2006-08-23 04:42:39 · 5 answers · asked by goring 6 in Science & Mathematics ➔ Physics
From the Hubble constant. It is observed from doppler shifted light that distant galaxies (which occasionally contain supernovae of known intrinsic brightness) recede from each other at a speed V proportional to how far apart they are D. That means they were all in one place D/V years ago. Small corrections can be made for gravitational braking and dark energy acceleration, but to first order, it's that simple.
2006-08-23 14:45:08 · answer #1 · answered by Dr. R 7 · 0⤊ 0⤋
It is determined from the cosmic background radiation, a microwave radiation that seems to come from every direction of space and would lead us to believe the temperature of space is somewhere around 5K. Through the use of thermodynamics and the idea that the universe is expanding (Big Bang Theory), we know that the universe must also be cooling. By knowing the current temperature, and estimating the rate of expansion and the initial temperature, we know about how long the universe has been around.
2006-08-23 04:49:16 · answer #2 · answered by msi_cord 7 · 0⤊ 0⤋
It was cut in half and we counted the rings.
2006-08-23 04:48:00 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Rp
2015-01-27 09:09:18 · answer #4 · answered by Anonymous · 0⤊ 0⤋
somone from the future told us
2006-08-23 04:49:53 · answer #5 · answered by jason m 1 · 0⤊ 0⤋