First Rocky Exoplanet Confirmed 155
Matt_dk writes "The confirmation of the nature of CoRoT-7b as the first rocky planet outside our Solar System marks a significant step forward in the search for Earth-like exoplanets. The detection by CoRoT and follow-up radial velocity measurements with HARPS suggest that this exoplanet has a density similar to that of Mercury, Venus, Mars and Earth, making it only the fifth known terrestrial planet in the Universe. The search for a habitable exoplanet is one of the holy grails in astronomy. One of the first steps towards this goal is the detection of terrestrial planets around solar-type stars. Dedicated programs, using telescopes in space and on ground, have yielded evidence for hundreds of planets outside of our Solar System. The majority of these are giant, gaseous planets, but in recent years small, almost Earth-mass planets have been detected, demonstrating that the discovery of Earth analogues — exoplanets with one Earth mass or one Earth radius orbiting a solar-type star at a distance of about 1 astronomical unit — is within reach."
By the time we get there (Score:5, Interesting)
By the time we actually got to one of these planets, would it still be able to sustain life? Should we be looking for planets that are in their early, less habitable stages?
Toasty little cinder (Score:5, Interesting)
Looks like this little guy is only 0.002 AU away from it's parent star. I wouldn't expect to find any life there, but still, this is an amazing discovery. As these methods get fine tuned it's only a matter of time before we start finding planets roughly Earth-like not only in form, but also in relation to the habitable zone around their star. I don't think we'll ever get a probe, much less a person, to any of them within my lifetime, but at least we'll have an interesting list of spots to visit when we do reach that capability :).
Re:Toasty little cinder (Score:4, Interesting)
Then again, perhaps their scientists are thinking much the same thing about us:
"A rocky planet, similar to our own, was discovered in a nearby solar system. However, having only a fifth of our planet's mass, and being located 500 AU from its star, the planet is probably much too cold to support life. Temperatures below 800 degrees are thought to be far too low in energy for the spark of life to begin."
Re:You are forgetting to account of GR (Score:4, Interesting)
The faster you go the shorter the time in both the travelers frame of reference and the destination stars frame of reference. We don't need to assume some guess about what will happen. This is all stage 1 physics. Its dead simple. We know how much time will have passed both in the ships reference frame and the stars. It won't be the same in all cases, but it is bounded to be equal to or below a classical estimate from Newtonian physics.
So at traveling at
You call that cold? (Score:5, Interesting)
Meanwhile, as scientists on an outer planet look our way:
"Rocky planets like the one recently discovered are turning out to be quite common throughout our area of space. Given a dense enough atmosphere, this planet could even support life like ours, although it's hot enough to kill all but the most tolerant extremophiles known. Spectroscopic analysis, though, reveals its deadly nature: much of its surface is covered with molten hydroxic acid, which forms toxic clouds and then falls as corrosive rain. If life-giving ammonia was ever present on the surface, it's long since combined with the abundant free oxygen in the atmosphere. Our chemists are still uncertain what could produce so much free oxygen; fantasists have speculated on forms of life that would metabolize oxygen in the same way that we metabolize hydrogen, but the analogy breaks down quickly as you look more closely at the chemistry involved."
I wonder how they're defining "planet" (Score:3, Interesting)
The summary (and TFA too ;-) reminded me of the recent debate over the definition of "planet".
One obvious problem is with the claim that we only knew of four "rocky planets" before this one. Since Mercury and Mars are included, it's likely that the definition they're using would also classify at least Titan and Triton as "rocky planets", giving us six.
But, (I can hear people saying), Titan and Triton aren't planets because they don't orbit the sun. Well, neither does this new planet; it orbits another star. Some people have seriously defined "planet" to mean objects that orbit our sun, and of course that definition immediately says that there can't be any more planets in the rest of the universe. If you accept this new object as a "rocky planet", what's your definition? You'll have to word it very carefully so that it includes things orbiting a distant star, but not those that are in orbits around local gas giants.
And if you find a good wording for that, you face another likely future problem: How small an object is allowed as the primary? Suppose a new rocky-planet-like object is found in orbit around a nearby "brown dwarf". The primary isn't a proper star, so is the object merely a moon and not a planet? It's also likely that we'll soon find Jupiter-class objects in free space, not orbiting a star; if one has a Mercury- or Mars-like object in orbit, would it be classified as a rocky planet or a moon? If it's a planet, then why isn't Ganymede also a planet?
I'd predict that in the not-too-distant future, as smaller things can be detected remotely, astronomers might decide to abandon such definitions that depend on the type of primary, and rewrite definitions so that they only use properties of the object itself. Either that, or they'll deprecate "planet" as a lay term that's not useful for scientific purposes. Dunno what they'd replace it with, though.
Meanwhile, the Sophists amongst us may be in for a lot of fun in the near future. Those of us who sat at the sidelines chuckling over the angst caused by the demoting of Pluto are probably looking forward to a lot more astronomical geek humor in the next few years.