Asteroids (Near Earth Objects) and the Asteroid Belt

Asteroids are rocks of various sizes that orbit the Sun. Most asteroids are irregularly shaped, and Ceres stands out as it is spherical. Ceres was upgraded to dwarf planet status at the same time that Pluto was downgraded. The picture above is of a typical asteroid and this case it is Bennu.

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

Asteroids exist in two main areas around the Sun:-

• Asteroid Belt between Mars and Jupiter
• Kuiper Belt which is outside the orbit of Neptune, which are also known as Trans-Neptunian Objects.

This article is about the asteroids in the belt between Mars and Jupiter. The Kuiper Belt includes the now demoted planet of Pluto to dwarf-planet status.

Most of the asteroids are between those two planets, but some are closer to the Sun, and some are further out. Some asteroids have had close encounters with the Earth, such as the asteroid that went past in Jan 2017. Fortunately, the massive ones have not hit for millions of years. An asteroid that does hit the Earth's atmosphere is usually 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 meteor showers, the periodic time of year when the Earth passes through debris left by the asteroid, which burns up in the atmosphere.

Meteroids can also be broken off parts from an asteroid. The main difference can be the size. If it is large, then it is 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 word "asteroeides", aster "star" + -eidos "form, shape". They were discovered after a search was carried out by astronomers who wanted to determine if Johannes Kepler's theory was correct. Kepler predicted that the planets were spaced out according to a pattern of numbers. One of those numbers pointed to a location in space without a planet. After searching, Giuseppe Piazzi found the asteroid Ceres on January 1st, 1801. Google

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

Asteroid Facts

• An Asteroid is a large lump of rock that orbit the Sun, predominately in the Asteroid belt between Mars and Jupiter and the kuiper belt
• Oumuamua is the name of an asteroid that is said to have originated from outside.
• The largest object discovered in the Asteroid Belt is Ceres, which has now been upgraded to dwarf planet status.
• There are three class types of asteroids, Amors, Apollo and Aten
• the moons of Mars are believed to be captured asteroids that got too close.
• Sir William Herschel, the German-born British Astronomer, coined the term Asteroid from Aster (Star) and Eidos (Shape).
• Asteroid Belts are not like those portrayed in Star Wars or Farscape with them all be clumped close together.
• Asteroids have been known to have moons, such as Asteroid 243 Ida
• Those asteroids that orbit the sun near Earth are referred to as Near Earth Objects (N.E.O.s).
• Ceres contains one-quarter of all asteroid mass in the belt.

The Asteroid Belt

The Asteroid Belt is a large area of space where most of the asteroids in the The Solar System reside. Asteroids outside these areas are still referred to as asteroids.

On the Solar System's outskirts is another region with asteroids. The outer area is called the Kuiper Belt rather than the Outer Asteroid Belt. Despite what you might have seen in a film, the asteroid belt is not an area where the asteroids are close together. To use the cliche, you can go for miles without seeing an asteroid and then see two simultaneously.

Our Solar System is not unique, there's other stars out there with their own Asteroid Belts. The star Zeta Leporis has been identified as having an asteroid belt. Phys.

The asteroid 2021 PH27 orbits the Sun inside the orbit of Earth. It gets closer to the Sun than Mercury and does a complete orbit within 113 days. Only Mercury completes an orbit faster than the mentioned asteroid. Jerusalem Post.

Asteroid Belts 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. Alternatively, more likely seen in the Star Wars film Star Wars V - The Empire Strikes Back, where to escape from the chasing Empire, Han Solo flies the Millennium Falcon, hides in an asteroid belt and thinks asteroids are all close together. The truth is that asteroids are not as tightly packed as they are in the film.

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

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 character. Phaeton stole his father's (Helios, the Sun God) chariot and rode it disastrously, prompting Zeus to destroy it.

Part of the reason is the discredited Titus-Bode Law or just bodes. The law stated that planets would extend from the Sun twice as far as before. It had been correct to predict Ceres and Uranus but did not work for Neptune. Wiki

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

Although they probably did not result from a planetary collision, another theory exists. Another theory is that when the planets formed, the asteroids could not combine and form a planet themselves. The planet would be a dwarf planet, smaller than Mercury.

Asteroid Types / Categories

Asteroids fall into one of five main categories:-

• Amors - Asteroids which cross Mars orbit but do not quite reach the orbit of Earth. Eros -- a target of the NEAR mission -- is a typical Amor.
• Apollos - Asteroids which cross Earth's orbit for over one year. Geographos represents the Apollos.
• Atens - Asteroids which cross Earth's orbit for less than one year. Ra-Shalom is a typical Aten.
• Atira - Asteroids that orbit within Earth's Orbit.
• Centaurs - Asteroids that orbit the Sun between Jupiter and Neptune.

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

Asteroid Panspermia Theory

It was once thought that life hitch-hiked on a comet, but after Rosetta Space Probe landed on comet Churyumov-Gerasimenko. No evidence of amino acids was found, and attention has turned to asteroids and meteors.

It is believed that some asteroids, with their composition, could be ideal for seeding life on this planet. Some asteroids have been found to contain water, which is one of the main ingredients for life on this planet.

Earth is the only planet or moon that can support life. Imagine that a meteor or comet did bring life to Earth. What if that asteroid crashed on Mars? Mars is inhospitable for life, so life would probably not have survived except for some extremophiles. Extremophiles are tiny creatures known to survive in the most extreme and hostile environments that humans would not be able to. An example of an extreme environment is one such as a volcanic vent.

Interstellar Asteroids

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

An asteroid does not have to orbit the Sun to be classed as an asteroid. Oumuamua is said to have come from outside and is not on a circular path around 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 asteroid off as an alien spaceship. The proponents of the theory believe that the aliens on board have either died or have decided that we are just not that interesting for communication.

Based on some 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.

Chances of an Asteroid Strike?

The chances of an asteroid strike are meagre. The last asteroid strike that did real damage was the asteroid that killed the dinosaurs millions of years ago. Asteroids constantly hit our planet, and they normally burn upon impact. Those that make it to land are so tiny that damage is minimal. An asteroid has killed a few people, but I would not lose sleep over it.

How are asteroids named?

Planets and dwarf planets are named after deities from Mercury to Sedna. Stars are given identification numbers; only bright stars like 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 the Taliban shot her.

The number associated with an asteroid, for example, 243, is associated with Ida, which means it is the 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 re-graded, while Pluto was downgraded to that of a Dwarf Planet. As asteroids are being discovered constantly, giving you the highest number is impossible and always changing.

They can also be dedicated to fictional characters such as James Bond, the British fictional spy or 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 discover an asteroid or do something good to get people's attention.

Do asteroids have moons?

Wrong, the first such asteroid 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 August 28th 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.

What are Asteroids made of?

Asteroids are, as said before, large lumps of rock. Some are not too dissimilar to the rocks we have on this planet. There are three main types of composition for asteroids. An asteroid can contain a mixture of compositions.

• Carbon - These are those that are closer to the Sun, which consists of carbon with trace amounts of oxygen, hydrogen and nitrogen.
• Silicates - These are further out from the Sun and consist of Oxygen and Silicon.
• Metallic - These contain large amounts of iron and nickel.

Once we enter space, the next race will be to mine and take control of the asteroids for their precious materials. The contents of these rocks will be of high value to The Future corporations of the Earth as we are using up all the natural resources left on Earth. World Atlas

Biggest/major Asteroids

The table below details a few asteroids whose information is 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. If you want more information on asteroids, then visit the NASA site. Some pages, when selected, will contain a picture of the asteroid, and 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 must enter the number with the name appended. For the F.F. asteroid, enter the name 1995FF to get the details.