Date: April 13, 2011
Title: Exploring the Solar System: Asteroid Belt
Podcaster: Thomas Hofstätter
Link: :: The Hidden Space Project :: http://hidden-space.at.tf
Description: Continuing our journey through the solar system, the next target of a space probe traveling to the outer solar system, is the asteroid belt. Although this group of masses has been calculated quite early, it took scientists about 100 years to really discover the first object. Until now, space and ground-based telescopes are looking for objects.
Bio: Born in 1993 near Vienna, Austria, Europe. Upper High School with focus on Computer Science.Interested in extreme small and extreme big, devious and uninvestigated things. My main aim is to bring astronomy to public and to establish secular interest in astronomy, physics and mathematics. Host of :: The Hidden Space Project :: at http://hidden-space.at.tf.
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Transcript:
Hello and welcome to this episode of 365 Days of Astronomy. My name is Thomas Hofstätter and I am the hoster of :: The Hidden Space Project :: at www.hidden-space.at.tf.
[Leon:] And I’m Leon Dombroski from the state of Connecticut in the United States.
Approaching the other region of the solar system, a space probe from earth passes the great asteroid belt. This is a collection of multiple asteroids orbiting earth between the orbit of Mars and Jupiter. The origin is not known clearly, but some objects have the size of a dwarf planet, and other are just small objects of a few centimeters in diameter.
[Leon:] One possible explanation is, that the asteroids have formed out of protoplanets because a greater planet wouldn’t be able to exist between Mars and Jupiter due to gravitational forces. It would also be possible that there has been shifting in the orbit position of the planets and it has been ripped apart by Jupiter as we have seen in some cases of asteroids.
Theoretical calculations about the asteroid belt began in the early 18th century. Scientists from all over the world calculated the number of objects in the belt and reached precise data. But it took about 100 years for astronomers to find the first object orbiting between Mars and Jupiter.
[Leon:] January 1, 1801, the Italian astronomer Giuseppe Piazzi, was the first to discover an object. He named it after the Roman god Ceres. First, he thought the object to be a comet, but reverted his opinion when he wasn’t able to detect a tail. Some years later, Heinrich Olbers discovered Pallas. Later, the asteroids have been numbered after their order of observation. For instance, the two asteroids are now called (1) Ceres and (2) Pallas. Using improved telescopes, later astronomers like William Herschel and Alexander von Humboldt made further observations.
Today, modern telescopes make it possible to detect even more asteroids and smaller and smaller objects. The Spitzer Space Telescope e.g. was designed to discover asteroids in a high rate. Infrared is the best way to find asteroids because they vary in the temperature in contrast to the other objects. But also the Hubble Space Telescope and some ground-based telescopes made huge improvements in the understanding of these objects.
[Leon:] One reason for the interest in asteroids in the main belt between Mars and Jupiter are the so-called Near Earth Objects (NEOs). These are objects that might cross earth’s orbit and might collide with our planet. To be able to prevent such an event in the future, scientists are surveying the asteroid belt.
Some space probes visiting the outer solar system, passing the asteroid belt, tried to discover some asteroids, which appeared to be quite difficult. The first probes like Pioneer 11 and the first two Voyager probes passed the belt without taking any images of asteroids. This made it clear that the matter density in the region is not as high as previously predicted. Today, the chance for a collision is expected to be one in a billion.
[Leon:] During closer observations with bigger telescopes located in space and on the ground, it has become clear that the density of matter (= asteroids) is not distributed equally. There are four “axis” at 2.50, 2.82, 2.96 and 3.28 Astronomical Units, the distance from earth and sun. In these positions, there are nearly no asteroids, which would attract each other with their gravitational force.
That it is possible for asteroids to even attract each other with their gravitational force that they begin to orbit around each other was long times thought to be impossible. When in the 1990s, the spacecraft Galileo passed the asteroid belt during its mission around Jupiter; scientists found a smaller object, orbiting the asteroid (243) Ida. Its name is Dactyl and its just 1.4km in diameter. Ida in comparison is 31km in diameter.
That’s it for today. I hope, you enjoyed it. If you have any questions, comments or suggestions, write me an email to hidden-space (at) gmx (dot) at or visit me at my website at www.hidden-space.at.tf.
Thanks for listening and clear-skies!
[Leon:] Good bye for now!
New stories are to come soon!
End of podcast:
365 Days of Astronomy
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