Mooning Around

3 November 2016

At … and variously at… … and… … and all these are useful but the latter two come with comments. The operative word here is 'model' – not actual physical evidence.

Just a few months ago, at … they were telling us that the moon migrated outwards from Earth until its orbit reached a critical distance when the Sun's gravitational influence overtook that of the Earth. Basically, the new paper reiterates this idea (or represents the published version of the theory). The mainstream theory of lunar formation involves a giant impact phase in the early solar system – and one impact with proto-earth resulted in a mass of loose material being lost. This material coalesced into the Moon. The impact set the angular momentum for the Earth-Moon system and gave earth a five hour day. Wow. Over millennia the moon has reded from the earth and the rotation has slowed – and gives us the current 24 hour day. Scientists have deduced this by working out how rapidly angular momentum of the Earth-Moon system has been transferred by the tidal forces between the two bodies, and working backwards came up with their answer. In other words, they have assumed a uniformitarian times scale – and ignored all other options.

According to Tall Bloke, one problem they have is that the moon is surprisingly earth like. Another anomaly is that if the mass condensed from a disc of material rotating around Earth's equator it should be in orbit over the equator – but is not. It is tilted away from the equator which suggests some further energy source has been introduced – but from where?

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