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.

“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 April 24, 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 April 24, 2014).

Share This



More Space & Time News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Risk of Asteroid Hitting Earth Higher Than Thought, Study Shows

Risk of Asteroid Hitting Earth Higher Than Thought, Study Shows

Reuters - US Online Video (Apr. 23, 2014) A group of space explorers say the chance of a city-obliterating asteroid striking Earth is higher than scientists previously believed. Deborah Gembara reports. Video provided by Reuters
Powered by NewsLook.com
Nuclear-Level Asteroids Might Be More Common Than We Realize

Nuclear-Level Asteroids Might Be More Common Than We Realize

Newsy (Apr. 23, 2014) The B612 Foundation says asteroids strike Earth much more often than previously thought, and are hoping to build an early warning system. Video provided by Newsy
Powered by NewsLook.com
Two US Astronauts Step out on Spacewalk for ISS Repairs

Two US Astronauts Step out on Spacewalk for ISS Repairs

AFP (Apr. 23, 2014) Two US astronauts stepped out on a brief spacewalk Wednesday to install a backup computer at the International Space Station after one failed earlier this month. Duration: 00:40 Video provided by AFP
Powered by NewsLook.com
NASA Chief Outlines Plan for Human Mission to Mars

NASA Chief Outlines Plan for Human Mission to Mars

AFP (Apr. 22, 2014) NASA administrator Charles Bolden, speaking at the 'Human to Mars Summit' in Washington, says that learning more about the Red Planet can help answer the 'fundamental question' of 'life beyond Earth'. Duration: 00:48 Video provided by AFP
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