Water Found On a Potentially Life-Friendly Alien Planet (nationalgeographic.com) 71
Data from the Hubble Space Telescope have revealed water vapor in the atmosphere of an Earth-size planet. "Although this exoplanet orbits a star that is smaller than our sun, it falls within what's known as the star's habitable zone, the range of orbital distances where it would be warm enough for liquid water to exist on a planet's surface," reports National Geographic. From the report: The discovery, announced this week in two independent studies, comes from years of observations of the exoplanet K2-18b, a super-Earth that's about 111 light-years from our solar system. Discovered in 2015 by NASA's Kepler spacecraft, K2-18b is very unlike our home world: It's more than eight times the mass of Earth, which means it's either an icy giant like Neptune or a rocky world with a thick, hydrogen-rich atmosphere. K2-18b's orbit also takes it seven times closer to its star than Earth gets to the sun. But because it circles a type of dim red star known as an M dwarf, that orbit places it in the star's potentially life-friendly zone. Crude models predict that K2-18b's effective temperature falls somewhere between -100 and 116 degrees Fahrenheit, and if it is about as reflective as Earth, its equilibrium temperature would be roughly the same as our home planet's. "This is the only planet right now that we know outside the solar system that has the correct temperature to support water, it has an atmosphere, and it has water in it -- making this planet the best candidate for habitability that we know right now," University College London astronomer Angelos Tsiaras, a coauthor of one of the two studies, said during a press conference.
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1/7 AU
Better this way?
The distance from Earth to Sun is known as Astronomical Unit and it's a standard unit of distance on solar systems scales.
Definitely better! (Score:3)
I would have loved to see that in the article. Aside from the units of measure, I would have settled for not having the "times closer" as an inverted form of "times further". The measurement could be in gigasmoots for all I care. Just use correct terminology.
(smoot unit: https://en.wikipedia.org/wiki/... [wikipedia.org])
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But do they have a hot tub?
"Data from the Hubble Space Telescope have revealed water vapor in the atmosphere...[with an] effective temperature ... somewhere between -100 and 116 degrees Fahrenheit."
Dude, the entire planet could be a hot tub! If that's not reason enough to send a probe, there will never be one.
The aliens are all dead already (Score:2)
revealed water vapor in the atmosphere
The folks there were obviously vaping.
They must have all died from that.
Not all that life friendly (Score:5, Interesting)
Red dwarfs have a nasty habit of flaring quite frequently and being that close to its star it could well be tidally locked by now so one face of the planet could be roasting and the other an ice sheet with only a small habitable part either side of the terminator. Which moves as the planet orbits.
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Life usually finds a way though.
Some space fairing, mycelial eating tardigrades for example.
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A sample size of N=1.
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However the planet being much more massive possibly with a much thicker atmosphere, (and possibly larger magnetic field) it can protect itself from increased flares.
Or it could be a lifeless ball of water. Like how earth was billions of years ago. However without much evidence of life outside of earth, we are unsure if earth is a special outlier, or life is a common chemical reaction when temperatures and pressures are right.
Normally for unknown information, we normally take what we see and assume it is a
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The problem with a much thicker atmosphere is it retains a lot of heat. I wouldn't be surprised to find that this planet is rather similar to venus with the only water vapour being in very high clouds and the surface a furnace.
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Depends on the atmosphere - CO2 (96.5% of Venus's atmosphere) and water vapor scatter a lot of thermal IR, so they cause a lot of heat retention. Oxygen, nitrogen, and many other common gasses, not so much.
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True, but CO2 is heavy stuff and much less likely to be blown away than lighter gases in a strong solar wind if the planet doesn't have a magnetic shield. Though perhaps the prevalence of CO2 on venus, mars and the early earth in our solar system is a fluke to do with the initial composition of the cloud it formed from and elsewhere its less common.
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True, though that has nothing to do with heat retention.
There's also a very limited number of gaseous molecules that you can make from the "big four" common atoms (CHON) that are long-term stable at warm temperatures and high solar radiation levels. Pretty much just N2, CO2, and H2O spring to mind. As solar radiation falls, methane, ammonia, and other such energy-rich molecules become more stable, but they're basically nonexistent in the inner solar system where sunlight degrades them into the lower-energ
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It's a super-Earth with a thick atmosphere, so we can be pretty certain that it conducts heat fairly effectively around the planet. It's also possible/likely considering the amount of water detected that it's an ocean world. Creatures living deep in a worldwide ocean are quite well protected from radiation flares and temperature swings.
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Venus has a thick atmosphere, is only just outside the habitable zone and rotates extremely slowly - look how that turned out.
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Or not. If it were tidelocked, the habitable part does not move as the planet orbits, since it's always the twilight region in all parts of the orbit. Note our moon as an example of tidelocked - the same face is always pointed at the primary....
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Yes you're right, my mistake.
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Journalism for Science always stink.
This story is the Hypothesis of the day, with some initial supporting evidence.
Now if this finds to be untrue, or the evidence didn't really fall into place. The general public will go SEE SCIENCE IS A BUNCH OF BULL. While Science itself was fine, it was just the media publishing trying to get something Clickbatey out to make money.
here we go (Score:2)
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Don't use rockets. Or beanstalk space elevators, unless we find something with far greater tensile strength than carbon nanotubes.
There's lots of other alternative launch systems that don't suffer from nearly the same problems - though they mostly require expensive large-scale infrastructure - though not nearly on the scale of a beanstalk. Something like the Airship-to-Orbit plan would probably still be effective though, especially if supplemented by a skyhook to deliver the final boost to orbital speeds.
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Re:here we go (Score:4, Insightful)
My daughter and I were discussing this on the drive to school this morning. I haven't done the math yet, but I'm spitballing it at 6 times Earth gravity. That would make you about a thousand pounds. That would mean very short mountains on the planet, and aquatic macrolife would have to be much more complex before it could crawl out onto land. The development of flight would be much more challenging, so its possible that intelligent life there, if any, may not be spacefaring.
The radio transmissions from the 1938 Olympics should reach there in 2048. Today, in between meetings, I'm going to work on "Could we hear that with Aricebo if we were listening?" My gut instinct is we probably couldn't.
If they have FTL travel 2048 might be an interesting year.
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Today, in between meetings, I'm going to work on "Could we hear that with Aricebo if we were listening?" My gut instinct is we probably couldn't
I remember reading somewhere that Arecibo would be what you would need to pick up our TV signals from orbit of Pluto.
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Your gut instinct is right. The 1938 Olympics wouldn't even make it to Alpha Centauri and probably not even to Pluto. Interstellar radio communication is non-trivial. It would almost never just happen by accident like that. It requires huge amounts of power and a specific target to do interstellar communication. If only it were so easy.
You have to actually aim and it has to be at the right frequency to not be completely attenuated by the N2 and O2 atoms in our thick soup of an atmosphere. 9-12 Ghz seems to
1938 Olympics (Score:2)
Why are we using that? Was it an especially strong broadcast? I'm just thinking perhaps not the best example of first contact having to explain who Hitler was...
Re: 1938 Olympics (Score:2)
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If it's the same [average] density then 8x the mass implies 8x the volume which implies 2x the radius. Gravity follows an inverse square law, so it's 8x for the mass over 4x for distance [from the centre] squared.
Roughly double,
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There's not enough information - you also need to know the planet's size. If Earth were twice the size with the same mass, you'd way 1/4 as much on the surface (g = G*M1/r^2)
Assuming a similar density to Earth, the planet would be twice the diameter (2x the radius = 8x the volume = 8x the mass at the same density), which would make the surface gravity 8/(2^2) = twice as high, and you'd weigh 330lb
Surface gravity isn't actually nearly as relevant to rocketry as you might expect though - most of your effort
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What water problems? Most of our planet is water. If you have a water problem then it's a YOU problem.
Nuke it (Score:2)
Nuke it before the little fuckers know we even exist.
Re: Nuke it (Score:3)
Water vapour? (Score:3)
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You can't. But they pretend they can through spectral analysis. It really is a wild guess. They don't really even know the size of the planet. At this point it becomes a religion.
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This isn't science, it is speculation. It is 111 light years away.
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Isn't "111 light years away" also just speculation at this point? I mean if you are going to interpret pixels on a screen as being a planet 111 light years away, why can't you also accept the same pixels as representing water on that planet?
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This isn't science, it is speculation. It is 111 light years away.
It's useless speculation.. 111 light years away is too far to even communicate with, much less visit. Until we can travel faster than light, it doesn't matter...
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Re:Water vapour? (Score:5, Informative)
Basically the same way we know what the sun is made of - spectroscopy. Every atom and molecule has it's unique spectra - very specific frequency bands of light that it will emit when energized, or scatter when light passes through it, based on the various ways it can store energy - vibrating molecular bonds.
Spread light from the sun through a prism, and you'll see narrow dark bands where atoms in the sun's atmosphere are scattering the light - the exact frequency of those bands gives you a "fingerprint" that you can then match up against combinations of known elements - e.g. if the "hydrogen line" is present you know there's hydrogen, because nothing else absorbs at quite that frequency - and then you know that many of the other lines are less dramatic/distinctive parts of hydrogen's fingerprint - unless any of those lines are considerably stronger than they should be, then you know there's something else there that's also absorbing at that frequency. It's sort of a puzzle of finding the combination of fingerprints that add up to what you see - but the fingerprints are distinctive enough that it's usually pretty straightforward for something like a sun, where energies are too high for molecules to exist. Molecules are a lot more mechanically complex, and have much "blurrier" fingerprints as a result, (and there's far, far more kinds of molecules than kinds of atom) so it makes it more challenging.
For interstellar planets - first you need to have characterized the sun's fingerprint really well, and then the planet has to pass directly between you and the sun so that it blocks some of the sun's light, causing it to dim very slightly. The planet itself will block everything equally, but the atmosphere will only block the fingerprints of the molecules in it. It'll be a tiny difference against the background of the unblocked sun, but our instruments are sensitive enough to pick it up. Then we do the same "fingerprint matching" on that tiny extracted signal. It's not perfect, because those blurrier molecular absorption lines are easier to mis-identify, but we can make a pretty solid estimate of the primary gasses present.
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Oops, just noticed I left off a piece of that first paragraph - should be
"...vibrating molecular bonds, atomic electron-shell energy differences, etc"
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"Every atom and molecule has it's unique spectra "
Every apostrophe has its unique use as well. And you are assuming that what is emitting light "over there" is behaving the same as "over here". It's just speculation. It's quite likely correct, but it's a bit early to pack your bags to go for a visit, which too many nerds seem willing to do.
At that point, it becomes a religion.
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You have no direct proof of that. It's just an assumption. It's a good one though.
Like I said, if you read what I wrote: " It's just speculation. It's quite likely correct"
"Light isn't going to be the same "over there" as it is here, right?"
Well, there is this thing called "blue shift" or "red shift", so at first glance, yes, it is not the same.
"I knew the school systems around these days were getting worse, but I didn't think it was quite THAT bad."
Where did you learn that clumsy turn of phrase? Space?
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1. If you are willing to go to this "things could be different elsewhere, it is all just speculation" against the evidence, then the red- and blue-shift you state as evidence for light being different is also just speculation. It's the same science, you can't have it both ways.
2. Our knowledge of red- and blue-shift is based on the same theory of spectral lines that is used to determine the composition of this planet's atmosphere, like @Immerman explained.
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You know of a direct proof that universal constants, etc. are in fact universal? Please do share, because last I heard that's one of the things astrophysicists are actually a little dubious about. One of the things that would resolve some inconsistent measurements would be if at least some of the "constants" varied over time - and if they can change over time, there's no particular reason to assume they can't also vary over space.
We can't know for certain without actually jumping a few thousand galaxies ov
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You know of a direct proof that universal constants, etc. are in fact universal?
You do know that science isn't math and there isn't such a thing as proofs right? There's evidence in science, not proofs. That's math.
Please do share, because last I heard that's one of the things astrophysicists are actually a little dubious about.
By your logic no scientific theory actually exists. We have evidence that the General Theory of Relativity works. It is not a direct proof.
One of the things that would resolve some inconsistent measurements would be if at least some of the "constants" varied over time - and if they can change over time, there's no particular reason to assume they can't also vary over space.
Citation Needed
We can't know for certain without actually jumping a few thousand galaxies over in several different directions and performing some in-depth experiments.
Citation Needed.
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>So your entire argument rests on your assertion that you don’t know any direct proof. Even though there is.
I know there's no such things as proof in science - you're the one who claimed such a proof exists.
We have lots of direct evidence that GR works in our local space, yes, absolutely. And a fair bit of much less direct evidence that it works the same way in other places. And a whole lot of evidence that it's either fundamentally flawed at large scales, or 96% of the mass of the universe is st
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>And you are assuming that what is emitting light "over there" is behaving the same as "over here"
To a very, very limited extent - a whole lot of confirmation of (sub-)atomic physics is inherent in spectroscopy.
It's an almost-sure thing that all stars are composed almost entirely of hydrogen - there's just not enough of anything else to build star-sized objects out of, plus physics would have to be *very* different to allow a small star to fuse helium in large quantities, much less anything heavier.
So, k
Ready (Score:2)
Fuel up the rockets, let's go!
Couldn't be worse than this shithole planet we're living on right now.
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This planet's fine, and since we evolved to be optimized for this one we'll almost certainly never find one better suited to human life, even if we could somehow reach them.
The shithole is all on us, and what we're choosing to do with the planetary oasis that birthed us.
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Fuel up the rockets, let's go!
Couldn't be worse than this shithole planet we're living on right now.
Oh sure.. At 1% C (which is pretty dang fast for us), it's going to take longer than recorded history to actually get there.
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No, the original paper says "with effective temperature between 200 K and 320 K", it was converted by nationalgeographic.com
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""There are still scientists with a modicum of self respect that use this archaic unit of measurement?"
Yes. Every single weatherman/meteorologist in the USA.
I know the terrorists want us to use Kelvin, but it ain't going to happen. #merica!
Or, more technically, ... (Score:3)
"Although this exoplanet orbits a star that is smaller than our sun, it falls within what's known as the star's habitable zone, ...
It's not earth-size though (Score:1)
TFA says it's 8 times the mass of earth, but then suddenly calls it earth-size in the link to the paper, where it is not claimed to be earth -size
Water, water everywhere (Score:2)
Water is ubiquitous. It's even found in some sunspots.
Wake me when they find free oxygen in the atmosphere of an exoplanet.
Anyone else thinking what I’m thinking ? (Score:2)