What Exactly IS a Comet?

Grade Level

6 - 8


1- 2 hrs


Earth Science

Comet Halley NASA
Comet P/Halley as taken March 8, 1986 by W. Liller, NASA



blank paper

colored pencils


Humans have been observing comets for thousands of years. Though comets appear infrequently, when they do appear, they can be visible to the naked eye at night as a bright white star with a long, misty white tail trailing behind it.

On November 12th, 2014, the Philae lander successfully landed on comet 67P after a 10-year, 3-billion-mile voyage aboard spacecraft Rosetta. The event marks the first-ever landing of a space vehicle on a comet. Both Rosetta and Philae are loaded with scientific equipment for measuring the composition, gravity, appearance, and surface of the comet, opening a new chapter in our scientific understanding of comets and our early universe.

But what is a comet, anyway?

An example of a text illustration.
An example of a text illustration.

What do we know about their surface, appearance, size, tail, color, brightness, age, movement … and even their smell? In each of the interviews below, scientists (some of whom were part of the Rosetta mission) describe various comet characteristics. As you listen to these interviews, take notes as the scientists describe what a comet is like. You can use this comet characteristics graphic organizer to help you write down these descriptions.

You will then incorporate your comet descriptions, literally, into your own text illustration of a comet. A text illustration uses actual descriptive text to form the shapes and objects in a drawing. This is a great way to quickly visualize all the information you’ve learned about comets.

How To Create a Text Illustration

 1. Start by lightly sketching a large drawing of a comet with a pencil. Do not color any parts of your illustration, and leave space around the outside for additional drawing. Here’s a printable comet sketch example.

2. Using colorful pencils, decorate parts of your comet illustration with the descriptive text you collected from various scientist interviews (see below). Try to match the text with the part of the comet that it describes. For example, you could outline the tail of your comet with the words that describe the tail, and fill the tail with the text that describes its smell and chemical composition. 
 3. Go further: How can you add the descriptions of comet characteristics that can’t be seen—such as movement and gravity—to your illustration? Try it!

Listen, Watch, Read About Comets

comet characteristics graphic organizer

SciFri Excerpt: Science Diction: Comet  Dec 17th, 2010

SciFri Excerpt: A Journey to the Oort Cloud, Where Comets are Born Jan 4th, 2013

SciFri Excerpt: ISON: The Comet of the Century… or Is It? Nov 22nd, 2013

SciFri Excerpt: Close-Up With a Comet Aug 15th, 2014

SciFri Excerpt: The First Touchdown on a Comet Nov 14th, 2014

SciFri Excerpt: Scientists Sniff Smelly Comet Oct 31st, 2014

SciFri Video: Comet’s Tail Shines Light on Sun Jun 7th, 2013

Common Core State Standards:


Next Generation Science Standards:

Disciplinary Core Idea ESS1.B Earth and the Solar System

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Meet the Writer

About Ariel Zych

Ariel Zych is Science Friday’s director of audience. She is a former teacher and scientist who spends her free time making food, watching arthropods, and being outside.