Universe

2. One of the basic building block of the universe, it is a massive system of stars, stellar remnants, gas, dust, and bound together by gravity.
4. The huge “explosion” 13.7 billion years ago in which the universe is thought to have been created.
6. It is the distance that light travels in one year.
7. Matter that gives out no light and does not interact with the electromagnetic force, but whose presence can be inferred from gravitational effects on visible matter.
8. A massive, luminous ball of gas.
9. A hypothetical “tunnel” through space-time that connects widely distant regions, thus providing a kind of short-cut through space-time.
10. A explosion caused by the collapse of an old massive star which has used up all its fuel.

1. The force of attraction that exists between any two masses.
3. is usually considered to have begun about 13.7 billion years ago in a gravitational singularity commonly known as the Big Bang.
5. A place in space where gravity pulls so much that even light cannot get out.