May 15, 2006
Missing Air of Mars
Astronomers seek to calculate earlier
atmospheric conditions on Mars based on the present rate of atmospheric
loss. But such attempts are inevitably flawed. The wild card is the role
of
planetary catastrophe in the past.
Mars has an atmosphere only one hundredth as dense
as the Earth's. Before space probes visited it, astronomers expected it
to be ten or more times thicker than it is. ESA's Mars Express orbiter
has come up with a possible explanation (see illustration above). The
orbiter has been measuring how much atmosphere is being removed from
Mars today by solar wind interactions. The total is about 1 kilogram
(2.2 pounds) per second, or about 100 tons per day. That's not fast
enough to have depleted Mars' atmosphere in the accepted length of
Martian history, but presumably when there was more atmosphere, the
process happened faster.
But the concept breaks down when you consider
Venus. By standard theory, Venus, Earth and Mars have a common origin in
the solar nebula. They must have received similar original amounts of
air and water. Earth has held on to most of its air and water because it
has a magnetic field to protect it from the solar wind. Neither Venus
nor Mars have magnetic fields today (although Mars is thought to have
had one early in its history). If Venus has been bombarded by solar wind
for as long as Earth and Mars, then its atmosphere should have been
depleted, too. But it isn't. Instead,
Venus' atmosphere is 90 denser
than Earth's atmosphere.
For the Electric Universe, there is no reason to
think of Venus, Earth and Mars as siblings. Nor is it reasonable to
think of them as moving along the same orbits for billions of years.
Each planet had a separate birth, and even if some or all were born in
the same set of plasma instabilities, their characteristics would be
dependent on the composition and discharge history of the particular
plasma cell in which they were individually formed.
After the birth event, the planets also have a
history. Each of them took part in several catastrophic events, the most
recent of which is commemorated by prehistoric humans in rock art and in
myth. It isn't necessary to suppose that Mars has been losing 100 tons
of air a day for billions of years because a few thousands of years ago
Mars went through a major event that could have stripped it of its
atmosphere and oceans all at once. Plasma interactions were undoubtedly
involved; history remembers them as the magical thunder weapon of the
warrior hero. But these plasma interactions were much more active than
those described above by the Mars Express researchers.
Electric discharge will sometimes take away
material (as in the 100 tons per day from the Martian atmosphere). But
it can also deposit new material in sorted layers. Or even a whole new
atmosphere. As space probes have returned data about density of
atmospheres among our solar neighbors, astronomers have been surprised
in many cases. Too much air on
Venus and Titan; too little on Mars.
Earth is considered the "just right" example of how much air a planet
should retain for its mass. But electrically speaking, there is no
standard initial atmosphere and subsequent changes are not necessarily
slow or steady. No wonder the planetary atmospheres don't appear to
comply with the astronomical texts.
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