Astrophysics

A large collection of billions of galaxies

Large collection of billions of stars

A star in the milky way galaxy

Orbit a star

Small planets

orbit planets

Orbit earth, built by humans

Lumps of rock and metal, found in asteroid belt, orbit sun

Lumps of ice and dust, highly elliptical orbits around sun

Provides the force that creates orbits

A force that pulls object toward the centre of a circle, caused by gravity

Constantly changing direction SO constantly accelerating SO resultant force

Tangent to the orbital circle

Mass (larger mass = larger gfs)
Distance (the closer you are to a star/planet, the stronger its gravitational field)

The larger the instantaneous velocity is needed to balance it

Elliptical and elongated
Long orbital periods
Tail points away from sun

When they are near the sun, the suns pull is stronger and they have most kinetic energy

When they are furthest from the sun where they have the most GPE

2 x pi x orbital radius / time period

1 day orbital periods
Orbit at same speed of earth rotating
Satellite dishes point at these satellites
Used for weather, communication, google earth

1. Nebula
2. Protostar
3. Main sequence star
4. Red/super red giant
5. White dwarf/supernova
6. Neutron star

A large cloud of dust and gas in space

Gravity pulls dust and gas together to form a protostar. As the temp rises, the particles gain energy and collide. The hydrogen nuclei undergo nuclear fusion to form helium nuclei. A star is born.

Thermal expansion and hydrogen are balanced

Hydrogen in core begins to run out, the star is compresses and then gains energy and expands into a red giant/super red giant

Small stars become unstable, eject outer layers of dust and gas and leave behind core

Big stars expand and contract several times and then explode into a supernova

The exploding supernova throws the layers of dust and gas into space, leaving behind a very dense core.

The hotter the star, the more light of higher frequencies it will emit, blue is the hottest, red is the coolest

How bright a star would be if it was a fixed distance from earth.

The lower the absolute magnitude, the brighter the star

A graph of absolute magnitude against temperature

A change in sound frequency caused by motion of the sound source, motion of the listener, or both.
This is because the wavelengths bunch up

Galaxies are moving away from one central point. The universe is expanding. The furthest galaxies are moving fastest
The black lines are shifting towards the red end of spectrum

Red shift – Universe is expanding, all matter started in one place?
Cosmic Microwave Background Radiation – Detecting CMBR everywhere we observe, leftover energy from explosion?