[meteorite-list] Solar System Slightly Older Than Previously Thought

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed Aug 24 13:31:25 2005
Message-ID: <200508241730.j7OHUMa10892_at_zagami.jpl.nasa.gov>

http://www.vuw.ac.nz/home/about_victoria/news_article.asp?ArticleID=1042149245

Ancient Solar System research published in Nature
Victoria University of Wellington (New Zealand)
August 25, 2005

A Victoria University scientist who has found the key to dating the very
beginnings of our Solar System will have his work published in the
prestigious scientific journal Nature today.

Dr Joel Baker, Senior Lecturer in the School of Earth Sciences, is the
lead author of a report that shows it is possible to date the formation
of our Solar System's oldest rocks with unprecedented resolution, using
cutting-edge geochemical analytical techniques. The results indicate the
Solar System is at least three million years older than previously thought.

Dr Baker, who completed a Master of Science at Victoria before
undertaking a PhD and ten years of research in Europe, says compressing
his results onto a more meaningful timeframe can make the significance
of his work clearer.

"If the 4.56 billion year history of the Earth is compressed into one
day, then Homo Sapiens appeared just a few seconds before the end of the
day. In contrast, my colleagues and I are building a picture of the very
first seconds of the Solar System to see why and how it formed."

Dr Baker's analysis of isotopes in an extremely small quantity of lead
(one billionth of a gram) from a meteorite found in the Sahara Desert
has shown this meteorite is 4.5662 billion years old - just one million
years younger than the conventionally accepted age of the Solar System
and at least 500 million years older than Earth's oldest rocks.

This meteorite is an igneous rock, like those erupted from volcanoes on
Earth, and is now, thanks to Dr Baker's research, confirmed as the
oldest and most precisely-dated igneous rock in our Solar System.

"Meteorites from space that arrive on Earth mainly come from asteroids
that orbit between Mars and Jupiter," Dr Baker explains.

"These asteroids formed around the young Sun at the very beginning of
our Solar System some 4.56 billion years ago. These meteorites are our
only direct record of the birth of our Sun and formation of planets
around it and, ultimately, why we are here on Earth."

The research shows that asteroids hundreds of kilometres across grew in
a few hundred thousand years and then melted incredibly quickly.

"However, melting of these asteroids was not caused by the same
processes which produce volcanism on Earth. The melting was driven by
heating from the decay of short-lived radioactive isotopes that were
injected into the young Solar System from the supernova, or explosion,
of a nearby dying star. This process may have ultimately triggered Solar
System formation, which our results now indicate is at least three
million years older than previously thought.'

Victoria's Dean of Science, Professor David Bibby, says Dr Baker has
made a remarkable discovery and demonstrated that he is a world leader
in his research area.

"Dr Baker is pushing the boundaries in isotopic geochemistry - a field
that has exciting applications in fields as diverse as geology,
environmental chemistry, archaeology, palaeontology, mining, medicine
and, of course, astronomy. The article in Nature recognises the
importance of Dr Baker's research and once again confirms Victoria's
reputation for having leading researchers teaching our students."
Received on Wed 24 Aug 2005 01:30:22 PM PDT