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Kiki explains: What are asteroids?

Team StoryWeavers|June 30, 2022, 18:39 IST|

Hello young learners, 

Kiki welcomes you back to another episode of Kiki’s Knowledge Corner! Before we start this episode, I would like to say that we are thrilled with your response to our previous posts on oceans, stars and the phases of the moon. This makes us extra motivated to make you better learners for life by bringing to you the knowledge of the world!

Keeping your curiosity about outer space in mind, we will learn about another kind of heavenly body in this edition – ASTEROID! They are small, rocky objects that travel through space all on their own, at an average speed of over 15 km/s! Many of them are brave enough to revolve around the Sun, while some of them pay a visit to planets like our Earth. 

Let’s explore more about them!

What are asteroids?

An asteroid is a big chunk of rock, carbon or metal which is found in outer space. As mentioned earlier, they revolve around the Sun, just like planets. However, unlike planets – which are mostly spherical – these asteroids are oddly shaped. Some of them are lumpy and others look like a potato.

Here is what an asteroid looks like

Asteroid in action

There have been over 20,000 asteroids discovered so far, and scientists believe that there are more, waiting to be found. 

How big are asteroids?

Asteroids are smaller compared to planets and some other heavenly bodies. They range from just a few feet across to hundreds of miles in diameter. Some of them are bigger than the states in our country! There are those that are so big that they are called mini planets. So far, the four biggest asteroids that have been discovered are Ceres, Vesta, Pallas and Hygiea. Each of these is at least 500 kilometres wide! And the biggest among them, Ceres, is considered a dwarf planet (a celestial body resembling a small planet) and occupies one-quarter of the entire weight of the asteroid belt.

What are the asteroids made of?

Asteroids are made of metal, stone or carbon. Most of the asteroids that revolve around the sun are made of carbon. Some asteroids are also made of stone and have some traces of metal like iron or nickel, while some are made of rock-like substances. Being made of rocks and metal make these asteroids very heavy! On average, they weigh 60 billion kilograms. That’s as heavy as 1 million African elephants!

Where are these asteroids located?

Most asteroids revolve around the Sun in a ring called the asteroid belt. The asteroid belt is located between the planets Mars and Jupiter. You can think of it as a belt zone reserved for asteroids between the rocky planets (Mercury, Venus, Earth and Mars) and the gas planets (Jupiter, Saturn, Uranus and Neptune). However, some of them do not revolve within the asteroid belt and are stray asteroids called ‘Trojan asteroids’.  There are other asteroids called Near-Earth asteroids that are closer to the Earth than the others.

Can an asteroid hit the Earth?

You must be wondering, can these near-Earth asteroids hit the Earth? Yes, it is possible for some of them. They have orbits that cause them to pass close to the Earth and probably even hit the surface.

The good news is that most of them don’t cause much damage, but sometimes they can cause giant craters on Earth’s surface. When they hit the Earth, they also have the potential to cause a lot of damage to the lives of animals and humans. Over 66 million years ago, a really big asteroid hit the Earth and made the dinosaurs extinct! However, scientists say that the chances of asteroids hitting the Earth are low in the near future! So we are absolutely safe for now!

Now that you know about asteroids and their possible impact on the Earth, tell us which other heavenly bodies you would want to learn about. Share your answers in the comments.

Also Read

Biggest known asteroid impacts on Earth




About the Author

Aparna is a mom, singer and dreamer. At BYJU'S, she writes stories about learning for children. She believes in the power of music, especially ghazal, the magic of the universe and happy learners. When not writing or singing, you will find her intensely engaged in conversations about life and the power of words.

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