2007-03-20 17:44:16 · 6 answers · asked by Coco 2 in Science & Mathematics ➔ Astronomy & Space
Not exactly experiments,
But look up 'Red Shift'
Stars that we know of, over time their images are shifting towards the red side of the spectrum. This could mean two things,...
Either that they are cooling - which we know they aren't, or they are moving away from us.
The stars in all directions appear to be doing this, so this is evidence of expansion...
This is a very simplified account.
The best example of this that I have seen is the duck swimming...
As a duck is sitting still in water, the ripples around it are the same in all directions.
If the duck starts swimming away. the ripples in front of it get closer together (because it is swimming into them), meanwhile the waves behind it get farther apart.
The red wavelengths are longer, so we know our 'ducks' are swimming away from us.
2007-03-20 17:50:07 · answer #1 · answered by Loulabelle 4 · 1⤊ 0⤋
Redshift. The further a galaxy is from us, the more redshifted it is. Redshift is how far spectral lines are shifted towards the red end of the spectrum when you look at the spectra (rainbow) of distant galaxies. This happens because the space between the galaxies is "stretching" which in turn stretches out the wavelengths of light as they travel from the galaxy over vast distances to Earth. The further away a galaxy is, the more expanding space the light has to travel through, so the more redshifted the light from the galaxy becomes. Since every galaxy is moving away from one another (as we observe through of redshift) then the universe must be expanding.
2007-03-21 00:50:49 · answer #2 · answered by Roman Soldier 5 · 0⤊ 0⤋
Edwin Hubble was first to discover that the universe is expanding.This was due to the observance of the red light shifting from distant stars
2007-03-21 15:36:33 · answer #3 · answered by najj 2 · 0⤊ 0⤋
Observation of the red shift in distant galaxies.
2007-03-21 00:47:29 · answer #4 · answered by Anonymous · 0⤊ 0⤋
have you ever heard an ems pass you by? it's a high pitched siren as it's coming to you then gets into a lower pitch as it goes away.
"doppler effect" that's how they know, but not with sound. with lights. light changes color as it speeds toward you or away. it's the way light waves work. from red (moving away) to blue (moving closer)
2007-03-21 00:50:31 · answer #5 · answered by Homer 4 · 0⤊ 0⤋
dopler effect observations
2007-03-21 00:59:20 · answer #6 · answered by doom98999 3 · 0⤊ 0⤋