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Bagnall Beach Observatory |
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MPC Observatory Code 433 |
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Astrometry of Asteroids |
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Astrometry is the measurement of the position of astronomical objects. Since asteroids are moving objects, their position is related to a particular time. By measuring the position of asteroids over time their orbits can be established. Sometimes establishing the orbit of an asteroid has a degree of urgency. In recent decades we have come to realise that some asteroids collide with the Earth and may do significant damage. Knowing in advance may give humankind the option of averting disaster. When a Near Earth Asteroid is discovered over two nights of observation, the orbital arc is so small that there is a wide range of possible extensions of that arc into an orbital “solution”. Some of the possibilities may include collision with the Earth. Usually, as measurements continue to come in, the orbit is refined and we find that the NEO will not collide with the Earth after all. Our knowledge of the origins and future of the solar system is also aided by establishing the orbits of all the minor planets. Already we have discovered that there are two major belts of asteroids—the Main Belt between Mars and Jupiter and the Kuiper Belt beyond Neptune. It will be interesting to find the interactions between the major planets and the asteroid belts. In so far as asteroids appear to be the building blocks of the solar system, what can we discover about their past and future? There are a number of impact craters in Australia formed by collisions with asteroids/meteoroids. (The dividing line between an asteroid and a meteoroid is simply one of size). Some of them are listed below with links to further information.
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The asteroid Gaspra |
Why do astrometry of asteroids? |
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The Wolfe Creek Meteor Crater in Australia is approximately 1 km wide and was caused by an asteroid that collided with the Earth a mere 300,000 years ago |
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NASA animation of large asteroid collision with Earth. |
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Wolfe Creek, W.A. http://www.ahc.gov.au/publications/geofossil/wolfe.html Woodleigh, W.A. http://www.doir.wa.gov.au/documents/gswa/gsd_fld_woodleigh.pdf Also see the next link for Woodleigh, Bedout High, Gosses Bluff and Tookoonooka http://www.alphalink.com.au/~dannj/craters.htm Gosses Bluff, Wolfe Creek, Veevers and Henbury |