Scientists Discover Exoplanet Less Than Twice the Mass of Earth 201
Snowblindeye writes with this excerpt from the European Southern Observatory:
"Well-known exoplanet researcher Michel Mayor today announced the discovery of the lightest exoplanet found so far. The planet, 'e,' in the famous system Gliese 581, is only about twice the mass of Earth. The team also refined the orbit of the planet Gliese 581 d, first discovered in 2007, placing it well within the habitable zone, where liquid water oceans could exist. Planet Gliese 581 e orbits its host star — located only 20.5 light-years away in the constellation Libra ('the Scales') — in just 3.15 days. 'With only 1.9 Earth-masses, it is the least massive exoplanet ever detected and is, very likely, a rocky planet,' says co-author Xavier Bonfils from Grenoble Observatory. Being so close to its host star, the planet is not in the habitable zone. But another planet in this system appears to be. ... The planet furthest out, Gliese 581 d, orbits its host star in 66.8 days. 'Gliese 581 d is probably too massive to be made only of rocky material, but we can speculate that it is an icy planet that has migrated closer to the star,' says team member Stephane Udry. The new observations have revealed that this planet is in the habitable zone, where liquid water could exist. '"d" could even be covered by a large and deep ocean — it is the first serious "water world" candidate,' continued Udry."
Astronomy (Score:5, Interesting)
How much do we really know about these planets, and how much is guessing? How close are these planets, really, to earth?
Planets and moons (Score:4, Interesting)
Gliese 581 d is probably too massive to be made only of rocky material...
Even if it isn't habitable, it might still be large enough to have a habitable moon perhaps?
Let's blow this popsicle stand (Score:2, Interesting)
Meh.
As in Moonraker, we send the sexy geniuses first, right? Or do we send the Telephone Sanitizers and hairdressers, like in HHGG?
Re:Extraterrestial life (Score:2, Interesting)
Finding organic living matter on other planets would be fantastic, but unfortunately that wont be the first kind of extra-terrestrial life we find (prospective there is any).
Our most advanced instruments are just now able to detect exoplanets, and soon enough they may be able to actually scan the surface for signs of life.
If we COULD send instruments there that could detect microscopic living organisms, we might actually have a lot better luck at finding life.
This just isnt feasible currently, and were going to have to stick with superficial surface scanning for creatures crawling around until we can actually send instruments there that could report back.
If we did find intelligent life, I think it would be a good idea to send a rocket with a screen and dvd player or something, with a big red button on it that plays it. Imagine being on Earth 200 years ago and finding something similar, with videos of aliens and things.
It would have been revolutionary, and eventually we may be able to greet another intelligent race in a similar fashion.
Oh the possibilities..
Everything except orbit and mass is speculation (Score:5, Interesting)
The science of extra-solar planet detection is very interesting, but speculation about surface conditions that might exist doesn't reflect the science at all, it's just fodder for the media and bloggers.
The only things we know are extremely rough estimates of orbital parameters and mass, although the host star is well characterised. The speculation is conjuring up quite specific images in people's minds, and while fun, they're not justified. It's leading people without an astronomy background astray.
What class? (Score:2, Interesting)
Re:Extraterrestial life (Score:3, Interesting)
1) Considering how many planets we have looked at and that we can't find life on any of them this makes Earth very extraordinary.
The only reason we are able to detect life on Earth is due to proximity - so you're just as guilty of jumping to conclusions as the GP. We've found planets that differ wildly from Earth because the easiest planets to detect are the fuck-all-huge ones. Just because we haven't observed Earth-like planets yet does not mean they aren't all over the bloody place. They're just rather hard to spot with current technologies.
Re:Extraterrestial life (Score:4, Interesting)
If we do an absorption spectrum reading of the atmosphere, which can be done at astronomical distances, and find free oxygen that would be a strong evidence for life on that planet. Oxygen is so reactive that it wouldn't exist very long in a planet's atmosphere before combining with something, unless here is a process like life to replenish it.
Re:Extraterrestial life (Score:3, Interesting)
Actually, it would be much wiser to simply continue to talk for the whole twenty years than dialog like that. You would give the recipient a lot of information over that time, and hopefully they would reciprocate.
Re:but what about Earth 2... (Score:3, Interesting)
If we were using our current detection technology to examine a solar system that has a planet exactly like earth, orbiting a star exactly like our sun, with the same orbital period, etc... how close would the solar system need to be for us to recognize those features? Could we recognize an earth-sized planet orbiting a star in the habitable zone if it were 20 light-years away? What about 30 light-years? How close would we need to be in order to recognize that it is covered in liquid H2O oceans? Would the presence of other larger and/or more-closely-orbiting planets (such as Jupiter, Saturday, Mercury, Venus, etc) make that even more difficult?
Anyone have any insight into this?
Re:'lighest'? (Score:3, Interesting)
Actually, wouldn't the correct term be 'least massive'? Heavy and light are measurements of weight generally and are pretty meaningless for objects that are in orbit. Unless it's considered kosher to use lightest/heaviest in this situation, sometimes I think English drifts faster than the average person can keep up with it.
Re:Whiplash. (Score:2, Interesting)
it's going to take a long time (both in ramping up the tech and in tasking the scope to just sit there and stare at a star, waiting for something to blip by) for the "earth-sized rock in the habitable zone with an earth-length orbital period!" announcements to start rolling in.
I wouldn't think that an "earth-length" orbital period is all that important to determining if a planet can support life or not. Remember, the type of the star it orbits determines where and how large the habitable zone will be, so if we find a planet relatively the same size as Earth orbiting a star that is not as hot as our sun, the habitable zone for this planet will be much closer to the star in question; thus the orbital period could possibly be much different than our own, depending on exactly how close that planet must be in order to sustain liquid water. Likewise, if an earth sized planet is found orbiting a star that burns much hotter than our sun, the habitable zone would be much farther away from that particular star, again resulting in a different orbital period from our own.