London: Life from outer space could be surviving on the outer fringes of the Earth`s atmosphere, in the form of bacteria, scientists have revealed.
Scientists, who are set to launch a mission to search for bacteria that could be living there, believe they could be close to discovering alien life forms much closer to home - on the outer fringes of Earth`s atmosphere.
British scientists, working with the European Space Agency, would launch a balloon carrying instruments to search the stratosphere for bacteria and other microorganisms.
They believe there could be species capable of surviving in the high levels of radiation, extreme cold and near vacuum found on the edge of space.
The organisms could be entirely new to science and may even have been brought here from outer space by hitching a ride on asteroids or comets.
Scientists also hope they may find new types of bacteria that have been thrown up into the atmosphere by erupting volcanoes.
"There are theories that life on Earth came from space, so we need to know that life can survive the conditions of space for this to be true," the Telegraph quoted Clara Juanes-Vallejo of the Cranfield University as saying.
"The environment in the stratosphere is very extreme. It can get down to 90 degrees C and is a near vacuum. There is also a lot of harmful radiation as there is not the same level of protection as we get from the atmosphere.
"If we know that life can survive in such an extreme environment, then it could also survive in places like Mars or on asteroids," said Vallejo.
The 60,000 pound balloon-borne mission, which has been developed along with electronics firm Alpha Micro, will be sent more than 21 miles into the air above the arctic circle where it will suck the thin air through a series of filters.
But scientists have already found bacteria on Earth, which thrives in similar conditions and some species of bacteria can form spores, which allows them to survive inhospitable conditions for long periods of time.
Nine years ago scientist from India attempted to discover if life could exist in the stratosphere but their findings were quickly cast into doubt by claims they had failed to ensure the collecting equipment was sterile.
The new mission, called CASS-E has been assembled in a sterile environment normally reserved for missions being sent to other planets such as Mars.
It also has been fitted with special seals to prevent any bacteria from Earth that is being carried on the surface of the instrument getting inside the sterile collection area.