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Jasper Nance

Tardigrades Could Live on Earth Until the Sun Dies

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Jasper Nance

In considering the relative brevity of human existence, astronomer Carl Sagan once wrote, "We are like butterflies who flutter for a day and think it is forever." The same could not be said of the microscopic animals known as tardigrades, which, scientists are now predicting in the journal Nature, could stick around on Earth until the Sun dies. 

The tardigrade, also known as the moss piglet or water bear, is an admirably durable little monster. It superpower is a sort of half-death state called cryptobiosis. When hard times come around, the tardigrade simply curls up, dries up, and mostly stops living, only to re-inflate and rejoin the world when conditions are more comfortable. Studies have shown that tardigrades can survive scorching heat, blistering cold, starvation, desiccation, radiation, and even the vacuum of space.

That's just on the individual level. There are more than 1000 different tardigrade species [PDF], and all have already been around for a long, long time. Scientists estimate that the first tardigrades appeared on the planet around 600 million years ago—about 370 million years before the first dinosaurs. The dinosaurs disappeared. The tardigrades kept on trucking. 

And according to the authors of the new paper, the moss piglets could just keep on trucking for another 10 billion years.

"A lot of previous work has focused on 'doomsday' scenarios on Earth—astrophysical events like supernovae that could wipe out the human race," co-author David Sloan of Oxford University said in a statement.

But humans are far from the toughest kids on the block. ("Human life is somewhat fragile to nearby events," as the researchers diplomatically put it.) Why not try to find out how sturdier species would fare in those same scenarios? To do so, the researchers calculated the effects of three doomsday events—an asteroid strike, a nearby supernova, and a gamma ray burst (another type of stellar explosion)—on tardigrades' environment and physiology.

You can probably guess what they discovered.

"Although nearby supernovae or large asteroid impacts would be catastrophic for people, tardigrades could be unaffected," Sloan said. "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."

Co-author Rafael Alves Batista, also of Oxford, said his team's findings should expand the scope of what we might consider a "habitable planet."

"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. 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."

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Courtesy Murdoch University
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Animals
Australian Scientists Discover First New Species of Sunfish in 125 Years
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Courtesy Murdoch University

Scientists have pinpointed a whole new species of the largest bony fish in the world, the massive sunfish, as we learned from Smithsonian magazine. It's the first new species of sunfish proposed in more than 125 years.

As the researchers report in the Zoological Journal of the Linnean Society, the genetic differences between the newly named hoodwinker sunfish (Mola tecta) and its other sunfish brethren was confirmed by data on 27 different samples of the species collected over the course of three years. Since sunfish are so massive—the biggest can weigh as much as 5000 pounds—they pose a challenge to preserve and store, even for museums with large research collections. Lead author Marianne Nyegaard of Murdoch University in Australia traveled thousands of miles to find and collected genetic data on sunfish stranded on beaches. At one point, she was asked if she would be bringing her own crane to collect one.

Nyegaard also went back through scientific literature dating back to the 1500s, sorting through descriptions of sea monsters and mermen to see if any of the documentation sounded like observations of the hoodwinker. "We retraced the steps of early naturalists and taxonomists to understand how such a large fish could have evaded discovery all this time," she said in a press statement. "Overall, we felt science had been repeatedly tricked by this cheeky species, which is why we named it the 'hoodwinker.'"

Japanese researchers first detected genetic differences between previously known sunfish and a new, unknown species 10 years ago, and this confirms the existence of a whole different type from species like the Mola mola or Mola ramsayi.

Mola tecta looks a little different from other sunfish, with a more slender body. As it grows, it doesn't develop the protruding snout or bumps that other sunfish exhibit. Similarly to the others, though, it can reach a length of 8 feet or more. 

Based on the stomach contents of some of the specimens studied, the hoodwinker likely feeds on salps, a jellyfish-like creature that it probably chomps on (yes, sunfish have teeth) during deep dives. The species has been found near New Zealand, Australia, South Africa, and southern Chile.

[h/t Smithsonian]

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Gregory H. Revera, Wikimedia Commons // CC BY-SA 3.0
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Space
Study Suggests There's Water Beneath the Moon's Surface
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Gregory H. Revera, Wikimedia Commons // CC BY-SA 3.0

Astronauts may not need to go far to find water outside Earth. As CNN reports, Brown University scientists Ralph E. Milliken and Shuai Li suspect there are significant amounts of water churning within the Moon’s interior.

Their findings, published in the journal Nature Geoscience, lean on the discovery of glass beads encased in the Moon’s volcanic rock deposits. As recently as 100 million years ago, the Earth’s moon was a hotbed of volcanic activity. Evidence of that volatile time can still be found in the ancient ash and volcanic rock that’s scattered across the surface.

Using satellite imagery, the researchers identified tiny water droplets preserved inside glass beads that formed in the volcanic deposits. While water makes up a small fraction of each bead, its presence suggests there’s significantly more of it making up the Moon’s mantle.

Milliken and Li aren't the first scientists to notice water in lunar rocks. In 2008, volcanic materials collected from the Moon during the Apollo missions of 1971 and 1972 were revealed to contain the same water-flecked glass beads that the Brown scientists made the basis of their recent study. They took their research further by analyzing images captured across the face of the Moon and quickly saw the Apollo rocks represented a larger trend. "The distribution of these water-rich deposits is the key thing," Milliken said in a press statement. "They're spread across the surface, which tells us that the water found in the Apollo samples isn't a one-off. Lunar pyroclastics seem to be universally water-rich, which suggests the same may be true of the mantle."

The study challenges what we know about the Moon's formation, which scientists think occurred when a planet-sized object slammed into the Earth 4.5 billion years ago. "The growing evidence for water inside the Moon suggests that water did somehow survive, or that it was brought in shortly after the impact by asteroids or comets before the Moon had completely solidified," Li said. "The exact origin of water in the lunar interior is still a big question."

The findings also hold exciting possibilities for the future of space travel. NASA scientists have already considered turning the Moon into a water station for astronauts on their way to Mars. If water on the celestial body is really as abundant as the evidence may suggest, figuring out how to access that resource will definitely be on NASA's agenda.

[h/t CNN]

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