There's a literal growing mystery aboard the International Space Station. What, exactly, is growing outside of the space station and how it is possibly surviving exposed to the vacuum of space?
Or is it all a big hoax?
A Russian official says cosmonauts found microbial life clinging to the outside of the ISS during routine exterior cleaning and sample collection.
If true, the sea plankton discovery would be pretty amazing: It means the organisms survived "amid factors of a space flight, such as zero gravity, temperature conditions and hard cosmic radiation," ITAR-TASS, a Russian news agency, reports.
Color NASA skeptical.
"As far as we're concerned, we haven't heard any official reports from our Roscosmos colleagues that they've found sea plankton," NASA spokesman Dan Huot told Space.com, adding the Russians weren't looking for sea plankton, but residue on the windows. "I'm not sure where all the sea plankton talk is coming from."
Let's assume it is true. What kind of organism could survive the stresses of a space flight and space? Extreme Tech points to tardigrades as an example of organisms that live in the most extreme environments.
Tardigrades can "survive extreme temperatures (slightly above absolute zero to far above boiling), amounts of radiation hundreds of times higher than the lethal dose for a human, pressure around six times more than found in the deepest parts of the ocean, and the vacuum of space," Extreme Tech reports.
Scientists and space enthusiasts eagerly wait confirmation that the Russians did indeed find sea plankton on the ISS.