Book 1, Question 87 · Video
Why Do Comets Grow Tails? A Dirty Snowball Meets the Sun!
A comet is like a dirty snowball from space, made of ice, dust and rock. When a comet gets close to the Sun, the heat turns ice into gas and releases dust, and solar wind, a stream
Read the full answer →What Crafty Clover says in this video
Intro
Hi! I'm Crafty Clover! Let's discover something amazing. Why do comets grow tails?
The Big Idea
Comets are icy space travelers. When they fly close to the Sun, they grow long, glowing tails! The Sun's heat and the solar wind team up to make them. Let's find out how!
A Comet Is a Dirty Snowball
Number one: a comet is a dirty snowball. Comets are made of ice, dust, and rock, like a dirty snowball from space! The solid middle is called the nucleus. It's often just a few kilometers wide.
Sun Heat Makes Gas and Dust
Number two: the Sun's heat makes gas and dust. When a comet gets close to the Sun, the heat turns its ice straight into gas. That releases dust, and makes a big, fuzzy cloud around the comet, called the coma.
Solar Wind Pushes a Tail
Number three: the solar wind pushes a tail. Solar wind is a stream of tiny particles flowing out from the Sun. It pushes the gas and dust away, creating a tail that can stretch for millions of kilometers!
Comet Nucleus, Two Tails
Let's look closer. Many comets have two tails! In the middle is the icy nucleus. The ion tail is straighter. It's made of gas that glows blue, and the solar wind pushes it straight back. The dust tail is curvy. It's made of dust that catches sunlight, and glows a warm yellow-white.
Quick Facts
Quick facts! A comet's tail always points away from the Sun. So when a comet is heading away from the Sun, its tail actually goes out in front of it! Halley's Comet swings by Earth about every seventy-six years. And most comets come from icy regions far, far beyond Neptune.
Think Like a Scientist
Now, think like a scientist! With a grown-up, try this. Hold a hair dryer, on a cool setting, near a loose scarf. What happens to the scarf? The moving air pushes the fabric away, just like the solar wind pushes a comet's tail! Try it from different sides. Does the scarf always point away from the dryer?
Outro
Comets grow tails when the Sun's heat and solar wind blow their ice and dust out into space. Keep wondering! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!