Featured Research

from universities, journals, and other organizations

First Measurements Of The Solar Wind Termination Shock By Voyager 2 Spacecraft

Date:
July 3, 2008
Source:
University of Iowa
Summary:
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 an article in the journal Nature.

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
Credit: NASA

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/.

The University of Iowa research was supported by NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., a division of Caltech. JPL manages the Voyager mission for NASA's Office of Space Science, Washington, D.C.


Story Source:

The above story is based on materials provided by University of Iowa. Note: Materials may be edited for content and length.


Cite This Page:

University of Iowa. "First Measurements Of The Solar Wind Termination Shock By Voyager 2 Spacecraft." ScienceDaily. ScienceDaily, 3 July 2008. <www.sciencedaily.com/releases/2008/07/080703113646.htm>.
University of Iowa. (2008, July 3). First Measurements Of The Solar Wind Termination Shock By Voyager 2 Spacecraft. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2008/07/080703113646.htm
University of Iowa. "First Measurements Of The Solar Wind Termination Shock By Voyager 2 Spacecraft." ScienceDaily. www.sciencedaily.com/releases/2008/07/080703113646.htm (accessed July 31, 2014).

Share This




More Space & Time News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Supply Ship Takes Off for International Space Station

Supply Ship Takes Off for International Space Station

AFP (July 30, 2014) The European Space Agency's fifth Automated Transfer Vehicle (ATV-5) is takes off to the International Space Station on an Ariane 5 rocket from French Guiana. Duration: 00:34 Video provided by AFP
Powered by NewsLook.com
Raw: Rocket Launches Into Space With Cargo Ship

Raw: Rocket Launches Into Space With Cargo Ship

AP (July 30, 2014) Arianespace launched a rocket Tuesday from French Guiana carrying a robotic cargo ship to deliver provisions to the International Space Station. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins