[meteorite-list] Microwave Can Tell If Life Existed On Mars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:50:22 2004
Message-ID: <200204021721.JAA06291_at_zagami.jpl.nasa.gov>

http://icliverpool.icnetwork.co.uk/0100news/0100regionalnews/page.cfm?objectid=11753227&method=full

£1/2m microwave that can tell if life existed on Mars
By Laura Davis
Daily Post (United Kingdom)
April 2, 2002

A TEAM of Liverpool scientists is investigating a piece of 100-year-old
meteorite to see if life could have existed on Mars.

The researchers are using the world's only microwave demagnetiser to change
the magnetic field of the rock.

This will show whether the temperature of the planet's surface was once high
enough to sustain life.

Prof John Shaw, director of the geomagnetism laboratory at
Liverpool University, is leading the project.

He said: "Mars has the same composition as Earth and was formed at around
the same time but, because it is smaller, it goes through its life cycle
faster and cooled quicker.

"If Mars had a liquid core, like Earth, its convection currents would have
made its surface warm enough for life-forms to exist on it long before life
began on Earth. This can be researched by looking at the magnetic field of
the rock."

The meteorite that Dr Shaw's team is testing fell to Earth in June 1911.

It landed in Alexandria, Egypt, where it is believed to have hit a dog,
killing it instantly.

Prof Shaw said: "People saw it fall. It broke open into bits. It was so cold
that they noticed frost had formed on it."

The stones from the meteorite, known as Nakhla, ranged in size from 20kg to
1,813kg.

Pieces of meteorite contain minerals which carry information on the magnetic
field of the planet they have come from at the time when they were formed
similar to a tape recording.

By gradually heating the samples and then cooling them back down, scientists
can measure this field.

Traditionally, they have used the Thellier method which involves physically
heating the sample to 600"C.

However, this causes chemical changes in the rock disrupting the results of
the experiment.

The microwave demagnetiser, built by Prof Shaw's team at a cost of £500,000,
raises the temperature of the rock's magnetic system without heating the
stone itself.

They are the only researchers to have successfully developed this technique.

Individual rock samples are placed in a cavity where they are bombarded with
very high frequency microwaves for a 10-second period.

The samples are heated in a series of steps to gradually demagnetise them.

Eventually all the geomagnetic contamination from Earth is removed and the
rock only contains the original magnetism from when it was formed on
Mars.

Results so far have revealed the planet had a magnetic field at the time the
rock was formed 1,250m years ago.

However, it did not have one 180m years ago.

Dr Shaw said this indicates there could once have been life on Mars.

He said: "This means that Mars must originally have had a liquid core.

"These results suggest it is much more likely that there was life on Mars in
the past. They also confirm our belief that Earth will one day cool to a
similar extent and will no longer be able to sustain life."

The research team plans to investigate a larger range of Mars rock samples
as well as older meteorites which may have recorded the magnetic fields at
the start of the universe.

Liverpool University has been approached by various organisations, including
American space agency Nasa, about selling the microwave demagnetiser.

However, Dr Shaw said the laboratory planned to carry out further research
before considering a sale.
Received on Tue 02 Apr 2002 12:21:32 PM PST