Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists get first close look at stardust

28.02.2003


For the first time, scientists have identified and analyzed single grains of silicate stardust in the laboratory. This breakthrough, to be reported in the Feb. 27 issue of Science Express, provides a new way to study the history of the universe.


"Astronomers have been studying stardust through telescopes for decades," said first author Scott Messenger, Ph.D., senior research scientist in the Laboratory for Space Sciences at Washington University in St. Louis. "And they have derived models of what it must be like, based on wiggles in their spectral recordings. But they never dreamed it would be possible to look this closely at a grain of stardust that has been floating around in the galaxy."

Most stardust is made of tiny silicate grains, much like dust from rocks on earth. Away from city lights, you can see the dust as a dark band across the Milky Way. This dust comes from dying and exploded stars. Scientists think stars form when these dust clouds collapse and that some of this dust became trapped inside asteroids and comets when our own sun formed.

The researchers found the stardust in tiny fragments of asteroids and comets--interplanetary dust particles (IDPs) --collected 20 km above the earth by NASA planes. A typical IDP is a mishmash of more than 100,000 grains gleaned from different parts of space. Until recently, ion probes had to analyze dozens of grains at one time and so were able to deduce only the average properties of a sample.



In 2001, with help from NASA and the National Science Foundation, Washington University bought a newly available and much more sensitive ion probe. Made by Cameca in Paris, the NanoSIMS probe can resolve particles as small as 100 nanometers in diameter. A million such particles side by side would make a centimeter. The grains in IDPs range from 100 to 500 nanometers. "So like the Hubble telescope, the NanoSIMS allows us to see things on a much finer scale than ever before," Messenger said.

Lindsay P. Keller, Ph.D., at NASA’s Johnson Space Center in Houston, first examined thin slices of IDPs under the transmission electron microscope. He identified the chemical elements in single grains and determined whether the grains were crystals or coated with organic material.

Using the NanoSIMS probe, the Washington University investigators then measured the relative amounts of two isotopes of oxygen in more than a thousand grains from nine IDPs. The data told them which grains had come from stars. The researchers discovered the first grain of stardust in the first half hour of their first NanoSIMS session. "Finding something that people have been seeking for such a long time was incredibly exciting," Messenger said.

Stardust was surprisingly common in the IDPs. "We found that 1 percent of the mass of these interplanetary dust particles was stardust," Messenger explained. "So stardust is about 50 times as abundant in these particles as in meteorites, which suggests that it comes from far more primitive bodies."

The isotopic measurements identified six stardust grains from outside our solar system. Three appeared to have come from red giants or asymptotic giant branch stars, two late stages in stellar evolution. A fourth was from a star containing little metal. The fifth and sixth possibly came from a metal-rich star or a supernova.

Although this work is just beginning, some novel findings have emerged. For example, one of the grains was crystalline, which contradicts the idea that silicate stardust grains are always amorphous. "A single grain of stardust can bring down a long-established theory," Messenger said.

The researchers will probe the history of stardust with further studies of IDP chemistry and microstructure. "The interstellar medium plays an incredibly important role in star formation, but you can learn only so much by using a telescope," Messenger said. "You can find out so much more by studying actual samples."



A grant from NASA funded this research.
Images of IDPs are available.

Tony Fitzpatrick | EurekAlert!
Further information:
http://www.wustl.edu/
http://stardust.wustl.edu
http://www.sciencemag.org/feature/express/expresstwise.shl

More articles from Physics and Astronomy:

nachricht From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison

nachricht Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>