Astronomy

3. a celestial object of very small radius (typically 30 km) and very high density, composed predominantly of closely packed neutrons.
6. a large planet of relatively low density consisting predominantly of hydrogen and helium
7. a unit of astronomical distance equivalent to the distance that light travels in one year
9. fifth planet from the Sun and the largest in the Solar System.
10. a region of space having a gravitational field so intense that no matter or radiation can escape.
11. a darkening of the moon caused by its entering the earth's shadow.
12. a small rocky body orbiting the sun.
13. a theoretical boundary around a black hole beyond which no light or other radiation can escape.

1. luminous giant star of low or intermediate mass in a late phase of stellar evolution
2. the curved path of a celestial object or spacecraft around a star
4. a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.
5. a region of the solar system beyond the orbit of Neptune
8. a star that suddenly increases greatly in brightness because of a catastrophic explosion that ejects most of its mass.