Mars Meteorites Landed on Earth

These meteorites are extremely valuable because they are the only physical samples of Mars available for analysis. The three meteorites listed below exhibit characteristics that for some researchers reveal the possible of existence of natural organic molecules and microscopic fossils.

The meteorite ALH84001 was found in Antarctica in December 1984 by a group of researchers of the project ANSMET; the meteorite weighs 1.93 kg. Some researchers assume that regular forms found within the meteorite could be fossilized microorganisms similar to nanobacteria. This meteorite also contains some magnetite which, on Earth, is found only in certain microorganisms.
The Nakhla meteorite, also from Mars, fell on Earth in June 28, 1911, at approximately 09:00 am in the town of Nakhla, Alexandria, Egypt.

A team from NASA's Johnson Space Center obtained a small sample of this meteorite in March 1998. They used optical microscopy, electron microscopy and other techniques to determine its content. The researchers found that the meteorite contained spherical particles of uniform size.

Analysis by gas chromatography and mass spectrometry (GC-MS) was used to study the aromatic hydrocarbons of high molecular weight. NASA scientists also identified internal cellular structures and exopolimeric secretions. They concluded that at least three quarter of the organic material could not have originated on Earth.

In 2006, NASA requested a larger sample of the Nakhla meteorite from the Natural History Museum of London. A large concentration of branching carbon was discovered in this second specimen.

Images published in 2006 started a debate in which some independent researchers claimed that Mars' carbon was of biological origin.

However, other researchers have stressed that carbon is the fourth most abundant element in the universe, so carbon that is in odd shapes or patterns does not necessarily have to be of biological origin.

The Shergotty meteorite, with a mass of 4 kg, fell on Shergotty, India on August 25, 1865, where witnesses immediately recovered it.

This meteorite is composed of pyroxene. Scientists have calculated that it was formed on Mars 165 million years ago and was exposed to liquid water for many years. Certain features of this meteorite suggest the presence of membranes or films of biological origin, but there is disagreement regarding this interpretation.