More settled science: Earth life either needs or doesn't need a moon

Earth may not have needed moon for life - Science - DiscoveryNews.com - msnbc.com

Scientists have long believed that without the moon's stabilizing gravitational influence, variations in Earth's tilt would have caused climate change too dynamic for complex life to evolve. Not so, concludes a new study that has implications for understanding conditions for life elsewhere in the solar system.
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In our own solar system, Mars shows evidence of extreme climate change, the result, scientists believe, of a rotational tilt that flips between zero and 60 degrees over time.
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Other factors impacting a planet's climate and suitability for life include its star's age, composition and the size and location of sibling planets in the system.

"It's a very complex problem for sure and we're not anywhere near solving it, but we're making positive steps as we slowly evaluate each of these conditions and discover what constraints they really place on whether life can exist there," Barnes said.