Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Each grain is different

15.08.2014

The interstellar dust particles from the Stardust mission show great variations in their elemental composition and structure

The space between the stars is not empty, but filled with interstellar matter – gas and dust particles. But all dust is not the same: An international team from 33 research institutes, including the Max Planck Institute for Chemistry in Mainz, discovered that the structure and chemical composition of interstellar dust particles collected by the Stardust spacecraft shows a wide diversity.


Stardust on the way through the universe: The unfolded „dust catcher“ of the spacecraft is clearly visible in this illustration. NASA/JPL


Cosmic searching for traces: The arrow points to a particle that was captured by the spacecraft, Stardust (left). Next to it, a magnified picture of the impact spot.

Westphal et al. 2014, Science/AAAS

2006 was an important year for the exploration of our solar system: NASA’s Stardust spacecraft brought back to Earth cometary dust as well as smallest amounts of material from the enormous space between the stars, the interstellar space.

This material is of scientific significance for various reasons: it refracts the light of stars and allows for conclusions about the size of the universe. It also provides the raw material for the formation of stars and planets and serves as a catalyst for the formation of molecules.

In the current issue of the science magazine ‘Science’, an international team from 33 research institutes presents, for the first time, the structure and chemical composition of interstellar dust particles, which were collected by the Stardust space craft.

The researchers identified seven particles with a total mass of a few picograms. One picogram is the equivalent of one trillionth of a gram. Even if the number of particles and mass seems very low, the extraterrestrial material is scientific unchartered territory for Peter Hoppe from the Max Planck Institute for Chemistry.

‘This is the first time that we were able to examine contemporary interstellar dust on Earth,’ says the researcher from Mainz. Previously, the extraterrestrial material could only be analyzed by means of spectroscopic observations.

‘We have found that the size, elemental composition and the structure of the particles differ to a great extent. We did not expect that.’ The term contemporary is relative for astrophysicists such as Hoppe, as the average lifetime of dust particles in interstellar space is around 500 million years; compared to our 4.6 billion year-old solar system this is quite a short period.

Contrary to predictions, two dust particles were found to be crystalline and not amorphous, i.e. without an ordered structure of atoms. ‘We had expected a crystalline structure in maximum two percent of the dust,’ says Jan Leitner, a member of Peter Hoppe’s team. According to previous theories, the majority of crystalline particles in interstellar space is destroyed by high-energy cosmic rays and shock waves or converted into amorphous dust.

For the collection of dust particles, the spacecraft was equipped with a special particle collector: On the top of the spacecraft, a tennis racket-sized round grid would protrude into space and catch dust particles on its surface.
Aluminum foil was wrapped around the walls of these sample tray frames. A specially developed aerogel was packed in the aluminum grid, which slowed down the particles on impact, keeping their structure intact.

The Stardust mission, which ran a total of six years, was divided into two phases for the collection of cometary dust and interstellar dust. First, the spacecraft collected interstellar dust at the front of the collector, for a period of 195 days. NASA turned the collector by 180 degrees for the subsequent flight through the tail of comet Wild 2, so that the cometary particles landed on the reverse side.

Back on Earth, spotting the dust particles presented a seemingly impossible task for scientists, as the dust collectors needed to be scanned micron by micron for impact. This would be the equivalent of an analysis of more than 1.5 million photos of the aerogel. Researchers then approached the public in an unprecedented mission and uploaded the photographs to a website.

Thousands of volunteers joined ‘Stardust@home’ and analyzed the images, following a detailed instruction, in order to find the sought-after dust. On the overall, the volunteers made three finds - a great success, which the 66 researchers expressed by naming the ‘30,714 Stardust@home dusters’ in the list of authors of the current issue of Science. Altogether, up to now, four dust particles where found on the aluminum foil and three in the aerogel.

Peter Hoppe’s team concentrated on the foil. The Mainz team had received a 90 square millimeter piece from NASA. “Searching the foil was a true labor of Sisyphus, as we analyzed approximately 50,000 images. As the dust craters are smaller than a thousandth of a millimeter, we scanned the foil, piece by piece, using an electron microscope,” the researcher Jan Leitner remembers.

The team found five particles. However, four of the craters only contained abrasion material from the solar cells of the spacecraft. One sample, however, was in fact extraterrestrial and received the unspectacular name I1044N,3. Chemical analysis revealed that this was a ferromagnesian silicate. Other samples contained iron sulfide and elemental iron in addition to aluminum, chromium, manganese, nickel and calcium. As it was not possible to prove the presence of these forms of iron by spectroscopic investigations from Earth, this was another success of two years of working for the researcher community.

Although only a small portion of the surface of the Stardust collector has been scanned, for the time being, the analysis of the interstellar dust is completed for Peter Hoppe and his team. The remaining samples are now available to scientists around the world for identification and analysis of further particles. Perhaps, these studies will provide some new surprises. (MMG/SB)

Original Publication

Westphal et al.
Evidence for interstellar origin of seven dust particles collected by the Stardust spacecraft
Science, 15. August 2014: Vol. 345 no. 6198 pp. 786-791
doi: 10.1126/science.1252496

Weitere Informationen:

http://www.mpic.de/en/news/press-information/news/each-grain-is-different.html

Dr. Wolfgang Huisl | Max-Planck-Institut für Chemie

Further reports about: Max-Planck-Institut Stardust crystalline interstellar mass particles spacecraft structure

More articles from Physics and Astronomy:

nachricht Meteoritic stardust unlocks timing of supernova dust formation
19.01.2018 | Carnegie Institution for Science

nachricht Artificial agent designs quantum experiments
19.01.2018 | Universität Innsbruck

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: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>