Comets & Asteroids

By: Jamari Stanton

Comets

  • A comet is a ball of frozen gases, dust, and rock about the size of a small town.
  • 4.5 billion years ago, as the sun was forming, there was leftover material.
  • The leftover material around the outside of the solar system became comets.
  • Far away: will look like a lump of ice and dust.
  • Close to sun: ball of light with a bright tail at the end.
  • Comets develop a tail when it reaches an area about the same distance from the sun as Jupiter.
  • When it gets close to the sun, ice begins to heat up and vaporize releasing the gas or dust particles creating an atmosphere called a coma.
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Halley's Comet

This picture was taken in March, 1986, the last time Halley's comet was visible from Earth. It was taken from Earth with a very high definition camera (200mm F2.5 lens Ektachrome)

Sungrazing Comets

Sungrazing comets are comets who reach a certain point in distance from the sun called Perihelion. Perihelion is is the point in orbit of a planet, comet, or asteroid in which it is at its closest point to the sun. To be considered a sungrazer, a comet needs to get about 850,000 miles from the sun. Most comets who are sungrazers are destroyed by the sun's intense heat. This video was posted by NASA Goddard (www.nasa.gov/goddard)
NASA | What is a Sungrazing Comet?

Comet Citations

"Comets." Solar System Exploration. N.p., n.d. Web. 08 Dec. 2014. <https://solarsystem.nasa.gov/faq/index.cfm?Category=Comets>.
"Halleys Comet March 1986 by Strongmanmike2002." PBase. N.p., n.d. Web. 09 Dec. 2014. <http://www.pbase.com/strongmanmike2002/image/67064676>.
"NASA | What Is a Sungrazing Comet?" YouTube. YouTube, n.d. Web. 09 Dec. 2014. <https://www.youtube.com/watch?v=A1yH_DuC88M>.

Asteroids

  • Asteroids are rocky, airless worlds that orbit our sun and are part of our solar system but are too small to be called planets.
  • The asteroid belt is a vast doughnut-shaped ring between the orbits of Mars & Jupiter containing tens of thousands of asteroids.
  • Meteors are objects that enter Earth's atmosphere that burn up before reaching the ground while meteorites refers to only the objects that make it to the ground. Asteroids are rocky bodies that are usually found in the asteroid belt.
  • Asteroids that pass close to Earth are called near-Earth objects.
  • About 2 billion years ago, the Vredefort Crater was formed when an asteroid struck the Earth in Free State, South Africa.
  • The crater has an estimated radius of 118 miles.
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Asteroid 243 Ida

This picture was taking on August 28, 1993. It was acquired by the Galileo aircraft's solid space imaging system.

Big asteroid buzzes past Earth and will again in 19 years

On October 18, 2013, an asteroid narrowly missed collision with Earth. In about 20 years, it is expected to directly hit us. NASA has told us that even some of the most dangerous asteroids do not pose a significant danger to Earth, what a relief! The probability of it striking Earth is approximately 1:63,000, Also, it has a danger rating of 1 out of 10 on the Torino Impact Hazard Scale. It seems we are safe for now, but that was definitely a close encounter with a catastrophe. A catastrophe is an event causing great and often sudden damage or suffering. Asteroids pass our planet everyday, but hopefully they will never make contact with us!

Asteroid Citing

"Asteroids: Overview." Solar System Exploration. N.p., n.d. Web. 09 Dec. 2014. <http://solarsystem.nasa.gov/planets/profile.cfm?Object=Asteroids>.
Line, Brett. "Asteroid Impacts: 10 Biggest Known Hits." National Geographic. National Geographic Society, 14 Feb. 2013. Web. 09 Dec. 2014. <http://news.nationalgeographic.com/news/2013/13/130214-biggest-asteroid-impacts-meteorites-space-2012da14/>.
"Images Of Asteroids Ida & Dactyl." Images Of Asteroids Ida & Dactyl. N.p., n.d. Web. 09 Dec. 2014. <http://neo.jpl.nasa.gov/images/ida.html>.
Brumfield, Ben. "Big Asteroid Buzzes past Earth and Will Again in 19 Years." CNN. Cable News Network, 01 Jan. 1970. Web. 08 Dec. 2014. <http://www.cnn.com/2013/10/18/tech/asteroid-near-pass/>.