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Canadian scientist examines melting Antarctic glacier, potential sea level rise – Globalnews.ca

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As icebergs drifted by his Antarctica-bound ship, David Holland spoke this week of how the melting glacier he’s cruising towards may contain warning signals for the coasts of far-off Canada.

The atmospheric and ocean scientist from Newfoundland is part of an expedition to one of the world’s most frigid and remote spots – the Thwaites glacier in the western portion of the continent – where he’ll measure water temperatures in an undersea channel the size of Manhattan.

“The question of whether sea level will change can only be answered by looking at the planet where it matters, and that is at Thwaites,” said Holland, director of the environmental fluid dynamics laboratory at New York University, during a satellite phone interview from aboard the South Korean icebreaker Araon.

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It’s over 16,000 kilometres from Holland’s hometown in Brigus, N.L., on Conception Bay, to the site about 100 kilometres inland from the “grounding zone” where the Thwaites’ glacier leaves the continent and extends over the Pacific.

The team’s 20,000 tonnes of drilling gear will be assembled to measure the temperatures, salinity and turbulence of the Pacific waters that have crept underneath and are lapping away at the guts of the glacier.

“If it (the water) is above freezing, and in salt water this means above -2 centigrade, that’s not sustainable. A glacier can’t survive that,” said Holland.

Since 2018, more than 60 scientists from the International Thwaites Glacier Collaboration group have been exploring the ocean and marine sediments, measuring warming currents flowing toward the deep ice, and examining the stretching, bending, and grinding of the glacier over the landscape below.

The Florida-sized Thwaites glacier faces the Amundsen Sea, and researchers have suggested in journal articles over the past decade it may eventually lose large amounts of ice because of deep, warm water driven into the area as the planet warms. Some media have dubbed Thwaites the “doomsday glacier” due to estimates that it could add about 65 centimetres to global sea level rise.

Holland notes current research models mainly suggest this would happen over several centuries, however there are also lower probability theories of “catastrophic collapse” occurring, where the massive ice shelf melts in the space of decades. “We want to pay attention to things that are plausible, and rapid collapse of that glacier is a possibility,” he said.

While Holland looks at the undersea melting, other scientists are examining how the land-based portions of Antarctic glaciers are losing their grip on points of attachment to the seabed, potentially causing parts to detach. Still other researchers point to the risk of initial fractures causing the ice shelf to break, much like a damaged car windshield.

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All of the mechanisms must be carefully observed to prove or disprove models on the rates of melting, said Holland.

“If the (water-filled) cave beneath the glacier we’re studying gets bigger, then Antarctica is losing ice and retreating, and if the cave collapses on itself, then (the cave) will disappear. This is how Antarctica can retreat, these kinds of specific events,” he said.

The implications of the glacier work reach back to Atlantic Canada – which along with communities along the Beaufort Sea and in southwestern British Columbia is the region most vulnerable to sea level rise in the country, according to federal scientists.

Everything from how to calculate the future height of dikes at the low-lying Chignecto Isthmus – the narrow band of land that connects Nova Scotia to the rest of the country – to whether the Fraser River lowlands may face flooding is potentially affected by glacial melting in Antarctica, he said.

Scenarios where Antarctica ice melts more quickly than expected are briefly discussed in the 2019 federal report Canada’s Changing Climate. Based largely on Intergovernmental Panel on Climate Change reports that refer to them as low-probability “tipping point” theories, the 2019 report invoked the possibility of one metre of sea level rise by 2100.

However, Blair Greenan, a federal oceanographer who oversaw the relevant chapter of the report, said in a recent interview that a rise in global sea levels approaching two metres by 2100 and five metres by 2150 “cannot be ruled out” due to uncertainty over ice sheet processes like Thwaites.

“We don’t know, nobody knows,” Holland said. “But it’s plausible these things can change, and several feet of sea level change would have a major impact on Atlantic Canada. What’s needed is glacier forecasting that resembles the kinds of accuracy that weather forecasting currently provides.”


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However, collecting glacier forecast data is a daunting undertaking in the short period – from late January until mid-February – when scientists can safely take readings. Helicopters will be ferrying a hot water drill, 30 barrels of fuel and water to Holland’s site beginning near the end of January. The drill will have to penetrate over a kilometre of ice to reach the 300 metres of undersea channel to take measurements.

As the data is collected, some scientists question whether there’s really much for Canadian coastal residents to worry about at this stage.

One study by Ian Joughin, a University of Washington glaciologist, has suggested Thwaites will only lose ice at a rate that creates sea level rise of one millimetre per year – and not until next century. At that rate it would take 100 years for sea levels to rise 10 centimetres.

In a telephone interview last week, Joughin said planning coastal protection and other measures for the more extreme scenarios may not be cost effective at this point, as it may take up to a century before the major risks starts to unfold.

However, Joanna Eyquem, a Montreal-based geoscientist who is studying ways to prepare infrastructure for rising sea levels, said in a recent email that glacier research shows sea level forecasts “are constantly evolving,” and adaptation efforts need to be quicker.

“The question is: How desperate does the situation need to be before we take action?” she asked.

This report by The Canadian Press was first published Jan. 23, 2022.

© 2022 The Canadian Press

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Crumbling comet could create meteor shower May 30 – Toronto Sun

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A crumbling comet could create a meteor shower on May 30.

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The ‘tau Herculids’ meteor display might be one of the most dramatic observed in over two decades, according to Space.com.

Meteor showers occur when dust or particles from asteroids or comets enter Earth’s atmosphere at a very high speed, the U.K. Sun explained.

This one is expected to be the product of a comet named 73P/Schwassmann-Wachmann, also known as SW3.

SW3 was first discovered in 1930 but did not reappear again until the 1970s, Republic World reported.

In 1995, astronomers noticed that the comet’s nucleus split into four smaller chunks, according to CNET.

It has continued to disintegrate more in the ensuing years.

The display is expected to be very visible in the Northern Hemisphere as it is occurring on a Moon-less night.

A consensus of experts predicts that the shower will be visible starting from 1 a.m. EST on May 31.

It is suggested viewers will want to be outside at least an hour before this so your eyes have a chance to adjust to the dark.

“The southwestern USA and Mexico are favored locations as the radiant, the area of the sky where these meteors come from, will be located highest in a dark sky,” Robert Lunsford wrote for AMS.

“The outburst may be seen from southeastern Canada and the remainder of the (eastern) USA, but at a lower altitude.”

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Boeing capsule returns from space station after test flight with no crew – CBC News

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Boeing’s crew taxi returned to Earth from the International Space Station on Wednesday, completing a repeat test flight before NASA astronauts climb aboard.

It was a quick trip back: the Starliner capsule parachuted into the New Mexico desert just four hours after leaving the orbiting lab, with airbags attached to cushion the landing. Only a mannequin was buckled in.

Aside from thruster failures and cooling system snags, Starliner appeared to clinch its high-stakes shakedown cruise, 2½ years after its botched first try. Flight controllers in Houston applauded and cheered the bull’s-eye touchdown.

NASA astronauts will strap in next for a trip to the space station. The space agency has long wanted two competing U.S. companies ferrying astronauts, giving it added insurance as it drastically reduced its reliance on Russia for rides to and from the space station.

Elon Musk’s SpaceX is already the established leader, launching astronauts since 2020 and even tourists. Its crew capsules splash down off the Florida coast; Boeing’s Starliner returns to the U.S. Army’s expansive White Sands Missile Range in New Mexico.

This image from NASA TV shows the Boeing Starliner approaching the International Space Station last Friday. (NASA/The Associated Press)

Boeing scrapped its first attempt to reach the space station in 2019, after software errors left the capsule in the wrong orbit and nearly doomed it. The company fixed the flaws and tried again last summer, but corroded valves halted the countdown. Following more repairs, Starliner finally lifted off from Cape Canaveral last Thursday and docked to the space station Friday.

Station astronauts tested Starliner’s communication and computer systems during its five days at the space station. They also unloaded hundreds of kilograms of groceries and other supplies that flew up in the Boeing capsule, then filled it with empty air tanks and other discarded gear.

A folded U.S. flag sent up by Boeing stayed behind, to be retrieved by the first Starliner crew.

“We’re a little sad to see her go,” station astronaut Bob Hines radioed as the capsule flew away.

Along for the ride was Starliner’s test dummy — Rosie the Rocketeer, a takeoff on the Second World War’s Rosie the Riveter.

The repairs and do-over cost Boeing nearly $600 million US.

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NASA's InSight Mars lander has taken its final selfie. Here it is – ZDNet

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InSight’s Final Selfie.


Image: NASA/JPL-Caltech

NASA’s InSight Mars lander has sent back its last selfie of its dust-covered solar panels and deck, in an image taken on its 1,211th ‘sol’ or Martian day of the mission on April 24. 

Insight has been roaming the red planet for the past 3.5 years, capturing images and data that allowed scientists to approximate its crust and core, and refine models of how planets evolved from dust circling the Sun. 

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Insight’s scientific mission is set to conclude in summer after which it will run out of power. The lander is solar-powered, but dust covering the seven-feet wide solar panels has reduced its production capacity from around 5,000 watt-hours per sol to 500 watt-hours per sol. Once these panels generated power equivalent to running an electric oven for 40 minutes, they now can only power one for 10 minutes. The lander is equipped with two 25 amp-hour lithium-ion rechargeable batteries for energy storage. 

SEE: NASA’s Mars helicopter just took these remarkable photos of the rover’s landing gear

With those constraints, even taking a selfie requires some calculation to stay within the spacecraft’s power budget. The selfie arm will now go into the “retirement pose”, according to NASA.    

“The arm needs to move several times in order to capture a full selfie. Because InSight’s dusty solar panels are producing less power, the team will soon put the lander’s robotic arm in its resting position (called the “retirement pose”) for the last time in May of 2022,” NASA JPL said

InSight launched from Vandenberg Air Force Base in California on May 5, 2018 and landed on Mars on November 26, 2018, six minutes after hitting the the Martian atmosphere at 12,300 mph (19,800 kilometers per hour), according to NASA. It was the eighth landing on Mars in human history. 

Dust has played a significant role in the InSight lander’s capability to continue the mission. An epic dust storm on Mars in 2018 is believed to have been behind the demise of NASA’s Opportunity rover. A similar storm could have threatened InSight’s mission, too. The threat from dust is two-fold: dust storms obscure available sunlight, while dust directly on the solar panels reduce their capacity to absorb sunlight.   

In September, 2021, on its 1,000th sol of the mission, InSight measured a “marsquake” with a magnitude of 4.2, which helped scientists see what’s happening beneath Mars’ surface. 

Located on the dark side of Mars at the time, dust on the solar panels was already restricting their power output. NASA used Insight’s robotic arm to sprinkle sand near one solar panel, hoping wind gusts would make the granules sweep off some of the dust. The plan worked.

SEE: NASA’s Mars lander is running out of power. Here’s what happens next

Then on January 7, 2022, InSight went into safe mode after a major dust storm obscured sunlight from its solar panels. But by that stage, performing the ‘sand sweep’ technique had become difficult because of reduced available energy. InSight’s engineers were hoping a whirlwind would clear dust from the panels and had restricted the use of science instruments. By February 15, the solar panels’ output levels had returned to pre-storm levels. 

InSight’s onboard computers for command and data handling are derived from NASA’s 2014 Mars Atmosphere and Volatile Evolution (MAVEN) and its 2011 Moon Gravity Recovery and Interior Laboratory (GRAIL) missions. The system has two redundant computers. Its core is a radiation-hardened 115.5 MHz CPU with a PowerPC 750 architecture called RAD 750 that was made by BAE Systems.

Its flight software is written in C and C++ on the VxWorks real-time operating system, which monitors the spacecraft’s health, checks for commands to execute, and handles communications and controls. It also checks commands for faults and handles corrective steps when it detects irregularities. 

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An animation of the last selfie.


Image: NASA/JPL-Caltech

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