Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Asteroids pile up

12.04.2002


There are more asteroids out there than we thought.
© NASA


New count doubles the rocks in asteroid belt.

There are twice as many asteroids between Mars and Jupiter as previously believed, according to the latest study. But the probability of a stray one colliding with Earth remains negligible.

Edward Tedesco of US research company TerraSystems Inc.and Francois-Xavier Désert of the Astrophysical Laboratory in Grenoble, France, found that there are between 1.1 million and 1.9 million asteroids swarming round the ’main asteroid belt’1.



Astronomers have previously studied individual asteroids, but Tedesco and Désert are among the first to perform a large-scale survey. They used the European Space Agency’s Infrared Space Observatory to observe a small region of the asteroid belt and extrapolated the number of asteroids to estimate the total number.

The study offers a "snapshot of the main belt", says Thomas Mueller, an astronomer at the Max Planck Institute in Munich, Germany. But the possibility of a collision with Earth remains minimal, according to Mueller.

Fears of a possible impact were raised last week2 when scientists forecast that there is a slim chance of a collision in 2880. It will take years before astronomers can discover the precise pathway for each asteroid in the belt, says Mueller, but this should not be a cause for concern. "The majority of all orbits of asteroids are relatively stable over millions of years and will not cross Earth’s orbit," he says.

Asteroids are faint and difficult to pin down with telescopes that detect visible light. Tedesco and Désert overcame this obstacle by measuring the infrared that the asteroids emit. They developed a mathematical model to estimate the entire population of asteroids based on those in a selected area of the belt. "It is a new method to derive an inventory of our Solar System," says Mueller.

Diverting disaster

If stray asteroids do end up on a collision path with Earth they could be deflected by changing the amount of sunlight they reflect, a second study has suggested3. When an unevenly heated body re-radiates heat, it alters the momentum of an object - this is called the Yarkovsky effect. This could be used to deflect an asteroid slightly in its orbit, according to Joseph Spitale, a planetary scientist at the University of Arizona.

But executing this deflection might be easier said than done. Spitale suggests coating the asteroid with a blanket of dirt 1 centimetre deep to change its surface heat conductivity, or using a small amount of explosive to modify the surface. "Their precise implementation is open to debate," he says.

References

  1. Tedesco, E.F. & Désert, F-X.The Infrared Space Observatory Deep Asteroid Search. The Astronomical Journal, 123, 2070 - 2082, (2002).
  2. Giorgini, J.D. et al. Asteroid 1950 DA’s encounter with Earth in 2880: physical limits of collision probability prediction. Science, 296, 132 - 136, (2002).
    Spitale, J.N. Asteroid hazard mitigation using the Yarkovsky effect. Science, 296, 77, (2002).


MEERA LOUIS | © Nature News Service

More articles from Physics and Astronomy:

nachricht Enhancing the quantum sensing capabilities of diamond
23.11.2017 | The Hebrew University of Jerusalem

nachricht Quantum optics allows us to abandon expensive lasers in spectroscopy
22.11.2017 | Lomonosov Moscow State University

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Underwater acoustic localization of marine mammals and vehicles

23.11.2017 | Information Technology

Enhancing the quantum sensing capabilities of diamond

23.11.2017 | Physics and Astronomy

Meadows beat out shrubs when it comes to storing carbon

23.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>