Featured Research

from universities, journals, and other organizations

New View Of The Heliosphere: Cassini Helps Redraw Shape Of Solar System

Date:
October 18, 2009
Source:
Johns Hopkins University
Summary:
The solar system, as defined by the heliosphere, the region of the sun's influence, may have a quite different shape than scientists had thought.

Images from the Ion and Neutral Camera (INCA), part of the Magnetospheric Imaging Instrument on NASA's Cassini spacecraft, suggest that the heliosphere may not have the comet-like shape predicted by existing models. The instrument imaged a population of hot particles that resides just beyond the boundary of where the solar wind collides with the interstellar medium, forming a termination shock.
Credit: JHU Applied Physics Laboratory

In a paper published Oct. 15 in Science, researchers from the Johns Hopkins Applied Physics Laboratory (APL) present a new view of the region of the sun’s influence, or heliosphere, and the forces that shape it. Images from one of the Magnetospheric Imaging Instrument’s sensors, the Ion and Neutral Camera (MIMI/INCA), on NASA’s Cassini spacecraft suggest that the heliosphere may not have the comet-like shape predicted by existing models.

Related Articles


“These images have revolutionized what we thought we knew for the past fifty years; the sun travels through the galaxy not like a comet but more like a big, round bubble” said Stamatios Krimigis, principal investigator for MIMI, which is orbiting Saturn. “It’s amazing how a single new observation can change an entire concept that most scientists had taken as true for nearly fifty years.”

As the solar wind flows from the sun, it carves out a bubble in the interstellar medium. Models of the boundary region between the heliosphere and interstellar medium have been based on the assumption that the relative flow of the interstellar medium and its collision with the solar wind dominate the interaction. This would create a foreshortened “nose” in the direction of the solar system’s motion, and an elongated “tail” in the opposite direction.

The INCA images suggest that the solar wind’s interaction with the interstellar medium is instead more significantly controlled by particle pressure and magnetic field energy density.

“The map we’ve created from INCA’s images suggests that pressure from a hot population of charged particles and interaction with the interstellar medium’s magnetic field strongly influence the shape of the heliosphere,” says Don Mitchell, MIMI/INCA co-investigator at APL.

Since entering into orbit around Saturn in July of 2004, INCA has been mapping energetic neutral atoms near the planet, as well as their dispersal across the entire sky. The energetic neutral atoms are produced by energetic protons, which are responsible for the outward pressure of the heliosphere beyond the interface where the solar wind collides with the interstellar medium, and which interact with the magnetic field of the interstellar medium.

“Energetic neutral atom imaging has demonstrated its power to reveal the distribution of energetic ions, first in Earth’s own magnetosphere, next in the giant magnetosphere of Saturn and now throughout vast structures in space—out to the very edge of our sun’s interaction with the interstellar medium,” says Edmond C. Roelof, MIMI/INCA co-investigator at APL.

Researchers from University of Arizona, Tucson, Southwest Research Institute, and University of Texas at San Antonio contributed to the article. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL. The Magnetospheric Imaging Instrument was developed by APL.

More information on the Cassini mission is available at: http://www.nasa.gov/cassini, http://saturn.jpl.nasa.gov and on the Magnetospheric Imaging Instrument Web site at http://sd-http://www.jhuapl.edu/CASSINI.


Story Source:

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


Journal Reference:

  1. S. M. Krimigis, D. G. Mitchell, E. C. Roelof, K. C. Hsieh, and D. J. McComas. Imaging the Interaction of the Heliosphere with the Interstellar Medium from Saturn with Cassini. Science, 2009; DOI: 10.1126/science.1181079

Cite This Page:

Johns Hopkins University. "New View Of The Heliosphere: Cassini Helps Redraw Shape Of Solar System." ScienceDaily. ScienceDaily, 18 October 2009. <www.sciencedaily.com/releases/2009/10/091016101807.htm>.
Johns Hopkins University. (2009, October 18). New View Of The Heliosphere: Cassini Helps Redraw Shape Of Solar System. ScienceDaily. Retrieved December 17, 2014 from www.sciencedaily.com/releases/2009/10/091016101807.htm
Johns Hopkins University. "New View Of The Heliosphere: Cassini Helps Redraw Shape Of Solar System." ScienceDaily. www.sciencedaily.com/releases/2009/10/091016101807.htm (accessed December 17, 2014).

Share This


More From ScienceDaily



More Space & Time News

Wednesday, December 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Rover Finds More Clues About Possible Life On Mars

Rover Finds More Clues About Possible Life On Mars

Newsy (Dec. 17, 2014) NASA's Curiosity rover detected methane on Mars and organic compounds on the surface, but it doesn't quite prove there was life ... yet. Video provided by Newsy
Powered by NewsLook.com
Evidence of Life on Mars? NASA Rover Finds Methane, Organic Chemicals

Evidence of Life on Mars? NASA Rover Finds Methane, Organic Chemicals

Reuters - US Online Video (Dec. 16, 2014) NASA's Mars Curiosity rover finds methane in the Martian atmosphere and organic chemicals in the planet's soil, the latest hint that Mars was once suitable for microbial life. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Geminids Meteor Shower Lights Up Skies in China

Geminids Meteor Shower Lights Up Skies in China

AFP (Dec. 16, 2014) The Geminids meteor shower lights up the skies over the Changbai Mountains in northeast China. Duration: 01:03 Video provided by AFP
Powered by NewsLook.com
Raw: Defense Satellite Launches from California

Raw: Defense Satellite Launches from California

AP (Dec. 13, 2014) A U.S. defense satellite launched from California's central coast on Friday after weather delays caused by a major storm that drenched the state. (Dec. 13) Video provided by AP
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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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