It is really difficult to imagine what exactly will happen after the doomsday strikes. Will our Earth be a no-man’s land? Will there be any form of life left? Well, scientists say yes and believe it will survive until the death of the Sun. Tardigrade, a tiny, eight-legged animal also known as ‘water bear’ will persist long after the humans on Earth have been wiped out, the researchers said.
A range of cataclysmic events such as a large asteroid strike or a nearby exploding star could vanish our species. However, none would be serious enough to completely eradicate all life. The tardigrade deemed to be an ultimate survivor on the Earth.
“A lot of previous work has focused on 'doomsday' scenarios on Earth – astrophysical events like supernovae that could wipe out the human race,” Dr David Sloan, one of the researchers of Oxford University said.
“Our study instead considered the hardiest species – the tardigrade. As we are now entering a stage of astronomy where we have seen exoplanets and are hoping to soon perform spectroscopy, looking for signatures of life, we should try to see just how fragile this hardiest life is.”
“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.”
Dr Rafael Alves Batista, his Oxford colleague, contrasted the tardigrade’s hardiness with human’s relative fragility. “Without our technology protecting us, humans are a very sensitive species,” he said.
“Subtle changes in our environment impact us dramatically. There are many more resilient species on Earth. Life on this planet can continue long after humans are gone.”
Dr Alves Batista said the tardigrade’s existence also gives hope for search for extra-terrestrial life. “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,” he said.
“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.”
Three possible cataclysmic events – an asteroid impact, a supernova and a gamma ray burst – were considered by the study.
Objects such as dwarf planet Pluto are big enough to cause the oceans of the Earth to boil if they hit. However, none of them are on a trajectory to intersect with our orbit.
Researchers say there is a chance that a supernova, an exploding star, could be big enough to wipe out life on Earth within our sun’s lifetime and this event is negligible.
Gamma-ray bursts would need to be no more than 40 light years away to pose a threat to life on Earth. The risk was again considered to be unlikely. The study has been published in the journal Scientific Reports.