How Asteroid 1950 DA Keeps It Together

-

The kilometer-size rubble pile appears to be held together by van der Waals forces. Karen Hopkin reports Aug 29, 2014 | |


From the depths of space, an asteroid hurtles toward Earth. [Well, our general vicinity.] But this is no ordinary hunk of galactic debris. Because the body of this asteroid seems to defy gravity. It’s bound by forces never observed on this scale in space.


That’s not the plot of a new summer blockbuster. It’s the result of a study in the journal . [Ben Rozitis, Eric MacLennan and Joshua P. Emery: ]


The asteroid in question is actually a kilometer-sized collection of rubble. In most cases, such space-faring pebble piles are held together by a combination of gravity and friction. But not so for our rocky interloper, dubbed “1950 DA.” This asteroid is rotating so rapidly that its pieces should have flung apart long ago.


Now, by analyzing the 1950 DA’s temperature and density, researchers conclude that cohesive forces called van der Waals attractions must be keeping the pieces clustered. Van der Waals forces may sound mysterious, but they’re well known on the small scale for their weak influence within and between molecules.


Blasting the asteroid, Hollywood style, could overcome these forces. But that might leave us with hundreds of smaller killer space rocks to dodge. The good news is, the asteroid won’t be in our area until 2880. So we have some time to figure it out.


—Karen Hopkin


[]


Comments

Post a Comment

Popular posts from this blog

New Heart Drugs More Expensive than Expected

-
Image
Two of the most anticipated new heart drugs to be launched in recent years have been priced well above analyst expectations, fuelling the debate about whether modern medicines cost too much July 27, 2015 | By Ben Hirschler LONDON (Reuters) - Two of the most anticipated new heart drugs to be launched in recent years have been priced well above analyst expectations, fuelling the debate about whether modern medicines cost too much. Praluent (alirocumab) injection, made by Sanofi and Regeneron Pharmaceuticals, and Entresto (sacubitril/valsartan) from Novartis are both treatments that represent significant advances for millions of patients at risk of serious heart problems. But their positioning in the marketplace was always likely to be contentious since they offer more effective alternatives to very cheap, off-patent drugs. The manufacturers have taken an ambitious view on pricing, arguing that the clear medical benefits of their products and their ability to keep patients out of ...
Read more

The Physics of Baseball: How Far Can You Throw?

-
Image
A sports science activity by Science Buddies By | | What is one trick to throwing a ball farther? Learn a little about physics--and how those baseball outfielders can make such impressive plays--with this fastmoving activity!  Key concepts MotionResistance Introduction Background When air resistance is very low, a projectile moves in the shape of a parabola—a type of mathematical curve. (You can do an Internet search for "parabola" to see what one looks like.) The path the ball follows (called its trajectory) will determine how far it goes before it hits the ground. Adjusting the ball’s initial angle and keeping its initial speed constant is one way to find out the best angle to throw a ball as far as possible. In this experiment you will throw a ball as hard as you can while changing the ball's initial angle relative to the ground. What angle do you think will make the ball go the farthest? Materials Sports ball of your choice (baseball, tennis ball, football, ...
Read more

Can the U.S. Jump-Start Offshore Wind Power?

-
The Department of Energy has awarded around a half-million dollars to New York, Maine, Rhode Island and Massachusetts state organizations to cooperate on scaling up the offshore wind industry in the region. Under the leadership of the New York State Energy Research and Development Authority (NYSERDA), the group will lay out a collaborative road map by the end of the year on how to build up the new industry. The project largely aims to reduce the cost of offshore wind projects, which has been a barrier to development, and establish a regional supply chain. Industry and state representatives learned about the federal grant at the first-ever offshore wind summit hosted by the White House yesterday. Offshore wind has struggled to take off in the United States. Europe, meanwhile, has more than 80 offshore wind farms with more than 10,000 megawatts of capacity. The White House summit marks a renewed effort to get the industry going in the United States, said various attendees. “There’s a...
Read more