Value of Astronomy in the Scientific Endeavor

Value of Astronomy in the Scientific Endeavor - years away...

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Value of Astronomy in the Scientific Endeavor Now back to the long term evolution side of the coin. We actually have a time machine! Not the H.G. Wells variety or G. Roddenberry's Guardian of Forever but something much simpler due to the large distances and finite speed of light (300,000 kilometers/second!). It takes time for radiation from a celestial object to reach the Earth. Therefore, when you examine an object at a large distance from us, you see it as it was . The farther away the object is, the longer it took the radiation to reach the Earth, and the further back in time you observe it. The Sun is 150 million kilometers from us, so you see the Sun as it was 8-1/3 minutes ago. The farthest object you can see without a telescope is the Andromeda galaxy about 2.8×10 19 kilometers from the Earth, so you see it as it was almost 3 million years ago. Recall that a light year is how far light travels in one year (about 9.46×10 12 kilometers). Therefore, the Andromeda galaxy is almost 3 million light
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Unformatted text preview: years away from us. (The speed of light is the key in the relationship between space and time, a fact used by Albert Einstein in developing his Relativity theories that are described in another chapter .) To study the evolution of long-lived objects like stars (with lifetimes of millions to billions of years) or galaxies, astronomers observe the objects of interest at different distances from the Earth so they are seen at different epochs. Therefore, the objects are seen at various different ages or evolutionary stages. Since light from remote objects can take millions to billions of years to reach the Earth, astronomers find out about the laws of physics at different times. What they find is that the universe has used the same laws of physics throughout its 14-billion year lifetime (and presumably will continue using those same rules). Pretty amazing!...
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