The search for aliens has taken another mysterious turn after scientists said they have discovered the essential ingredients for life on ancient meteorites.
The space-faring rocks, which at approximately 4.5 billion years old are the same age as the Earth, were found to contain both liquid water and organic compounds.
Although the presence of these compounds does not mean the meteorites ever contained life, it does hint at how it may be present elsewhere in the universe.
The meteorites, named Zag and Monahans, are believed to have originated from the asteroid belt, between the orbits of Mars and Jupiter.
They were examined when they first fell to Earth in Morocco and Texas in 1998, and were found to contain liquid water.
But, at the time, scientists did not have the technology to detect small amounts of amino acids.
Now, using new powerful spectrometers and ion beams, researchers have been able to analyse the molecular composition of the salt crystals that were found among both rocks.
The study's lead author Dr Queenie Chan, a postdoctoral researcher at the UK's Open University, said: "We collected the tiny salt crystals from the meteorites and dissolved them in water so that we could extract the amino acids and separate any organic compounds to analyse them.
"We conducted our experiments in one of the cleanest laboratories in the world at the NASA Johnson Space Centre, which avoided any contamination from things such as dust in the air."
Dr Chan said researchers believe the salt in the halite crystals that became embedded in Zag and Mohanans may have originated in Ceres, a dwarf planet in the asteroid belt.
The meteorites themselves however originated from a different asteroid in the belt.
Dr Chan explained: "Each salt crystal, which is about two millimetres in size and the colour of a blue sapphire, is essentially a little package full of organic compounds and the necessary building blocks of life.
"What's even more incredible is that the salt crystals from both meteorites are believed to be from the largest asteroid in the asteroid belt, Ceres, which suggests that it could be a suitable place for the formation of life."
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But Dr Chan said that at some point, both Zag and Monahans would had been "heated to 950C so any trace of liquid water present in it would have gone".
"This proves to us the salt crystals and the meteorites come from two different asteroids."