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This Massive Stellar Flare Would Have Been Catastrophic for Nearby Planets

Not too far away, a small star recently unleashed an unexpectedly intense series of flares. The series kicked off with a behemoth eruption that was 10,000 times more powerful than anything ever recorded from the sun. For a few brief moments, the star blazed many times brighter than normal.

Another half-dozen flares and two weeks later, the episode ended. But the explosive cluster had been hotter, more powerful, and longer-lasting than scientists had expected to see. It would definitely not be good news for any planets orbiting close to the tempestuous star.

The star is a young red dwarf that is only about one-third the sun’s mass. It’s part of a binary dwarf system called DG Canum Venaticorum (or DG CVn for short), located about 60 light-years away. Red dwarfs are the most plentiful type of star in the galaxy, outnumbering everyone else by about three to one. Small, cool, and remarkably long-lived, these stars are considered by many scientists to be excellent hosts for life-friendly planets.

But on April 23, you would not have wanted to be anywhere near this little star. Spinning 30 times faster than the sun, the star’s rapid rotation amplified a burgeoning distortion in its magnetic field. When the tension finally snapped, it launched the mega-flare into space. As observed by NASA’s Swift satellite, that initial explosion reached a temperature of about 200 million Celsius (more than 12 times hotter than the center of the sun). It released enough high-energy X-rays to briefly outshine the star itself — and its nearby friend — in all wavelengths of light.

If a comparable flare had erupted from the sun and been followed by a cloud of charged particles, Earth would be in a bit of trouble, says astronomer Rachel Osten of the Space Telescope Science Institute. Those particle storms that often accompany flares are called coronal mass ejections, and when they’re energetic enough, they can disrupt both ground- and space-based communication systems.

“In terms of our own space weather, it is the mass ejections and energetic particles that can do the most damage,” she says. “The effects [of this mega-flare] would be worse than the biggest space weather event we’ve experienced so far.” (Here’s a description of the massive 1859 eruption known as the Carrington Event.)

But in addition to messing with power grids, knocking out short-wave radio communication systems and disrupting the global positioning system, such a mega-flare would have a notable bright side: Spectacular auroras, observable down to very low latitudes instead of just around the poles.

Of course, this little star’s super-spasm was no threat to our home planet. But any planets in its life-friendly zone would have been in for a rough time. “It must surely have been catastrophic,” says astrophysicist Stephen Drake of NASA’s Goddard Space Flight Center.

Red dwarfs are cooler than the sun, so planets warm enough to have liquid water on their surfaces orbit nearer the star, at perhaps one-tenth the Earth-sun distance. Because of that, these planets are tidally locked in orbit and always have the same face pointed toward their star. In other words, one half of the planet is bathed in perpetual day, the other half blanketed by endless night.

A mega-flare of this size, followed by a coronal mass ejection, would not be a welcome occurrence for a planet snuggled close to DG CVn — especially not for the part of the planet staring at the star.

“Any ozone layer on the star-facing hemisphere would surely be destroyed, the upper atmosphere would be hit by this large pulse of radiation, and then, maybe several hours later, if the geometry lined up, the associated coronal mass ejection would crash into the planet’s magnetosphere, and likely completely collapse it to the planet’s lower atmosphere on the star-facing hemisphere,” Drake says. “I would imagine that this, if the planet supported life, would produce the kind of major extinction event that we see a number of examples of in the Earth’s history.”


Many astronomers are excited about the possibilities of finding habitable planets around red dwarf stars. In addition to being close to the star and relatively easy to spot, these planets also have the luxury of maturing into old, old, old age. Red dwarf stars are exceptionally long-lived, with lifespans calculated to be on the order of trillions of years, so any nearby extraterrestrial lifeforms theoretically have lots of time to evolve.

But one of the chief concerns raised when discussing habitable planets around red dwarfs is the stars’ propensity for violent stellar outbursts, which could deal deadly blows to any organisms struggling to gain a toehold on their home worlds.

Yet flares the size recorded earlier this year around DG CVn are rare, Drake says, and tend to occur when the stars are very young — as this star is. Scientists estimate DG CVn is only about 30 million years old, which makes it less than one percent of the solar system’s age. So, planets forming around it are still very young, and far from habitable at this point.

“Any planets it may have in its habitable zone are still completely inhospitable to life,” Drake says. “Their surfaces are likely still molten. It took life perhaps a billion years to eventually develop on the Earth, as you know, so DG CVn still has lots of time to become the host star of a planet with life.”

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Tardigrades become first animals to survive vacuum of space

Blogging on Peer-Reviewed Research In September last year, a team of scientists launched a squad of tiny animals into space aboard a Russian satellite. Once in orbit, the creatures were shunted into ventilated containers that exposed them to the vacuum of space. In this final frontier, they had no air and they were subjected to extreme dehydration, freezing temperatures, weightlessness and lashings of both cosmic and solar radiation. It’s hard to imagine a more inhospitable environment for life but not only did the critters survive, they managed to reproduce on their return to Earth. Meet the planet’s toughest animals – the tardigrades.

Hypsibiusdujardini.jpgTardigrades are small aquatic invertebrates that are also known as “water bears”, after their impossibly cute shuffling walk (see video below). They also happen to be nigh-invincible and can tolerate extreme environments that would kill almost any other animal. They can take temperatures close to absolute zero, punishing doses of radiation and prolonged periods of drought. And now, they have become the only animals to have ever survived the raw vacuum of space.


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Bacteria inspire drug that protects against radiation sickness

Blogging on Peer-Reviewed ResearchFor comic book characters, big doses of radiation are a surefire way of acquiring awesome superpowers, but in real life, the results aren’t quite as glamorous. A victim of acute radiation poisoning can look forward to hair loss, bleeding, the destruction of their white blood cells and bone marrow, and severe damage to their spleen, stomach and intestines.

Radiation doesn’t kill cells directly, but it can cause so much damage that they commit suicide, by enacting a failsafe program called apoptosis.  Now, Lyudmila Burdelya and colleagues from Roswell Park Cancer Institute have found a way to block this cellular kill-switch, using a drug inspired by the unlikeliest of sources – the tail of the food-poisoning bacterium, Salmonella.

In early animal tests, the drug saved the lives of monkeys and mice that had been exposed to lethal doses of radiation. With further development and clinical trials, it could be used to protect cancer patients undergoing radiotherapy, or even people who are more inadvertently exposed through accidents or nuclear attacks.


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Bdelloid rotifers – the world’s most radiation-resistant animals

Blogging on Peer-Reviewed ResearchBdelloid rotifers are one of the strangest of all animals. Uniquely, these small, freshwater invertebrates reproduce entirely asexually and have avoided sex for some 80 million years. At any point of their life cycle, they can be completely dried out and live happily in a dormant state before being rehydrated again.

This last ability has allowed them to colonise a number of treacherous habitats such as freshwater pools and the surfaces of mosses and lichens, where water is plentiful but can easily evaporate away. The bdelloids (pronounced with a silent ‘b’) have evolved a suite of adaptations for surviving dry spells and some of these have had an unexpected side effect – they’ve made the bdelloids the most radiation-resistant animals on the planet.

Radioactive danger

Ionising (high-energy) radiation is bad news for living cells. Far from granting superpowers, it damages DNA, often completely breaking both strands of the all-important molecule. If you think of DNA as a recipe book for the various parts of a living thing, the double-stranded DNA breaks that are caused by ionising radiation are like tearing the book up into small chunks.

Absorbed doses of radiation are measured in Grays and ten of these are more than enough to kill a human. In comparison, bdelloids are  a hundred times harder. Eugene Gladyshev and Matthew Meselson from Harvard University found that two species shrugged off as much as 1,000 Grays and were still active two weeks after exposure.