For humans, life is undoubtedly fragile. In fact, the list of things that have the potential to wipe out mankind is unsettlingly long and includes things like an astroid, exploding stars, a global pandemic, biological or nuclear warfare, or even global warming. But while life on a post-apocalyptic Earth sounds far from appealing, scientists believe they've determined there might be at least one survivor. According to a new study, the eight-legged nearly-microscopic tardigrade will likely be the last creature living on Earth.
A collaborative study between researchers at Oxford and Harvard found tardigrade "will survive the risk of extinction from all astrophysical catastrophes, and be around for at least 10 billion years – far longer than the human race," Oxford has reported. According to Oxford University theoretical cosmologist David Sloan, Harvard University astrophysicist Abraham Loeb, and Rafael Alves Batista, an Oxford postdoctoral research assistant at the Beecroft Institute for Particle Astrophysics and Cosmology, the tardigrade will likely live until the Sun dies.
These findings aren't too surprising given the tardigrade's reputation for resilience. Multiple studies have found tardigrades, which are often known as "water bears" or "moss piglets," can survive extreme temperatures, intense pressure, lethal radiation, a decade worth of dehydration, and even the vacuum of space. But researchers wanted to know just how resilient Earth's "hardiest species" really is.
To do this they simulated three astrophysical events – supernovae, gamma-ray bursts, and large asteroids – which would likely wipe out most, if not all, life on Earth. They detailed their findings in a report published Friday in Scientific Reports.
"A lot of previous work has focused on 'doomsday' scenarios on Earth - astrophysical events like supernovae that could wipe out the human race. Our study instead considered the hardiest species - the tardigrade," Oxford University reported Sloan said. "To our surprise we found that although nearby supernovae or large asteroid impacts would be catastrophic for people, tardigrades could be unaffected."
According to Sloan, the tardigrades' ability to survive bodes well for the resilience of life in general. "It seems that life, once it gets going, is hard to wipe out entirely. Huge numbers of species, or even entire genera may become extinct, but life as a whole will go on."
The researchers say the tardigrade's resilience also raises another question: if the tardigrade could survive such extreme conditions on Earth, might another extremophile species be living in presumed uninhabitable environments elsewhere in the universe?
"Tardigrades are as close to indestructible as it gets on Earth, but it is possible that there are other resilient species examples elsewhere in the universe," Batista said in a statement to Oxford. "In this context there is a real case for looking for life on Mars and in other areas of the solar system in general. If Tardigrades are earth’s most resilient species, who knows what else is out there?"