Home > Astronomy > Expansion of the Universe

How can we tell if the universe is expanding?

Answer 1

Astronomers study the spectrum of distant galaxies and find the red shift.

The Doppler effect is used to find the red shift..When a galaxy is moving away from us the light waves get elongated The far way galaxies are moving faster than near ones. obeying Hubble law..

By signing up, you agree to our Terms of Service and Privacy Policy

Answer 2

Ariana Acosta

The redshift of distant galaxies is a phenomenon that indicates whether or not the universe is expanding. It happens because light from distant galaxies is stretched as the universe expands, increasing their wavelengths and shifting them toward the red end of the spectrum.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.