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How old is the Universe?
Question Date: 2003-03-20
Answer 1:

The Big Bang created the universe 14 billion years ago, so it would be impossible to see anything farther than 14 billion light years away, because nothing existed- not even space or time. The most distant thing we can see is the fading fireball of the Big Bang itself, a bit less than 14 billion light years away. We can't see the first instant of the Big Bang, because the universe was too hot and dense- it only became transparent when it cooled to a few thousand degrees. We see the fireball in any direction we look, because the Big bang occurred everywhere- even here. This is because space itself has expanded. At the time of the Big Bang, space was a single point, so everywhere in the universe was all the same place (sounds like a garbled sentence- but the wording is correct!) The expansion of space has "red-shifted" the fireball far down the electromagnetic spectrum- down past red and infra red, all the way to microwaves- so its now called the "cosmic microwave background".

Red-shifting is similar to the reduction of a sound's pitch as the source speeds away from you. If not for this phenomenon the fireball would still be bright, like a sun covering the entire sky. Nothing in space could be colder than the fireball, so the temperature of space would be a few thousand degrees. Thanks to the extreme red-shift, we receive only a small fraction of the fireball's original heat. It is possible for objects in dark, empty space to cool down to about -415 degrees Fahrenheit, or 5 degrees above absolute zero. This is the temperature of space!

Answer 2:

We think it is about 13 billion years old, but we can't say for sure. We believe that it is older than 10 or 11 billion years, but younger than 15 billion years. This is one of the biggest questions of modern astronomy and cosmology!

Answer 3:

The universe is somewhere between 10 and 20 billion years old. This is a wide range and scientists are working on getting a better answer. If you do some research, you may be able to find a more accurate answer than what I have given.

Answer 4:

As you can probably imagine, this is a hard number to measure, and I don't entirely understand how it is done. However, I've heard that astronomers think the universe is 11.2-20 billion years old.

Answer 5:

This is a question that is guaranteed to create lots of argument, even among scientists. Current cosmology models place the age at between 13 and 15 billion years old. By this measure, the sun is a youngster at 4.5 billion years old. This age is determined by measuring the rate of expansion of the visible universe and extrapolating back to when it started expanding (the big bang). This time agrees fairly well with the age as determined by the oldest stars, using models of stellar aging.

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