Featured Research

from universities, journals, and other organizations

New Light On Early Formation Of Earth And Mars

Date:
November 25, 2007
Source:
NASA, Johnson Space Center
Summary:
Mars was covered in an ocean of molten rock for about 100 million years after the planet formed, according to new research. The finding indicates that the both Earth and Mars cooled slower than scientists thought and a mechanism to keep the planet interiors warm is required.

Planet Mars.
Credit: NASA, J. Bell (Cornell U.) and M. Wolff (SSI)

A team of scientists from NASA's Johnson Space Center (JSC) and the Lunar and Planetary Institute and the University of California, Davis (UCD) has found that terrestrial planets such as the Earth and Mars may have remained molten in their early histories for tens of millions of years. The findings indicate that the two planets cooled slower than scientists thought and a mechanism to keep the planet interiors warm is required.

These new data reveal that the early histories of the inner planets in the solar system are complex and involve processes no longer observed. Evidence of these processes has been preserved in Mars, while it has been erased in Earth. So Mars is probably the best opportunity to understand how Earth formed.

The formation of the solar system can be dated quite accurately to 4,567,000,000 years ago, said Qing-Zhu Yin, assistant professor of geology at UC Davis and an author on a new paper. Mars' metallic core formed a few million years after that. Previous estimates for how long the surface remained molten ranged from thousands of years to several hundred million years.

The persistence of a magma ocean on Mars for 100 million years is "surprisingly long," Yin said. It implies that at the time, Mars must have had a thick enough atmosphere to insulate the planet and slow down cooling, he said.

Scientists think that early crust formation alone cannot account for the slow cooling magma ocean seen in large planets. This new evidence instead implies that Mars, at one time, had a primitive atmosphere that acted as the insulator. “The primitive atmosphere was composed mostly of hydrogen left over from accretion into a rocky planet, but was removed, probably by impacts, about 100 million years after the planet formed,” said Debaille.

Debaille and her colleagues performed precise measurements of neodymium isotope compositions of nine rare Martian meteorites called shergottites using mass spectrometers at JSC and UCD. Shergottites, named after the first-identified meteorite specimen that fell at Shergotty, India, in 1865, are a group of related meteorites from Mars composed primarily of pyroxene and feldspar.

The scientists examined shergottites because their large range in chemical compositions is thought to be a fingerprint of the formation of their deep sources very early in the history of Mars.

“These rocks were lavas that were made by melting deep in Mars and then erupted on the surface," said Brandon. “They were delivered to Earth as meteorites following impacts on Mars that exhumed them and launched them into space." Mars meteorites are a treasure chest of information about that planet and have been the focus of extensive research by scientists.

The metallic element samarium has two radioactive isotopes that decay at a known rate to two daughter neodymium isotopes. By precisely measuring the quantities of neodymium isotopes, Debaille was able to use these two radiometric clocks to derive the times of formation of the different shergottite sources in the Martian interior.

“We expected to find that their sources all formed at the same time,” said Debaille. “But what we found instead was that the shergottite sources formed at two different times. The oldest formed at 35 million years after the solar system began to condense from ice and dust into large planets about 4,567 million years ago. The youngest formed about 110 million years after the solar system began to condense.”

Debaille and her colleagues found that the scenario that best fits the data is one where a global-scale magma ocean formed from melting in Mars during the final stages of accretion and then slowly solidified over this time period.

“The most recent physical models for magma oceans suggest they solidify on timescales of a few million years or less, so this result is surprising,” said Brandon. “Some type of insulating blanket, either as a rocky crust or a thick atmosphere, is needed as an insulator to have kept the Martian interior hot.”

Vinciane Debaille (LPI), Alan Brandon (JSC), Qing-zhu Yin and Ben Jacobsen (UCD) present these new findings in a paper published in the Nov. 22 issue of Nature.


Story Source:

The above story is based on materials provided by NASA, Johnson Space Center. Note: Materials may be edited for content and length.


Cite This Page:

NASA, Johnson Space Center. "New Light On Early Formation Of Earth And Mars." ScienceDaily. ScienceDaily, 25 November 2007. <www.sciencedaily.com/releases/2007/11/071121220939.htm>.
NASA, Johnson Space Center. (2007, November 25). New Light On Early Formation Of Earth And Mars. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2007/11/071121220939.htm
NASA, Johnson Space Center. "New Light On Early Formation Of Earth And Mars." ScienceDaily. www.sciencedaily.com/releases/2007/11/071121220939.htm (accessed September 1, 2014).

Share This




More Space & Time News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Space Shuttle Discovery's Legacy, 30 Years Later

Space Shuttle Discovery's Legacy, 30 Years Later

Newsy (Aug. 30, 2014) The space shuttle Discovery launched for the very first time 30 years ago. Here's a look back at its legacy. Video provided by Newsy
Powered by NewsLook.com
Experiment Tests Whether Universe Is Actually A Hologram

Experiment Tests Whether Universe Is Actually A Hologram

Newsy (Aug. 27, 2014) Researchers at Fermilab are using a device called "The Holometer" to test whether our universe is actually a 2-D hologram that just seems 3-D. Video provided by Newsy
Powered by NewsLook.com
SpaceX’s Falcon 9 Rocket Explodes After Liftoff

SpaceX’s Falcon 9 Rocket Explodes After Liftoff

Newsy (Aug. 23, 2014) The private spaceflight company says it is preparing a thorough investigation into Friday's mishap. Video provided by Newsy
Powered by NewsLook.com
Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Newsy (Aug. 21, 2014) Russian cosmonauts say they've found evidence of sea plankton on the International Space Station's windows. NASA is a little more skeptical. 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