Asteroids are large rocks that are from the formation of the Solar System. The word asteroid literally translates to “star rock” in Latin. They are known as minor planets because of their size, which is bigger than a meteor but smaller than a planet. Three of the larger asteroids are Ceres, Pallas, and Vesta.
The Main Asteroid Belt is a large ring of asteroids located between the orbits of Mars and Jupiter. The asteroid belt appears patchy when seen because there are large clusters of asteroids in some areas and none in other areas. This patchiness (Kirkwood Gaps) is caused by Jupiter’s gravitational impact on the belt.
Jupiter prevent any objects from forming in the gap between Mars and Jupiter This caused the small objects that were there to collide with each other. The collusion created what is known as an asteroid. Thousands of asteroids gather together in the Main Asteroid Belt.
The Dawn Mission
The Dawn mission was created to study the asteroid Vesta and dwarf planet Ceres. From 2011 to 2012, the space-craft explored the giant asteroid Vesta, delivering new insights and thousands of images. After about a year of studying Vesta, it begins its orbit for Ceres in 2012. The Dawn mission goals was to characterize the condition and progress the occurrence of space million of years ago. The Dawn mission hopes to create a picture of what the solar system looked back in time.
These asteroids were all named after the female family members of Jupiter, a Roman god. Ceres, his sister, Vesta, another sister, and Pallas, his daughter. Much of the femininity is left out of astrology, but these asteroids help add the femininity back into the astrological chart.
In January 1, 1801 Giuseppe Piazzi, an Italian Catholic priest, discovered and named the minor planet after the Roman goddess of agriculture. Ceres is the largest asteroids and was the first to be discovered. Ceres is similar to Earth because it is separated into a crust, mantle, and core. Its diameter is approximately 974 kilometers and it rotates every 9.08 hours. Its gravity is 19% of the moon’s gravity, 8.31% of Mars’ gravity, and only 3% of Earth’s gravity. It orbits the sun 17.882 km/s for approximately 4.60 earth years. The average mass of this asteroid is 9.4 x 10^20 kg, which is 4% the mass of our Moon.
On March 28, 1802 Pallas was discovered approximately one year after Ceres. Heinrich Wilhelm Olbers, a German astronomer and physician named the asteroid after the goddess of wisdom. Pallas was originally classified as a comet, but was reclassified because of its uniformed motion was uncharacteristic to a comet. The mass of Pallas is 22% of the mass of Ceres. It has a diameter of 522 kilometers. Every 3,000 years, Pallas will lap Ceres because of its 35 degree orbital inclination. The mass of Pallas is 22% of the mass of Ceres. This asteroid appears dimmer due to it being relatively farther away from Earth. Analysis of an impacted crater on the asteroid has indicated that Pallas was hit by something large in the past, generating lots of fragments. It is thought that this impact may have produced the "Pallas family" objects that continue to orbit with the asteroid to this day.
On March 29, 1807 Heinrich Wilhelm Olbers discovered Vesta, making it the fourth asteroid to be discovered. Vesta is the second most massive asteroids in our Solar System. The asteroid measures 578 km by 458 km and has a mass of 2.67 x 1020 kg. Although Vesta is about half the size of Ceres, it appears brighter in our sky, because its surface is whiter than that of Ceres, reflecting a lot more of the sun's light. Vesta rotates on its axis every 5.342 hours and has an axial tilt of 29º. Hubble images have revealed ancient lava flows because of its melted interior. Vesta's surface is dry, which may be caused by its closer distance to the sun. This leads to the belief that asteroids are simple cold, dead rocks floating in space. There is a gigantic impact basin so deep that it exposes the asteroid’s mantle at the South pole. The mantle is thought to be 10 km below the asteroid’s surface.
Dawn Mission - http://dawn.jpl.nasa.gov/science/Why.html
Nomenclature - http://www.alwaysastrology.com/asteroids.html