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Giant dying star explodes as scientists watch in real time — a first for astronomy – CNN

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(CNN)The death of a star is one of the most dramatic and violent events in space — and astronomers had an unprecedented front-row seat to the explosive end of a stellar giant.

Ground-based telescopes provided the first real-time look at the death throes of a red supergiant star. While these aren’t the brightest or most massive stars, they are the largest in terms of volume.
One popular red supergiant star is Betelgeuse, which has captured interest due to its irregular dimming. While it was predicted that Betelgeuse may go supernova, it’s still around.
However, the star at the heart of this new research, located in the NGC 5731 galaxy about 120 million light-years away from Earth, was 10 times more massive than the sun before it exploded.
Before they go out in a blaze of glory, some stars experience violent eruptions or release glowing hot layers of gas. Until astronomers witnessed this event, they believed that red supergiants were relatively quiet before exploding into a supernova or collapsing into a dense neutron star.
Instead, scientists watched the star self-destruct in dramatic fashion before collapsing in a type II supernova. This star death is the rapid collapse and violent explosion of a massive star after it has burned through the hydrogen, helium and other elements in its core.
All that remains is the star’s iron, but iron can’t fuse so the star will run out of energy. When that happens, the iron collapses and causes the supernova. A study detailing these findings published Thursday in The Astrophysical Journal.
“This is a breakthrough in our understanding of what massive stars do moments before they die,” said lead study author Wynn Jacobson-Galán, a National Science Foundation Graduate Research Fellow at University of California, Berkeley, in a statement.
“Direct detection of pre-supernova activity in a red supergiant star has never been observed before in an ordinary type II supernova. For the first time, we watched a red supergiant star explode.”

This artist's impression shows a red supergiant star releasing a gas cloud in the final year of its life.

The final moments of stellar death

Astronomers were first alerted to the star’s unusual activity 130 days before it went supernova. Bright radiation was detected in the summer of 2020 by the University of Hawaiʻi Institute for Astronomy Pan-STARRS telescope on Maui’s Haleakalā.
Then, in the fall of that year, the researchers witnessed a supernova in the same spot.
They observed it using the W.M. Keck Observatory’s Low Resolution Imaging Spectrometer on Maunakea, Hawai’i, and named the supernova 2020tlf. Their observations revealed that there was material around the star when it exploded — the bright gas that the star violently kicked away from itself over the summer.
“It’s like watching a ticking time bomb,” said senior study author Raffaella Margutti, an associate professor of astronomy and astrophysics at UC Berkeley, in a statement. “We’ve never confirmed such violent activity in a dying red supergiant star where we see it produce such a luminous emission, then collapse and combust, until now.”
Some of these massive stars likely experience consequential internal changes that cause the tumultuous release of gas before they die, the finding has shown.
The work was conducted while Jacobson-Galán and Margutti were still at Northwestern University. They had remote access to the Keck Observatory’s telescopes in Hawai’i, which was “instrumental in providing direct evidence of a massive star transitioning into a supernova explosion,” Margutti said.
“I am most excited by all of the new ‘unknowns’ that have been unlocked by this discovery,” Jacobson-Galán said. “Detecting more events like SN 2020tlf will dramatically impact how we define the final months of stellar evolution, uniting observers and theorists in the quest to solve the mystery on how massive stars spend the final moments of their lives.”

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Explainer-Scientists struggle to monitor Tonga volcano after massive eruption

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Scientists are struggling to monitor an active volcano that erupted off the South Pacific island of Tonga at the weekend, after the explosion destroyed its sea-level crater and drowned its mass, obscuring it from satellites.

The eruption of Hunga-Tonga-Hunga-Ha’apai volcano, which sits on the seismically active Pacific Ring of Fire, sent tsunami waves across the Pacific Ocean and was heard some 2,300 kms (1,430 miles) away in New Zealand.

“The concern at the moment is how little information we have and that’s scary,” said Janine Krippner, a New Zealand-based volcanologist with the Smithsonian Global Volcanism Program.

“When the vent is below water, nothing can tell us what will happen next.”

Krippner said on-site instruments were likely destroyed in the eruption and the volcanology community was pooling together the best available data and expertise to review the explosion and predict anticipated future activity.

Saturday’s eruption was so powerful that space satellites captured not only huge clouds of ash but also an atmospheric shockwave that radiated out from the volcano at close to the speed of sound.

Photographs and videos showed grey ash clouds billowing over the South Pacific and metre-high waves surging onto the coast of Tonga.

There are no official reports of injuries or deaths in Tonga https://www.reuters.com/business/environment/impact-assessment-aid-efforts-underway-world-responds-tonga-tsunami-2022-01-16 yet but internet and telephone communications are extremely limited and outlying coastal areas remain cut off.

Experts said the volcano, which last erupted in 2014, had been puffing away for about a month before rising magma, superheated to around 1,000 degrees Celsius, met with 20-degree seawater on Saturday, causing an instantaneous and massive explosion.

The unusual “astounding” speed and force of the eruption indicated a greater force at play than simply magma meeting water, scientists said.

As the superheated magma rose quickly and met the cool seawater, so did a huge volume of volcanic gases, intensifying the explosion, said Raymond Cas, a professor of volcanology at Australia’s Monash University.

Some volcanologists are likening the eruption to the 1991 Pinatubo eruption in the Philippines, the second-largest volcanic eruption of the 20th century, which killed around 800 people.

The Tonga Geological Services agency, which was monitoring the volcano, was unreachable on Monday. Most communications to Tonga have been cut after the main undersea communications cable lost power.

LIGHTNING STRIKES

American meteorologist, Chris Vagasky, studied lightning around the volcano and found it increasing to about 30,000 strikes in the days leading up to the eruption. On the day of the eruption, he detected 400,000 lightning events in just three hours, which comes down to 100 lightning events per second.

That compared with 8,000 strikes per hour during the Anak Krakatau eruption in 2018, caused part of the crater to collapse into the Sunda Strait and send a tsunami crashing into western Java, which killed hundreds of people.

Cas said it is difficult to predict follow-up activity and that the volcano’s vents could continue to release gases and other material for weeks or months.

“It wouldn’t be unusual to get a few more eruptions, though maybe not as big as Saturday,” he said. “Once the volcano is de-gassed, it will settle down.”

 

(Reporting by Kanupriya Kapoor; Editing by Jane Wardell and Michael Perry)

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Astronauts at Risk of 'Space Anemia' | Health | thesuburban.com – The Suburban Newspaper

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MONDAY, Jan. 17, 2022 (HealthDay News) — Astronauts can develop a condition called space anemia because their bodies destroy more red blood cells than normal when in space, a groundbreaking study shows.

Assessments of 14 astronauts over six months between space missions found that 54% more blood cells were destroyed while they were in space than when they were on Earth, according to findings published Jan. 14 in Nature Medicine.

“Space anemia has consistently been reported when astronauts returned to Earth since the first space missions, but we didn’t know why,” said lead author Dr. Guy Trudel of the Ottawa Hospital Research Institute in Canada. “Our study shows that upon arriving in space, more red blood cells are destroyed, and this continues for the entire duration of the astronauts’ mission.”

Before this study, it was believed that space anemia was due to fluid shifting into an astronaut’s upper body upon arrival in space.

Astronauts lose 10% of the liquid in their blood vessels this way. It was thought that their bodies rapidly destroyed 10% of their red blood cells to restore the balance, and that red blood cell control returned to normal after 10 days in space.

But this study found that red blood cell destruction is a primary effect of being in space, not just the result of fluid shifts.

On Earth, our bodies create and destroy 2 million red blood cells every second. But the astronauts in this study — both male and female — destroyed 3 million every second while in space.

Five of 13 astronauts in the study were clinically anemic when they returned to Earth. One of the 14 did not have blood drawn on landing.

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The researchers also found that space anemia is reversible, with red blood cells levels progressively returning to normal three to four months after astronauts returned from space.

“Thankfully, having fewer red blood cells in space isn’t a problem when your body is weightless,” Trudel said in a hospital news release. “But when landing on Earth and potentially on other planets or moons, anemia affecting your energy, endurance and strength can threaten mission objectives. The effects of anemia are only felt once you land, and must deal with gravity again.”

The findings could be prove useful for patients who develop anemia after long illnesses that require bed rest. Bed rest has been shown to cause anemia, but how it does so is unknown.

The mechanism may be like what occurs in space anemia, according to Trudel, who plans to investigate this theory in future research.

More information

The American Academy of Family Physicians has more on anemia.

SOURCE: The Ottawa Hospital, news release, Jan. 14, 2022

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Western scientists study meteorite made famous after crashing into B.C. woman's bedroom – CBC.ca

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A meteorite that ripped through a roof and landed inches from a B.C. woman’s head is believed to be around 470 million years old, Western researchers say. 

Ruth Hamilton of Golden, B.C. was woken abruptly on the night of Oct. 3, when the small charcoal grey rock the size of a melon broke through her ceiling and landed between her floral pillowcases. 

After coming to terms with the surreal experience, she lent the rock to Western University’s physics and astronomy department in London, Ont., where researchers are working to map its orbital journey around the sun before it arrived in Hamilton’s bedroom. 

“It was very exciting getting it because any time you see a new meteorite, it’s kind of like Christmas Day,” said adjunct professor Phil McCausland, who leads the investigation.  

A hole in the ceiling is seen above a meteorite resting on a bed inside a residential building in Golden, B.C., in an undated handout photo. Ruth Hamilton says she was sound asleep when she was awakened by her dog barking, the sound of a crash through her ceiling and the feeling of debris on her face. (Submitted by Ruth Hamilton)

Upon inspection, McCausland found that the meteorite is an L chondrite, one of the most commonly found types of meteorites to fall on Earth.

What’s not so common about Hamilton’s meteorite is where it originates in the sky.

“This rock has a very interesting and unusual orbit,” said McCausland. 

The meteorite is embedded with shards of plywood and metal from the roof. (Submitted by Phil McCausland)

“Chondrite meteors are thought with good evidence to have come from the early solar system, but they went through a major asteroid breakup event. So there is a big body in the asteroid belt that broke up about 470 million years ago,” he said. 

“From then, a bunch of material has been delivered around the inner solar system, some of it arriving on Earth. And this, prospectively, is one of those pieces.”  

McCausland said so far, the orbits of only a handful of L chondrite meteors are known. 

“What happens out in space is that the cosmic rays interact with the rock and end up irradiating it, so that it has somewhat activated isotopes that decay over time,” he said. “We can detect what the decay products are that are coming out of this, the gamma rays and so on. And that gives us a handle on the orbital history of the rock.” 

Afternoon Drive9:04Meteorite analysis at Western University

Phil McCausland, an adjunct professor at Western University, and lead investigator, speaks with CBC Afternoon Drive host Chris dela Torre about a meteorite discovered in Golden, B.C. 9:04

He added that researchers are looking to dash cam and surveillance footage, as well as local photographers who captured the fireball event, to reconstruct the rock’s flight path. 

Under Canadian law, the meteor is owned by its finder – in this case, Ruth Hamilton. It’s hers to sell, donate, or keep. 

Meanwhile, McCausland will ensure a sample is registered with the Meteoritical Society, where it will be available for future scientific research.
 

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