Scientists have determined that a species widely considered the most indestructible on the planet will be the last survivors on Earth, set to survive another 10 billion years until the Sun itself dies.
The species, a micro-animal with eight legs that reaches up to 1.5mm long, is known as the tardigrade – or water bear – and is the subject of research conducted by scientists from Oxford University and Harvard, published today in the journal Scientific Reports.
The scientists looked at phenomena likely to wipe out the majority of life on Earth, including major asteroid impacts, gamma ray bursts and supernovae, and found that the tardigrade would survive such cataclysmic events. As a result, nothing would be sufficient to stop the tardigrade surviving until the death of the Sun, long after humans had vanished from Earth.
“Without our technology protecting us, humans are a very sensitive species. Subtle changes in our environment impact us dramatically,” said study co-author Dr Rafael Alves Batista, post-doctoral research associate in the Department of Physics at Oxford University. “There are many more resilient species’ on earth. Life on this planet can continue long after humans are gone.”
Importantly, this also raises hope for finding similar extraterrestrial life on seemingly inhospitable planets.
“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,” added Batista. “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.”
The tiny creatures are equipped with some significant survival traits that will allow them to survive in such adverse conditions. They can live for three decades with neither food nor water, and can survive in incredible extremes, at temperatures up to 150°C, in the depths of the sea and even in the freezing vacuum of space.
The research shows that while human life is sensitive to the calamities that could befall our planet, life as a wider concept endures.
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,” said study co-author Dr David Sloan, a Post-Doctoral Research Associate in the Department of Physics at Oxford University.
“To our surprise we found that although nearby supernovae or large asteroid impacts would be catastrophic for people, tardigrades could be unaffected.
“Therefore 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.”