Scientists have claimed that they may have found alien life floating above the Earth.
Professor Milton Wainwright from the University of Sheffield claims to have recovered an unusual sample of organic matter from a height of 27,000m.
He writes in the controversial Journal of Cosmology that particles of this size cannot be lifted from Earth to that height without some unusual process - say a violent volcanic eruption - occurring, and that none was operating within three years of the sampling trip.
But the claims are not new for Wainwright, who has written as recently as 2010 about a similar idea - to general silence from most researchers.
Above: one of the claimed samples of alien life
Wainwright, who works at the University’s Department of Molecular Biology and Biotechnology said in a statement:
"In the absence of a mechanism by which large particles like these can be transported to the stratosphere we can only conclude that the biological entities originated from space. Our conclusion then is that life is continually arriving to Earth from space, life is not restricted to this planet and it almost certainly did not originate here."
"If life does continue to arrive from space then we have to completely change our view of biology and evolution," he said.
"New textbooks will have to be written!"
However without further study and analysis by a wider group of scientists it seems clear that the research cannot, alone prove that alien life exists, let alone that it might dominate over other processes of natural selection and evolution.
The Journal of Cosmology, in which the study is published, has in the past been accused of publishing fringe theories with a questionable peer-review policy.
Wainwright accepts that the findings might equally be explained if another process which can lift such organisms into the upper stratosphere can be found.
"It will be argued that there must be an, as yet, unknown mechanism for transferring large particles from Earth to the high stratosphere," he said.
But he maintains that his team "stand by our conclusions".
"The absolutely crucial experiment will come when we do what is called ‘isotope fractionation’. We will take some of the samples which we have isolated from the stratosphere and introduce them into a complex machine – a button will be pressed. If the ratio of certain isotopes gives one number then our organisms are from Earth, if it gives another, then they are from space. The tension will obviously be almost impossible to live with!"
HuffPost await the results with interest.