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EarthCaching: Meteors, Comets, Asteroids & Impact Craters
Earthcaching is a form of geocaching that allows students to explore nature while learning practical lessons about earthscience.
A meteorite is an object originating in space that survives an impact with earth. Most objects that come within range of our planet burn up shortly after entering the earth’s atmosphere, and for this reason few meteors survive to become meteorites.
An asteroid is the name given to rocks or particles that orbit the sun. The definition is very broad, in part because of the fact that asteroids vary in size and composition. They can be tiny dust particles, or they can be hundreds of kilometers in diameter.
Many people confuse asteroids and meteors. A meteor is a piece of an asteroid that has entered the Earth’s atmosphere. Most meteors are tiny particles of dust or very small rocks that burn up as they enter the atmosphere. Others may remain intact and fall to the surface of the Earth, at which point they become categorized as meteorites.
Scientists believe that comets originated during the formation of the solar system over 4.6 billion years ago. Comets are composed of an organic material that covers a ball of ice, and they are frequently referred to as dirty snowballs. Comets themselves are relatively dark, so their brightness comes from sunlight reflecting off of the many dust particles in the coma and tail.
Comets also have a crust that is made of rocky, organic substances that have led scientists to question whether comets had a role in the appearance of life on Earth.
Impact craters are impressions in the surface of a planet or other body in space due to violent collisions. Impact craters can be seen on Mars, Mercury, the Moon, comets and asteroids. Researchers have also found impact craters on Earth, which are more difficult to discover.
Hundreds of huge impact craters exist around the world, the product of collisions that happened millions of years ago. The largest verified example of an impact crater, the Vredefort Crater in South Africa, is nearly 300 kilometers in diameter.
In some cases identifying an impact crater can be difficult, since geologic factors such as volcanic activity can cause the formation of craters that are similar to impact craters. For example, the Wilkes Land Crater in Antarctica is larger than the Vredefort Crater, but has not yet been positively identified as an impact crater.
Asteroid 2012 DA14 - Our planet Earth had a very close encounter with an asteroid on 15th February 2013, the day after St.Valentine's Day. The asteroid which goes by the unusual name of 2012 DA14 missed our home planet by just 17,200 miles, which, in space terms, is a very near miss. Any time an object comes within the orbit of the Moon it’s a close call. Asteroid 2012 DA14 was discovered in 2012 by a Spanish dentist turned amateur astronomer and had been closely tracked ever since.
A meteorite is an object originating in space that survives an impact with earth. Most objects that come within range of our planet burn up shortly after entering the earth’s atmosphere, and for this reason few meteors survive to become meteorites.
An asteroid is the name given to rocks or particles that orbit the sun. The definition is very broad, in part because of the fact that asteroids vary in size and composition. They can be tiny dust particles, or they can be hundreds of kilometers in diameter.
Many people confuse asteroids and meteors. A meteor is a piece of an asteroid that has entered the Earth’s atmosphere. Most meteors are tiny particles of dust or very small rocks that burn up as they enter the atmosphere. Others may remain intact and fall to the surface of the Earth, at which point they become categorized as meteorites.
Scientists believe that comets originated during the formation of the solar system over 4.6 billion years ago. Comets are composed of an organic material that covers a ball of ice, and they are frequently referred to as dirty snowballs. Comets themselves are relatively dark, so their brightness comes from sunlight reflecting off of the many dust particles in the coma and tail.
Comets also have a crust that is made of rocky, organic substances that have led scientists to question whether comets had a role in the appearance of life on Earth.
Impact craters are impressions in the surface of a planet or other body in space due to violent collisions. Impact craters can be seen on Mars, Mercury, the Moon, comets and asteroids. Researchers have also found impact craters on Earth, which are more difficult to discover.
Hundreds of huge impact craters exist around the world, the product of collisions that happened millions of years ago. The largest verified example of an impact crater, the Vredefort Crater in South Africa, is nearly 300 kilometers in diameter.
In some cases identifying an impact crater can be difficult, since geologic factors such as volcanic activity can cause the formation of craters that are similar to impact craters. For example, the Wilkes Land Crater in Antarctica is larger than the Vredefort Crater, but has not yet been positively identified as an impact crater.
Asteroid 2012 DA14 - Our planet Earth had a very close encounter with an asteroid on 15th February 2013, the day after St.Valentine's Day. The asteroid which goes by the unusual name of 2012 DA14 missed our home planet by just 17,200 miles, which, in space terms, is a very near miss. Any time an object comes within the orbit of the Moon it’s a close call. Asteroid 2012 DA14 was discovered in 2012 by a Spanish dentist turned amateur astronomer and had been closely tracked ever since.
93 pages, Kindle Edition
First published February 6, 2012
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