Some asteroids may die before ever reaching the sun
A space rock mystery may finally be solved.
Scientists have long-thought that asteroids end their lives in the solar system by making a final death-dive into the sun, but a new study suggests that at least some space rocks appear to disintegrate before ever coming close to the star.
The study may bring us closer to understanding how to protect the Earth from an asteroid strike.
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The new study, published in the journal Nature this week, details theoretical modeling done with 100,000 images of about 9,000 near-Earth objects (NEOs) -- asteroids and comets that can come near the planet -- seen over the course of eight years by the Catalina Sky Survey in Arizona.
The researchers produced a model of the NEO population in the solar system based on the Catalina data, and found something strange.
The model showed that there should be about 10 times more NEOs coming within about 8.6 million miles of the sun than are actually observed.
After about one year spent verifying their data, the scientists think they may have an answer for why some asteroids are missing from the solar system's cosmic pool: The space rocks appear to be breaking apart.
"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," study co-author Robert Jedicke said in a statement.
The study's authors still aren't exactly sure what could be causing the asteroids to disintegrate, but they have some ideas.
It looks like darker asteroids are more likely to break up before reaching the sun than bright ones, so those dark space rocks may have a different composition than others in the solar system.
"What's great about this result is that it tells us that the near-Earth objects are a changing population being actively reshaped in dramatic fashion by the sun," NASA scientist Amy Mainzer, who is not an author of the study, told Mashable via email.
"Not only are the NEOs getting flung all around by gravitational interactions with the planets, but the sun seems to do a pretty good job of shredding some unlucky ones!"
The next steps in planetary protection
Scientists haven't actually seen an asteroid break up in this manner, and new studies will be necessary to confirm the statistical findings, but this could be a good starting point for explaining the odd asteroid mystery.
This new analysis may also help to explain why there appear to be a fair number of meteor streams that don't actually have a parent object leaving bits of material in its wake.
It's possible that the parent bodies could have been destroyed by the sun after leaving behind that debris for the Earth to run into along its orbit.
By learning more about the composition of these asteroids, scientists may be able to develop new ways to deflect harmful objects that might be on a collision-course with the planet.
"If we could figure out the mechanism that's breaking these things up, that may tell us about the internal structure of asteroids, and that's paramount to understanding and to practical applications of planetary protection," said Peter Brown, an astronomy and physics professor at the University of Western Ontario. Brown was not affiliated with the new study.
"We have to understand how an asteroid is put together -- is it a gravel pile; is it a rubble pile; is it a monolithic rock, etc. -- if we're going to deflect or worry about trying to move an asteroid around."
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Miriam Kramer worked as a staff writer for Space.com for about 2.5 years before joining Mashable to cover all things outer space. She took a ride in weightlessness on a zero-gravity flight and watched rockets launch to space from places around the United States. Miriam received her Master's degree in science, health and environmental reporting from New York University in 2012, and she originally hails from Knoxville, Tennessee. Follow Miriam on Twitter at @mirikramer.
