Are their any experiments which provide evidence that the universe is expanding?

Answer 1

It's called the Doppler effect. As a planet, star, Galaxy,etc... moves away from the observer (us) it gets a redshift, if it moves toward us, it gets a blue shift. It is like when an ambulance drives past, you can hear the pitch change as it comes down the road and passes you. It is the same thing in principle. They simply measure the redshift to determine how the object is moving and how fast. That is how they know.

EDIT-- Think of it like this: a bunch of dots are glued to a balloon. When you inflate the balloon all the dots will spread apart; each one will be farther away from the other dots than it previously was no matter where is is on the balloon.

Answer 2

Experiments, no. At least, not to my knowledge.

Observable evidence, yes.

As Seraph pointed out, astronomers have been using Doppler's theories to explain why the majority of deep sky objects produce spectrographs where the spikes relating to abundent chemicals as we can see them in our chemistry classes in high school are shifted in various degrees to ward the red while some of those same spikes are shifted in various degrees toward the violet.

Doppler theorized that anything that produces waves that is travelling toward the observer or that the observer is travelling toward or both, will have shorter wavelengths than if the distance between the object and the observer is increasing or going away.

When objects are going away, their spectral wavelengths will increase, and will shift toward the red, whereas when objects are approaching their spectral wavelengths will decrease, which will shift toward the purple.

The vast majority of observable deep sky objects fit the category of red spectral shifting, so, according to Dopplers theory, that means that most of the observable deep sky objects are moving away from us observers here on Earth, which is NOT the center of the universe any more than it is the center of the solar system, so the theory is that they're moving away from everything else, too.

Answer 3

Not experiments, but direct observation of distant galaxies. Because of a phenomenon called redshift, the light from distant galaxies moves to the red end of the electromagnetic spectrum. The greater the shift towards red, the greater the velocity at which a galaxy is moving away from us. Observations of distant galaxies have shown this pattern; in fact, the greater the distance, the greater the velocity.

Answer 4

Yes. I would suggest a book you may like : " A brief History of Time", by Stephen Hawking, the Nobel Prize.

Answer 5

Of course ... the latest has been the study of super novae, their distance and recession velocities. The results support accelerating expansion.

Answer 6

yes