What does the new Earth-like planet mean?
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Hours after the story broke, it was already being hailed as one of the biggest scientific breakthroughs of the year: the announcement by astronomers, earlier this week, of the discovery of the most Earth-like extrasolar planet found to date.
Astronomers, planetary scientists and, most of all, exobiologists rejoiced at news of the discovery, which suggests that Earth is not unique in the Universe, and neither, it seems, is Earth-bound life.
But how likely is it that this newly found planet, anonymously labelled "581 c," actually harbors life of some kind? And just what do we hope to accomplish in the endless search for planets beyond our eight (or seven, now that Pluto has been demoted) closest neighbors?
581 c orbits a small, cool red dwarf 20.4¡ light years from Earth Â- a mere stone's throw in galactic distances. It is about one and a half times as large as Earth, but over five times as massive. It orbits its star and completes a year in just 13 days.
The key to the possibility of life on 581 c is its temperature. As far as scientists understand it today, life can only exist where there is liquid water. Liquid water can only exist in a narrow range of temperatures.
Every one of the 220 previously discovered exoplanets is either too cold because it orbits a dim star from too great a distance, or is too hot because it orbits a bright star too closely. Scientists talk about an ideal "Goldilocks range" for water, and life, to exist.
The really tantalizing characteristic of 581 c is its location: it seems to fall right into that narrow range of conditions, the so-called habitable zone, that is able to support liquid water. As a result, average surface temperatures are probably nearly identical to Earth's, ranging from 32 degrees to 104 degrees Fahrenheit.
All of these facts are suggestive, but it may be decades before scientists can say for sure whether the habitable zone is actually inhabited. The only certain conclusion to be drawn right now is that 581 c is unlike any other planet currently known to scientists.
Astronomers, planetary scientists and, most of all, exobiologists rejoiced at news of the discovery, which suggests that Earth is not unique in the Universe, and neither, it seems, is Earth-bound life.
But how likely is it that this newly found planet, anonymously labelled "581 c," actually harbors life of some kind? And just what do we hope to accomplish in the endless search for planets beyond our eight (or seven, now that Pluto has been demoted) closest neighbors?
581 c orbits a small, cool red dwarf 20.4¡ light years from Earth Â- a mere stone's throw in galactic distances. It is about one and a half times as large as Earth, but over five times as massive. It orbits its star and completes a year in just 13 days.
The key to the possibility of life on 581 c is its temperature. As far as scientists understand it today, life can only exist where there is liquid water. Liquid water can only exist in a narrow range of temperatures.
Every one of the 220 previously discovered exoplanets is either too cold because it orbits a dim star from too great a distance, or is too hot because it orbits a bright star too closely. Scientists talk about an ideal "Goldilocks range" for water, and life, to exist.
The really tantalizing characteristic of 581 c is its location: it seems to fall right into that narrow range of conditions, the so-called habitable zone, that is able to support liquid water. As a result, average surface temperatures are probably nearly identical to Earth's, ranging from 32 degrees to 104 degrees Fahrenheit.
All of these facts are suggestive, but it may be decades before scientists can say for sure whether the habitable zone is actually inhabited. The only certain conclusion to be drawn right now is that 581 c is unlike any other planet currently known to scientists.
Viewing Comments 1 - 2 of 3
sean
posted 5/01/07 @ 12:58 AM EST
Yeah, theres 8 planets in the solar system excluding Pluto, not 7. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Count it out.
Martin
posted 5/24/07 @ 4:37 PM EST
James Lovelock suggested that one can identify a planet where life exist if its atmosphere is in an unstable, dynamic equilibrium. It means that if the atmosphere of a planet is not inert, then you have life, no matter what kind of life. (Continued…)
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