Beyond The Milky Way
Science: KS3, topic 3.6.5
Beyond The Milky Way
There are at least 100 billion galaxies in the Universe. Each galaxy is thought to contain 100 billion stars. On a clear night, you could view up to 5,000 stars in the night sky.
Other galaxies
- Galaxies are held together by gravitational forces.
- Our nearest galaxy after The Milky Way is called Andromeda.
- We are unable to see most galaxies because they are too far away.
- The Milky Way is a spiral galaxy.
- Other galaxy types include elliptical and irregular.
Life and death of stars
- Stars are formed in nebulae, which are clouds of dust and gas.
- Stars use hydrogen gas as a fuel, which they convert into helium.
- When stars run out of hydrogen, they will die.
- Large stars will explode in a large explosion called a supernova.
- After a star explodes as a supernova, it can form a black hole.
The Big Bang
- All of space is contained within the Universe.
- The Big Bang theory says that all matter was created in a large explosion over 13.7 billion years ago.
- Before the Big Bang, everything that we see in our Universe today was focused in a tiny single point.
- After the Big Bang, the tiny single point expanded and is still expanding today.
- As the Universe expands, it slowly cools.
Test yourself on Beyond The Milky Way
Which of these is NOT a type of galaxy?
Which of the following is true of our Universe?
The Big Bang
The Universe cools as it expands. What would most likely happen to its temperature if the expansion stopped?
Andromeda is our next nearest galaxy after the Milky Way. What does this tell us about the distance of other galaxies from us?