Livermore lab chemist accurately dates first objects to form in the solar system

September 05, 2002

LIVERMORE, Calif. -- A geochemist from the Lawrence Livermore National Laboratory, teaming with researchers from the Royal Ontario Museum, the University of Hawaii and Moscow State University, has accurately dated Calcium Aluminum-rich inclusions (CAIs), the oldest objects in our solar system, to be 4.57 billion years old.

In addition, the team has determined that chondrules, another of the earliest objects in the solar system, are 2 to 3 million years younger than CAIs.

The findings, by Ian Hutcheon of LLNL, Yuri Amelin of the Royal Ontario Museum, Alexander Krot of the University of Hawaii and Alexander Ulyanov of Moscow State University, will be published in the Sept. 6, 2002 edition of Science. The article is titled "Pb Isotopic Ages of Chondrules and Ca-Al Rich Inclusions."

Using mass spectrometers to study CAIs and chondrules found in chondritic meteorites, the team was able to determine the ages of the objects by measuring the decay of uranium 238, which is found in both objects and decays into lead. Using an ion microprobe, Hutcheon dated CAIs and chondrules by detecting the decay of aluminum 26 -- also found in both objects -- into magnesium 26.

By comparing the lead and magnesium isotope contents in the CAIs and chondrules, the team determined how old the objects are. Aluminum 26 decays much faster than uranium, and these measurements enabled the team to determine the small difference in age between CAIs and chondrules with unprecedented precision.

"This is the first piece of evidence proving that CAIs are 2 to 3 million years older than chondrules," Hutcheon said. "We were able to make this conclusion based on our measurements." CAIs and chondrules are millimeter-size objects found in primitive meteorites. They formed when dusty regions of the solar nebula were heated to very high temperatures. The dust melted and then crystallized, forming first CAIs and then chondrules. Larger objects, like asteroids and planets, took longer to form and are about 10 to 50 million years younger than the CAIs and chondrules.

"All these objects didn't just form in a snap," Hutcheon said. "By determining the ages of CAIs and chondrules, we can better date asteroids and planets and learn more about the early history of the solar system."
-end-
Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by the University of California for the U.S. Department of Energy's National Nuclear Security Administration.

Laboratory news releases and photos are also available electronically on the World Wide Web of the Internet at URL http://www.llnl.gov/PAO and on UC Newswire.

DOE/Lawrence Livermore National Laboratory

Related Solar System Articles from Brightsurf:

Ultraviolet shines light on origins of the solar system
In the search to discover the origins of our solar system, an international team of researchers, including planetary scientist and cosmochemist James Lyons of Arizona State University, has compared the composition of the sun to the composition of the most ancient materials that formed in our solar system: refractory inclusions in unmetamorphosed meteorites.

Second alignment plane of solar system discovered
A study of comet motions indicates that the Solar System has a second alignment plane.

Pressure runs high at edge of solar system
Out at the boundary of our solar system, pressure runs high.

What a dying star's ashes tell us about the birth of our solar system
A UA-led team of researchers discovered a dust grain forged in a stellar explosion before our solar system was born.

What scientists found after sifting through dust in the solar system
Two recent studies report discoveries of dust rings in the inner solar system: a dust ring at Mercury's orbit, and a group of never-before-detected asteroids co-orbiting with Venus, supplying the dust in Venus' orbit.

Discovered: The most-distant solar system object ever observed
A team of astronomers has discovered the most-distant body ever observed in our solar system.

Discovery of the first body in the Solar System with an extrasolar origin
Asteroid 2015 BZ509 is the very first object in the Solar System shown to have an extrasolar origin.

First interstellar immigrant discovered in the solar system
A new study has discovered the first known permanent immigrant to our solar system.

A star disturbed the comets of the solar system in prehistory
About 70,000 years ago, when the human species was already on Earth, a small reddish star approached our solar system and gravitationally disturbed comets and asteroids.

Scientists detect comets outside our solar system
Scientists from MIT and other institutions, working closely with amateur astronomers, have spotted the dusty tails of six exocomets -- comets outside our solar system -- orbiting a faint star 800 light years from Earth.

Read More: Solar System News and Solar System Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.