About one in 10 rocky planets around stars like our Sun may host a moon proportionally as large as Earth's, researchers say.
Our Moon is disproportionately large - more than a quarter of Earth's diameter - a situation once thought to be rare.
Using computer simulations of planet formation, researchers have now shown that the grand impacts that resulted in our Moon may in fact be common.
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Also, our Moon has served to stabilise the tilt of the Earth's axis - or its obliquity - which could otherwise have varied drastically over relatively short time scales. That in turn would wreak drastic changes to the way heat from the Sun is distributed around the planet.
http://www.bbc.co.uk/news/science-environment-13609153It's just simulation, but it might turn out to have important implications for the development of complex life on planets.