Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nature paper: Burning asteroids may play ’more important climate role than previously recognized’

29.08.2005


Asteroid dust may influence weather, study finds



Dust from asteroids entering the atmosphere may influence Earth’s weather more than previously believed, researchers have found.

In a study to be published this week in the journal Nature, scientists from the Australian Antarctic Division, the University of Western Ontario, the Aerospace Corporation, and Sandia and Los Alamos national laboratories found evidence that dust from an asteroid burning up as it descended through Earth’s atmosphere formed a cloud of micron-sized particles significant enough to influence local weather in Antarctica.


Micron-sized particles are big enough to reflect sunlight, cause local cooling, and play a major role in cloud formation, the Nature brief observes. Longer research papers being prepared from the same data for other journals are expected to discuss possible negative effects on the planet’s ozone layer.

"Our observations suggest that [meteors exploding] in Earth’s atmosphere could play a more important role in climate than previously recognized," the researchers write.

Scientists had formerly paid little attention to asteroid dust, assuming that the burnt matter disintegrated into nanometer-sized particles that did not affect Earth’s environment. Some researchers (and science fiction writers) were more interested in the damage that could be caused by the intact portion of a large asteroid striking Earth.

But the size of an asteroid entering Earth’s atmosphere is significantly reduced by the fireball caused by the friction of its passage. The mass turned to dust may be as much as 90 to 99 percent of the original asteroid. Where does this dust go?

The uniquely well-observed descent of a particular asteroid and its resultant dust cloud gave an unexpected answer.

On Sept. 3, 2004, the space-based infrared sensors of the U.S. Department of Defense detected an asteroid a little less than 10 meters across, at an altitude of 75 kilometers, descending off the coast of Antarctica. U.S. Department of Energy visible-light sensors built by Sandia National Laboratories, a National Nuclear Security Administration lab, also detected the intruder when it became a fireball at approximately 56 kilometers above Earth. Five infrasound stations, built to detect nuclear explosions anywhere in the world, registered acoustic waves from the speeding asteroid that were analyzed by LANL researcher Doug ReVelle. NASA’s multispectral polar orbiting sensor then picked up the debris cloud formed by the disintegrating space rock.

Some 7.5 hours after the initial observation, a cloud of anomalous material was detected in the upper stratosphere over Davis Station in Antarctica by ground-based lidar.

"We noticed something unusual in the data," says Andrew Klekociuk, a research scientist at the Australian Antarctic division. "We’d never seen anything like this before - [a cloud that] sits vertically and things blow through it. It had a wispy nature, with thin layers separated by a few kilometers. Clouds are more consistent and last longer. This one blew through in about an hour."

The cloud was too high for ordinary water-bearing clouds (32 kilometers instead of 20 km) and too warm to consist of known manmade pollutants (55 degrees warmer than the highest expected frost point of human-released solid cloud constituents). It could have been dust from a solid rocket launch, but the asteroid’s descent and the progress of its resultant cloud had been too well observed and charted; the pedigree, so to speak, of the cloud was clear.

Computer simulations agreed with sensor data that the particles’ mass, shape, and behavior identified them as meteorite constituents roughly 10 to 20 microns in size.

Says Dee Pack of Aerospace Corporation, "This asteroid deposited 1,000 metric tons in the stratosphere in a few seconds, a sizable perturbation." Every year, he says, 50 to 60 meter-sized asteroids hit Earth.

Peter Brown at the University of Western Ontario, who was initially contacted by Klekociuk, helped analyze data and did theoretical modeling. He points out that climate modelers might have to extrapolate from this one event to its larger implications. "[Asteroid dust could be modeled as] the equivalent of volcanic eruptions of dust, with atmospheric deposition from above rather than below." The new information on micron-sized particles "have much greater implications for [extraterrestrial visitors] like Tunguska," a reference to an asteroid or comet that exploded 8 km above the Stony Tunguska river in Siberia in 1908. About 2150 square kilometers were devastated, but little formal analysis was done on the atmospheric effect of the dust that must have been deposited in the atmosphere.

The Sandia sensors’ primary function is to observe nuclear explosions anywhere on Earth. Their evolution to include meteor fireball observations came when Sandia researcher Dick Spalding recognized that ground-based processing of data might be modified to record the relatively slower flashes due to asteroids and meteoroids. Sandia computer programmer Joe Chavez wrote the program that filtered out signal noise caused by variations in sunlight, satellite rotation, and changes in cloud cover to realize the additional capability. The Sandia data constituted a basis for the energy and mass estimate of the asteroid, says Spalding.

The capabilities of defense-related sensors to distinguish between the explosion of a nuclear bomb and the entry into the atmosphere of an asteroid that releases similar amounts of energy - in this case, about 13 kilotons - could provide an additional margin of world safety. Without that information, a country that experienced a high-energy asteroid burst that penetrated the atmosphere might provoke a military response by leaders who are under the false impression that a nuclear attack is underway, or lead other countries to assume a nuclear test has occurred.

Neal Singer | EurekAlert!
Further information:
http://www.sandia.gov

More articles from Studies and Analyses:

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

nachricht Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>