Sheffield scientists say the organism most likely originated in the 'watery environment' of a meteorite. Jorge Geurrero/AFP/Getty Images

Scientists from the University of Sheffield claim they have discovered evidence of alien life -- a finding that could change the narrative of how life evolved on Earth if proved correct.

The team sent a balloon 16 miles above the Earth's surface to gather cosmic dust samples in the stratosphere during the recent Perseid meteor shower. After it returned, researchers found fragments of single-celled algae known as diatoms.

Their continuing research aims to figure out where such organisms in the stratosphere originated. "Are they exiting from Earth or falling into our planet from space?" the report questioned.

Critics say this is not the first time organisms have been found in the atmosphere and that the journal that published the findings, the Journal of Cosmology, is highly controversial among mainstream scientists.

According to PBS, the scientists have also not fully analyzed their findings, and a similar study published by the journal claiming that life was found in a meteorite was widely discredited.

But on the basis of the size of the diatom and the height at which it was collected, the Sheffield scientists argue that it could not have come from Earth.

They say that it would take an event like a violent volcanic eruption to elevate a diatom of that mass to the stratosphere and no such eruption took place for three years before the experiment.

"There is certainly no way, as is often casually suggested by unthinking critics, that a particle, like the (diatom) could simply float into the stratosphere or be carried up by winds," the report said.

Also, the Sheffield scientists say such relatively large and dense particles could not have remained at those heights for more than six hours -- making it even less likely they were lofted into the stratosphere by some earthly force.

Furthermore, the scientists say the particle is remarkably free of soil or any other solid material, suggesting it came from a watery environment, not volcanic debris.

This leaves two options for the origin of the diatoms, according to the scientists: Earth's oceans or outer space, where it could have come from the watery environment of a comet.

The report's concluding remarks point out that similar organisms were found in meteorites that fell in Sri Lanka -- a claim that sparked debate within the scientific community at the time.

Al Jazeera