50 Facts About Asteroids

Much like planets, these small, rocky celestial bodies make their journey around the Sun, but, asteroids are way too small to join the ranks of Mars, Venus and the Earth. Don’t be fooled by their size though! 66 million years ago, a single asteroid hit Earth, and wiped out an entire population of dinosaurs. So, keep on reading to discover 50 facts about Asteroids. 

Fact 1: In 1801, Giuseppe Piazzi discovered “Ceres”, what he believed to be an entirely new planet. 

  • He later found out that Ceres wasn’t a planet after all, but it was one of the millions of asteroids in space. 

Fact 2: Ceres measured 940 kilometres across.

  • At the other end of the scale, the smallest asteroid ever studied is the 2-meter space rock, ‘2015 TC25’, which was observed when it made a close flyby near Earth in October 2015.

Fact 3: The majority of the known asteroids in the solar system orbit the Sun in a band between the orbits of Mars and Jupiter.

  • This band is called the Asteroid Belt. 

Fact 4: Most asteroids are irregularly shaped, although a few of the largest are nearly spherical, such as Ceres. 

  • Moreover, the surfaces of most asteroids are usually covered in dust.

Fact 5: Asteroids are relatively small objects.

  • Only around 200 known asteroids measure more than 100km across. 

Fact 6: Over 600,000 known asteroids are found in our solar system alone. 

  • 150 of these known asteroids have a small companion moon, with some having 2 moons. 

Fact 7: It was Astronomer William Herschel who first coined the term “Asteroid” which means “star like”. 

  • Herschel constructed his first large telescope in 1774, after which he spent 9 years carrying out sky surveys to investigate double stars.

Fact 8: Theories suggest that the asteroid belt is actually made up of the remnants of a planet that failed to develop when the solar system began to form. 

  • However, according to NASA, the total mass of the belt is less than the moon and far too small to weigh in as a planet.

Fact 9: Ceres is not only the first asteroid to be discovered, but, it is also the largest known asteroid to date. 

  • It takes Ceres about 1,682 Earth days (4.6 Earth years) to make one trip around the sun. 

Fact 10: The average surface temperature of a typical asteroid is -100℉ (-73℃). 

  •  Moreover, asteroids have stayed mostly unchanged for billions of years.

Fact 11: In 2012, a company called Planetary Resources, Inc. announced its plans for extracting water and mining space rock, for precious metals, from asteroids. 

  • Shortly after this announcement, NASA has also begun working on plans for its own asteroid-capture mission. 

Fact 12: In September 2016, NASA launched OSIRIS-REx.

  • It stands for the Origins Spectral Interpretation Resource Identification Security-Regolith Explorer spacecraft which travelled to a Near-Earth asteroid, called Bennu. 

Fact 13: In 1991 ‘1991 BA’ was discovered, it is the smallest known asteroid and measures only 6 meters across.

  •  It is a mere speck compared to Ceres.

Fact 14: Most of the asteroids in the Main Belt are made of rock and stone.

  •  A small portion of them contain iron and nickel metals. 

Fact 15: In 2007, NASA’s launched its Dawn mission with the purpose of exploring Vesta in 2011. 

  • The spacecraft also made touch-down on Ceres in 2015, making it the first spacecraft to visit Vesta and Ceres. 

Fact 16: Apollo asteroids are a class of asteroids whose orbits cross with Earth’s.

  • The first Apollo asteroid was discovered in 1918 by Max Wolf, who observed this from Heidelberg, Germany. 

Fact 17: An asteroid impact around 65 million years ago caused a chain reaction that led to the sudden mass extinction of dinosaurs.  

  • It marked the end of the Cretaceous period and with it, the entire Mesozoic Era, opening the Cenozoic Era that continues today.

Fact 18: In 2006, Japan’s Hayabusa became the first spacecraft to land and take off successfully from an asteroid.

  • The spacecraft returned to Earth in June 2010, and the samples it recovered are currently under observation.

Fact 19: On June 30, 1908, an asteroid about .15 kilometres in width exploded over Siberia.

  • The explosion ripped through the air above a remote forest in Siberia, near the Podkamennaya Tunguska river.

Fact 20: In 1991, NASA’s Galileo became the first spacecraft to take close-up images of asteroids.

  • It was also the same aircraft that discovered the first moon to orbit an asteroid in 1994.

Fact 21: You can no longer name asteroids after your pets. 

  • However, in 1985, an astronomer received approval to name his asteroid Mr. Spock, after the cat that had kept him company during long hours at work.

Fact 22: Asteroids that come close to Earth are called ‘Near Earth Objects’, NEOs for short. 

  •  NASA keeps a close eye on these asteroids. 

Fact 23: One asteroid was named after Leonard Nimoy, the first actor who played the role of Spock in “Star Trek”.

  • On June 2, 2015, a 9.6- km wide asteroid was named ‘4864 Nimoy’ in his honour.

Fact 24: One theory of how life came to be on Earth suggests that asteroid and comet collisions may have been responsible for bringing water-ice and other carbon-based molecules to the planet. 

  • The frequent collisions essentially brought the life-building components to Earth and allowed life to evolve. 

Fact 25: Asteroids were formed at the same time as other objects in our solar system. 

  • These space rocks can give scientists a lot of information about the history of planets and the sun. 

Fact 26: Seven asteroids have been named in honour of the crew of the Space Shuttle Columbia who all perished in 2003. 

  • On February 1, 2003, the Space Shuttle Columbia disintegrated during atmospheric entry, killing all seven crew members.

Fact 27: In September 2017, the Near-Earth asteroid ‘3122 Florence’ cruised by Earth at a distance of 4.4 million miles away.  

  • The asteroid was 2.8 miles across and had two moons.  

Fact 28: On average, a meteoroid the size of a car enters the Earth’s atmosphere at least once a year. 

  • The meteoroid creates an impressive fireball which burns up before even reaching the planet’s surface.

Fact 29: 26% of a stony meteorite’s composition is iron.

  •   And 18% Silicon and 14% Magnesium.

Fact 30: Iron meteorites are made up from 91% iron. 

  • And Nickel 8.5% and Cobalt 0.6%. 

Fact 31: Some asteroids have their own moons orbiting around them. 

  •  In 1993, a tiny moon called Dactyl was discovered orbiting the large asteroid, Ida. 

Fact 32: ‘2 Pallas’ (with a diameter of 544km) and ‘4 Vesta’ (roughly 580km across) are two of the largest known asteroids that have been discovered. 

  • Both are rocky minor planets that astronomers have been observing since the 1800s.

Fact 33: Asteroids are not only rich in precious metals but contain water as well.

  • The metallic asteroids are composed of up to 80% iron and 20% a mixture of nickel, iridium, palladium, platinum, gold, magnesium and other precious metals such as osmium, ruthenium and rhodium.

Fact 34: An asteroid would have to be over a quarter-mile wide to cause a global disaster.

  • An impact would raise enough dust into the atmosphere to effectively create a “nuclear winter” which could severely disrupt agriculture around the world. 

Fact 35: On February 15, 2013, an asteroid slammed into the atmosphere over Chelyabinsk, Russia, injuring 1,200 people.

  • The space rock was about 65 feet wide when it entered the Earth’s atmosphere.

Fact 36: Metallic asteroids are often found in the middle region of the main belt. 

  • Metallic asteroids often appear reddish in colour and are mainly composed of nickel-iron. 

Fact 37: ‘C-type’ (or carbonaceous) asteroids make up 75% of all the known asteroids, making them the most common type of space rock. 

  • ‘C-type’ asteroids are greyish in colour and consist of clay and stony silicate rocks, and inhabit the main belt’s outer regions.

Fact 38: The ‘S-type’ (or siliceous) asteroids are greenish to reddish in colour and account for about 17% of known asteroids.

  • They are mainly found in the inner portion of the asteroid belt and are made up of silicate materials and nickel-iron.

Fact 39: Asteroids are found primarily in 4 groups.

  • There are the ones found in the main belt between Mars and Jupiter, those that are in the Kuiper belt, third are those in the scattered disc, and lastly, the space rocks found in the Oort cloud. 

Fact 40: ‘Amor’ asteroids have orbits that are close to Earth but do not cross the planet’s path.

  • These Near-Earth asteroids were named after the archetype object ‘1221 Amor’.

Fact 41: Sunlight has an effect on the motion of an asteroid.

  • In fact, just an ounce of force from an imbalance of sunlight is enough to steer asteroids into Earth-crossing orbits, and to drastically alter the layout of the solar system.

Fact 42: In September 2013, one asteroid came too close to the Earth and is expected to make a close encounter again in 2032. 

  • And if that asteroid does hit Earth, it would unleash a force equal to at least 2000 atomic bombs. 

Fact 43: An asteroid called Chariklo actually has its own ‘two rings’. 

  • Scientists made the surprise discovery in 2013 when they watched it pass in front of a star.

Fact 44: Trojan asteroids operate outside of the main belt.

  •  These asteroids share an orbit with the planet Jupiter. 

Fact 45: The term ‘near’ in Near-Earth asteroid is actually a misnomer.

  • NEO’s don’t come close to the planet at all.

Fact 46: Asteroids are often pitted or cratered.

  • For instance, the asteroid Vesta has a giant crater that is 285 miles wide!

Fact 47: More than 100 tons of material from asteroids and comets falls toward Earth each day.

  • These small pieces of space rock burst into a fireball upon entering Earth’s atmosphere and disintegrate before hitting the planet’s surface. 

Fact 48: NASA’s Psyche mission is set to launch in 2022 with the purpose of exploring an all-metal asteroid named ‘16 Psyche’.

  • What makes the asteroid Psyche so interesting is that it appears to have an exposed nickel-iron core.

Fact 49: According to the European Space Agency, roughly 10,000 of the known asteroids are Near-Earth Asteroids.

  • NEA’s include the Amor, Apollo, Atira and Aten asteroids. 

Fact 50: Earlier this month, NASA tracked a large space rock that zoomed past Earth at nearly 50,000 mph, narrowly missing the planet.

  • The U.S. space agency made the discovery on September 9, 2019. 


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