Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Asteroid fragments on a fast collision course

15.07.2004


Collisions in the Asteroid Belt result in the asteroids being completely destroyed and shattered into countless pieces. Computer simulations predict that most of these fragments will eventually fall into the Sun. Some of them, however, will hit the Earth after millions of years as meteorites. It is possible that this could also occur much earlier. In certain positions in the Asteroid Belt, the orbiting time of an object around the sun is a multiple of the orbit of the giant planet Jupiter. The so-called orbital resonance can lead to a disruption in the object’s orbit. It can change the orbit so much that the object would cross the Earth’s orbit and collide with the Earth. Up until today, when this might occur has only been theoretically calculated. But, a new measurement method developed by a research team at the Institute for Isotope Geology at ETH Zurich can now bring more certainty to the subject. The team has established that it could take just a few hundred thousand years for such an object to collide with our planet.

Concentrations of noble gases tell the travel time of an asteroid

Collisional fragments from asteroids in space are constantly being hit by cosmic radiation. This creates noble gases from nuclear reactions. These gases do not enter into any further chemical reactions. Therefore, during the entire duration of the radiation, i.e. the travel time of the fragment in space, they accumulate in the fragment. After measuring the concentration of these socalled cosmogenic inert gases, the travel time from original body to Earth can be calculated. The higher the concentration, the longer the meteorite was underway.



Fossil meteorites: participants in a catastrophe

The researchers used meteorites for their tests that are assumed to be the results of a huge asteroid collision in the recent history of the solar system. These meteorites were found in a stone quarry in southern Sweden in a 480 million year old seabed deposit. What is astonishing is that the fragments still show the traces of the inert gases absorbed more than 500 million years ago.

"Tom Dooley" allows measurement of very small amounts of gas

The Noble Gas Laboratory at ETH Zurich has a highly sensitive mass spectrometer, nicknamed "Tom Dooley", that is specialized for the measurement of extremely small amounts of gas. This instrument, developed at ETH, condenses the test gas into a tiny volume in order to raise the concentration to the point that even rare gases, such as the helium or neon in a single dust particle, can be measured. The sensitivity of this instrument is more than a hundred times higher than conventional mass spectrometers. The device is unique, world wide. Using this instrument, the young researcher Philipp Reza Heck found a method for measuring a very small amount of cosmic inert gas. To do this, just a few micrograms of lightweight meteorite sample is melted with an infrared laser and the gas is then set free and cleaned. Heck then measures the isotopes of the elements helium and neon with "Tom Dooley" spectrometer.

Confirmation of the shorter travel time

With the new method, it could be proven for the first time that the noble gases in the meteorites in southern Sweden were already on in the meteorites 480 million years ago. The calculated travel time was reduced to a few hundred thousand years, which corresponds to the lower limits predicted by the computer simulations. These were the first fragments to arrive on Earth after a great collision. The short radiation age is a clue that the collision took place in the proximity of an orbital resonance in the Asteroid Belt. In addition, it could be proven that the fossil meteorites from southern Sweden all stem from the same event. The newly developed method from the Institute for Isotope Geology makes it possible to confirm the theories about the behaviour of asteroid fragments in space. This will make it significantly easier for researchers to predict future collisions with our planet.

Probala Rolf | alfa
Further information:
http://www.ethz.ch

More articles from Earth Sciences:

nachricht Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen

nachricht Shallow soils promote savannas in South America
20.10.2017 | Senckenberg Forschungsinstitut und Naturmuseen

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>