Orbits, red shift, big bang

What is an orbit?

The curved path of one celestial object or spacecraft around another celestial object

What force causes something to remain in circular orbit?

Gravity provides the force that allows planets and both natural and artificial satellites to maintain in circular orbits. It is also has a changing velocity.

What is Newton’s first law?

An object travelling at a certain velocity will continue to travel at that velocity unless acted upon by a resultant force.

What does red shift tell us?

Almost everything is moving away from us and the universe is expanding.

What is a Doppler effect?

If an object is moving towards you, it has a short wavelength if it is moving away it has a longer wavelength

What is red shift?

The displacement of spectral lines towards long wavelengths in radiation from distant galaxies.

What is the Big Bang theory?

A theory that says the universe began as a small dense region which 13.8 billion years ago exploded and caused the universe to expand outwards.

What is microwave background radiation?

In the Big Bang theory, lots of energy in the form of high frequency gamma rays were admitted the expansion of the universe stretched out the wavelength of these waves and they now appear microwave radiation.