrial
| revolution would probably be at the bottom of the list of
| likely explanations, simply because of how statistically
| unlikely it appears to be.
| [deleted]
| sgt101 wrote:
| I would like them to find methane & oxygen in an atmosphere. I
| don't have a clue really, but I think that would be pretty
| convincing evidence of life. I expect that they are busy looking
| and we will get a result like that in the not too distant future
| - if the JWST can do it and if such atmospheres do exist in
| substantial numbers.
| teaearlgraycold wrote:
| Make it oxygen, methane and water and I'll happily consider
| alien life discovered.
| nickff wrote:
| Methane has been detected on Mars, and is not regarded as proof
| of 'life'. In addition to bacteriological sources of methane,
| it can be produced through geochemical processes. I am not sure
| which, if any atmospheric gasses would be proof-of-life.
|
| https://en.m.wikipedia.org/wiki/Methane_on_Mars
| HPsquared wrote:
| There's also a LOT of methane on Saturn's moon Titan.
| ben_w wrote:
| IIRC, chemical bio-signatures are _out of equilibrium_
| chemicals: if some environment has only CH4 or only O2 that
| says basically nothing, but if it has _both_ CH4 and O2
| then (because these rapidly react to form H2O and CO2) the
| combination would suggest some process is creating methane
| and oxygen from water and carbon dioxide, which suggests[0]
| life.
|
| [0] I don't know anything else which does this, but that's
| mostly because I'm a software engineer and my highest
| chemistry qualification is a 22 year old GCSE grade B.
| sgt101 wrote:
| I have a Biology A level (!) and also gave up Chemistry A
| level after 1 year (!!) and I think that you are right.
| mohaine wrote:
| I'm pretty sure lot of gasses would, just not the natural
| ones. CFCs and many other man made gasses have no viable non-
| alive natural sources.
| nickff wrote:
| Im not sure what proportion of the atmosphere would have to
| be a certain gas to spot it. In addition, JWST doesn't have
| enough resolution to see small spots on an exoplanet. I
| don't think JWST could spot earth-like levels of CFCs.
| wongarsu wrote:
| Exactly. Detecting CO2 is cool, but it's very stable and found
| in lots of places. Finding more reactive gases would be more
| exciting, because that might imply they're being replenished
| from somewhere, presumably either geological processes or life.
| And some gasses like oxygen don't really get produced by
| geological processes.
| mysterydip wrote:
| > CO2 is an indicator of the metal enrichment (i.e., elements
| heavier than helium, also called "metallicity")
|
| I'm confused; aren't literally all but one of the elements
| heavier than helium?
| astrolx wrote:
| Yes, everything heavier than hydrogen and helium is called
| metals by astronomers. It's a misleading term for the public,
| but very widely employed.
|
| (I'm an astronomer)
| kzrdude wrote:
| So it's a three-element periodic table: Hydrogen, Helium,
| Metals. :)
| Keyframe wrote:
| Four actually. There are also heavy metals
| tomrod wrote:
| More, once we include the combinatoric number of music
| genres produced by certain grouping of heavy metals on
| the third cluster from a medium-sized, boring star the
| metal designates as Sol.
| Keyframe wrote:
| That explains how we got to both dark matter and dark
| energy.
| mpweiher wrote:
| Yes.
|
| And that's giving far too much weight to the Metals ;-)
|
| (1% of total mass)
|
| The universe really is just Hydrogen + Helium + rounding
| error...
| [deleted]
| Eupraxias wrote:
| Actually, I've heard it called just "Hydrogen and Dirty
| Hydrogen"
| moffkalast wrote:
| The universe is a zeppelin
| quickthrower2 wrote:
| Not a led zeppelin though
| ant6n wrote:
| But a metal zeppelin
| kzrdude wrote:
| I heard there might be interesting stuff happening with
| the metals though. They are self-conscious and stuff?
| aaaaaaaaaaab wrote:
| Yes, they are pretty self-conscious. E.g. gold constantly
| thinks she's looking too yellow.
| simonh wrote:
| The jury's out on that metaphysically speaking, but even
| if so that's a rounding error of the rounding error. This
| handy chart breaking down the universe by subject area is
| a useful guide.
|
| https://www.explainxkcd.com/wiki/index.php/2640:_The_Univ
| ers...
| dan353hehe wrote:
| Wait, the metal talks? And it thinks with its metal?
| lubujackson wrote:
| They're Made of Meat -> They're Made of Metal: way cooler
| dekhn wrote:
| the metal sings! they can sing by squirting air through
| their metal!
| cmrdporcupine wrote:
| It's really metal through their metal
| hermitcrab wrote:
| Reminds me of numbers for database programmers - 0, 1 and
| many.
| mysterydip wrote:
| I would've aced my chemistry class!
| ithkuil wrote:
| Hydrogen, helium, light metal, and heavy metal
| GolfPopper wrote:
| Can't we just consider the heavy metal noise?
| agentwiggles wrote:
| AC/DC published a study in 1980 asserting that rock and
| roll ain't noise pollution.
| jacquesm wrote:
| Doesn't this have to do with the formation of those elements?
| As in 'anything heavier than helium is a metal because it was
| formed in the explosion of a first generation star'? Rather
| than the chemical definition of what a metal is they probably
| should have used '2nd generation or later elements' but then
| again, computer programmers call little boxes with wires
| attached to them 'mice' and nobody bats an eye (and in fact,
| that use has now become commonplace).
| jagger27 wrote:
| With the small exception of a tiny bit of lithium made
| before star formation, yes.
| jacquesm wrote:
| By what process was that Lithium created?
| astrolx wrote:
| https://en.wikipedia.org/wiki/Cosmological_lithium_proble
| m#L...
| jacquesm wrote:
| Wow, I never knew that, thank you so much. So then, what
| are the chances of there being some primordial heavier
| than Helium atoms in your body?
|
| We may not be just 'star stuff', but some 'big bang'
| stuff as well :) (Probably would be anyway if you look at
| Helium and Hydrogen).
| credit_guy wrote:
| Ok, completely unrelated, but here's a riddle: how many
| nuclear reactions are there in a thermonuclear bomb?
|
| 1. Fission of the plutonium pit
|
| 2. Fusion of a small amount of deuterium-tritium at the
| center of the plutonium pit (designed to be a source of
| extra neutrons to boost the yield of the plutonium
| fission)
|
| 3. Fission of Lithium-6. Yep, Lithium can undergo fission
| when bombarded with neutrons. It can't sustain chain
| reaction, but it's fission nonetheless. The main idea is
| to generate Tritium, which goes into the next phase, but
| the energy generated during the fission of Lithium is
| nothing to sneeze at. Pound for pound, it generates about
| as much energy as the plutonium.
|
| 4. Fusion of the hydrogen (tritium produced from the
| previous step, and deuterium that's stored in the form of
| Lithium Deuteride from the beginning)
|
| 5. Fission of a rod of plutonium in the middle of the
| cylinder containing the hydrogen (fission is returning
| the favor and boosts the fusion reaction)
|
| 6. Fission of the uranium temper. The main point of the
| uranium temper is to be heavy and contain the nuclear
| reactions for a tiny bit of time, so more generations of
| reactions can happen, but the secondary outcome is that
| some of the U-238 nuclei will undergo fission when
| bombarded by the neutrons from the inside of the bomb.
| MauranKilom wrote:
| Giving rise to this parody of sorts:
|
| https://www.explainxkcd.com/wiki/index.php/2340:_Cosmologist.
| ..
| GordonS wrote:
| For anyone else curious, the planet in question is WASP-39b,
| which is a long way away. From Wikipedia:
|
| "WASP-39b is in the Virgo constellation, and is about 700 light-
| years from Earth"
| maxnoe wrote:
| While the statement is obviously true, relatively speaking 700
| light years is pretty close when it comes to star systems.
|
| It's only ~20 times further away than the closest star.
| Aperocky wrote:
| Correction, about 175 times further away.
| GordonS wrote:
| Yes, it's "close" in galactic terms, but in human terms it
| might as well be 7 million light years away.
| bratbag wrote:
| Depends on how our propulsion tech advances.
|
| From the local timeframe of people on the ship, a constant
| 1g of acceleration and then deceleration would get people
| there in a little under 13 years.
| ben_w wrote:
| Correct me if I'm wrong, but doesn't that have a peak
| speed of 0.9999961908c, thus a gamma factor of 362.3, and
| therefore the CMB ahead of you would be blue-shifted from
| 2.7 K to 989.1 K?
| hermitcrab wrote:
| But how do you keep up 1g of acceleration as your ship
| becomes more and more massive, the faster it goes?
| shiftingleft wrote:
| How much faster than the speed of light are we going here
| tsimionescu wrote:
| Not at all. But those 13 years are from the perspective
| of the people on the ship (also, from. Their perspective,
| the distance they travel is much much smaller). From the
| perspective of people on Earth, the ship arrives on that
| planet many thousands of years later.
|
| Edit: actually, from the perspective of people on Earth,
| it will roughly arrive 700+1 years later.
| DesiLurker wrote:
| coolworlds did a video on constant 1G acceleration travel
| : https://youtu.be/b_TkFhj9mgk
|
| bottomline, you get progressively closer to speed of
| light and time slows for you so you can cover larger and
| larger distance in local frame. problem is finding this
| 1G drive.
| hansvm wrote:
| It's close enough to be useful for generational ventures,
| and in terms of one-way travel time, it takes much less
| than 700 years from the perspective of the ship to traverse
| that distance.
| simonh wrote:
| Only if the ship is travelling at close to the speed of
| light, and we have no reasonable technology likely to be
| able to achieve that, especially for large vehicles.
| tsimionescu wrote:
| > in terms of one-way travel time, it takes much less
| than 700 years from the perspective of the ship to
| traverse that distance.
|
| Only if either cruising at a large percent of the speed
| of light, or with constant acceleration. Neither of these
| is achievable with any technology we know exists, but
| neither is ruled out by current physics either.
| hwillis wrote:
| If we can go 1% the speed of light, a 70,000 year journey
| is roughly the length of time humans have been living in
| shelters. It's an extremely long time, but it's firmly a
| social and technical problem. The people who step off that
| spaceship will have nothing in common with Earth, and even
| if they spend 95% of their time in suspended animation not
| aging, they may very well not even speak the same language
| that their ancestors did when they left here.
|
| A 7 million year period is very different. Humans split off
| from chimpanzees 7 million years ago. The people that step
| off that ship will probably not be human. Even with
| radiation shielding, even with genetic engineering, keeping
| genes stable enough to stay compatible with current humans
| is... unlikely. It's easy to _say_ they could just have DNA
| on file, but the actual reality of that challenge is mind-
| boggling. How do you handle a space ship where you have to
| account for _wind erosion in the hallways_?
| daniel-cussen wrote:
| People think about space travel exactly in the same terms
| as the History of European Colonialism. Like exactly.
| Every first contact movie "take me to your leader" is
| right out of the letters to the king written by Hernan
| Cortez and Francisco Pizarro, looting the Aztec and by
| far the most gigantic, the Kechwa fortune after taking
| the Inca hostage. That's like 200 years of Chile's
| current gold production, and this is a mining country
| with modern technology to the point it exports eg
| explosives for mining. Just an insane amount of gold
| whose accounting was not possible to do correctly. Like
| doing the accounting of a casino from the movie _Casino_.
| Gold like it was iron ingots. Fucking stupid stupid
| amounts of wealth, all for going overseas.
|
| So people think, OK, who plays the Europeans? Some movies
| say Earthlings do, other movies say aliens do. Either
| way, plunder and pillage. Like one movie, very
| enlightened, said the aliens just wanted our gold. That's
| wantable. But like think of it in terms of apes, like a
| primatologist. Aliens would be going somewhere with shit
| technology right? Well the real reason would be to get
| our nice biosphere, before we wreck it long-term
| ourselves. That they could want. So, for a rough handle
| for alien's interest in humans, look at primatology or
| study of cetaceans. Yeah we spend trillions on space
| travels, rockets, telescopes. I doubt we've even spent a
| billion on primatology. Cetaceans I think has cost more
| than a billion. There's just way more money and brains in
| whales than apes.
|
| I think space colonization will be similar to European
| Colonialism but only for the Solar System. After that, it
| sucks. And it doesn't stop sucking for at least 700
| light-years.
| ben_w wrote:
| > People think about space travel exactly in the same
| terms as the History of European Colonialism. Like
| exactly.
|
| This I agree with.
|
| > I think space colonization will be similar to European
| Colonialism but only for the Solar System.
|
| This I disagree. Without von Neumann machines, at best
| the initial colonisation of the Sol system will be like
| whichever human first found Iceland or Greenland, but
| only if they got there via a shipwreck.
|
| If we do get von Neumann replicators soon enough to avoid
| that, we may just Dyson this system and go directly to
| every galaxy in our future light cone.
| daniel-cussen wrote:
| The von Neumann machines are a process. It has many
| different organs. von Neumann worked on the brain in
| particular, that was a big bottleneck and still is,
| others eg Henry Ford specialized in an analog of the
| muscle. The Industrial revolution at one point
| specialized in textiles, one of the many many things
| performed by the fingers of the only real unique organ
| humans possess, the human hand. But it took a huge amount
| of fingers finging, like people would spend so so so much
| time weaving, slaving away at the loom, replacing that
| function with machines to give everyone good clothes
| (everybody has good clothes), was worth I think...two
| fingers per person. It was also a finger-intensive
| process, the machine could remove fingers, machines still
| do, that's why that one industrialist specialized in
| hiring child labor for the machines and visited orphanage
| after orphanage, saying hey children have small fingers
| that's perfect for these machines.
|
| And that ties into why we have ten fingers, like we have
| thirty-two teeth at adulthood and need some removed, that
| is after losing the first round of teeth in childhood.
| There's replacements. Some monkeys used for experiments
| need to be kept in cages, watching cartoons (meant for
| human children, same ones, they don't make special
| cartoons for the monkeys), and the monkeys (I wish I
| remembered what species this was) stop and stare at the
| screen, paralized. Keeps them pretty happy while they're
| isolated from each other in cages. Normally they're not
| kept in cages, except for this experiment, you know why?
| This experiment required them having all ten fingers,
| like humans, but if left hanging around as a group they
| bite each others's fingers off like in the first three
| minutes. Just to figure out who gets to fuck, basic
| pecking order, right off the bat. Ten fingers is like ten
| shirts. In _Utopia_ Thomas More...well one of his
| characters, he specifically wrote that book within a book
| to defray responsibility...said if you have ten shirts
| you are a clotheshorse. Too many clothes. Because they
| had such a huge cost. A cost of drudgery, then performed
| by the mechanical loom. That 's one organ.
|
| von Neumann machine. Organ by organ.
|
| Like can you imagine a whale telling another whale
| e=mc^2? Who gives a shit! Want a Nobel Prize you
| blowhole? Gotta keep hunting squid every day, that's the
| bottom line, philosophy (don't know the whale word for
| this) is for when both us whales are full. The human hand
| is what gives that the power it has, humans are busting
| open a bottleneck of life with our hands. I'm typing this
| with all my fingers. I couldn't do this by voice. It
| would come out different, not as spinal. In fact my hands
| are writing faster than my inner monologue. They
| absolutely have a life of their own.
|
| Yeah shipwrecks. For sure there were people crossing the
| Atlantic via shipwreck, they could flat-out never make it
| back. Even then people could be disbelieving and say, "eh
| old Mariner's tale.". Nobody buys those stories, nobody
| buys the stories about sea monsters (whales intelligently
| ramming ships crossing their territory), everybody thinks
| sailors are full of shit. That's what happened with the
| Vikings, who did cross the Atlantic, but couldn't exploit
| it nicely (from the explorer's point of view) like the
| Hispanics. It's also because Vikings crossed before the
| Black Death, so they weren't infected with smallpox.
| Bioweapon. Back to the shipwrecks: this fact, that you
| can't make it back, was critical to the Atlantic Slave
| Trade: Africans had no hope of returning to Africa, once
| an African sold an enemy off to the Europeans headed for
| America, he had no worries of seeing that enemy return to
| Africa. That was key. A Colonial historian told me this.
___________________________________________________________________
(page generated 2022-08-27 23:00 UTC)