Fw: Researchers: Mars once hummed with magnetism, like Earth
- Subject: NUFOIA: Researchers: Mars once hummed with magnetism, like Earth
Date: dinsdag, 4. mei 1999 8:57
April 29, 1999
Web posted at: 3:55 p.m. EDT (1955 GMT)
(CNN) -- New information from the Mars Global Surveyor spacecraft suggests
the barren planet once had geology like that of Earth, with a torrid
spurting molten rock and massive plates drifting on the surface.
Plate tectonics -- which is the way big sections of a planet's surface
around over billions of years -- was thought to be a process that only
happened on Earth and that required water, a basic precondition for life.
it happened on Mars too, that would add new ammunition for those who
life existed there at one time.
This may mean the very young Mars resembled the very young Earth, but that
Mars ran out of its internal energy sources and became a geologically dead
planet early in its history, said Norman F. Ness of the University of
Delaware and co-author of the study.
"The data suggests that Mars was once magnetic and was far more similar to
Earth's global magnetic field than had previously assumed," Ness said.
Planetary fraternal twins
Evidence of this magnetic field is frozen in rocks that were molten when
magnetic field existed. When the rocks hardened they retained the original
magnetism, and that now has been detected and mapped by the spacecraft.
"At the present time there is no evidence of a global magnetic field on
Mars," Ness said. "That means the dynamo died and what is left is the
of that dynamo, stored in the crustal rocks like a magnetic tape
A composite image of Mars made up of of 9 color strips taken by Mars Global
Surveyor on 9 successive orbits from pole-to-pole over the planet in March
"If it were possible to say that early Mars did in fact have plate
that would be another argument that would lead you toward expectation of
on Mars, because it would be more Earth-like," said John Connerney, one of
the authors of a report on the subject in this week's edition of the
Mars and Earth are like fraternal twins created 4.5 billion years ago,
Connerney said in a telephone interview. Bigger twin Earth is still driven
its fiery heart to push its continents apart and smash them together, while
Mars is cold with only magnetic indications that this once took place.
Steve Maran, assistant director of space sciences at NASA's Goddard Space
Flight Center, where Connerney is based, called the report "mind-blowing."
"(Connerney's report means) The early Mars was like an early Earth and
something made that all go away," Maran said by telephone. "It's gone from
live planet to a dead planet and it increases our interest in getting
rocks back and looking for the possibility of early microbial life on
Not all are convinced. In an accompanying article, paleomagnetist Ronald
Merill of the University of Washington, Seattle, was quoted as saying, "If
plate tectonics was operating on Mars, it worked differently or it was
recorded differently by the rocks."
Connerney's research was based on data gathered by the Mars Global
an unmanned craft launched by the National Aeronautics and Space
Administration to repeatedly orbit the planet at low altitude, low enough
see patches of magnetized rock on the surface.
At first, the magnetized patches seemed random, but as the spacecraft
gathered more information, a pattern of "zebra stripes" of positive and
negative charges emerged -- very similar to what scientists found on the
floor of Earth.
On Mars, the stripes seem to be more strongly magnetized and much larger,
Connerney theorized they were formed by plate tectonics, the same process
that on Earth accounts for earthquakes, volcanoes and some mountain ranges.
Earth's oceans are essential to the process, lubricating the plates and
helping them slip more easily. But this does not necessarily mean there
ever oceans on Mars -- though Connerney believes some water was necessary,
possibly enough to support some kind of life.
'What happened to the water?'
"It would be surprising if water weren't there, in apparent river beds and
large canyons," Connerney said. "The real mystery today has been, what
happened to the water?"
Vicki L. Hansen, a Southern Methodist University geologist, said that the
fate of Mars also awaits the Earth. She said that eventually Earth also
exhaust its internal energy and its molten core will cool. This will shut
down the planet's magnetic field and allow radiation from the sun to strip
away the Earth's atmosphere and water.
"What Mars went through at a very young age is what will occur on the Earth
eventually," she said.
Ness said that Mars died much more quickly than Earth because the red
is smaller and had much less internal heat generated by friction and the
decay of radioactive minerals.
The Associated Press and Reuters contributed to this report.
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