Asteroids
- Most asteroids orbit the sun in a belt between Mars and Jupiter.
- Believed by many scientists to be the remnants of a failed planet.
- Some asteroids are pulled free of their normal orbit by Mars' gravitational pull, thus sending them on an elliptical orbit which brings them close or within Earth's own orbit.
- Asteroids formed by aggregation of dust same as the planets aggregated, and at the same time.
- Ceres, the largest asteroid, began amalgamating all the other asteroids on its way toward becoming a small planet.
- Jupiter, however, prevented Ceres from completing its mission.
- Jupiter's mass and graivty disturbed the motions of the asteroids.
- As a result, collisions shattered much of the asteroids.
- Ceres remained at 914 km (568 miles) across.
- Dozens of asteroids ranging from 100-522 km (62-324 miles) also remained.
- And finally, tens of thousands of smaller fragments, most too small to catalog, complete the belt.
- Other groups of Asteroids orbit in other parts of the Solar System.
- Positions of orbits vary from near Earth to near Jupiter.
- Ceres provides us with a time-capsule of events in the solar system.
- Some 4.5 billion years ago, planetsimiles were scattered throughout space.
- Unlike science-fiction, asteroids are not as closely clustered in space.
- These bodies are far enough away that space, if viewed from Ceres, would be similar to that from Earth.
- Neighboring asteroids would appear occasionally as a bright "star" drifting across the night sky.
- A substantially closer look at an asteroid neighbor is likely about once in a million years.
- Four well-known asteroids are:
- 1 Ceres
- Discovered in 1801 - the first asteroid to be discovered.
- Length of one Revolution about the sun is about 4.6 Earth years.
- Distance from the sun is 2.77 AU.
- Broadest distance/diameter is 914 km or 568 miles.
- Gravity is 0.04 (where Earth's is 1.0).
- Composed of carbonaceous rock .
- No atmosphere.
- Pallas
- Discovered in 1802.
- Length of one Revolution about the sun is about 3.63 Earth years.
- Distance from the sun is 2.77 AU.
- Broadest distance/diameter is 522.
- Gravity is 0.02
- Composed of meteoric rock .
- No atmosphere.
- Juno
- Discovered in 1804.
- Length of one Revolution about the sun is about 4.61 Earth years.
- Distance from the sun is 2.67 AU.
- Broadest distance/diameter is 244
- Gravity is 0.01
- Composed of rock and iron.
- No atmosphere.
- 4 Vesta
- Discovered in 1807.
- Length of one Revolution about the sun is about 5.59 Earth years.
- Distance from the sun is 2.36 AU.
- Broadest distance/diameter is 500 km or 311 miles.
- Gravity is 0.02
- Composed of basaltic, meteoritic rock.
- No atmosphere.
- Other asteroids of interest:
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