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Weird Exoplanet Orbits Could Screw Up Alien Life
astroengine writes "Life is good in the Solar System. We have Jupiter to thank for that. However, if the gas giant's orbit were a little more elliptical, there's every chance that Earth would become rather uncomfortable very quickly. Researchers looking at the zoo of exoplanets orbiting distant stars have simulated several scenarios of differing exoplanet orbits and find that many don't resemble our cozy Solar System. In fact, weird exoplanet orbits may be the deciding factor as to whether extraterrestrial life can form or not."
For complex life to develop, you need conditions that do regularly provide evolutionary pressure, without completely wiping out all life.
Asteroid impacts are fine and even very useful for wiping out stagnant populations (like the dinosaurs) and giving room for new species to develop into, but they shouldn't be so big that they demolish the entire planet, or occur so often that no life is possible on the surface of the planet. Jupiter plays a huge role in that.
But there are also other factors. I'm pretty sure that our big moon and the tides it generates are a big factor in creating ever changing environments that provide a lot of opportunities and evolutionary pressure for populations, and that's all caused by a devastating Mars-sized impact. But another one like that would easily wipe out all life here.
Weather, seismic activity, it all plays a role. I definitely think our planet has a good chance of being reasonably unique.
First, Although the smaller inner planets would be hard pressed for life the moons of the gas giants orbiting closer to the sun could harbor life. There are only 8 (Or 9) planets in our solar system but there are over 300 moons.
Add to this that scientists seem to expect that life will only evolve on rocky earth like planets so it seems like a small chance. I know that the earth is the only example of life bearing planet that we have but to expect all life in the universe to exist in the same way that we do is narrow sighted. It would not surprise me to find out that there are fish swimming in a methane ocean on a distant planet in temperatures that would kill us.
Some day I fully expect to hear "It's Life, but not as we know it" and it not be a star trek reference. Well, Ok, how about only 1/2 a star trek reference. ;)
Of course, the fact that we are finding these weird systems may simply be because they are the easiest to detect and all the stars with planetary systems like ours are thought to not have planets because we can't detect the planets using current methods and data.
Remember, Jupiter orbits the sun once every 12 years. So, if we were trying to detect our own solar system at 10 light years, how long would it take to detect Jupiter's effect on Sol's position?
There is no "-1 offended" or "-1 you don't agree with me" mod options for a reason.
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True, but highly elliptical orbits pose not only the problem of harsh conditions, but of rapidly changing, oscillating conditions. This becomes a problem for the evolution of a biochemistry because every complex chemical system is only stable in a rather narrow interval. If the oscillation is large enough, there might just be no stable biochemistry possible.
Given that you need a reasonable amount of complexity to implement the basic necessities of life, in particular information storage, as well as a metabolism, I don't see much of an alternative to a carbon-based biochemistry. Carbon-based chemistry is the most versatile system, able to build a near infinite variations of molecules - this is a singular property among all the elements.
However, organic molecules tend to be not overly stable outside of a rather small temperature range. On the one hand, this is good for life, because it provides the necessary chemical reactivity and flexibility to make a living system possible. On the other hand, this severely limits possible habitats for extraterrestrial life. On the gripping hand, the conditions on Earth are not just favourable for any random biochemistry, they are favourable for the most complex class of chemical compounds possible. This does not exclude the possibility of other biochemistries adapted to other conditions, it does, however limit the set of possible conditions for life.
Ubi solitudinem faciunt, pacem appellant.