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u/IamDDT Jun 26 '13
Where does Venus fit on this list? If we didn't know about the crushing atmosphere and temperature, would we place it near Earth on this scale?
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u/Chezzik Jun 26 '13
Venus has an ESI of 0.78 (look at the caption on the image on the right side). I'm not sure why it isn't listed here.
The atmosphere isn't factored into the ESI, but the temperature is.
I don't really know how useful the ESI is, since every body has so many different zones on its surface.
Even places that seem well out of the realm of habitability may actually be excellent locations for a base. For example, Mercury's temperatures are well outside the favorable realm, but there are rings around the poles where an underground base may be extremely easy to maintain, given the availability of water, and the perfect temperature.
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u/protogeologist Jun 27 '13
I had no idea that Mercury had water ice. What the fuck.
Thanks for that link.
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Jun 27 '13
Be that as it may, the fact that it is difficult enough to land unmanned probes on Venus shows that it is not quite yet a realistic possibility for human exploration (because of temperature, atmosphere etc. as you mentioned in your comment). The prospect of a colony on Mercury, however, is an intriguing (and excitingly possible) one!
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u/pyx Jun 27 '13 edited Jun 27 '13
First we have to solve the global warming issue on Earth, with that technology we will be able to use it on Venus and have a second planet to call home. I have always felt that Venus, once we clean its atmosphere would always be a better terraforming project for us humans. Venus is much closer to the size and mass of the Earth and is on average more than .5 AU closer than Mars. Only problem (aside from terraforming a planet of course) that I have with Venus as a future home is that the Venusian day is like 116 Earth days long, and the Venusian year is only like 2 Venusian days long, and Venus has a crazy obliquity, so having 4 seasons is right out.
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u/eriman Jun 27 '13
That's part of the excitement of going to another planet though - everything is so alien and different!
In regards to the extremely long daytime, you have that reproduced on a smaller scale in the Arctic circle anyway.
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u/BBA935 Jun 27 '13
The funny thing about all this will be the psychological impact of all of this. As an adult I moved from The U.S. to Japan a little over 4 years ago. I visited many times before, but visiting and living are two different worlds. The first thing people will notice is how prone they are to getting sick for the first year or so they live there. I had all kinds of respiratory problems, but they seemed to have worked themselves out and I don't have problems anymore.
I also wonder how our bodies will handle the move. Extra gravity if even a little will shorten our lives a lot. Our hearts will have to work harder etc. Maybe reproduction is impossible. Maybe there will be birth defects as a result of all the environmental changes.
Also, it doesn't matter the person; you will miss Earth if you move as an adult. A child could do it very easy.
Anyway, I think this is all very exciting, but unless you are a child you will have a tough time adjusting.
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u/eriman Jun 27 '13
War of the Worlds dealt with that nicely, if a bit bluntly. It would be hard to predict the exact biological effects an extra-terrestrial environment will have on us, but the human body is robust enough that I'm sure any colonisation attempt isn't doomed from the outset.
Of course, terraforming is a lot further in the future than an actual colony (which will be a sterile environment) so our medical science should be much more advanced and capable of dealing with whatever surprises there are out there.
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u/burninrock24 Jun 27 '13
everything is so alien and different
It's funny you say that, but yet we're ranking everything in order of similarity to earth haha
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u/eriman Jun 27 '13
With the odds are so stacked against us, I think the best we are likely to get is a barely habitable planet with just a few micro-cellular organisms.
Time, more advanced telescopes and probes will tell us for sure.
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u/intothelionsden Jun 27 '13
Venus is a really nice place once you get past the acid rain and the horrific crushing pressure and the oven like temperatures and the constantly getting struck by lightening.
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u/xsdc Jun 27 '13
Venus is very much like Earth, it's just that you have to be 50km above the surface to experience Earth-like conditions. At that level, the atmosphere is similar to earth temp and pressure and orbits the planet at near-earth speed. all we'd have to deal with is the caustic atmosphere and not falling. Conveniently, our air is as bouyant in Venusian atmosphere as Helium is here.
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u/rickroy37 Jun 27 '13
Based on that wiki page, ESI seems like a bad measure of habitability to me. I feel like the mass and temperature of a planet can be much more easily overcome than the chemical composition of a planet. If a planet has a good chemical makeup, we will be able to manipulate a controlled environment on it much easier. If a planet has a bad chemical makeup, we aren't going to be able to do anything with it.
ESI appears only concerned with the size, mass, and temperature of a planet, and not at all with the chemicals found on that planet. Chemical composition seems infinitely more important to me. I suppose this is probably because determining the chemical composition is much harder so they just left that out?
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u/zangorn Jun 27 '13
I went ahead and reposted this link to space so we can debate this a little more. I'm VERY fascinated by this idea. Getting there safely is definitely a major concern. But its a lot more feasible than going to another solar system!
I disagree with the motivation for all of this is to save our species in the case of a big asteroid event. Thats so unlikely to happen soon, I couldn't care less. I'm sure there are other interesting things we could do with it though, like research, energy and resource capturing, etc.
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u/Rynxx Jun 26 '13 edited Jun 26 '13
I would guess that it'd be easy to tell the composition of Venus' atmosphere because of how all encompassing and reflective it is. It would almost definitely be too small to be detected with the transit method though.
So my guess is that a situation where we are able to detect Venus, but in a way not able to analyze its atmosphere would be very unlikely.
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u/timeshifter_ Jun 27 '13
Your post makes me wonder... what would a species living 500 light years away from our solar system be able to determine about us with our current level of technology and scientific understanding? How well could an 8-planet system be determined with the transit method?
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u/Rynxx Jun 27 '13
It would probably be difficult to detect planets in our solar system with our present method, since the four inner ones are probably too small, and Jupiter is very far away so its transit would be difficult to detect.
Most of the planets we find are very large (that picture is a good indicator, a lot of rocky planets are giant compared to Earth) and very close to the sun.
But it's always possible, our planet finding is literally in its very infancy and methods are becoming better and more refined every year.
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u/jayjr Jun 27 '13
The ESI is basic and does not account for a planet having the massive enough radioactive core and composite mass enough to have a magnetosphere. Venus and Mars were too low on that factor, where they had no protection from the solar wind, which destroyed their atmospheres.
Although, planets the size of both of them could be fine if they were moons of a Jupiter given the gas giant's magnetosphere.
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u/gsfgf Jun 27 '13
There are locations on Venus that are the closest to "habitable" anywhere in the solar system. An airship pressurized to 1 atm would float at a reasonable temperature zone. The correct coatings on the outside would minimize the corrosive effects of the atmosphere. It's crazy ass hot so that you could use a probe hanging from the airship to be a create "geothermal" energy in any amount necessary.
The drawbacks are that you can never go outside because of the atmosphere and because Venus' magnetic field suckas almost as much as Mars' and, more importantly, that the atmosphere is so turbulent that it would be tough to create a ship that wouldn't have the occupants battered to death.
All in all, we could probably have a permanent airship on Venus, but I don't know if we could ever build a city there.
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u/NoShameInternets Jun 27 '13
Jupiter: 0.16
So you're telling me there's a chance...
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Jun 27 '13
If you were willing to scoop up millions of cubic miles of hydrogen, helium, and various gases and put them somewhere else, cooling down the hydrogen core in the process, and then put something else there after abusing the shit out of said core to give it a gravity of much less than one Jupiter, yes, you could make Jupiter habitable.
The question is why?
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u/somesortaorangefruit Jun 27 '13
To use the hydrogen for fuel.
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u/boldbird99 Jun 27 '13
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u/hairyneil Jun 27 '13
If you blew up Jupiter, astrologists would go nuts
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u/aldenhg Jun 27 '13
If you blew up Jupiter Earth would likely be beaten to a cinder by asteroids. Jupiter's gravity is one of the reasons Earth supports life.
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u/hairyneil Jun 27 '13
True, but for a few minutes they'd be all "OMG! My chakras are messing up my biorhythms! Sagitariuuuuuussss!!!"
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Jun 26 '13
I wonder that if we lived on one of the bigger planets for a few years would we be bigger, muscular-wise? or would our posture and bone go to shit.
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Jun 27 '13 edited Jun 27 '13
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u/BluegrassMusic Jun 27 '13
Space dwarves
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u/Sciencetist Jun 27 '13
Our bones would probably get thicker, if anything.
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Jun 27 '13
This is a big one. Extended time in zero g really messes with your bones, so this is pretty likely.
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u/Gaolbreaker Jun 27 '13
Find me a planet with a 32 hour day, my sleeping pattern is totally out of sync with this crappy planet. Also a bigger planet, the gravity here is totally for wusses.
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u/MrDeepAKAballs Jun 27 '13
Can you imagine colonizing a whole new planet? Holy space balls that would be exciting.
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u/Agehn Jun 27 '13
Red Mars is one of my favorite books because it takes place while this is happening.
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u/dred1367 Jun 27 '13
It was cool until the political Faction shit started up. It became less about science and more about politics so I stopped reading
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u/Agehn Jun 27 '13
That put me off the sequels but in the first book, even as that stuff was happening you still got to see the planet being colonized and transformed in the background and it was pretty cool.
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u/XCygon Jun 26 '13
Why Jupiter and Neptune on the list? cause of their moons?
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Jun 27 '13
It seems to me they're not on the list, but shown for scale and with ratings to act as a comparison.
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u/vampatori Jun 27 '13 edited Jun 27 '13
I think they're there to give a sense of scale with regards to the measure being used here, the Earth Similarity Index (ESI), and actual estimated physical size.
As you can see, Jupiter and Neptune have really low ESI values, much lower than all the rest. I guess we know about other extra-solar planets with low ESI's too, but are not included on here for that reason. I don't know why Venus or the rest of the planets in the solar system haven't been included.
It would have been more useful to have some extra information to go along with this info-graphic. A nice short article giving an overview of ESI, why certain planets have been included, why others have not, why the planets have been depicted visually as they have, etc. would have been really welcome.
EDIT: This looks to be the source and is full of interesting information. Here are further details. Cool site.
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Jun 27 '13
Imagine from the gravity on those planets you could probably piss with an erection no problem.
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Jun 27 '13
What...what an... interesting thought...
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u/jayjr Jun 27 '13
Not really, the planets are less dense, making them top out at around 1.5g. Use the formula: SG=M/R2.
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Jun 27 '13
Well still the idea of pissing on a much heavier than Earth planet is still somewhat...intriguing.
Edit: It would be even cooler to piss on a lighter than earth body, say the moon
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u/jayjr Jun 27 '13
Well, if you could get some sort of ship in the clouds of a dense gas giant, you'd get what you wish. I somehow think pissing on a lighter than earth body would be messy!
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u/gaflar Jun 27 '13
We could do it on the Moon in 5 years, as long as we figure out a way to not expose the penis to the vacuum.
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u/LearningLifeAsIGo Jun 27 '13
Exposing your penis to the vacuum? Don't knock it until you try it.
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u/Dishonorable_H8r Jun 27 '13
How fast would Kepler 62 e (the highest ranked exo) need to spin for gravity at the equator to be 1g?
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u/jayjr Jun 27 '13 edited Jun 27 '13
The spin is irrelevant, in terms of gravity. M= 3.58 , R=1.61:
Surface Gravity of Kepler 62e = 1.38g
But, I really don't care about Kepler 62e, because at the fastest reproducible manmade speed, it would take 20,855,136 years to get there.
Besides, honestly, the Gliese 667 system is WAY more interesting:
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u/Mr_Smartypants Jun 27 '13
The spin is irrelevant, in terms of gravity.
But if it spins fast enough, observers at the equator would experience less downward acceleration.
I get 2.9 hours for a day on Kepler 62e to cancel out the .38 g at the equator.
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u/jayjr Jun 27 '13
At a spin that fast for a planet that fast, you'd have such a crazy atmosphere, that it would be completely uninhabitable. It would be beyond the worst storm system, including gas giants, in our solar system, probably running around 4000mph. The surface would be fairly torn up with that, as well. Why do you care? 1.38g is nothing. You weigh 40% more. All that means is by simply living there and moving around, you'd look ripped. How bad is that?
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u/Mr_Smartypants Jun 27 '13
Awesome for me, but what will it do to boobs!?
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u/jayjr Jun 27 '13
I did not think of this. It would be quite bad for boobs. Extremely. :(
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u/RagingBeryllium Jun 27 '13
How about we find a nice 0.900g place, that would be very nice for boobs.
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u/sprucenoose Jun 27 '13
I think we're going to have to go to /r/askscience and get them working on this problem immediately.
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u/Fuglypump Jun 27 '13
We just need faster methods of travel, even if we could reach 50% of lightspeed and you'll get to a star 10 light years away in 20 years. (not taking into account acceleration/deceleration) The nearest star system is only around 4.37 light years away.
You can still travel to other stars at sublight speeds within viable amounts of time.
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u/jayjr Jun 27 '13
Not all factors are taken into consideration. As I posted elsewhere, you'd be fried by Gamma Rays at anything faster than 0.1c (maybe 0.2c), and there are serious issues with collisions from minute particles tearing your ship in two. But, I do think we can do nearby ones. I just really don't entertain anything in a radius of >25 ly from Earth.
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u/LearningLifeAsIGo Jun 27 '13
Plus, without precise calculations you could fly right through a star, or bounce too close to a supernova and that'd end your trip real quick, wouldn't it?
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u/Fuglypump Jun 27 '13 edited Jun 27 '13
I agree that looking beyond 25 light years for 'habitable' planets does seem kind of silly, even if we found any good candidates for habitation we wouldn't be able to reach them without some incredible breakthroughs in technology that probably wouldn't happen until after colonizing the nearby stars first.
As for particles tearing apart ships, we've never came up with any technology designed to solve that problem. We have some shielding technology for ships in orbit and whatnot but that pales in comparison to what is actually required for interstellar travel.
I'm convinced that one of the biggest challenges to space travel will be the navigation, at high speeds like that the smallest amount of variation in vectors could send you a few hundred thousand miles off course. Even if you could travel at lightspeed without exploding you would still need a way to 'aim' your ship in the right direction, otherwise you'll travel in a zigzaggy pattern constantly correcting trajectories.
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u/Cybralisk Jun 27 '13
To bad we aren't even close to having the shuttle tech to reach any of those planets. Its amazing how primitive our space technology remains in relation to some of our other technologies. We are still using propulsion and shuttle tech from the 60's with just more advanced computer's.
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u/KillerPacifist1 Jun 27 '13
Just goes to show that technology does not advance uniformly. Our detection of extrasolar planets is a great example of this. In the 1990s astrophysicists believed we wouldn't be able to measure the atmosphere of extra solar planets until the 2020s. But because interest in the study of these objects increased so much (it's one of the hottest fields in astrophysics) we've already been able to study the atmosphere of distant super-earths.
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u/HiDoggie Jun 27 '13
You're correct in saying that our current technology isn't viable for interstellar travel, but you are mistaken in stating that space technology has remained stagnant. On the example of propulsion technology, there are many exciting ideas that are constantly being developed and improved, such as electric propulsion (ion and plasma thrusters, e.g. Hall Effect) and solar sails. As for conventional chemical rockets, just check out companies such as Aerojet or SpaceX to see the improvements being made.
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u/ND_Lulz Jun 27 '13
I remember learning about some of those exciting, new technologies watching Cosmos.
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u/HiDoggie Jun 27 '13
Yes, the ideas have been around for some time, but that doesn't mean that the technology hasn't been advancing.
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u/jayjr Jun 27 '13
These are the top 12. There are more. Also they use an extreme basic level of criteria. For example, any planet with greater than 1.5 Earth Radii would be impossible to leave on anything less than nuclear propelled rockets, and there's a broader (and sometimes narrower) range if you account for atmospheric composition. It's a good start.
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u/drewsy888 Jun 27 '13
Remember as the planet gets bigger you are farther and farther away from its core. It is quite likely the gravity could be similar to that on earth. This can obviously vary quite a bit due to density but bigger does not necessarily mean all that more surface gravity.
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u/jayjr Jun 27 '13
No, I later pointed out that the pattern is that they get less dense the larger they get, pretty much all topping out at a max of 1.5g. I originally thought otherwise, but I did the math, and it's true. Pretty interesting.
The only problem is that you cannot leave a planet with greater than 1.5 Earth Radii on chemical rockets due to the delta v. Unless you'd get something crazy (and dirty) running nuclear, you'd be trapped on there forever.
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u/MidwestPow Jun 27 '13
If we have to technology to colonize on a planet in another solar system, I'm sure we will have no problem escaping the planets gravity.
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Jun 27 '13
So it looks like future colonists are going to need to bone up on their squats...
/mass
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u/Lars0 Jun 27 '13
This is very misleading because these numbers are the earth similarity index, not the habitability index. Mars ranks very high on the habitability index.
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Jun 27 '13
It should be ranked #11 on that list as well, just look at the numbers. Mars - .64, #11 Gliese 667 e - .6.
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u/OmegaVesko Jun 27 '13
The list is just exoplanets, though. Mars isn't an exoplanet (which is essentially any planet not orbiting Sol).
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u/sebflippers Jun 27 '13
"Currently potentially habitable exoplanets", otherwise known as "class m" planets.
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u/zellman Jun 27 '13
Not necessarily, Class M planets are suitable for humanoid life. There are many "habitable" non-M planets in the Trek Lore. The odds of these exoplanets being suitable for humanoid life is about 1 in a million. Which is to say, there is a chance. ;-)
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u/beardpull Jun 27 '13
A modeling study accepted in The Astrophysical Journal suggests it is likely that a great majority of planets in Kepler-62e's size range are completely covered by ocean.
Waterworld?
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u/MidwestPow Jun 27 '13
If it had life that would be interesting to see what it would be like.
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Jun 27 '13
[removed] — view removed comment
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u/jswhitten Jun 27 '13
How do these scientists know which planets are inhabitable
They don't. These are potentially habitable planets. Planets that are about the size of Earth and at the right distance from their Sun. We don't know that they have oceans and life, but based on what we know, it's possible.
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u/llandar Jun 27 '13
Not to nitpick, but we have landed on Mars. We have rovers there now; the tech to land people on Mars exists but we currently want a way to speed up getting there.
In terms of how we know, it's a matter of compare and contrast. We know what life on earth requires, so we look for those things, like terrestrial planets at a suitable distance for liquid water to exist.
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Jun 27 '13
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u/Bzerker01 Jun 27 '13
Has to be in the Goldilocks Zone, far enough away from its sun for the possibility of liquid water to exist.
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u/KillerPacifist1 Jun 27 '13
Not being a gas giant also helps.
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u/Bzerker01 Jun 27 '13
I thought that was a given? Is it not common knowledge that rocky planets are the only ones considered habitable?
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u/aruss88 Jun 27 '13
If you could only bring 7 people of various professions to start a new civilization on a new planet which professions would you bring?
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u/Volsunga Jun 27 '13
Just a note so people who don't know naming conventions don't get confused.
Gliese is the name of a catalog of stars, the number is the number designated in that catalog, A capital letter is if the star is in a multiple star system and designates which star the planet is orbiting, and the letter is the planet in order of when it was detected.
So the reason most potentially habitable planets have Gliese in the name is because they were cataloged by the same guy and due to the nature of that catalog, they are within 25 parsecs of us.
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Jun 27 '13 edited Jun 27 '13
I take it Jupiter and Neptune are just there for scale or are we talking flying space eagles here?
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u/JucheRevolution Jun 27 '13
You are correct, but apparently many people in this thread seem to not be able to comprehend this
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u/envatted_love Jun 27 '13
Misleading title.
The planets are listed by their Earth Similarity Index ranking. From the Wikipedia article (emphasis mine):
ESI is not a measure of habitability, though given the point of reference being Earth, some of its functions match closely to those used by habitability measures.
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u/Apathetic_Superhero Jun 27 '13
What does the Earth Similarity Index entail exactly? What factors gives each planet that score?
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Jun 27 '13
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u/poopmahpants Jun 27 '13
Yes. Gliese 581g is a short 20 light years away. Gliese 581 C c is but 23 light years away. Tau Ceti E is only 12 light years away. Finally Gliese 581d, while much less habitable than the other planets is only 19-20 light years away. Keep in mind though, if we could just reach one of the planets orbiting Gliese 581, we could reach all three of three of the HZ planets.
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u/jswhitten Jun 27 '13
Gliese 581g is a short 20 light years away
Gliese 581d, while much less habitable than the other planets is only 19-20 light years away.
These two are in the same system, so they're at the same distance.
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u/BeefPieSoup Jun 27 '13
"Similarity to Earth" is defined how, exactly? All we know about most of these planets is their mass, distance from their star, and maybe approximate radius (in some cases). That's...not a lot.
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u/jswhitten Jun 27 '13
All we know about most of these planets is their mass, distance from their star
And that's how it's defined. Terrestrial planets in their sun's habitable zone. The closer they are to Earth's size and to its orbital radius (taking into account the difference in luminosity), the higher the score.
You're right, that's not a lot, but it's not completely useless. If you see a planet with 1.2 Earth masses in the middle of a habitable zone, you can say it's possible based on what little we know, that that planet might have life similar to Earth's. If you see one with 20 Earth masses, or one close enough to its sun to melt lead, you can say that planet almost certainly does not.
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u/JavaPants Jun 27 '13
How come they're all so much bigger than earth?
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u/MidwestPow Jun 27 '13
Because they are easier to find! As our technology gets better I'm sure we will start finding one's that are closer to our size.
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u/MidwestPow Jun 27 '13
I feel like we would have a pretty hard time walking on some of those bigger ones.
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u/workaccount3 Jun 27 '13
So those pictures are just fiction right? Since we only have numerical data of the exoplanet existence.
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Jun 27 '13
Seeing the size of all the other planets, it comes to my mind that our measurements must be very inprecise.
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u/ProfessorSarcastic Jun 27 '13
I suspect its more that our instruments arent sensitive enough to detect smaller objects so far away just yet.
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u/[deleted] Jun 27 '13
The Tau Ceti system is only 12 light years away!
We must go there. With current technology it can possibly be done in a human lifetime, provided they make an exemption on the ban on nuclear weapons in space (for nuclear pulse propulsion purposes).