18 Apr 14
2 edits
I have already read this link some time ago. I find it interesting to note that the reason why it has taken so long to detect such an Earth-sized planet within the habitable zone is not because they are rare but rather because such small planets orbiting that far out from their star have been so far extremely difficult to detect with current technology.
Even this one was only detected with much difficulty!
18 Apr 14
1 edit
Originally posted by humyYeah, the signal was pretty buried in the mud. It would have been a lot easier if it had been 50 ly away instead of 500. If you keep that number, an Earth every 500 ly and the galaxy at 5000 ly deep and 100,000 ly wide then it would be 10 deep and 40,000 spread out so something like 400,000 such planets in our galaxy alone.
I have already read this link some time ago. I find it interesting to note that the reason why it has taken so long to detect such an Earth-sized planet within the habitable zone is not because they are rare but rather because such small planets orbiting that far out from their star have been so far extremely difficult to detect with current technology.
Even this one was only detected with much difficulty!
My guess is they all would have liquid water, water seems ubiquitous in the universe.
I would think the real question would be, is there oxygen there too? That would imply life, at least OUR kind of life.
18 Apr 14
Originally posted by sonhouseI think the statement that "liquid water + oxygen implies life" is awfully strong.
Yeah, the signal was pretty buried in the mud. It would have been a lot easier if it had been 50 ly away instead of 500. If you keep that number, an Earth every 500 ly and the galaxy at 5000 ly deep and 100,000 ly wide then it would be 10 deep and 40,000 spread out so something like 400,000 such planets in our galaxy alone.
My guess is they all would ha ...[text shortened]... question would be, is there oxygen there too? That would imply life, at least OUR kind of life.
I don't see any reason why life must exist on such a planet.
18 Apr 14
Originally posted by forkedknightOf course, that goes without saying. Just looking at possibilities. If the distribution of Earth-like planets is right though, out of hundreds of thousands of them, SOME of them should have that combination.
I think the statement that "liquid water + oxygen implies life" is awfully strong.
I don't see any reason why life must exist on such a planet.
19 Apr 14
1 edit
Originally posted by humyThe main method for detecting planets is by observing transits. To reliably observe a transit you need the transit to occur at least 3 times. For a planet at earths orbital distance and size, this means observing the star for three years.
I have already read this link some time ago. I find it interesting to note that the reason why it has taken so long to detect such an Earth-sized planet within the habitable zone is not because they are rare but rather because such small planets orbiting that far out from their star have been so far extremely difficult to detect with current technology.
Even this one was only detected with much difficulty!
The Kepler space telescope, the main tool we have for such detection's has been in space for just over 5 years, and it takes a while for its data to get analyzed, so the vast majority of its confirmed detection's are for planets with much shorter orbital periods.
However, the numbers of earth like planets known should rise significantly over the next few years.
http://en.wikipedia.org/wiki/Methods_of_detecting_exoplanets
http://en.wikipedia.org/wiki/Kepler_mission
For those interested, I highly recommend this lecture on the subject:
19 Apr 14
2 edits
Originally posted by forkedknightI would agree with you that "liquid water + oxygen implies life" is currently strictly false because this is a false inference because we don't yet know exactly how common or rare abiogenesis is. Even if abiogenesis is common and occurs almost on every planet with liquid water, there is good scientific reason to believe that oxygen, if anything, hinders rather than promotes the process so, unless you are specifically talking about Earth-like life, oxygen should have nothing to do with it.
I think the statement that "liquid water + oxygen implies life" is awfully strong.
I don't see any reason why life must exist on such a planet.
However, if or when we have evidence, in the form of current life on a planet, that abiogenesis usually has occurred at sometime in the past of planets currently rich in both liquid water and oxygen, with this new information, the "liquid water + oxygen implies life" would be changed from a false inference to a true one.