Astronomy

3. Most famous dwarf planet.
5. a hypothetical structure connecting disparate points in spacetime, and is based on a special solution of the Einstein field equations.
6. an interstellar object of planetary mass which is not gravitationally bound to any star or brown dwarf.
8. The hottest planet in the solar system
10. They result from the supernova explosion of a massive star, combined with gravitational collapse, that compresses the core past white dwarf star density to that of atomic nuclei.
11. the second biggest planet in the solar system.
12. a fundamental interaction which causes mutual attraction between all things with mass.
13. a layer of gas or layers of gases that envelop a planet.
16. a physical theory that describes how the universe expanded from an initial state of high density and temperature.
18. a star of relatively small size and low luminosity.
19. hypothetical form of matter thought to account for approximately 85% of the matter in the universe.
20. The largest planet in the solar system
21. any planet beyond our solar system.

1. A place in space where gravity pulls so much that even light can not get out.
2. a powerful and luminous explosion of a star.
4. The biggest black holes in the universe.
7. a giant cloud of dust and gas in space.
9. a stream of charged particles released from the upper atmosphere of the Sun called the corona.
14. The galaxy which will colide with the Milky Way
15. The closes planet to the sun.
17. a path of a body revolving around an attracting centre of mass, as a planet around the Sun or a satellite around a planet.