Comets - What is a comet?
Welcome to Quatr.us Study Guides!

Comets

Comet
Comet

Comets are balls of leftover rock and ice that were originally part of a nebula formed when a star exploded into a supernova. These balls didn't form into planets when most of the material in our nebula merged together, about 4.5 billion years ago. Instead, the comets kept on circling around the Sun on their own.

Most comets come near Earth just once and then shoot off into outer space, going out beyond our solar system for thousands of years before they circle back again. A few comets have smaller orbits, staying mostly within our solar system. Some cross Earth's orbit every year, like Comet Swift-Tuttle. We see Halley's Comet once every 75 years or so.

When a comet gets close enough to the Earth, some of the smaller rocks that are associated with that comet get sucked into Earth's gravity and come falling down to the Earth. We call these meteors. Some comets end up hitting other planets or hitting the Sun, or they come close enough to Jupiter to be affected by Jupiter's gravity and whipped out of the solar system like rocks in a slingshot.

When comets get nearer to the Sun, the heat of the Sun warms them up and melts off some of their ice. After about 800 visits near the Sun, the comets are just balls of rock. Many of the asteroids near Earth are old dead comets.

There are probably comets going around other stars as well as our own, but they are too small for our telescopes to see yet.

More about space

Bibliography and further reading about space:

Mercury
Planets
Physics
Quatr.us home


Celebrating Black History Month with the pharaoh Hatshepsut, the queen Shanakdakhete, the poet Phillis Wheatley, the medical consultant Onesimus, the freedom fighters Toussaint L'Ouverture, Denmark Vesey, Yaa Asantewaa, and Samora Moises Machel, and the civil rights leader Martin Luther King, Jr.
Please help other teachers and students find us: link to this page from your class page.
Karen Carr is Associate Professor Emerita, Department of History, Portland State University. She holds a doctorate in Classical Art and Archaeology from the University of Michigan. Follow her on Instagram or Twitter.
Cite this page
  • Author: K.E. Carr
  • Title:
  • Site Name: Quatr.us Study Guides
  • Publisher: Quatr.us
  • Date Published:
Proud of your class page, homework page, or resource page? Send it in and win a Quatr.us "Great Page!" award!
Sign up for more free articles and special offers in Quatr.us' weekly newsletter:
We will never share your e-mail address unless you allow us to do so. View our privacy policy. Easy unsubscribe links are provided in every email.
Comment on This Article

Cool stuff we've been enjoying: Looking for birthday gifts? Check out these new Chromebooks - all the computer you need for only $229.00!. Then study in peace with these Beats wireless headphones - for the exact same price! When you're done, show off your presentation or watch a movie with this excellent smartphone projector for only $39.99!


Does your class page honor diversity, celebrate feminism, and support people of color, LBGTQ people, and people with disabilities? Let us know, and we'll send you a Diversity Banner you can proudly display!
Looking for more?
ADVERTISEMENT
Quatr.us is loading comments...
(Comments will appear after moderation, if they are kind and helpful. Feel free to ask questions, and we'll try to answer them.)
Cite this page
  • Carr, K.E. . Quatr.us Study Guides, . Web. 26 February, 2017
ADVERTISEMENT