Rocky Visitors, Part 1: Asteroids, Comets, and Meteoroids

Asteroids, comets, and meteoroids - these visiting rocks from outer space are often beautiful objects that light up the night sky (or the source of a lot of worry and panic!).  In this first part of the Rocky Visitors series, we’ll be learning about the differences between asteroids, comets, meteors, and meteorites, along with some cool and interesting fun facts.  

 Asteroids 

Asteroids are basically giant, ancient boulders floating around in space. On average, an asteroid is around 4.5 billion years old, which is as old as the solar system itself! This is because while the solar system was still forming 4.5 billion years ago, things were messy. As the planets were being created, rocks were constantly colliding with each other, sometimes breaking off into smaller rocks. Things eventually calmed down, and some of these smaller rocks have survived ever since. We call them asteroids, and you can find most of them in a place called the Asteroid Belt, which is between Mars and Jupiter.  

The white ring is called the Asteroid Belt and it's where 75% of the Solar System’s meteorites are located. You can find the other 25% in the inner solar system or outer regions in the Trojans Hildas, and Greeks areas. 

Comets 

Comets are like asteroids; except they’re made up of more ice. This causes them to shine brighter than asteroids. It also gives them a beautiful aura of dust that wraps around and behind them in a long, glowing tail. In fact, the tails of comets can be hundreds of millions of miles long! Comets are some of the most beautiful things we can see in space with our own eyes. Ever since humans looked up to the stars, comets have been studied and recorded. And it turns out that many comets we see today are actually these same comets! 

On the left is an image taken of Comet Halley in 1986. Comet Halley returns to Earth every 76 years, so the next time we’ll be able to see will be in 2061! On the left is a diagram showing Comet Halley’s orbit through the Solar System.  

Meteoroids 

You’ve probably heard of meteors and meteorites, but you may be wondering what in the world a meteoroid is. Meteoroids are just smaller versions of asteroids that float around in space. In fact, many meteoroids are bits of asteroids or comets that have broken off in space. If a meteoroid enters Earth’s atmosphere and burns up in a glowing flame, then it becomes a meteor. But if the meteoroid makes it through Earth’s atmosphere without flaming up and hits the ground, we call it a meteorite. Meteorites come from asteroids, but probably not comets. This is because the stuff that comets are made from is really fragile and burns up extremely easily in Earth’s atmosphere. So, it never makes it to the ground. Most meteorites are found in Antarctica, where they are easy to spot against the white snow.  

This is a picture of a meteor from the Perseid Meteor Shower, which happens around August every year. If you watch this August, you’ll be able to see about 1 meteor per minute. Also, here’s a video of the shower: https://tinyurl.com/PerseidsMeteor  

That concludes our quick overview of asteroids, comets, and meteoroids. In the next article, we’ll dive more deeply into asteroids and all their rocky epic!