Space Physics

Gravitational Force Formula

W = m x g

Orbital Motion Proportionality

The greater the mass of the planet, the stronger the gravitational PULL.

Orbital Speed Formula

V = 2Pir/T

Why does a Satellite stay in Orbit?

A satellite stays in orbit because its forward motion balances the gravitational force. The faster its going, the higher it can orbit.

Describe and explain what happens when an interstellar cloud forms a protostar.

The gravitational attraction between dust and gas particles causes them to draw closer together, when this happens, pressure is increased as particles get closer.

Describe and explain what happens as a protostar becomes a stable star.

A protostar becomes a stable star when the inward force of gravitational attraction is balanced by the outward force of temperature increase.

State what is meant by a moon.

A natural object orbiting a planet.

What happens when the sun runs out of hydrogen?

When the sun runs out of Hydrogen to fuse, the outward pressure can no longer balance the inward gravitational force, causing it to collapse as it expands into a red giant. It sheds its outer layers as a planetary nebula and leaves behind a white dwarf.

State what is meant by Redshift.

Redshift is the increase in the wavelength of light from distant galaxies, making the light shift towards the RED end of the spectrum.

Why does redshift happen.

As a galaxy moves away from us the light waves it emits are stretched, this stretching increases the wavelength and decreases the frequency causing a redshift.

How is Redshift evidence for expansion?

Redshift is direct evidence that the universe is expanding, the higher the redshift, the faster the galaxy is moving, the further it is from us.