Where do asteroids go to die? New evidence challenges old assumptions.

An international team of scientists have debunked the theory that asteroids and comets end their existence with a final plunge into the sun. Turns out, they disintegrate long before that.

|
Courtesy of NASA
Vesta is an asteroid. It has a set of three craters known as the 'snowman.' A new study, published Wednesday in the journal Nature, counters the commonly held theory that asteroids end their existence after plunging into the sun.

Scientists have long believed that the demise of asteroids close to Earth happen in a fiery collision with the sun. But by examining nearly 9,000 near-Earth objects, or NEOs, an international team of researchers have recently found that asteroids and comets crumble long before they reach the surface of the blazing star.

Residing in the doughnut-shaped asteroid belt between Mars and Jupiter, the NEOs that wander into our solar system typically follow their orbits without interference with Earth for billions of years. But occasionally, some are nudged by the gravitational forces of Saturn or Jupiter, and are led astray toward Earth.

So, scientists from Finland, France, the United States, and the Czech Republic got together a couple of years ago to formulate a model for the millions of NEOs to plan for future asteroid surveys and human space exploration missions.

According to Robert Jedicke of the University of Hawaii Institute for Astronomy, an author on the study published Wednesday in the journal Nature, their model, which used more than 100,000 images acquired over about eight years by the Catalina Sky Survey (CSS) near Tucson, Ariz., matched most of their data on NEOs – except in areas close to the sun.

Based on their calculations, there should be many more asteroids close to the sun than they actually found. For every 10 NEOs they expected to find within 10 solar diameters of the sun, only one was observed.

"If we weren't scientists, we might have said it's close enough, but something didn't feel right," Dr. Jedicke told The Los Angeles Times.

After another year of verifying their calculations, the team realized that it wasn’t their analysis that was off – it was the assumption of how asteroids disappear.

It turns out that asteroids are dying out as they approach the sun, but long before they would have collided. Although the authors are yet to be sure of how exactly the asteroids break up as they near the sun, they reached some other telling conclusions. Brighter asteroids, for instance, survived longer than dark asteroids, which absorb more light. And smaller asteroids disintegrate faster than bigger ones.

Their work also shed some light on the shooting stars that enter the Earth’s skies. The meteors are dislodged pieces of parent NEOs on their orbit but astronomers typically have trouble finding the latter. This study suggests that the parent asteroids may have already disappeared.

"Perhaps the most intriguing outcome of this study is that it is now possible to test models of asteroid interiors simply by keeping track of their orbits and sizes," lead author Mikael Granvik, of the University of Helsinki in Finland, said in a statement.

"This is truly remarkable and was completely unexpected when we first started constructing the new NEO model."

You've read  of  free articles. Subscribe to continue.
Real news can be honest, hopeful, credible, constructive.
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

QR Code to Where do asteroids go to die? New evidence challenges old assumptions.
Read this article in
https://www.csmonitor.com/Science/2016/0218/Where-do-asteroids-go-to-die-New-evidence-challenges-old-assumptions
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe