Asteroids are small or minor planets that are members of the inner Solar System and that move in elliptical orbits primarily between the orbits of Mars and Jupiter.
Millions of asteroids exist, but their total mass is only a few hundredths of the mass of the Moon. These rocky fragments range in size from 1 km/0.6 mi to 900 km/560 mi in diameter.
The Chicxulub Impact was an asteroid that landed on the Yucatán Peninsula in Mexico around 66 million years ago. The event was the cause of the Cretaceous–Paleogene extinction event, a mass extinction in which 75% of plant and animal species on Earth became extinct, including all non-avian dinosaurs.
The first person to discover an asteroid was Italian priest and astronomer Giuseppe Piazzi in 1801. He discovered Ceres on January 1, 1807 naming it after the Roman goddess of agriculture. Ceres is 582 miles in diameter, the largest object in the asteroid belt that lies between the orbits of Mars and Jupiter. It is the only dwarf planet within the orbit of Neptune.
The word ‘asteroid’, meaning star-shaped, was coined by William Herschel in 1802.
German astronomer Heinrich Wilhelm Matthäus Olbers discovered 4 Vesta, the brightest asteroid and the second-most massive body in the asteroid belt in 1807.
Discovered on December 22, 1891, 323 Brucia was the first asteroid to be found by the use of astrophotography. It was also the first of over 200 asteroids discovered by Max Wolf, a pioneer in that method of finding astronomical objects.
In March 1989 an asteroid passed through the exact position where Earth was only six hours earlier.
On October 29, 1991 Galileo became the first spacecraft to visit an asteroid when it made a flyby of 951 Gaspra. The American spacecraft flew by it on its way to Jupiter.
The asteroid 243 Ida was the first asteroid found to have a moon when it was visited by NASA's Galileo probe on August 28, 1993. The moon, which is about 1.6 kilometers (1 mile) in diameter, was named Dactyl.
NASA's robotic space probe NEAR Shoemaker touched down on Eros on February 12, 2001, becoming the first spacecraft to orbit and soft land on an asteroid. To the surprise of the controllers, the spacecraft was undamaged and operational after the landing at an estimated speed of 1.5 to 1.8 meters per second.
The Chicxulub Impact was an asteroid that landed on the Yucatán Peninsula in Mexico around 66 million years ago. The event was the cause of the Cretaceous–Paleogene extinction event, a mass extinction in which 75% of plant and animal species on Earth became extinct, including all non-avian dinosaurs.
The first person to discover an asteroid was Italian priest and astronomer Giuseppe Piazzi in 1801. He discovered Ceres on January 1, 1807 naming it after the Roman goddess of agriculture. Ceres is 582 miles in diameter, the largest object in the asteroid belt that lies between the orbits of Mars and Jupiter. It is the only dwarf planet within the orbit of Neptune.
German astronomer Heinrich Wilhelm Matthäus Olbers discovered 4 Vesta, the brightest asteroid and the second-most massive body in the asteroid belt in 1807.
Discovered on December 22, 1891, 323 Brucia was the first asteroid to be found by the use of astrophotography. It was also the first of over 200 asteroids discovered by Max Wolf, a pioneer in that method of finding astronomical objects.
In March 1989 an asteroid passed through the exact position where Earth was only six hours earlier.
On October 29, 1991 Galileo became the first spacecraft to visit an asteroid when it made a flyby of 951 Gaspra. The American spacecraft flew by it on its way to Jupiter.
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| NASA image of 951 Gaspra; colors are exaggerated |
The asteroid 243 Ida was the first asteroid found to have a moon when it was visited by NASA's Galileo probe on August 28, 1993. The moon, which is about 1.6 kilometers (1 mile) in diameter, was named Dactyl.
The Galileo spacecraft also made other important discoveries about Ida. It found that Ida is a heavily cratered asteroid that is about 31 kilometers (19 miles) in diameter. It also found that Ida has a peculiar shape, with two large lobes connected by a narrow neck.
NASA's robotic space probe NEAR Shoemaker touched down on Eros on February 12, 2001, becoming the first spacecraft to orbit and soft land on an asteroid. To the surprise of the controllers, the spacecraft was undamaged and operational after the landing at an estimated speed of 1.5 to 1.8 meters per second.
Between 2006 and 2007, an asteroid about five meters across was temporarily captured by Earth’s gravity, giving us a tiny second moon for about nine months.
The Japanese Hayabusa space mission was the first to return samples of an asteroid (25143 Itokawa) to Earth for analysis.
After arriving at Itokawa, in November 2005, Hayabusa landed on the asteroid and collected samples in the form of tiny grains of asteroidal material, which were returned to Earth aboard the spacecraft on June 13, 2010.
The Jupiter trojans are a large group of asteroids that share the orbit of the planet Jupiter around the Sun. The first one discovered, 588 Achilles, was spotted in 1906 by German astronomer Max Wolf. By convention they are named after mythological figures from the Trojan War. Around one million of them are larger than 1 km in diameter.
The Japanese Hayabusa space mission was the first to return samples of an asteroid (25143 Itokawa) to Earth for analysis.
After arriving at Itokawa, in November 2005, Hayabusa landed on the asteroid and collected samples in the form of tiny grains of asteroidal material, which were returned to Earth aboard the spacecraft on June 13, 2010.
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| A computer rendering of Hayabusa above Itokawa's surface |
The Jupiter trojans are a large group of asteroids that share the orbit of the planet Jupiter around the Sun. The first one discovered, 588 Achilles, was spotted in 1906 by German astronomer Max Wolf. By convention they are named after mythological figures from the Trojan War. Around one million of them are larger than 1 km in diameter.
The asteroid 99942 Apophis, which is classified as a near-Earth and potentially hazardous asteroid, has a diameter of 370 meters (1,210 feet). It caused alarm in December 2004 when initial observations suggested that there was a 2.7% chance of a collision with Earth on April 13, 2029. However, subsequent observations provided more accurate predictions that ruled out the possibility of an impact in 2029. During the brief period when there was concern about its potential impact, Apophis achieved a record-high rating of level 4 on the Torino scale on December 27, 2004.
On Friday April 13, 2029, 99942 Apophis will pass by Earth closer than the moon and will visible to the naked eye from rural as well as darker suburban areas. It will be the closest asteroid of its size in recorded history.
TK7 was the first Trojan asteroid discovered sharing the Earth's orbit around the Sun. It was discovered in October 2010 by astronomers from Athabasca University, UCLA, and University of Western Ontario.
On January 22, 2014, ESA scientists reported the detection, for the first definitive time, of water vapor on Ceres. The finding was unexpected because while comets are typically considered to sprout jets and plumes, asteroids do not generally exhibit such features.
TK7 was the first Trojan asteroid discovered sharing the Earth's orbit around the Sun. It was discovered in October 2010 by astronomers from Athabasca University, UCLA, and University of Western Ontario.
On January 22, 2014, ESA scientists reported the detection, for the first definitive time, of water vapor on Ceres. The finding was unexpected because while comets are typically considered to sprout jets and plumes, asteroids do not generally exhibit such features.
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| Ceres Wikipedia commons |
594913 ʼAylóʼchaxnim (provisional designation 2020 AV2) is a near-Earth asteroid discovered by the Zwicky Transient Facility on January 4, 2020. It is the first asteroid discovered to have an orbit completely within Venus's orbit.
On September 26, 2022, NASA's Double Asteroid Redirection Test spacecraft deliberately collided with the asteroid the minor-planet moon of the asteroid Didymos. The space mission wanted to see how much a spacecraft impact deflects an asteroid through a transfer of momentum as a method of planetary defense against near-Earth objects (NEOs).
On Friday April 13, 2029, 99942 Apophis, a 370-meter diameter asteroid will pass by Earth closer than the moon and will easily be observed with the naked eye.
An asteroid hits the ground about 1,000,000,000,000,000,000 times harder than a raindrop.
Any asteroid 82 feet (25 m) in diameter or less won't make it to Earth's surface—it will burn up in the planet's atmosphere.
In spite of the way they are portrayed in sci-fi films, a space vehicle can travel safely through the asteroid belt. The distance between two objects in the asteroid belt ranges in the hundreds of thousands of miles. Astronauts would probably not even realize they were flying through the belt.
Ceres is the largest asteroid. It is 940 km/584 miles in diameter.
Vesta has a light-colored surface and is the brightest asteroid as seen from Earth.
A 100 mile-long asteroid in our solar system, 241 Germania, is believed to boast mineral wealth worth $95.8 trillion — nearly equivalent to the world’s total annual gross domestic product.
NASA believes the value of minerals on the asteroid belt exceeds $600,000,000,000,000,000,000.
The Kuiper belt is a circumstellar disc in the Solar System extending beyond the orbit of Neptune, at 30 to 50 astronomical units from the Sun. It is similar to the asteroid belt between Mars and Jupiter, but far larger—20 times as wide and 20 to 200 times as massive. Like the asteroid belt, it consists mainly of small bodies that are remnants from the Solar System's formation.
On Friday April 13, 2029, 99942 Apophis, a 370-meter diameter asteroid will pass by Earth closer than the moon and will easily be observed with the naked eye.
An asteroid hits the ground about 1,000,000,000,000,000,000 times harder than a raindrop.
Any asteroid 82 feet (25 m) in diameter or less won't make it to Earth's surface—it will burn up in the planet's atmosphere.
In spite of the way they are portrayed in sci-fi films, a space vehicle can travel safely through the asteroid belt. The distance between two objects in the asteroid belt ranges in the hundreds of thousands of miles. Astronauts would probably not even realize they were flying through the belt.
Ceres is the largest asteroid. It is 940 km/584 miles in diameter.
Vesta has a light-colored surface and is the brightest asteroid as seen from Earth.
A 100 mile-long asteroid in our solar system, 241 Germania, is believed to boast mineral wealth worth $95.8 trillion — nearly equivalent to the world’s total annual gross domestic product.
NASA believes the value of minerals on the asteroid belt exceeds $600,000,000,000,000,000,000.
The Kuiper belt is a circumstellar disc in the Solar System extending beyond the orbit of Neptune, at 30 to 50 astronomical units from the Sun. It is similar to the asteroid belt between Mars and Jupiter, but far larger—20 times as wide and 20 to 200 times as massive. Like the asteroid belt, it consists mainly of small bodies that are remnants from the Solar System's formation.
The Kuiper belt is home to three officially recognized dwarf planets: Haumea, Makemake, and Pluto, the largest and most massive member.
Sources Daily Express, Hutchinson Encyclopedia © RM 2011
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