13 June 2009

Life and gravity

One of 'seven mysteries' of gravity: life on earth 'needs' it. But what is it?
G is the least well-defined of all the constants of nature. It has been pinned down to only 1 part in 10,000, which makes it look pretty rough and ready next to...the Planck constant, which is accurate to 2.5 parts in 100 million...
..."We can make measurements that determine its size, but we have no idea where this value comes from," says John Barrow of the University of Cambridge. "We have never explained any basic constant of nature."

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