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Year 5 - Space : Breaking Boundaries: Asteroids, Meteorites and Bolides


The four largest asteroids: 1 Ceres, 4 Vesta, 2 Pallas, and 10 Hygiea
(Image source:

An asteroid is a space rock. It is a small object in the Solar System that travels around the Sun.  Asteroids are the leftover rock and other material from the formation of the Solar System. These rocks were too small to come together to make a planet and they range from very small (smaller than a car) to 600 miles (1000 km) across. Most asteroids in our Solar System are in the asteroid belt between Mars and Jupiter and the ones that come close to Earth are called Near-Earth asteroids.

Meteors and Meteorites

From Meteoroid to Meteorite
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Sometimes, when asteroids smash into one another, small pieces can break off and they are called meteoroids. They range in size from large pieces of rock to tiny dust particles. If a meteoroid comes close enough to Earth and enters Earth’s atmosphere, it vaporizes and turns into a meteor: a long streak of light in the sky. Sometimes, when many meteors fall and enter the Earth's atmosphere at the same time, it is called a meteor shower. When a meteor fall and don’t vaporize completely in the atmosphere and land on Earth, it is called a meteorite.


(Image source: American Meteor Society)

When a meteor falls into the Earth's atmosphere, it vaporizes and you can see a long streak of light in the sky. Bigger meteors are known as fireballs where they are brighter than the planet Venus as they fall to Earth. However, bolides are meteors which are even brighter and more massive than fireballs and often explode in the atmosphere. Some astronomers classify bolides as fireballs that produce a sonic boom as they streak through the atmosphere.

Science ABC video - What are Asteriods?

The Dr. Binocs Show - Meteors

2013: Rare superbolide landed in Chelyabinsk, Russia

(Video source: wikipedia commons)

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