(WBIR - Knoxville) Hollywood movies featuring asteroids that threaten to destroy Earth usually show a gigantic solid rock tumbling through space towards the planet.
A researcher at the University of Tennessee says a gravity-defying asteroid that poses one the largest threats to Earth is actually more like a giant clump of flour.
"This near-Earth asteroid is named '1950 DA' because it was initially discovered in 1950. After that, it disappeared until it was located again in 2001," said Ben Rozitis, a post-doctoral researcher at the University of Tennessee. "It's around a kilometer wide. If this thing were to impact the Earth, it would cause damage on a global scale."
The asteroid is spinning so fast, Rozitis says scientists initially believed it must be a huge chunk of metal in order to withstand gravitational forces and remain in one piece. They now believe something very different: the asteroid is a massive sticky ball made up of small rocks and space dust.
The fact that the rocks and dust are not flying apart means the asteroid is being held together by something more than gravity. The breakthrough observation from Rozitis is the asteroid is holding together due to "cohesive forces."
"The cohesive forces involved in keeping this asteroid together, you can actually see them in everyday life. In particular, if you're baking a cake and you're using flour, you'll notice how the flour clumps together in lumps. It's the same cohesive forces, except in this case it is asteroid dust."
The research was just published in the journal Nature. The findings are of worldwide interest because you need to know what asteroids are made of and how they're held together if you someday want to stop one from destroying the planet.
In this case, if you have a ball of space rocks barely holding together like a clump of flour, you do not want to stop it by hitting it head-on.
"This is like a big pile of rubble. If you slam anything into it, the body would just break apart into lots of different pieces, which could become a problem if they were on a collision course with Earth. Instead of having one missile hitting you, you've got a shotgun aimed at you instead," said Rozitis.
If the asteroid is spinning so fast that the middle of it generates negative-gravity, you most certainly do not want to implement a deflection plan that involves landing on it.
"It wants to throw you off, like when you go on a merry-go-round. So if you try to land near the equator, you'll just be thrown off," said Rozitis.
The research is positive news as scientists attempt to gain a greater understanding of asteroids and how to mitigate any threats to life on Earth. There is also plenty of time to come up with a plan for how to deal with 1950 DA. Researchers say the next possible collision would happen in the year 2880.
"It is not a current threat, at the moment," said Rozitis. "The likelihood of a collision has also gone down over the last decade. At one point, it was predicted to have a 1-in-300 chance of hitting Earth. Now it's believed to be more like 1-in-20,000."