By the time the light from some stars gets here, they are already dead. For those stars, we see only their ghosts. We see their light. But their bodies perished long, long ago. But they themselves died long ago. John, i have seen further back in time than any man before me millions of years into the past - William Herschel a telescope is a time machine We can not look into space without seeing back in time we As long as you look into space, you must see the past. In one second, light travels 300,000 kilometers or 186,000 miles. That's nearly the distance from the Earth to the Moon. So the Moon is about one light-second away. Next time when you look at the Moon, you will be seeing one second into the past. The next time you look up at the moon, you see a second of history. All of nature is in motion. But that spindle turning is the beginning of a revolution, one that dwarfs all the shots fired and bombs ever detonated in the sheer magnitude of its effect on our civilization. That's here. That's home. That's us. On it, everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teaher of morals, every corrupt politician, every superstar, every supreme leader,
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