Asteroids frequently pass the orbital path of the Earth, but the number of known interlopers is significantly smaller than theories would predict. Until now, astronomers have been puzzled when attempting to locate these missing fragments of metal and rock, hurtling through space. Now, a team of researchers believes they have discovered the fate of these extraterrestrial boulders and mountains - they were swallowed by the sun.

The discovery was made as an international assemblage of scientists worked to develop a model of the Near-Earth objects (NEO's) for study by observatories and spacecraft. The majority of these objects originate in the asteroid belt that sits between the orbits of Mars and Jupiter.

In order to be classified as a NEO, an asteroid must travel closer to Earth 1.3 times the distance from the Earth to the sun. Currently, astronomers know of approximately 9,000 of these bodies. The research team in this latest study examined 100,000 images taken of the objects, recorded over a period of eight years.

Analysis revealed that these images showed just 10 percent of the objects predicted by theory. Astronomers spent a significant amount of time assuring their results were correct. When they became confident in the observations, the researchers realized their notions of how orbits work within 10 solar diameters of the sun needed to be revised.

"The discovery that asteroids must be breaking up when they approach too close to the Sun was surprising and that's why we spent so much time verifying our calculations," said Dr. Robert Jedicke, from the University of Hawai'i Institute for Astronomy.

Meteor showers on Earth are commonly the result of debris left behind by a NEO. One feature of the observations that initially surprised the astronomers was the discovery that many of these debris trails could not be traced to a precise source. Researchers soon realized that these orphan trails could be explained if the parent bodies which shed the material were swallowed by our parent star.

Astronomers had previously noted that NEO's which come close to the sun tend to be lighter-colored than those that stay further out into space. This would suggest dark asteroids are destroyed by the sun more often than those with a lighter hue.

Asteroids and comets striking Earth have often had a dramatic - and devastating - effect on life on our planet. Perhaps our world would be far different today if it were not for the sun destroying vast numbers of these space-borne objects.