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Nakhla meteorite's
two sides and its inner surfaces after
breaking it in 1998
Scanning electron
microscope (SEM) image of the surface of a grain of the
meteorite showing small pits filled with material. On Earth, such pits are caved by
bacteria.
SEM
image of a chip of the Naklha meteorite
, depicting
biomorph material: the
larger, broad knife-like and the small, donut-shaped
features.
The Nakhla meteorite, the first example of a
Nakhlite type meteorite of the SNC
Group type of meteorites, fell to Earth, from Mars, on
the 28th of June, 1911, at
approximately 09:00 in the Nakhla region of Abu Hommos, Alexandria, Egypt.[1][2] The
meteorite fell in about forty pieces and was witnessed by many
individuals to have exploded in the upper atmosphere and to have
fallen into the ground, the fragments burying themselves up to a
meter in depth in some places. The stones recovered from this
meteorite ranged in size from 20g to 1813g, and it is estimated a
total weight of 10kg (22 pounds) had fallen.[1]
Martian
origins
As of 2008, there are a total of seventy-seven cataloged
meteorites recovered from around the world that are thought to have
originated from Mars,[3]
including the Nakhla meteorite. These are considered to have been
ejected by the impact of
another large body colliding with the Martian surface and traveled
through the solar system for an unknown period of time
before penetrating the Earth's
atmosphere.
Examination of the Nakhla meteorite in March 1999, using an optical
microscope and a powerful scanning electron
microscope (SEM), by a team from NASA's Johnson Space Center,
has revealed rounded particles of a limited size range.[4]
London's Natural History Museum, which holds several intact
fragments of the meteorite, agreed on 2006 for NASA researchers to
break one open, providing fresh samples.[5] Upon
publishing the results, a debate was opened by some at the 37th
Lunar and Planetary Science Conference in March 2006 in Houston,
Texas, and postulated that the carbon-rich content within the pores
of the rocks hinted at remains of living matter.
Because carbon is the
fourth most abundant element in the universe after hydrogen,
helium, and oxygen, curious and minute shapes in meteorites are not
enough to convince most scientists that bacteria once lived on
Mars.[6]
The Nakhla
dog
One such fragment of the Nakhla meteorite was said to be
observed by a farmer named Mohammed Ali Effendi Hakim in the
village of Denshal, near Nakhla, to have landed, not only in his
field, but on a dog and, apparently, vaporized the animal. Since no
remains of the dog were ever recovered and there was only one known
eyewitness to the dog's death, this story remains apocryphal.[1]
However, the story of the Nakhla dog has become something of a
legend among astronomers and is even recorded in several editions
of The Catalog of Meteorites.
At the time of the impact, the dog's death was publicized in
both Arabic and English newspapers as being the first recorded
death of an animal, including humans, by a meteorite, though since
then both the facts as to whether a dog was actually killed by
meteorite in Nakhla and the notion that this was the first ever
recorded animal fatality by meteorite have come into question.
References
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