Conglomerate, in geology, a sedimentary rock composed of rounded rock fragments cemented together by a finer-grained material such as sand or clay. The fragments, which are commonly quartz or limestone but can be almost any type of rock, originally may have accumulated on beaches or in beds of streams.
He is famous for a phrase he never said, for wearing turtlenecks and for hosting the original 'Cosmos' TV series. As enthusiastic about the stars as he was about marijuana, Carl Sagan led a very surprising life. Here are 10 cool facts.
So much of our cosmological history starts with the much-discussed big bang, but what led up to that cataclysmic moment? And did time even exist back then?