Meteorite provides new clues about the conditions that existed when the early Solar System was being formed

Imperial College London News Release

Under strict embargo for
14.00 Eastern Time / 19.00 London Time
Thursday 17 September 2009

Researchers have discovered an unusual kind of meteorite in the Western Australian desert and have uncovered where in the Solar System it came from, in a very rare finding published today in the journal Science.

Meteorites are the only surviving physical record of the formation of our Solar System and by analysing them researchers can glean valuable information about the conditions that existed when the early Solar System was being formed. However, information about where individual meteorites originated, and how they were moving around the Solar System prior to falling to Earth, is available for only a dozen of around 1100 documented meteorite falls over the past two hundred years.

Dr Phil Bland, the lead author of today's study from the Department of Earth Science and Engineering at Imperial College London, said: "We are incredibly excited about our new finding. Meteorites are the most analysed rocks on Earth but it's really rare for us to be able to tell where they came from. Trying to interpret what happened in the early Solar System without knowing where meteorites are from is like trying to interpret the geology of Britain from random rocks dumped in your back yard."

The new meteorite, which is about the size of cricket ball, is the first to be retrieved since researchers from Imperial College London, Ondrejov Observatory in the Czech Republic, and the Western Australian Museum, set up a trial network of cameras in the Nullarbor Desert in Western Australia in 2006.

The researchers aim to use these cameras to find new meteorites, and work out where in the Solar System they came from, by tracking the fireballs that they form in the sky. The new meteorite was found on the first day of searching using the new network, by the first search expedition, within 100m of the predicted site of the fall. This is the first time a meteorite fall has been predicted using only the data from dedicated instruments.

The meteorite appears to have been following an unusual orbit, or path around the Sun, prior to falling to Earth in July 2007, according to calculations by the research team, which includes scientists from the Natural History Museum in London. The team believes that it started out as part of an asteroid in the innermost main asteroid belt between Mars and Jupiter. It then gradually evolved into an orbit around the Sun that was very similar to Earth's. The other meteorites that researchers have data for follow orbits that take them back, deep into the main asteroid belt.

The new meteorite is also unusual because it is composed of a rare type of basaltic igneous rock. The researchers say that its composition, together with the data about where the meteorite comes from, fits with a recent theory about how the building blocks for the terrestrial planets were formed. This theory suggests that the igneous parent asteroids for meteorites like today's formed deep in the inner Solar System, before being scattered out into the main asteroid belt. Asteroids are widely believed to be the building blocks for planets like the Earth so today's finding provides another clue about the origins of the Solar System.

Dr Bland added: "We're not the first team to set up a network of cameras to track fireballs, but other teams have encountered problems because meteorites are small rocks and they're hard to find in vegetated areas. Our solution was quite simple – build a fireball network in a place where it's easy to find them. The Nullarbour Desert is ideal because there's very little vegetation and dark rocks show up really easily on the light desert plain.

"It was amazing to find a meteorite that we could track back to its origin in the asteroid belt on our first expedition using our small trial network. We're cautiously optimistic that this find could be the first of many and if that happens, each find may give us more clues about how the Solar System began," said Dr Bland.

The researchers' network of cameras takes a single time-lapse picture every night to record any fireballs in the sky. When a meteorite falls, researchers can then use complex calculations to uncover what orbit the meteorite was following and where the meteorite is likely to have landed, so that they can retrieve it.

The research was funded with grants from the UK Science and Technology Facilities Council, the Czech Republic and the European Union.

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*** Images of the recovered meteorite and the desert camera network and images from the sky cameras are available in 300 dpi - please contact Laura Gallagher for further details ***

For further information please contact:

Laura Gallagher
Research Media Relations Manager
Imperial College London
e-mail: l.gallagher@imperial.ac.uk
Telephone: +44 (0)207 594 8432 or ext. 48432
Out of hours duty Press Officer: +44 (0)7803 886 248

Notes to editors:

1. "An anomalous basaltic meteorite from the innermost main belt" Science, 17 September 2009 (embargoed for 14.00 Eastern Time) Lead author: Dr Phil Bland, Imperial College London (for full list of authors please see paper)

2. CSIRO Exploration & Mining applies world-leading science and technology to raise Australia's competitive advantage in this vital sector.

3. The Western Australian Museum makes major contributions t o the collection, conservation and research of Western Australia's natural, social and maritime history and the cultural heritage of the State's Indigenous communities.

4. Ondrejov Observatory (or Astronomical Institute of the Czech Academy of Sciences) is the leading institution of the astronomical research in the Czech Republic. The main research areas are: the Sun and solar activity, interplanetary matt er, including interaction with terrestrial atmosphere, stars, interstellar matter and galaxies.

5. Consistently rated amongst the world's best universities, Imperial College London is a science-based institution with a reputation for excellence in teaching and research that attracts 13,000 students and 6,000 staff of the highest international quality. Innovative research at the College explores the interface between science, medicine, engineering and business, delivering practical solutions that improve quality of life and the environment - underpinned by a dynamic enterprise culture.

Since its foundation in 1907, Imperial's contributions to society have included the discovery of penicillin, the development of holography and the foundations of fibre optics. This commitment to the application of research for the benefit of all continues today, with current focuses including interdisciplinary collaborations to improve health in the UK and globally, tackle climate change and develop clean and sustainable sources of energy.