2007-03-01 16:56:45 · 6 answers · asked by Rachel 3 in Science & Mathematics ➔ Astronomy & Space
98% of asteroids are in the main asteroid belt between Mars and Jupiter,
The mass of the entire belt totals only 4% of the mass of our moon and the mass of Ceres (the first to be discovered and the largest by far) is one third of the mass of the entire belt,
Which might lead you to think that there are not that many asteroids in the belt but you would be wrong.
We are now finding them at a rate of about 5,000 a month, using automated search facilities.
As of January 6, 2007, from a total of 364,833 registered minor planets, 147,951 have orbits known well enough to be given permanent Minor Planet Centre official numbers.Of these, 13,554 have official names
Current estimates put the total number of asteroids above 1 km in diameter in the solar system to be between 1.1 and 1.9 million.
The thing to realise is that there are very few large asteroids and huge numbers of small ones.
The mass of all the asteroids of the Main Belt is estimated to be about 3.0-3.6×10^21 kg, or about 4% of the mass of our moon. Of this, 1 Ceres comprises 0.95×10^21 kg, some 32% of the total. Adding in the next three most massive asteroids, 4 Vesta (9%), 2 Pallas (7%), and 10 Hygiea (3%), brings this figure up to 51%; while the three after that, 511 Davida (1.2%), 704 Interamnia (1.0%), and 3 Juno (0.9%), only add another 3% to the total mass. The number of asteroids then increases rapidly as their individual masses decrease.
But the largest 7 asteroids between them have 54% of the total mass of the belt,
It is thought that these asteroids are remnants of the protoplanetary disc, and in this region the incorporation of protoplanetary remnants into the planets was prevented by large gravitational perturbations induced by Jupiter during the formative period of the solar system. Some asteroids have moons or are found in pairs known as binary systems.
The view that these are the shattered remnants of a planet that lay between Mars and Jupiter is no longer regarded as credible,
2007-03-01 17:27:27 · answer #1 · answered by Anonymous · 0⤊ 0⤋
More than 10,000 objects have been identified. Numerous smaller object are present. The number is not a constant since some asteroids may be in contact, help together by their feeble gravity, but get pulled apart when passing by a large asteroid.
2007-03-01 17:08:11 · answer #2 · answered by novangelis 7 · 0⤊ 0⤋
11
2007-03-01 17:00:34 · answer #3 · answered by Eric 2 · 0⤊ 1⤋
No exact count has ever been achieved because there are still many asteroids that haven't been detected for one reason or another.
2007-03-01 17:08:17 · answer #4 · answered by Chug-a-Lug 7 · 0⤊ 0⤋
Countless
2007-03-01 17:08:53 · answer #5 · answered by anusen1970 2 · 0⤊ 1⤋
about one planet's worth, roughly triple the size of neptune
hmmmm.......
2007-03-01 16:59:04 · answer #6 · answered by ỉη ץ٥ڵ 5 · 0⤊ 1⤋