Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Some cosmic rays originate within solar system, researchers find

31.10.2002


Researchers have found that a portion of anomalous cosmic rays -- charged particles accelerated to enormous energies by the solar wind -- results from interactions with dust grains from a belt of comet-sized objects near Pluto’s orbit. These objects make up what is known as the Kuiper Belt, a remnant of the formation of the solar system.



"This novel finding shows how dust in the cosmos may play an important role for producing the most energetic particles known," says Dr. Nathan Schwadron, a senior research scientist in the Space Science and Engineering Division of Southwest Research Institute (SwRI) in San Antonio, Texas. The study by Schwadron and colleagues at SwRI and the University of Michigan was published October 30 in Geophysical Research Letters, a journal of the American Geophysical Union.

"Dust grains are produced in vast amounts through collisions of Kuiper Belt objects," says Schwadron. "These particles give us a glimpse of the early stages of our solar system when the dust content was much larger, and could parallel other more dusty stellar systems that exist now."


Recent observations of anomalous cosmic rays are puzzling because of the unexpected presence of iron, silicon and carbon, notes Schwadron. "This finding varies from the traditional explanation of anomalous cosmic rays which were thought to be devoid of easily charged elements."

The interstellar medium has lots of carbon, silicon and iron atoms, but electrical charging (ionization) of these elements prevents them from penetrating deeply within the solar system. "Our team looked for a source already inside the solar system to account for the unusual anomalous cosmic rays -- and we found one in the tiny comet-like grains from the nearby Kuiper Belt," says Schwadron.

As the grains produced by collisions in the Kuiper Belt drift in toward the sun, they are bombarded by solar wind particles, which causes sputtering and frees the carbon, silicon and iron atoms from within. At that point, those particles interact with solar radiation, transforming them into ions (charged particles). The solar wind then sweeps them out and accelerates them to anomalous cosmic ray energies at the edge of the solar system, where they are bounced to and fro by magnetic fields in the solar wind and in the medium beyond the solar system, according to Schwadron.

Tom Bogdan, program director in the NSF Division of Atmospheric Sciences, which partly funded the research, says, "This is a big step toward solving the long-standing mystery of the origin of the anomalous component of cosmic rays. The research underscores the power of remote sensing: Sampling of Kuiper Belt material with unmanned space probes is a huge and difficult enterprise. The detection locally of the anomalous cosmic ray component provides information on the conditions that prevail in this remote region of our solar system."

"Anomalous cosmic rays" are so named because they form in the relative vicinity of the Earth, near the sun, and have lower energy than galactic and intergalactic cosmic rays, which form in the far reaches of the galaxy and beyond. Cosmic rays, the most energetic particles in the cosmos, move throughout the universe at light speed and constantly bombard the Earth.

"The discovery that anomalous cosmic rays can be generated from material in the Kuiper Belt provides a tool for understanding its mass distribution and composition and for probing the plasma-dust interactions in space," says Schwadron.

Cosmic rays also are believed to play a role in evolution. "Cosmic rays are a double-edged sword. They cause genetic mutation and are harmful to living organisms, but on the upside stimulate biological evolution," Schwadron says. "Cosmic rays are our only available sample of matter from the far reaches of the distant galaxy, and from other galaxies. They can tell us a lot about what’s in the universe, and we can now use them to study what’s in the Kuiper Belt. Their relationship to the creation or maintenance of life is also worth a closer look."

This program was supported with funding from NSF, NASA, and SwRI.

Harvey Leifert | AGU
Further information:
http://www.agu.org/

More articles from Physics and Astronomy:

nachricht Gamma-ray flashes from plasma filaments
18.04.2018 | Max-Planck-Institut für Kernphysik

nachricht How does a molecule vibrate when you “touch” it?
17.04.2018 | Universität Regensburg

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: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

Im Focus: The Future of Ultrafast Solid-State Physics

In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.

Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...

Im Focus: Stronger evidence for a weaker Atlantic overturning

The Atlantic overturning – one of Earth’s most important heat transport systems, pumping warm water northwards and cold water southwards – is weaker today than any time before in more than 1000 years. Sea surface temperature data analysis provides new evidence that this major ocean circulation has slowed down by roughly 15 percent since the middle of the 20th century, according to a study published in the highly renowned journal Nature by an international team of scientists. Human-made climate change is a prime suspect for these worrying observations.

“We detected a specific pattern of ocean cooling south of Greenland and unusual warming off the US coast – which is highly characteristic for a slowdown of the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

New capabilities at NSLS-II set to advance materials science

18.04.2018 | Materials Sciences

Strong carbon fiber artificial muscles can lift 12,600 times their own weight

18.04.2018 | Materials Sciences

Polymer-graphene nanocarpets to electrify smart fabrics

18.04.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>