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Asteroid Belt, Near Earth Objects

Asteroid Facts

What is an Asteroid?

In the most simplestic of terms, Asteroids are rocks of various sizes that orbit the Sun. The majority of asteroids are irregular shaped, Ceres is one that stands out as it spherical in nature. Ceres was upgraded to Dwarf Planet status at the same time that Pluto was downgraded.

Asteroids are also referred to as Minor Planets and the I.A.U. site that monitors them is known as I.A.U. Minor Planet Center . Those that come close to Earth are known as Near Earth Objects.

Asteroids exist in two main areas around the Sun, the first is the Asteroid Belt between Mars and Jupiter and the second is in the Kuiper Belt outside the orbit of Neptune, which are also known as Transneptunian Objects . This article is about the belt between Mars and Jupiter. The Kuiper Belt includes the now demoted planet of Pluto to dwarf-planet status.

The vast majority of the asteroids are between those two planets, however there are some that closer in to the Sun and there are some that are further out. A number of asteroids have had close encounters with the Earth such as the asteroid that went past in Jan 2017. Fortunately, the really big ones have not hit for millions of years. An asteroid that does hit the Earths atmosphere is tended to be referred to as a meteor.

Asteroids and meteoroids were created when the universe was young or as a result of a collision. Some travel through space on a circular journey, others erratically. Some asteroids have been known to be the source of meteors showers, the periodic time of year when the Earth passes through a large amount of debris which they burn up in the atmosphere.

Meteroids can also be broken off parts from an asteroid. The main difference can be the size, if its large then its an asteroid, anything smaller is a meteoroid. There is no real clear size definition for when an object is an asteroid or a meteor.

The term Asteroids was coined by Sir William Herschel from the greek asteroeides, aster "star" + -eidos "form, shape". They were discovered after a search was carried out by astronomers who wanted to find out if a theory by Johannes Kepler was correct or not. Kepler predicted that the planets were spaced out according to a pattern of numbers. One of those numbers pointed to a location in space where there was no planet. After searching, the asteroid Ceres was found on the 1st January 1801 by Giuseppe Piazzi. Google

After Ceres was discovered, more asteroids were found which led astronomers to the conclusion of a asteroid belt containing hundreds of small and large objects. Their paths are erratic, it is believed that one of these asteroids hit Earth and caused the death of the dinosaurs.

Asteroid Field in Films

You've also probably seen Farscape episodes such as Bone to be Wild where the crew of Moya hide out in an asteroid field or more likely in the Star Wars film Star Wars V - The Empire Strikes Back where in order to escape from the chasing Empire, Han Solo flies the Millennium Falcon hides in an asteroid belt and think asteroids are all close together. The truth is that asteroids are not tightly packed in as they are in the film.

The gaps between the asteroids are vast and can easily be navigated. Asteroids are forever being discovered as there is so many and not all have monitored. Asteroids are monitored in case they plan to get to close. They are far too many of them to list. What we do know is that none of them competes with the largest asteroids for size, if they did, we probably known about them now.

Are the asteroids the remains of a Planet?

There is a theory that all the asteroids were once part of a planet in ancient times. That planet is referred to as Phaeton after the Greek Mythological characterl. Phaeton stole his father (Helios, the sun God)'s chariot and rode it with disastrous results which prompted Zeus to destroy it.

Part of the reason is the discredited Titus-Bode Law or just bodes. The law stated that planets would extend out from the sun twice the distance as the one before. It had been correct to predict Ceres and Uranus but didn't work for Neptune. Wiki

The total mass of all the asteroids in the belt is only about 4% the mass of the moon and less of the Earth. Of those asteroids, the largest four asteroids (Ceres, Vesta, Pallas, Hygiea) make up half the mass of all the asteroids. In addition, the asteroids are composited of different materials signifying that they are from different sources. If the asteroids were the result of a planet then they should all have the same composition. Cornell

Although they were probably not the result of a planet that was smashed up, there is another theory to their existence. Another theory is that when the planets were forming, the asteroids were not able to merge and form a planet themselves. The planet would be a dwarf planet, smaller than Mercury.

Asteroid Types / Categories

Asteroids fall into one of three main categories :-

The biggest asteroid is Ceres, now classed as a dwarf planet. It is situated between Mars and Jupiter and doesn't resemble a planet that we would recognise, i.e. a sphere. It is named after the goddess of harvest.

It was once thought that life hitch-hiked on a comet but after rosetta space probe landed on Comet Churyumov-Gerasimenko but failed to find any evidence of amino acids, attention has turned to asteroids and meteors.

Interstellar Asteroid (Oumuamua)

An Interstellar Asteroid is one that travels between two star systems. At present we know of one such asteroid, that asteroid is known as Oumuamua. The asteroids name is a Hawaiian word meaning Scout. A Hawaiian word was chosen because it was discovered by scientists in Hawaii.

An asteroid doesn't have to necessarily orbit the Sun to be classed as an asteroid. Oumuamua is said to have come from outside the Solar System and isn't on a circular path round the Sun. N.A.S.A. refer to it as an asteroid so there you go, an asteroid is just a large piece of rock in space.

Some people have tried to pass the rock off as an alien spaceship. The proponents of the theory believe that the aliens onboard have either died or have decided that we are just not that interesting to communicate with.

Based on a number of calculations, scientists believe that the source of the asteroid could be Hip 3757 in the constellation of Cetus or HD 292249 in the constellation of Monoceros.

What is the chance of an Asteroid Strike?

Low, very low, the last asteroid strike that did real damage was the asteroid that killed the Dinosaurs millions of years ago. Our planet is hit constantly by asteroids, they normally burn up on impact. Those that do make it to land are so tiny that damage is minimal. A few people have been killed by an asteroid but I wouldn't loose sleep over it.

How are asteroids named?

Planets and dwarf planets are named after deities from Mercury to Sedna. Stars are given identification numbers and only bright stars such as Sirius have traditional / proper names. Asteroids can be named after the person who discovered them such as 792 Metcalfia whose discoverer was Joel Hastings Metcalf.

An asteroid can be dedicated to someone, someone who had impressed the discoverer, such as 316201 Malala which was dedicated to the young female rights activist Malala Yousafzai, the young Pakistani girl who came to world attention when she was shot by the Taliban.

The number associated with an asteroid which for example, 243 is associated with Ida means it is 243rd asteroid to have been discovered. Therefore the asteroid first discovered is also the largest, Ceres. Ceres was once a planet before being downgraded to an asteroid. It was regraded at the same time Pluto was downgraded to that of a Dwarf Planet. As asteroids are being discovered all the time, it is not possible to give you the highest asteroid number, its always changing.

They can also be dedicated to fictional characters such as James Bond, the British fictional spy or to Donald Duck, the Disney cartoon character. James Bond's asteroid's ID is 9007 so it was thought logical at the time to name the asteroid after the character. In conclusion, if you want an asteroid named after you, all you need to do is to discover an asteroid or do something good that will get peoples attention.

Do Asteroids Have Moons?

Wrong, the first such asteroid that was discovered to have a moon was Asteroid 243 Ida. It was first acknowledged that asteroids could have moons in February 1994 when scientists discovered that when the Galileo space probe flew past on 28th August 1993, the probe had taken a photo of Ida and its moon Dactyl. N.A.S.A.

Ida is named after the Greek Mythical Nymph Ida who looked after Zeus when he was a baby. Dactyl is the name of mythical creatures that lived on Mount Ida on Crete, a Greek Island.

List of the biggest/major Asteroids?

The table below details a number of asteroids whose information is made available from the N.A.S.A. website. Clicking on a link will allow you to see more information and possibly a photo of the asteroid in question. If you want more information on asteroids then visit the NASA site. Some pages when selected will contain a picture of the asteroid, some will contain the path the asteroid takes. If I have not generated a path picture for the asteroid you want, visit the NASA Asteroid Simulator and replace 'CERES' with the asteroid you want e.g. Chiron. For some asteroids you will need to enter Number with the Name appended. For the FF asteroid, enter the name 1995FF to get the details.

NameOrbital PeriodOrbital Eccentricity
Ceres 4.60.0760091
1995 FF3.540.707
Anne Frank3.290.643
1989 JA2.350.484
1994 PC11.560.328
James Bond3.890.1529682
1998 VD351.960.4764134
1998 DV92.310.433
1998 WT240.610.4176079
1997 XF111.730.4839260
1999 GU330.5066437
2000 GE22.020.5553660
1998 OR23.70.5724495
2002 EY22.270.487
1989 UQ0.880.2645364
1998 FH121.140.5396870
2002 NT72.290.5288348
1992 UY44.330.6185427
1994 CC2.090.4170200
1999 AN101.760.5621658
1999 BJ82.620.5499278
1997 NC10.810.2081955
1998 FW43.950.7207825
2000 WO1070.870.7806842
1998 SH361.130.5708843
1999 DB71.320.1947923
2002 CU111.350.2952510
1999 VP111.130.5835692
1998 BB101.430.4246656
2000 DP1071.590.3766546
1999 AQ100.910.2356715
2000 RS111.450.3206528
1998 SC151.440.4145031
1998 TA1.910.479
2000 RD532.340.4276651
2001 GQ21.340.5030368
1999 MN0.550.6654310
2000 QW72.730.4681603
1999 FA1.120.1327468
1999 SO51.130.0652315
2000 DO11.70.6819185
2001 FE902.680.4945854
2000 UG112.670.5729651
1989 UP2.550.4718604
2000 YF291.820.3710597

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Comments and Questions

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who was the discover
Donald, good point, I will check and correct my information.
You have a great web site! Should not you list the last column of the asteroid data as (Earth) years, and not days? Even a high-speed bullet couldn't travel around the 'Sun' within the times stated.
what is the real meaning of asteroids and which mineral does it contain
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