Astronomy Facts

28 May 2007

related tags: Science | Space | MSN Encarta |

1. Jupiter, Saturn, Uranus, and Neptune all have rings.

2. The Sun is middle-aged; it’s halfway through its 10-billion-year lifetime.

3. Astronomers think that all of the normal matter in the universe makes up
only about 5 percent of the contents of the universe. Dark matter is thought
to make up about 25 percent, and a strange form of energy known as the
cosmological constant is thought to make up the remaining 70 percent.
Venus

4. As a result of the greenhouse effect, Earth’s average temperature is
comfortable rather than freezing, and Venus is a horrid place, hot enough to
melt lead.

5. Pulsars are dead stars that have collapsed. Some spin around in as
little as 1/500 second, pretty fast for a body that contains as much mass as
the Sun.

6. The Sun–as big as it seems to those of us on Earth–is actually on the
small side for a star. It’s a dwarf star; giants and supergiants are much
larger, and neutron stars are even smaller.

7. Earth’s galaxy, the Milky Way, contains about 400 billion stars. That’s
not all: There are hundreds of billions of other galaxies in the universe,
some of which are much larger and contain many more stars than the Milky
Way.

8. Wherever you are in the universe, distant clusters of galaxies seem to
move away from you. The farther away they are, the faster they recede. This
leads many astronomers to believe that the universe is expanding.

9. Astronomers have discovered dozens of planets orbiting stars other than
the Sun. We know of many more planets outside our solar system than inside.

10. Explosions on the Sun send particles into space, creating luminous
displays called auroras that can be seen from Earth.

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