Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UI researchers make first measurements of the solar wind termination shock

07.07.2008
Two University of Iowa space physicists report that the Voyager 2 spacecraft, which has been traveling outward from the Sun for 31 years, has made the first direct observations of the solar wind termination shock, according to a paper published in the July 3 issue of the journal Nature.

At the termination shock the solar wind, which continuously expands outward from the sun at over a million miles per hour, is abruptly slowed to a subsonic speed by the interstellar gas.

Don Gurnett, professor of physics in the College of Liberal Arts and Sciences and principal investigator for the plasma wave instrument on Voyager 2, and Bill Kurth, UI research scientist and Voyager co-investigator, said that the shock crossing was marked by an intense burst of plasma wave turbulence detected by the UI instrument, as well as by various effects detected by other instruments on the spacecraft.

At the time of the shock crossing, August 31, 2007, Voyager 2 was at a distance of 83.7 astronomical units (AU), roughly twice the distance between the Sun and Pluto. At this great distance, it took 11.2 hours for the radio signal from the spacecraft to reach Earth.

Shock waves in the thin, ionized gas -- called plasma -- that exists in space are similar in some respects to the shock waves produced by an airplane in supersonic flight. Shock waves in space are believed to play an important role in the acceleration of cosmic rays, which are very energetic atomic particles that continually bombard Earth. The most energetic cosmic rays, which are potentially hazardous to astronauts, are believed to be produced in intense shock waves caused by supernova explosions -- immense stellar explosions that occur in massive stars toward the end of their lives.

The termination shock is believed to be responsible for the origin of less energetic cosmic rays called "anomalous cosmic rays." The recent observations at the termination shock are expected to help physicists understand how cosmic rays are produced by the turbulent fields that exist in such shocks. Gurnett said, "There is no way for us to make direct measure of a super nova shock, so the Voyager 2 measurements at the termination shock provide us the best opportunity in the foreseeable future to understand how cosmic rays are produced by supernova cosmic shocks."

Kurth noted that while some aspects of the termination shock matched scientists' expectations, a number of the observations made by Voyager were surprising and will cause a number of theories to be revised.

Gurnett noted that Voyager 2, launched in 1977, is moving at a speed of 38,000 miles an hour. Even at this considerable speed, the spacecraft will still take 30,000 years to reach a distance equal to that of the nearest star.

The sounds of Voyager's encounter with shock waves at various planets and other sounds of space can be heard by visiting the space audio Web site at: http://www-pw.physics.uiowa.edu/space-audio/.

Gary Galluzzo | EurekAlert!
Further information:
http://www.uiowa.edu
http://www-pw.physics.uiowa.edu/space-audio/

More articles from Physics and Astronomy:

nachricht New research identifies how 3-D printed metals can be both strong and ductile
11.12.2017 | University of Birmingham

nachricht Three kinds of information from a single X-ray measurement
11.12.2017 | Friedrich-Schiller-Universität Jena

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: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

Blockchain is becoming more important in the energy market

05.12.2017 | Event News

 
Latest News

New research identifies how 3-D printed metals can be both strong and ductile

11.12.2017 | Physics and Astronomy

Scientists channel graphene to understand filtration and ion transport into cells

11.12.2017 | Materials Sciences

What makes corals sick?

11.12.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>