Different Directions

Different Directions

near-Earth Asteroids

These are objects in a near-Earth orbit without the tail or coma of a comet. As of May 2012, 8,880 near-Earth asteroids are known, ranging in size from 1 meter up to ~32 kilometers (1036 Ganymed). The number of near-Earth asteroids over one kilometer in diameter is estimated to be about 981. The composition of near-Earth asteroids is comparable to that of asteroids from the asteroid belt, reflecting a variety of asteroid spectral types.

NEAs survive in their orbits for just a few million years. They are eventually eliminated by planetary perturbations which cause ejection from the Solar System or a collision with the Sun or a planet.

See this video

From the Study Astronomy Online at Swinburne University</p><p class=

All material is © Swinburne University of Technology except where indicated."



Measurements

1 meter = 3 feet

1 kilometer = 0.621371192 miles
or 4 or 5 average downtown city blocks

32 kilometers = 19.8839275727938 miles

Terms

coma = A diffuse cloud of gas and dust surrounding the nucleus of a comet.

spectral type = an indication of the physical and chemical characteristics of a star or other space object based on the spectrum of light that it emits.

planetary perturbations = the deviation or change of a celestial body from its regular orbit caused by the presence of one or more other bodies that act upon it.

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