GPS News  
IRON AND ICE
Avoiding An Asteroid Collision

Illustration only.
by Staff Writers
Tel Aviv, Israel (SPX) Sep 14, 2010
Though it was once believed that all asteroids are giant pieces of solid rock, later hypotheses have it that some are actually a collection of small gravel-sized rocks, held together by gravity. If one of these "rubble piles" spins fast enough, it's speculated that pieces could separate from it through centrifugal force and form a second collection - in effect, a second asteroid.

Now researchers at Tel Aviv University, in collaboration with an international group of scientists, have proved the existence of these theoretical "separated asteroid" pairs.

Ph.D. student David Polishook of Tel Aviv University's Department of Geophysics and Planetary Sciences and his supervisor Dr. Noah Brosch of the university's School of Physics and Astronomy say the research has not only verified a theory, but could have greater implications if an asteroid passes close to earth.

Instead of a solid mountain colliding with earth's surface, says Dr. Brosch, the planet would be pelted with the innumerable pebbles and rocks that comprise it, like a shotgun blast instead of a single cannonball. This knowledge could guide the defensive tactics to be taken if an asteroid were on track to collide with the Earth.

A large part of the research for the study, recently published in the journal Nature, was done at Tel Aviv University's Wise Observatory, located deep in the Negev Desert - the first and only modern astronomical observatory in the Middle East.

Spinning out in space
According to Dr. Brosch, separated asteroids are composed of small pebbles glued together by gravitational attraction. Their paths are affected by the gravitational pull of major planets, but the radiation of the sun, he says, can also have an immense impact. Once the sun's light is absorbed by the asteroid, rotation speeds up. When it reaches a certain speed, a piece will break off to form a separate asteroid.

The phenomenon can be compared to a figure skater on the ice. "The faster they spin, the harder it is for them to keep their arms close to their bodies," explains Dr. Brosch.

As a result, asteroid pairs are formed, characterized by the trajectory of their rotation around the sun. Though they may be millions of miles apart, the two asteroids share the same orbit. Dr. Brosch says this demonstrates that they come from the same original asteroid source.

Looking into the light
During the course of the study, Polishook and an international group of astronomers studied 35 asteroid pairs. Traditionally, measuring bodies in the solar system involves studying photographic images. But the small size and extreme distance of the asteroids forced researchers to measure these pairs in an innovative way.

Instead, researchers measured the light reflected from each member of the asteroid pairs. The results proved that in each asteroid pair, one body was formed from the other.

The smaller asteroid, he explains, was always less than forty percent of the size of the bigger asteroid. These findings fit precisely into a theory developed at the University of Colorado at Boulder, which concluded that no more than forty percent of the original asteroid can split off.

With this study, says Dr. Brosch, researchers have been able to prove the connection between two separate spinning asteroids and demonstrate the existence of asteroids that exist in paired relationships.



Share This Article With Planet Earth
del.icio.usdel.icio.us DiggDigg RedditReddit
YahooMyWebYahooMyWeb GoogleGoogle FacebookFacebook



Related Links
Tel Aviv University
Asteroid and Comet Mission News, Science and Technology



Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


IRON AND ICE
Scientists find 'rubble pile' asteroids
Tel Aviv, Israel (UPI) Sep 13, 2010
Asteroids made of gravel-sized rocks held together by gravity could hit the Earth like a shotgun blast rather than a single cannonball, Israeli researchers say. It was long theorized that these "rubble pile" asteroids, if they spun fast enough, could throw off material through centrifugal force to create a second collection of rocks - a "separated" twin - that would spin around the su ... read more







IRON AND ICE
Unusual Feed Supplement Could Ease Greenhouse Gassy Cows

Discovery Offers Hope Of Saving Sub-Saharan Crops From Devastating Parasites

Grain rots in India as millions starve

Farm Management Choice Can Benefit Fungi Key To Healthy Ecosystems

IRON AND ICE
Chip revenue expected to grow 31.5 percent in 2010: Gartner

Computer data stored with 'spintronics'

Protein From Poplar Trees Can Be Used To Greatly Increase Computer Capacity

Polymer Synthesis Could Aid Future Electronics

IRON AND ICE
India, Russia to develop transport planes

Airbus eyes 150-jet China contract: report

Air China to buy four Boeing 777s

Lufthansa traffic rises as A380 takes off for China: airline

IRON AND ICE
Toyota to launch six new hybrids by end of 2012

China's Geely unveils ambitious plans for Volvo

Japan's Nissan unveils new brand for China

Audi posts sales records in China, US

IRON AND ICE
EU eyes Mercosur markets to fuel recovery

Kenya invites tenders to build new port

China helping world economic recovery but risks remain: PM

Walker's World: China's hurtful nest-egg

IRON AND ICE
Forestry Professor Helps Shape Future Of Global Industry Research

Logging spells danger for Europe's last primeval forest

Scots Pine Shows Its Continental Roots

Most New Farmland Comes From Cutting Tropical Forest

IRON AND ICE
A Snapshot Of Sea Ice

Satellites Reveal Russian Fires Worst In 14 Years

The Predictable Events Of The February Earthquake In Chile

Satellite Data Reveal Seasonal Pollution Changes Over India

IRON AND ICE
Don't wait for US on cap-and-trade, OECD urges Canada

Australia hopes for carbon capturing 'sponges'

Australia to address price on carbon

EU calls for overhaul of UN carbon credit system


The content herein, unless otherwise known to be public domain, are Copyright 1995-2010 - SpaceDaily. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement