Have scientists found alien life in our atmosphere?

Researchers from the University of Sheffield in England think so. They reported that tiny organisms that came back aboard a balloon sent high into the stratosphere are too big to have floated up from the surface of our planet.

alien life
A scanning electron micrograph of one of the diatoms found on a microscope stub aboard the balloon.

“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," Dr. Milton Wainwright, astrobiology professor at the university, said in a written statement. "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.”

Wainwright told The Independent that he's 95 percent certain the organisms come from space.

But other scientists aren't so sure.

"I'm very skeptical," Dr. Seth Shostak, senior astronomer with the SETI (Search for Extra-Terrestrial Intelligence) Institute, told The Huffington Post in an email. "This claim has been made before, and dismissed as terrestrial contamination."

The researchers said they took precautions to avoid picking up bits of terrestrial life during the experiment. Microscope stubs on the balloon were exposed to the atmosphere only at altitudes of 22 to 27 kilometers (13.7 to 16.8 miles). They acknowledged that there could be some mechanism for transporting large particles high into the atmosphere. But since no such mechanism has been discovered, they said, the next likely explanation is that the "diatoms" come from space.

Still, other experts say there's simply not enough evidence.

"They should try a lot harder to look for more mundane ways this beastie made it up there," astronomer Dr. Philip Plait wrote for Slate magazine. "They dismiss other pathways, just stating they won’t work, but I’m unconvinced... In other words, if they can’t figure it out, it must be aliens. This 'god of the gaps' argument leaves me underwhelmed."

It's not the first time the Sheffield team has come under fire. Astrobiologist Dr. Chandra Wickramasinghe, another member of the research team, was criticized back in January for reporting that fossils inside a meteorite discovered in Sri Lanka were proof of extraterrestrial life.

Wickramasinghe believes the organisms found in Earth's stratosphere may have hitched a ride aboard meteors from other planets, suggesting that life exists in other parts of the galaxy, as reported by the University Herald.

The new findings were published in the Journal of Cosmology -- which itself has been viewed skeptically by some scientists. Dr. Sean Carroll, an astrophysicist at Caltech, told The Huffington Post in an email that it "is not a serious journal."

Wainwright said the next step would be to perform "isotope fractionation" on the sample recovered from the balloon -- essentially, analyzing the ratio of certain carbon isotopes in the organisms to determine their origins. The team hopes to confirm their findings by repeating the experiment in October during the Halley's comet meteor shower.

“If life does continue to arrive from space then we have to completely change our view of biology and evolution,” Wainwright said. “New textbooks will have to be written!”

If the team compiles enough evidence to convert the skeptics, that is.

Also on HuffPost:

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  • This is the Pioneer Plaque, one of two cosmic dog-tags attached to the Pioneer 10 and 11 spacecraft, the first human-made matter to leave the solar system. Carl Sagan and his wife Linda, along with astronomer Frank Drake, designed the plaque. It contains a map of the solar system with the path of the spacecraft, as well as images of a man and a woman, which were criticized for their nudity when the plaques were created.

  • The Golden Records, sent out with the Voyager I and II spacecraft, contain diagrams representing basic scientific concepts, but may be most notable for their inclusion of music, ranging from Chinese musician Guan Pinghu to early rocker Chuck Berry. The records will remain on the interstellar probes for their multi-millennial mission, passing relatively close to a star in about 40,000 years. If extraterrestrials can manage find these needles in the galactic haystack, they'd almost certainly be advanced enough to find us.

  • The Arecibo message, which was broadcast as a radio signal in 1974, contains a representation of the numbers 1-10, as well as various information about the chemicals that make up life on this planet. At the bottom, there's even a diagram of the picturesque Arecibo telescope. Frank Drake and Carl Sagan also contributed to the design, which is depicted here in color to remove ambiguity from the different parts of the message. We definitely can't expect a reply to this one; it will take 25,000 years to reach its target and another 25,000 before we'd receive any response. Donald Campbell, professor of astronomy at Cornell University later <a href="http://web.archive.org/web/20080802005337/http://www.news.cornell.edu/releases/Nov99/Arecibo.message.ws.html" target="_hplink">confirmed this</a>, saying, "It was strictly a symbolic event, to show that we could do it."

  • The first Cosmic Call message, sent out from a radio telescope in Ukraine, included a signal with this information. It's a sort of numerical dictionary, which matches up binary representations of numbers with the symbols that will be used to represent them in the rest of the message. Subsequent parts of the message go on to define mathematical operations and fundamental scientific facts. <a href="https://docs.google.com/viewer?a=v&q=cache:54E2DsuQ1JIJ:www.astrosurf.com/luxorion/Documents/seti-dutil-dumas.pdf+&hl=en&gl=us&pid=bl&srcid=ADGEESiKrcWWCBuKAIg6lQyKOUySNwqyHXRgmd9RcF6nWq5U6Ji3qZ4RJXzC55NvR19JhUV9I3oeoyI29jMAwXWc8-mOuJSG8bBTzxWCUvxWl-FxwMa2EREg5uDxFYpeggirJ0VWvKpU&sig=AHIEtbSFFlViE_wfSo8H2LXQFyLJq5lCCQ" target="_hplink">A detailed explanation can be found here</a>. <a href="http://www.matessa.org/~mike/dd-pr.html" target="_hplink">Canadian physicists Yvan Dutil and Stephane Dumas led the efforts</a> to send the Cosmic Call, which was sent alongside a transmission of the Arecibo message. Image courtesy Yvan Dutil and Stephane Dumas.

  • The Teen-Age Message, composed in part by teens from across Russia, was broadcast in August and September 2001. In addition to bilingual greetings in Russian and English, the broadcast includes the "1st Theremin Concert for Aliens," a series of famous melodies played on the <a href="http://www.youtube.com/watch?v=cd4jvtAr8JM" target="_hplink">electronic instrument</a>. The image above contains several glyphs representing various aspects of humanity and life on planet earth. Image: Alexander Zaitsev

  • In 2008, <a href="http://www.nasa.gov/topics/universe/features/across_universe.html" target="_hplink">NASA transmitted</a> the Beatles' 'Across The Universe' in the direction of the North Star, Polaris, located 431 light years away. The transmission was sent from a station outside Madrid that's part of NASA's international antenna array known as the Deep Space Network. It celebrated the 40th anniversary of the song's recording and the 50th anniversary of NASA's founding. When NASA notified Paul McCartney, the former Beatle told the Administration to "Send my love to the aliens."