Comets: Ice and Dust That Travel Around the Sun

Comets are like dirty snowballs floating in space. They are made of ice, dust, and small rocks. Comets move around the Sun on big oval paths called orbits.

Step-by-step — what happens to a comet

1. Nucleus (the comet's heart): This is the solid center of ice and dust. It is usually just a few kilometers across — small compared to planets.
2. Coma (the fuzzy cloud): When a comet gets closer to the Sun, the Sun warms the ice. The ice turns into gas and carries dust away, making a fuzzy glowing cloud around the nucleus called the coma.
3. Tails: The Sun pushes the gas and dust away from the comet, so the comet grows one or two tails that always point away from the Sun. There are two kinds:
   • Dust tail — looks yellowish or white and curves a little.
   • Ion (gas) tail — looks blue and is straight because the solar wind pushes it out.
4. Orbit: Comets travel on very stretched-out oval tracks around the Sun. Some come back every few years (like Halley's Comet every 76 years). Others come from very far away and visit only once in a very long time.

Where comets come from

Most comets start far from the Sun in places called the Kuiper Belt or the Oort Cloud. These are like big neighborhoods of icy objects way past the planets.

Easy and safe activity to try with an adult: Make a little "comet"

1. Mix water with a little dirt and a few small pebbles in an ice-cube tray or small container (this makes the "dirty snowball").
2. Freeze it until solid.
3. Take the frozen ball outside on a warm day and watch as the ice starts to melt. The dirt and pebbles come out of the ice, like a comet releasing dust. (Do this with an adult and don\'t use dry ice!)

Comets are beautiful and can teach us about the far edges of our solar system. Would you like a simple drawing to show a comet and its two tails?