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What caused ancient mass extinction? Hot ocean water blamed – National Post

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WASHINGTON — Scientists think they’ve figured out the falling dominoes that led to Earth’s largest mass extinction and worry that human-caused climate change puts the planet on a vaguely similar path.

Some 250 million years ago, about 90 per cent of sea life and 70 per cent of land life went extinct in what is now called the Great Dying. Scientists have long speculated that massive volcanic outbursts triggered the cataclysmic event, but how that worked was still a bit fuzzy. It wasn’t the lava itself.

A new study in Thursday’s journal Science used complex computer simulations to plot out what happened after the volcanoes blew: It led to ocean temperatures rising by about 20 degrees (11 degrees Celsius), which then starved the seawater of oxygen. That hot oxygen-starved water caused the mass marine die-off, especially farther from the equator.

After the volcanoes blew, the level of heat-trapping carbon dioxide soared to a level more than 12 times what it is today , said study lead author Justin Penn, an Earth sciences researcher at the University of Washington.

Water loses oxygen when it warms, much like a warm can of cola goes flat, Penn said. Scientists looked at dozens of modern species to see what happens to them in warmer, oxygen-starved water and that helped them understand the past extinction.

One of the keys in the research is that more species died off away from the equator. That’s because tropical species were more acclimated to low oxygen levels, Penn said.

While humans aren’t warming the Earth anywhere close to as much as what happened naturally 250 million years ago, “this puts our future into the category of contenders for true catastrophe,” said study co-author Curtis Deutsch, an Earth scientist at the University of Washington.

The ancient die-off “shows almost exactly what lies at the end of the road we’re on,” Deutsch said. “We’re really doing the same thing to Earth’s climate and oceans.”

The study calculates that if heat-trapping carbon dioxide emissions continue on current levels, by the year 2300, the globe will experience 35 to 50 per cent of the extinction level seen in the Great Dying.

University of Leeds paleontologist Paul Wignall said no current global warming scenario envisions 20 degrees of warming in the next few centuries, so it could be millennia away.

However, even an event 10 per cent as bad as the Great Dying “would be dreadful,” said Wignall, who wasn’t part of the study.

Other outside scientists said the study provides a scary glimpse into Earth’s possible future.

“Because we are warming up the Earth at a rapid rate, results from this study could prove to very useful in understanding” what happens to life in future oceans, University of Southern California Earth scientist David Bottjer said in an email.

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Follow Seth Borenstein on Twitter at @borenbears .

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

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Getting used to life in space – Canada News – Castanet.net

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Canadian astronaut David Saint-Jacques says he is slowly getting used to life in space.

The Quebecer spoke to reporters for the first time today since arriving at the International Space Station Dec. 3. The Canadian Space Agency set up a video link at its headquarters south of Montreal.

Saint-Jacques says he is adjusting to the sensation of living in microgravity, proving his point by dropping his microphone and continuing to talk as it remained floating in place.

He says he was thunderstruck when he emerged from the Soyuz capsule that brought him to the station along with fellow astronauts Anne McClain of NASA and Oleg Kononenko of the Russian space agency, Roscosmos.

He says he was dazzled by the sight of the sun rising over Earth and by the general beauty of the cosmos.

The 48-year-old physician is expected to conduct a series of experiments in orbit on topics such as the physical impacts of gravity on the body.

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Voyager 2 has finally entered interstellar space, more than 40 years after its launch – MIT Technology Review

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It’s only the second object made by humans to ever reach this distance, following Voyager 1 in 2012.

The long journey: Since launching more than 40 years ago back in 1977, the probe has traveled 11 billion miles to get to cross into interstellar space. While it launched before Voyager 1, its flight path put Voyager 2 on a slower path to reach this milestone.

What does that mean? No, Voyager 2 hasn’t left the solar system. Our solar system is huge and goes way beyond its last planet. Instead, it means Voyager 2 has left the heliosphere, the pocket of particles and magnetic fields created by our closest star. Solar wind, the charged plasma particles that come out from the sun, generates this bubble.

How do they know? Today NASA announced that on November 5, researchers saw a steep drop-off in the speeds of solar winds around the probe. Now no solar wind is being observed, indicating the craft is in interstellar space.

What now? It’s estimated it will take about 30,000 years for Voyager 2 to leave the solar system by flying beyond the Oort Cloud, a ring of icy objects that is believed to encircle the sun, way beyond the furthest planets. Sadly the spacecraft won’t still be sending us data at that point. Right now it takes about 16.5 hours for scientists to receive data from the spacecraft, and it has an estimated five to 10 years of life left. In that time it will relay back new information about the new environmental conditions that surround it.

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  • NASA/JPL-Caltech

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NASA's Voyager 2 becomes 2nd craft in interstellar space – Prince George Citizen

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WASHINGTON — NASA’s Voyager 2 is now the second human-made object to zip away from the sun into the space between the stars.

Voyager 2 last month exited “this bubble that the sun creates around itself,” longtime NASA mission scientist Ed Stone said Monday. The spacecraft is now beyond the outer boundary of the heliosphere, some 11 billion miles (about 18 billion kilometres) from Earth.

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It’s trailing twin Voyager 1, which reached interstellar space in 2012 and is now 13 billion miles (21 billion kilometres) from Earth. Interstellar space is the vast mostly emptiness between star systems.

Even though they are out of the sun’s bubble, the Voyagers are still technically in our solar system, NASA said. Scientists maintain the solar system stretches to the outer edge of the so-called Oort Cloud. It will take about 30,000 years for the spacecraft to get that far.

Scientists know that Voyager 2 has left the sun’s influence because of four different instruments that are measuring solar particles and different types of rays. They showed a dramatic change on Nov. 5, indicating the spacecraft was now in between the stars. One of the instruments measures solar plasma and this is the first time NASA saw a drop in that key instrument; the same instrument wasn’t working on Voyager 1.

The twin Voyagers launched from Cape Canaveral, Florida, in 1977, and zipped by Jupiter, Saturn, Uranus and Neptune. Voyager 2 has already logged more than 18.5 billion miles (30 billion kilometres) on its interstellar trip going 34,191 mph (55,025 kph).

“Both spacecrafts are very healthy if you consider them senior citizens,” Voyager project manager Suzanne Dodd said.

She said the probes should last at least five, maybe 10 more years, but the cold — the temperature outside the vehicles is about 49 degrees below zero (minus 45 Celsius) — and waning power supply will eventually end their usefulness.

Yet the two Voyagers will keep travelling and in 40,000 years or so they’ll get close to the next stars, or actually the stars, which are moving faster, will get close to them, Stone said.

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Follow Seth Borenstein on Twitter at @borenbears .

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

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