| Question |
Answer |
| geocentric | an earth-centered universe |
| cosmic address | place of earth in the universe |
| galaxy | great island of stars in space |
| Milky Way | galaxy in which our solar system resides |
| Local Group | a group of galaxies |
| galaxy clusters | galaxies with more than a few dozen members |
| super cluster | a region of tightly packed galaxies |
| universe | the sum total of all matter and energy |
| expanding | average distances between galaxies increase with time |
| Big Bang | the beginning of expansion - 14 billion years ago |
| nuclear fusion | the process by which atomic nuclei smash together to make a heavier nuclei |
| supernova | titanic explosion in which a star dies |
| early universe | made up of hydrogen and helium |
| age of the solar system | 4.5 billion years |
| speed of light | 300,000 km per sec |
| light year | distance light travels in a year - 6 trillion miles |
| brightest star | Sirius |
| fact of light | the farther away we look in distance, the further back we look in time |
| Orion Nebula | a giant cloud in which stars and planets are forming |
| Andromeda Galaxy | closest galaxy - 2.5 million light years |
| age of universe | 14 billion years |
| observable universe | the portion of the universe that we can observe |
| definition of planet | 1) orbits around a star
2) round shape
3) clear neighborhood around orbit |
| number of stars | more than 100 billion |
| speed of Earth | 600 miles per hour |
| astronomical unit | Earth's average orbital distance - 93 million miles |
| ecliptic plane | a flat plane defined by the Earth's orbital path |
| axis tilt | 23.5 degrees |
| Polaris | name for the North Star |
| speed of solar system | 500,000 miles per hour |
Spanish 3
