the increase in the wavelength of light (and decrease in its frequency) caused by the movement of a star or galaxy away from us

the theory that the our whole universe started in a hot, dense state, then expanded and cooled over fourteen billion years

cosmic microwave background radiation is electromagnetic radiation produced in the hot early universe which has since been ‘stretched’ to the microwave part of the spectrum.

The changing universe

Physics

In the Solar system and beyond unit, pupils learnt about the scale and content of the Solar system and the universe, and about gravitational force and the motions that cause days and seasons on the Earth.

Gravity in space

Messier objects were first seen in the 17th century, using newly invented telescopes. In what ways is a **Messier object** different to a star?  

a variable star of changing brightness within the distant galaxy

a variable (distant) galaxy of changing brightness

the redshift of a star within the distant galaxy

What is used to measure the distance to a distant galaxy?

the further away from us they are, the faster they are moving through space

the further away from us they are, the faster they are orbiting around us

the further away from us they are, the faster they are moving away from us

the further away from us they are, the faster they are moving towards us

What is the relationship between the movement of galaxies and their distance from us?

According to the **Big Bang Theory**, where was all matter about 13.7 billion years ago?

Spiral galaxies are spinning faster and the universe is expanding more quickly than our current understanding has predicted. What ideas might explain what is going on and improve our understanding?

planets are often rocky or have a rocky core

an icy rock pulled towards the Sun from beyond Pluto

a rock pulled towards the Sun from the Asteroid Belt

an icy rock pulled towards the Sun from the orbit of a gas giant planet

a burning rock falling through Earth's atmosphere

by not looking at them through anything with a glass lens

by standing on top of a very high mountain

by looking on a completely clear night with no high clouds

How can we reduce the amount that stars twinkle when we observe them?

300 000 000 000 000 (three hundred trillion)

Approximately how many stars are there in the Milky Way galaxy?

The speed at which a galaxy is moving away from us can be calculated from its {{}}.

What absorbs particular frequencies of light to create absorption lines in light from a distant star?

Starter Quiz