Light seconds, light years, light centuries: How to measure extreme distances - Yuan-Sen Ting
View full lesson: http://ed.ted.com/lessons/how-do-we-measure-distances-in-space-yuan-sen-ting When we look at the sky, we have a flat, two-dimensional view. So how do astronomers figure the...
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Light is the fastest thing we know. It's so fast that we measure enormous distances by how long it takes for light to travel them. In one year, light travels about 6,000,000,000,000 miles, a distance we call one light year. To give you an idea of just how far this is, the Moon, which took the Apollo astronauts four days to reach, is only one light-second from Earth. Meanwhile, the nearest star beyond our own Sun is Proxima Centauri, 4.24 light years away. Our Milky Way is on the order of 100,000 light years across. The nearest galaxy to our own, Andromeda, is about 2.5 million light years away Space is mind-blowingly vast. But wait, how do we know how far away stars and galaxies are? After all, when we look at the sky, we have a flat, two-dimensio...
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Light is the fastest thing we know. It's so fast that we measure enormous distances by how long it takes for light to travel them. In one year, light travels about 6,000,000,000,000 miles, a distance we call one light year. To give you an idea of just how far this is, the Moon, which took the Apollo astronauts four days to reach, is only one light-second from Earth. Meanwhile, the nearest star beyond our own Sun is Proxima Centauri, 4.24 light years away. Our Milky Way is on the order of 100,000 light years across. The nearest galaxy to our own, Andromeda, is about 2.5 million light years away Space is mind-blowingly vast. But wait, how do we know how far away stars and galaxies are? After all, when we look at the sky, we have a flat, two-dimensio...
