Asteroids, Comets
and Meteoroids
What do you already know about Asteroids, Comets and Meteoroids
The Solar System is not just made up of planets, dwarf planets and moons. It also contains much smaller objects, some of which are held in orbit and others that are whizzing around!
Asteroids
Asteroids are made up of rock and metal. They come in all shapes and sizes, most are not a sphere shape like the planets and dwarf planets. They are usually a lumpy irregular shape covered in craters. Like the planets in the Solar System they orbit the sun.
Most Asteroids are contained within the Asteroid Belt, which is located between Mars and Jupiter in the Solar System. There are thousands of asteroids in the Asteroid Belt. No asteroids are bigger than the dwarf planets and in fact if you put all the asteroids in the Asteroid Belt together it would still be smaller than the Earth’s moon. There is a lot of space between asteroids in the Asteroid Belt as they are very spread out over a large area.
Asteroids are rocks left over from when the solar system formed billions of years ago. When this happened, the sun, planets and moons formed. Asteroids are leftovers from that happening.
NASA have sent unmanned spacecraft to fly past asteroids and one has even taken a sample from the surface of an asteroid near Earth called Bennu. The spacecraft then made its way back to Earth so the sample could be studied.
Vesta is the 2nd largest object in the Asteroid Belt. Ceres, a dwarf planet is the 1st biggest. It is around 326 to 330 miles wide.
NASA’s OSIRIS-REx spacecraft took this photo of the asteroid Bennu.
Meteoroids
Meteoroids are a much smaller version of an asteroid. Sometimes they are a part of an asteroid that has been broken off. They are made of rock or metal and most are about the same size as a pebble, however some are a bit bigger and some are even smaller. They are called meteoroids while they are floating out in space.
A meteor is a meteoroid that has entered the Earth’s atmosphere and burns up as it travels through the atmosphere at high speed.
A meteorite is a meteoroid that has entered the Earth’s atmosphere and carries on through right to the Earth’s crust crashing into the surface. This is often because it is large enough to survive the trip through the atmosphere. When it crashes into the Earth it will form a crater. This is also how craters have been created on other planets and moons in the Solar System.
Did you know...
It is thought a massive meteorite hit Earth and caused a chain reaction that killed all the dinosaurs. It crashed into Earth near to where Mexico is now.
This crater in South Africa was formed over 2 billion years ago by an asteroid hitting Earth estimated to be 6 - 15 miles wide.
Comets
Comets are made mainly of ice but also contain a small amount of dust or rock too.
Comets are found on the outer edge of our Solar System far away from the Sun. Sometimes though something causes them to change direction and a comet travels in the direction the Sun. As they travel through the Solar System and get closer to the Sun they start to melt and the ice turns to liquid and then a gas to create a ‘tail’ as they are moving.
Halley’s Comet is a well known comet as it is the only one discovered that can be seen by the human eye from Earth. Other comets discovered are much further away from us and special equipment is needed to view them. Halley’s Comet is made of ice, rock and dust. It orbits our Sun, travelling past Earth about every 76 years. When it gets close to the Sun, the ice starts to melt and creates a glowing head and a massive tail that can stretch for millions of miles. It was last seen by Earth in 1986 and will be seen again in 2061.
An image taken in 1986. There are recordings of Halley's Comet been seen in the past, one of which is the Bayeux Tapestry, created to record events in 1066.
What we've learnt...
Asteroids are rocks of all shapes and sizes up in space. Most are found in the Asteroid Belt.
The largest asteroid is the Vesta Asteroid. Ceres is larger but now called a Dwarf Planet.
Meteoroids are a much smaller version of an asteroid up in space.
A meteor is a meteoroid that has entered the Earth’s atmosphere and burns up.
A meteorite is a meteoroid that has entered the Earth’s atmosphere and crashes into the surface.
Comets are up in space and are made mainly of ice.
Test your knowledge...
Asteroids, Comets and Meteoroids Quiz
If you click the correct answer the box will turn green. If it’s the wrong answer it will turn red and then show you what the correct answer was. Remember to read/listen to the questions carefully! If you are listening to the questions using Text To Speech make sure you pause it after it has read the questions and answers so you have a chance to think!
#1. What is an asteroid?
#2. Where is the Asteroid Belt?
#3. What is the name of a rock that burns up in Earth’s atmosphere?
#4. What is the name of a rock that has hit Earth’s surface?
#5. What is the comet called that was last seen in 1986?
Results
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