Thursday, June 26, 2008
Recent Science Making Life More Possible in Universe?
There have been several big pieces of news the last few weeks that point the way towards life possibly being more common in the universe than we expect. I haven't heard others put this stuff together so I thought it might be useful to put the pieces together. I'm a big fan and follower of astrobiology and exoplanets so I love tracking this stuff.
First, it looks like rocky planets roughly the size of Earth (known as super earths) might be more common than we thought. First, three rocky Super Earths were found in a single solar system; these run very close to their sun so they are way too hot to support life, but the fact that several rocky core planets were found in one system is surprising. Solid rocky planets are one requirement based on the life forms we know about today. The fact that they are close to their sun is more an artifact of how we detect planets today, which is based on the slight wobble induced on the star by orbiting planets. We either can only detect very large planets forcing a large wobble on the star or planets that are close by that induce a wobble.
There was also recent news of astronomers surveying suns similar to ours. They found that one out of three of the stars surveyed held rocky planets! I can't track down the link right now, but this is huge. Again, it points to rocky planets around stars similar to our own being a common occurrence, not the exception. Keep in mind that just a decade ago there was doubt that planets themselves would be a common occurrence versus the exception.
The next major finding is of course the detection of water on Mars this week. Again, water is a necessary component of life. While the water does not flow freely on Mars today, the big results the last few years was that in the past the water flowed freely across the landscape. The fact that water is still there is also important.
Finally, evidence has been found that Mars was hit by a giant asteroid billions of years ago. It was so large that it gouged a piece of the planet off. The Earth was hit by a similar asteroid, forming the Moon. This is important; there are theories that a large Moon is a necessary pre-condition for life since it attracts away life-killing asteroids (as is the presence of Jupiter sized planets to play interference, and many exosolar gas giants have been found as well). While the impact on Mars didn't create a giant moon, it does show that massive planet-gouging asteroids hitting planets may not be an exceptional occurrence.
Put these all together, and the conditions begin to (tentatively) look like life could be more common than we expect:
First, it looks like rocky planets roughly the size of Earth (known as super earths) might be more common than we thought. First, three rocky Super Earths were found in a single solar system; these run very close to their sun so they are way too hot to support life, but the fact that several rocky core planets were found in one system is surprising. Solid rocky planets are one requirement based on the life forms we know about today. The fact that they are close to their sun is more an artifact of how we detect planets today, which is based on the slight wobble induced on the star by orbiting planets. We either can only detect very large planets forcing a large wobble on the star or planets that are close by that induce a wobble.
There was also recent news of astronomers surveying suns similar to ours. They found that one out of three of the stars surveyed held rocky planets! I can't track down the link right now, but this is huge. Again, it points to rocky planets around stars similar to our own being a common occurrence, not the exception. Keep in mind that just a decade ago there was doubt that planets themselves would be a common occurrence versus the exception.
The next major finding is of course the detection of water on Mars this week. Again, water is a necessary component of life. While the water does not flow freely on Mars today, the big results the last few years was that in the past the water flowed freely across the landscape. The fact that water is still there is also important.
Finally, evidence has been found that Mars was hit by a giant asteroid billions of years ago. It was so large that it gouged a piece of the planet off. The Earth was hit by a similar asteroid, forming the Moon. This is important; there are theories that a large Moon is a necessary pre-condition for life since it attracts away life-killing asteroids (as is the presence of Jupiter sized planets to play interference, and many exosolar gas giants have been found as well). While the impact on Mars didn't create a giant moon, it does show that massive planet-gouging asteroids hitting planets may not be an exceptional occurrence.
Put these all together, and the conditions begin to (tentatively) look like life could be more common than we expect:
- Rocky planets around Suns like ours appears to be common
- Liquid water has been found on a second planet in our solar system -- if its on a second in one system, the odds of it being in others is higher
- Cataclysmic asteroids hitting planets might be common, increasing the odds of large Earth-sized Moons on other planet
Labels: astrobiology, exoplanets, space
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Not only do large satellites wipe smaller bodies, they also tend to stabilize the obliquity of the planet, making the climatic conditions more stable.
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