Mars Had an Ancient Impact Like Earth

quixote9 writes "The BBC reports on a set of Nature articles showing that Mars had an impact about four billion years ago by a huge asteroid. This was about the same time that a much bigger object slammed into the Earth, throwing material into orbit around our infant planet. This material is thought to have coalesced to form the Moon. 'It happened probably right at the end of the formation of the four terrestrial planets — Mercury, Venus, Earth and Mars,' said Craig Agnor, a co-author on the Francis Nimmo study. 'In terms of the process of the planets sweeping up the last bits of debris, this could have been one of the last big bits of debris.' There's a theory that having a big moon is important to the development of life, because the much bigger tides create a bigger intertidal zone, but people used to think having a huge Moon like ours was a once-in-a-universe event."

Comments

Re:Hopefully.

[MBGMorden]

IF you RTFA then you'll find no mention of some freaking 'Huge' moon being necessary to life. While it didn't appear in the article, I've seen quite a bit of stuff suggesting that a big moon could be a necessity. While the tidal issue is news to me, the most common thing I've heard quoted as that a large moon serves as an anchor for a planet, significantly reducing the amount of wobble in it's orbit. A wobble of less than 1 degrees can have serious climate impacts on Earth (the Sahara was once a jungle . . .), but we generally don't wobble much because of the moon anchoring us down. Other rocky planets like Mars or Venus wobble MUCH more, which would make climate conditions that would be difficult for life to spring up.

IIRC, one special that I saw suggested that while life might have formed in the absence of the Moon, it probably would have been confined to the oceans only.