Unexplained bacteria have been found on the outer hull of the International Space Station (ISS), according to Russian . The cosmonaut, who has spent a year in orbit across two missions and is about to embark on a third, says they were found in swabs taken of the station’s exterior.
Shkaplerov thinks these bacteria couldn’t have simply hitched a ride during the launch of the space station or on spacecraft that have visited for more than two decades, concluding that they must have blown in from some extraterrestrial source. Of course, once the possibility of an alien origin was raised, in the media began.
This is not the first time such extraordinary statements have come from the Russians, who reported that sea plankton, usually Earth-bound organisms, had been found growing on the outside of ISS windows in 2014. While this tentative claim was , details of the latest one are still scant. Russians have collected numerous
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The notion of life surviving the harsh conditions of space is not new. Some have speculated that a younger, wetter Mars might have been a suitable location for life’s genesis, life that was then ferried to Earth within rocks blasted from the Martian surface by meteor impacts.
Seeding life
Others have considered the unlikely prospect of life freely floating throughout the entire galaxy, maybe simple life forms embedded in rock and dust, or even the basic biological chemicals wrapped up within large carbon molecules. They say through this “panspermia”, unsuspecting planets, including Earth, were seeded with the ingredients for life.
If so, this seeding should continue today, and alien life could be constantly drizzling down on Earth. Panspermia adherents have also suggested that , are due to the arrival of space germs. Others suspect that the red rains that fell in Kerala, India, in 2001 were deposited by a passing comet. But critters of a more earthly origin, microalgae whipped up by storms, were found to be responsible for tainting the deluge.
Bear in mind that there has been no evidence for the arrival of extraterrestrial germs, so Shkaplerov’s claim, if true, would have great significance. But before talk of aliens can be seriously considered, earthly explanations must be ruled out.
Planetary plodders
What there is firm evidence for is the ability of terrestrial microbial life to survive in space for months and maybe years, shown in tests in extreme simulated environments and . So, some hardy bacteria could survive the harsh environment of space, and earthly contamination remains an obvious source for Shkaplerov’s findings.
A more intriguing possible source of contamination doesn’t require rockets to reach the ISS. With an orbit that dips to just over 400 kilometres above the surface of our planet, the ISS is not truly free of Earth’s atmosphere, and, maybe can be carried aloft, landing on the station. We know very little about these high-living bacteria, and while they might appear alien, they are definitely terrestrial in origin. In fact, Russia’s Roscosmos space agency has proposed raising the upper limit of what we consider to be Earth’s biosphere to 400 kilometres from the current altitude of 20 kilometres, to reflect this.
Shkaplerov returns to the ISS in December, and further tests may provide clues to the origin of his mysterious bacteria. Are these likely to reveal the presence of alien germs? Given previous claims, and the potential for earthly sources, don’t bet your house on it.
