Martian colony in Britain
Nasa scientists, who used a scanning electron microscope to take snaps, say the bumpy surface resembles a fossilised colony of microbacteria – a simple form of life.
The meteorite from Mars fell on Egypt in 1911.
Last month it emerged that Nasa scientists believe Martian bacteria arrived on Earth on a meteorite which smashed into the Antarctic 13,000 years ago.
Their fossilised remains have been found in the rock, which was blasted out of Mars 16 million years ago as the solar system was forming.
The meteorite, called Allen Hills 84001, made headlines in 1996 after fossils were found in it. Scientists believed they were bacteria from Earth that contaminated the rock while it lay in the frozen wastes.
But a Nasa report says there is strong evidence they originated on Mars.
The Nasa study, led by Kathie Thomas-Keprta, found carbonate discs and tiny magnetite crystals inside the space rock. Scientists were able to use high resolution electron microscopes that were not available 13 years ago.
They concluded “unusual chemical and physical properties” in the meteorite were “intimately associated within and throughout these carbonate disks”. That, they said, was evidence of interaction with water on Mars more than 3.5 billion years ago.