Researchers find new information about Earth's origins

October 5, 2006
Mukul Sharma and Rasmus Andreasen (Joseph Mehling '69)

Mukul Sharma and Rasmus Andreasen (Joseph Mehling '69)

Two Dartmouth researchers have learned more about the origins and makeup of the solar nebula, the large gaseous cloud thought to have spawned the solar system. Mukul Sharma, assistant professor of Earth sciences, and graduate student Rasmus Andreasen, have found evidence that more than one dying star, or supernova, contributed to the makeup of the solar nebula, which in turn, provides insights into the evolution of planets and asteroids soon after their birth some 4,500 million years ago.

Their study appears in Science Express, the advance online publication of the journal Science, on October 5, 2006.

"Supernovae are dying stars that burst with tremendous energy creating new isotopes and throwing a huge amount of material into interstellar space," says Sharma. "There are two mechanisms that forge isotopes in a supernova-some are produced by high temperature disintegration of previously existing isotopes and others by neutron-induced transmutations.

It has been commonly thought that a single type of supernova supplied isotopes to the primordial soup that was the hot and spinning solar nebula. By investigating the samarium and neodymium isotopic composition of primitive meteorites, which are building blocks of planets, we find that those isotopes that were produced by high temperature disintegration did not mix well in the solar nebula while those generated by neutron-induced transmutations did."

This finding led the researchers to conclude that there was more than one type of supernova matter. A possible reason for a sluggish mixing in the solar nebula is the increase in the grain size from the sun outwards, which then would affect how isotopes were absorbed on the surfaces of grains.

This research also has a bearing on using the samarium and neodymium isotopes in meteorites as way to understand the evolution of Earth and other planets. The researchers found that carbonaceous stony meteorites that come from the distant edge of the asteroid belt possess a distinct blend of samarium and neodymium isotopes in comparison with the stony meteorites with little carbon, an asteroid called 4 Vesta, and the Moon.

"This suggests that the isotopic composition of the Earth prior to any evolutionary modifications should be akin to these carbon-poor meteorites," says Sharma. "However there is a small but resolvable gap between the neodymium isotopic composition of the Earth's upper mantle and the presumed composition of the entire Earth. This indicates that there was formation of continents on Earth within a few million years after its birth. The neodymium isotopes are telling us that these continents are buried somewhere on Earth and hidden from direct observation."

Source: Dartmouth College

4.3 /5 (67 votes)  

Rank 4.3 /5 (67 votes)
Tags

Related Stories
Relevant PhysicsForums posts
  • Wind Waves in Reservoir ~ Wind run-up and Wind set-up
    createdFeb 08, 2012
  • Balance of oxygen in the atmosphere
    createdFeb 01, 2012
  • The case for a methanol-based economy
    createdJan 30, 2012
  • Weather in a rotating cylinder
    createdJan 25, 2012
  • Importance of difference between SVP over ice and water?
    createdJan 19, 2012
  • Ozone and atmosphere sampling
    createdJan 16, 2012
  • More from Physics Forums - Earth

More news stories

New views show old NASA Mars landers

(PhysOrg.com) -- The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter recorded a scene on Jan. 29, 2012, that includes the first color image from orbit showing ...

Space & Earth / Space Exploration

created 43 minutes ago | popularity 5 / 5 (1) | comments 0 | with audio podcast

'Pyramids' planted to revive Philippine corals

Thousands of small "pyramids" are being planted off the Philippines' famous Boracay resort island in an effort to bring its nearly destroyed coral reefs back to life, an environment group said Thursday.

Space & Earth / Environment

created 49 minutes ago | popularity not rated yet | comments 0

Distorting the lens

(PhysOrg.com) -- One of the most bizarre predictions of Einstein's Theory of General Relativity is the existence of back holes, objects that are so dense that not even light can escape from their gravitational ...

Space & Earth / Astronomy

created 26 minutes ago | popularity 5 / 5 (1) | comments 0

Europe's ATV space ferry set for launch to Space Station

(PhysOrg.com) -- Fuel, water, oxygen, air and most of the dry cargo have been loaded into ESA's third Automated Transfer Vehicle, Edoardo Amaldi, as the 9 March liftoff approaches.

Space & Earth / Space Exploration

created 26 minutes ago | popularity not rated yet | comments 0

Spaceborne precipitation radar ships from Japan to U.S.

(PhysOrg.com) -- Japanese scientists and engineers have completed construction on a new instrument designed to take 3-D measurements of the shapes, sizes and other physical characteristics of both raindrops ...

Space & Earth / Space Exploration

created 22 minutes ago | popularity not rated yet | comments 0


Inspired by steel, nanomanufacturing gets wear-resistant carbide tip

(PhysOrg.com) -- Scientists at the University of Pennsylvania, the University of Wisconsin-Madison and IBM Research - Zurich have fabricated an ultrasharp silicon carbide tip possessing such high strength ...

Borexino Collaboration succeeds in spotting pep neutrinos emitted from the sun

(PhysOrg.com) -- To learn more about how the sun works, scientists study particles that are emitted from it into space due to thermonuclear reactions that occur inside; by applying known physics principles, ...

Samsung can continue selling Galaxy tabs in Germany: court

South Korea's Samsung Electronics can continue to sell its Galaxy Tab 10.1N tablet computer in Germany, a German court ruled Thursday, rejecting a bid by arch-rival Apple to have them banned.

Engineers find inspiration for new materials in Piranha-proof armor

(PhysOrg.com) -- It’s a matchup worthy of a late-night cable movie: put a school of starving piranha and a 300-pound fish together, and who comes out the winner?

New target for Alzheimer's drugs

(Medical Xpress) -- Biomedical scientists at the University of California, Riverside have identified a new link between a protein called beta-arrestin and short-term memory that could open new doors for the ...

What kind of chocolate is best? The last you taste, says a new study

(Medical Xpress) -- Like to save the best for last? Here’s good news: If it’s the last, you’ll like it the best. That is the finding of a new study published in Psychological Science, a journal of the Associ ...