Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stardust findings override some commonly held astronomy beliefs

18.12.2006
Contrary to a popular scientific notion, there was enough mixing in the early solar system to transport material from the sun's sizzling neighborhood and deposit it in icy deep-space comets.

It might have been like a gentle eddy in a stream or more like an artillery blast, but evidence from the Stardust mission shows that material from the sun’s vicinity traveled to the edge of the solar system, beyond Pluto, as the planets were born.

"Many people imagined that comets formed in total isolation from the rest of the solar system. We have shown that's not true," said Donald Brownlee, the University of Washington astronomer who is principal investigator, or lead scientist, for Stardust.

"As the solar system formed 4.6 billion years ago, material moved from the innermost part to the outermost part. I think of it as the solar system partially turning itself inside out," said Brownlee, the lead author of 183 on the primary paper detailing the first research results from the Stardust mission, published in the Dec. 15 edition of the journal Science. Brownlee is a coauthor of the other six papers on Stardust results being published in Science, which also are the subject of a news conference and scientific presentations at the fall meeting of the American Geophysical Union in San Francisco.

The National Aeronautics and Space Administration's Stardust mission was launched in February 1999 and met comet Wild 2 (pronounced Vilt) beyond the orbit of Mars in January 2004. The comet formed more than 4.5 billion years ago and had remained preserved in the frozen reaches of the outer solar system until 1974 when a close encounter with Jupiter shifted the comet's orbit to a path between Mars and Jupiter. After a 2.88 billion-mile journey, Stardust returned to Earth last January with a payload of thousands of tiny particles from Wild 2.

Among the biggest surprises, Brownlee said, was finding material that formed in the hottest part of the solar system.

"If those materials had gotten any hotter they would have vaporized," he said. "The most extreme particle was the second one we worked on in my lab. These types of particles are among the oldest things in the solar system."

That particle was a calcium-aluminum inclusion, a rare material seen in some meteorites and the very type of matter that scientists used as an argument for flying Stardust to less than 150 miles from Wild 2. At that close range, the fast-moving particles could have seriously damaged the spacecraft, but Brownlee and others felt it was necessary to take that risk if they were to have a chance to determine an upper limit of material that formed near the sun that ended up at the farthest fringes of the solar system.

"Truthfully, we really didn't expect to find anything from the inner solar system. Instead, it showed up in the second particle we looked at," he said. The scientists also found magnesium olivine, a primary component of the green sand found on some Hawaiian beaches and, like a calcium-aluminum inclusion, one of the first things to form in the cooling solar nebula.

Brownlee estimates that as much as 10 percent of the material in comets came from the inner solar system. "That's a real surprise because the common expectation was that comets would be made of interstellar dust and ice."

But interstellar dust has a glassy characteristic, he said, while the particles that formed around stars and are found in comets are partially crystalline. It was suggested previously that interstellar dust had been mildly heated to transform its glassy substance into the crystalline comet contents.

"What we've seen, I believe, is totally incompatible with that interpretation," Brownlee said. "The particles we've seen have been heavily heated. Astronomical interpretations will be affected by that."

Wild 2's personality seems to be different from that of comet Tempel 1, which was closely examined in a mission called Deep Impact. In that case, a probe crashed into the comet surface and the properties of the resulting dust were analyzed using the infrared part of the spectrum. But Brownlee notes that while Tempel 1 was examined remotely from a distance, Stardust returned actual samples for scientists to study.

"The comets may be different from each other, or different observations could simply be a result of the different techniques used to examine them. It is a challenge for us to understand how they are different and why," he said.

Besides the UW, other major partners for the $212 million Stardust project are NASA's Jet Propulsion Laboratory, Lockheed Martin Space Systems, The Boeing Co., Germany's Max-Planck Institute for Extraterrestrial Physics, NASA Ames Research Center, the University of Chicago, The Open University in England and NASA's Johnson Space Center.

Brownlee has noted the irony that the tiny specks of comet dust are being examined by some of the largest investigative tools, such as the 2-mile-long Stanford Linear Accelerator. But with more than 150 scientists studying dust from Wild 2, Stardust also is driving the advance of new technology, including development of the world's highest-resolution microscope at the Lawrence Livermore National Laboratory.

"We're doing things no one ever imagined we could do, even at the time we launched the mission," Brownlee said. "We've taken a pinch of comet dust and are learning incredible things."

Vince Stricherz | EurekAlert!
Further information:
http://www.washington.edu

More articles from Physics and Astronomy:

nachricht SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute

nachricht New survey hints at exotic origin for the Cold Spot
26.04.2017 | Royal Astronomical Society

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

Control of molecular motion by metal-plated 3-D printed plastic pieces

27.04.2017 | Materials Sciences

Move over, Superman! NIST method sees through concrete to detect early-stage corrosion

27.04.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>