TITLE
Find out what comets are, what they’re made of, how they form, and more!
Some scientists believe comets brought water to Earth billions of years ago. There are two types of water, “heavy water” and “normal water.” Earth’s oceans contain both kinds. Comets are mostly ice. Scientists study the water on comets. They discovered that comets and oceans had similar amounts of heavy and normal water.
Select an activity below to download the PDF.
Making Connections
Text-to-Self
How old will you be the next time Halley’s Comet returns to Earth’s sky? Will you try to see the comet? Please explain your answer.
Text-to-Text
Have you read any other books about space objects? If so, how were those objects similar to or different from comets?
Text-to-World
Humans living long ago would have seen comets in the sky. Those humans did not have the technology to study comets. How do you think they may have explained bright moving space objects then?