Seeing is believing....
or is it?
Go out tonight and look up at the stars (admittedly something easier for those of us living in the country than our city-dwelling cousins). You are looking at something that never existed the way you are seeing it.
Think about it. Light travels at a finite speed according to Einstein. The distance to stars is measured in light-years, or the number of years it takes light to reach your eyes from the star. So when you look at a star that is, say, 2000 light years away, you are actually seeing what that star was like 2000 years ago. It could have exploded into nothingness yesterday....but you won't see it for another two millenia!
Now, every star is a different distance away from Earth, and so the timeline of what you see in the sky at night covers an almost unimagineable span of time. You are seeing some stars where they were fifty years ago; others a few centuries ago; and still others millenia ago. But since the universe is in motion, the actual relation of one star to another at this exact moment in time is not what you see, and in fact, you will NEVER see it.
Stars, suns, planets and other astonomical phenomena may have come and gone...and we won't know it for centuries or longer.
Go out tonight and look up at the stars (admittedly something easier for those of us living in the country than our city-dwelling cousins). You are looking at something that never existed the way you are seeing it.
Think about it. Light travels at a finite speed according to Einstein. The distance to stars is measured in light-years, or the number of years it takes light to reach your eyes from the star. So when you look at a star that is, say, 2000 light years away, you are actually seeing what that star was like 2000 years ago. It could have exploded into nothingness yesterday....but you won't see it for another two millenia!
Now, every star is a different distance away from Earth, and so the timeline of what you see in the sky at night covers an almost unimagineable span of time. You are seeing some stars where they were fifty years ago; others a few centuries ago; and still others millenia ago. But since the universe is in motion, the actual relation of one star to another at this exact moment in time is not what you see, and in fact, you will NEVER see it.
Stars, suns, planets and other astonomical phenomena may have come and gone...and we won't know it for centuries or longer.
posted by Just Some Guy on the Radio at 8:25 AM
1 Comments:
Hey Jack Handey, that is a deep thought!
I love this piece. It's so true. Add to it that most of the stars visible to us are very close to us. The only non-star objects we can see with the naked eye (save a few moons around neighboring planets and our own moon) is a smattering of barely visible galaxies, the brightest of which is the Andromeda galaxy. Yet the number of stars we DO see seems countlessly large. As you pointed out, looking up means looking back, which is a very awe-inspiring thought.
Don't get me started on this subject, Bill. I'll be here all day. This requires you, me and a six pack sometime soon.
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