1						2
						3
								4								5
																6					7
						8
									9
						10
	11
															12
												13
										14
15
																				16
										17
									18
							19
														20

Across 3. The branch of science that deals with celestial objects, space, and the physical universe as a whole 4. a type of galaxy with spiral arms emerging from a smooth central hub. Also called a pinwheel galaxy 5. What is the abbreviation for Global Positioning System 6. A hot luminous massive ball of gas that makes energy by nuclear fusion 9. a spiral galaxy with a central bar-shaped structure composed of stars. 10. an artificial satellite stationed in space for the purpose of telecommunications. ... 13. The path of one object around another, more massive object in space 15. the violent event that gave birth to the universe about 13 billion years ago; The explosion of dense matter that, according to current cosmological theories, the event that marked the origin of the universe 17. who confirmed the exsistance of other galaxies outside our own 18. One of the factors that make up a galaxy 19. a body consisting of millions of stars, gas and dust held together by gravity and seperated from other galaxies by empty space 20. A cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter.

Down 1. A satellite orbit that goes from pole to pole and is generally 800km above the earth 2. an orbit above the equator in which a satellite takes the same time to circle Earth as Earth takes to spin on its axis. 7. A galaxy with an oval or round shape and no spiral arms; they are mostly made up of old stars 8. is the collection of objects in orbit around Earth that were created by humans 11. The force that attracts a body toward the center of the earth, or toward any other physical body having mass. 12. The galaxy in which we live; also the pale band of stars running across the sky when we look along th eokane of our galaxy 14. A galaxy that cannot be classed as ellipticals, spirals or barred spirals and has no regular shape or form 16. A group of galaxies held together by gravity