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Comets, Meteors and Asteroids

As well as planets and stars, there are other objects which wander in space such as comets, meteors and asteroids.
The nucleus of a comet is like a ball of rock and dirty snow. As these objects get close to the sun the frozen gases and dust begin to heat and cause a long tail of vaporized gases, dust and debris to flow behind them. As it melts a cloud of gases and dust forms a coma. The head of the comet is the nucleus and coma together.

Comets are believed to be in long eliptical orbits that take them from beyond the orbit of Uranus to around the sun. These objects are found in the Kuiper Belt between Uranus and Neptune and the Oort Cloud from way out beyond Pluto.

The name "comet" comes from the Greek meaning "long-haired" because of their tails. Chinese astronomers record several observations as well. Comets throughout history have been thought to bring bad luck but these are just natural phenomena of the solar system.


Asteroids are made of rocky and/or iron-nickel material and most are found in an orbit between Mars and Jupiter. Most are pitted with impact craters and dust left from collisions with other objects in the solar system. The largest asteroid is Ceres, which is 933 kilometers (580 miles) across. Many asteroids, including all of the largest asteroids, orbit the sun between Mars and Jupiter in the Asteroid Belt.





Meteors, known also as shooting stars, are usually sized from a grain of sand to about a softball. As the meteor enters the Earth's atmosphere it becomes very hot due to friction like when you rub your hands together for a few moments. They become bright and seem to streak across the sky.

When the Earth enters a meteoroid stream left by a comet it produces a meteor shower. These showers can be predicted and come every year or so. They are named after the constellation that the meteors appear to be coming from.









1. Download the document below and create a Venn diagram using three circles - one for each of comets, meteors and asteroids.

2. Assign each of the characteristics into its correct position in the Venn diagram to show the similarities between comets, meteors and asteroids. 

 These links will be helpful:  http://curious.astro.cornell.edu/comets.php 


Comets http://www.cascaeducation.ca/CSA/CSA_Astro9/files/html/datasheets/comet.html

Meteors http://www.cascaeducation.ca/CSA/CSA_Astro9/files/html/datasheets/meteor.html

Asteroids http://www.cascaeducation.ca/CSA/CSA_Astro9/files/html/datasheets/asteroid.html


Helen Feutrill,
Apr 18, 2011, 9:29 PM