Featured Research

from universities, journals, and other organizations

Scientists Say Mars Has A Liquid Iron Core

Date:
March 7, 2003
Source:
NASA/Jet Propulsion Laboratory
Summary:
New information about what is inside Mars shows the red planet has a molten liquid iron core, confirming the interior of the planet has some similarity to Earth and Venus.

New information about what is inside Mars shows the red planet has a molten liquid iron core, confirming the interior of the planet has some similarity to Earth and Venus.

Researchers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., analyzing three years of radio tracking data from the Mars Global Surveyor spacecraft, concluded that Mars has not cooled to a completely solid iron core, rather its interior is made up of either a completely liquid iron core or a liquid outer core with a solid inner core. Their results are published in the March 7, 2003 online issue of the journal Science.

"Earth has an outer liquid iron core and solid inner core. This may be the case for Mars as well," said Dr. Charles Yoder, a planetary scientist at JPL and lead author on the paper. "Mars is influenced by the gravitational pull of the Sun. This causes a solid body tide with a bulge toward and away from the Sun (similar in concept to the tides on Earth). However, for Mars this bulge is much smaller, less than 1 centimeter (0.4 inch). By measuring this bulge in the Mars gravity field we can determine how flexible Mars is. The size of the measured tide is large enough to indicate the core of Mars can not be solid iron but must be at least partially liquid."

The team used Doppler tracking of a radio signal emitted by the Global Surveyor spacecraft to determine the precise orbit of the spacecraft around Mars. "The tidal bulge is a very small but detectable force on the spacecraft. It causes a drift in the tilt of the spacecraft's orbit around Mars of one-thousandth of a degree over a month," said Dr. Alex Konopliv, a planetary scientist at JPL and co-author on the paper.

The researchers combined information from Mars Pathfinder on the Mars precession with the Global Surveyor tidal detection to draw conclusions about the Mars core, according to Dr. Bill Folkner of JPL, another co-author of the paper.

The precession is the slow motion of the spin pole of Mars as it moves along a cone in space (similar to a spinning top). For Mars, it takes 170,000 years to complete one revolution. The precession rate indicates how much the mass of Mars is concentrated toward the center. A faster precession rate indicates a larger dense core, compared to a slower precession rate.

In addition to detection of a liquid core for Mars, the results indicate the size of the core is about one-half the size of the planet, as is the case for Earth and Venus, and that the core has a significant fraction of a lighter element such as sulfur.

In addition to measuring the Mars tide, Global Surveyor has been able to estimate the amount of ice sublimated, changed directly into a gaseous state, from one pole into the atmosphere and then accreted onto the opposite pole. "Our results indicate the mass change for the southern carbon dioxide ice cap is 30 to 40 percent larger than the northern ice cap, which agrees well with the predictions of the global atmosphere models of Mars," said Yoder.

The amount of total mass change depends on assumptions about the shape of the sublimated portion of the cap. The largest mass exchange occurs if we assume the cap change is uniform or flat over the entire cap, while the lowest mass exchange corresponds to a conically shaped cap change.

JPL manages the Mars Exploration Program for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.


Story Source:

The above story is based on materials provided by NASA/Jet Propulsion Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Jet Propulsion Laboratory. "Scientists Say Mars Has A Liquid Iron Core." ScienceDaily. ScienceDaily, 7 March 2003. <www.sciencedaily.com/releases/2003/03/030307071457.htm>.
NASA/Jet Propulsion Laboratory. (2003, March 7). Scientists Say Mars Has A Liquid Iron Core. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2003/03/030307071457.htm
NASA/Jet Propulsion Laboratory. "Scientists Say Mars Has A Liquid Iron Core." ScienceDaily. www.sciencedaily.com/releases/2003/03/030307071457.htm (accessed July 28, 2014).

Share This




More Space & Time News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

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
This Week @ NASA, July 25, 2014

This Week @ NASA, July 25, 2014

NASA (July 25, 2014) Apollo 11 celebration, Next Giant Leap anticipation, ISS astronauts appear in the House and more... Video provided by NASA
Powered by NewsLook.com
Space to Ground: Coming and Going

Space to Ground: Coming and Going

NASA (July 25, 2014) One station cargo ship leaves, another arrives, aquatic research and commercial spinoffs. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
Powered by NewsLook.com
How A Solar Flare Could Have Wrecked Earth's Electronics

How A Solar Flare Could Have Wrecked Earth's Electronics

Newsy (July 25, 2014) Researchers say if Earth had been a week earlier in its orbit around the sun, it would have taken a direct hit from a 2012 coronal mass ejection. 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