The Universe Flashcards
What is a galaxy?
A large collection of stars, planets, as and dust held together by gravity.
What galaxy do we live in?
The Milky Way
Approximately how many stars are in the Milky Way?
About 100 billion
What is a light-year?
The distance light travels in one year, roughly 9.46 trillion km.
How far is Andromeda, our closest galaxy neighbour?
About 2 million light years away
What are quasars?
Extremely distant, energetic objects believed to be powered by black holes.
How far is Earth from the center of the Milky Way?
About 28 000 light years
What is the Oort Cloud?
A spherical shell of icy objects surrounding the solar system, marking its outer boundary.
What is the observable universe?
The portion of the entire universe that we can observe from Earth.
Define supercluster:
A massive group of smaller galaxy clusters.
What is a nebula?
A cloud of gas and dust in space, often a region where new stars are formed.
What is the distance from Earth to the nearest star, Proxima Centauri?
About 4.3 light years
What shape is the Milky Way?
A barred spiral galaxy
What is the universe expanding into?
It is expanding in all directions, increasing the space between galaxies.
What is dark energy?
A mysterious force causing the acceleration of the universe’s expansion.
What is the age of the universe?
Approximately 13.7 billion years
What is cosmic background radiation?
The thermal radiation left over from the Big Bang.
What is a black hole?
A region in space where gravity is so strong that not even light can escape.
What is the Big Bang Theory?
The theory that the universe began as a single point and has been expanding since.
