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Telescopes capture supermassive black hole devouring star

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Astronomers have captured the moment a supermassive black hole shredded a star the size of our Sun, releasing images Monday showing the devastating process in unprecedented detail.

Using telescopes from the European Southern Observatory (ESO), they were able to monitor light flaring from the process — known as a tidal disruption event — from a black hole just over 215 million light years from Earth.

They observed the star being physically torn apart as it was sucked into the black hole’s giant maw.

“The idea of a black hole ‘sucking in’ a nearby star sounds like science fiction,” said Matt Nicholl, a lecturer and Royal Astronomical Society research fellow at the University of Birmingham, lead author of Monday’s study.

“But that’s exactly what happens in a tidal disruption event.”

When a star strays too close to a supermassive black hole, it is subjected to the phenomenal strength of the black hole’s gravity.

The star can be physically torn apart and its matter pulled into long strings, a process known as “spaghettification”.

“When these forces exceed the star’s cohesive force, the star loses pieces that rush into the black hole,” Stephane Basa, a researcher from the Marseille Astrophysics Laboratory, told AFP.

“This exceptional influx of matter produces intense electromagnetic emissions, which last for several months while the debris is digested.”

Basa said that around half of the star remained after the tidal disruption event.

“‘Only’ half of its mass has disappeared,” he said.

“That’s already titanic.”

Read also: Black hole discoveries win 2020 Nobel Prize for Physics

‘A monster’

While other tidal disruption events have previously been observed, the powerful burst of light they emit are often obscured by a curtain of dust and debris.

Because they discovered the event just a short time after the star was ripped apart the team were able to pinpoint how the obscuring debris forms.

Using high powered telescopes, they observed the event as the light flare grew in luminosity then gradually faded — a process of some six months.

Nicholl said that the observations suggested the star involved had roughly the mass as our own sun, but that the black hole was “a monster… which is over a million times more massive.”

The team behind the study, published in the journal Monthly Notices of the Royal Astronomical Society, said they hoped it would help scientists to better understand how matter behaves in the extreme gravity environments surrounding supermassive black holes.

Last week a trio of scientists, Roger Penrose of Britain, Reinhard Genzel of Germany and Andrea Ghez of the US, were awarded the Nobel Physics Prize for their research into black holes, dubbed by the Novel committee “one of the most exotic phenomena in the universe.”

 

 

 

Source:- The Jakarta Post – Jakarta Post

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Arctic sea ice at record low October levels: Danish institute – Hurriyet Daily News

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COPENHAGEN-Agence France-Presse

Arctic sea ice at record low October levels: Danish institute

Sea ice in the Arctic was at record lows for October, as unusually warm waters slowed the recovery of the ice, Danish researchers said on Oct. 28.    

Diminishing sea ice comes as a reminder about how the Arctic is hit particularly hard by global warming.    

Since the 1990s, warming has been twice as fast in the Arctic, compared to the rest of the world, as a phenomena dubbed “Arctic amplification,” causes air, ice and water to interact in a reinforcing manner.    

“The October Arctic sea ice extent is going to be the lowest on record and the sea ice growth rate is slower than normal,” Rasmus Tonboe, a scientist at the Danish Meteorological Institute (DMI), told AFP, noting that the record was unequaled for at least 40 years.    

According to preliminary satellite data used by the institute, sea ice surface area was at 6.5 million square kilometers (2.5 million square miles) on 27 October.    

Every year, some of the ice formed in the Arctic waters melts in the summer.    

It usually reaches a low point of about five million square kilometers, but then re-forms to cover about 15 million square kilometers in winter. Warmer temperatures are now reducing both the summer and winter extent of the ice.    

Satellite data has been collected to monitor the ice precisely since 1979, and the trend towards a reduction is clear.

For the month of October, measurements show an 8.2 percent downward trend in ice over the last 10 years.

Already in September, researchers noted the second-lowest extent of sea ice recorded in the Arctic, though not quite hitting the low levels recorded in 2012.    

But warmer-than-normal seawater slowed the formation of new ice in October.        

Water temperatures in the eastern part of the Arctic, north of Siberia, were two to four degrees warmer than normal, and in Baffin Bay, it was one to two degrees warmer, DMI said in a statement.    

The institute said this was following a trend observed in recent years, which was described as a “vicious spiral.”

“It’s a trend we’ve been seeing the past years, with a longer open water season making the sun warm the sea for a longer time, resulting in shorter winters so the ice doesn’t grow as thick as it used to,” Tonboe said.    

Since the melting ice is already in the ocean it does not directly contribute to the rise in sea levels.    

But as the ice disappears sunlight “gets absorbed in the ocean, helping to further warm the Earth,” Claire Parkinson, a climate scientist at NASA, told AFP in September.    

Thus, with less ice reflecting sunlight, oceans are heated directly.    

Over the last 40 years, the Arctic has also become more of a strategic interest to world powers.    

Less ice in certain areas opened up new maritime routes, which are destined to play a larger role in international trade, meaning a larger financial stake for Arctic state actors.    

The region is also estimated to house 13 percent of the world’s oil reserves and 30 percent of undiscovered natural gas deposits.    

Germany’s Potsdam Institute for Climate Impact Research (PIK) said on Oct. 27 that under current levels of atmospheric CO2 – roughly 400 parts per million – the melting of Arctic sea ice would raise global temperatures by 0.2C.    

That’s on top of the 1.5C of warming our current emissions levels have rendered all but inevitable, and the safer cap on global warming aimed for in the Paris climate accord. 

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City of Vernon extends temporary patio permits for a full year – Vernon News – Castanet.net

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The City of Vernon is extending temporary measures so businesses can use outdoor spaces in response to impacts of the COVID-19 pandemic. 

The city created a temporary outdoor commercial use program this past summer, allowing businesses to expand patios into parking lots, sidewalks and parking stalls, so customers and staff could continue practising physical distancing. 

With the extension, businesses can continue using the spaces in the downtown business improvement area until next fall. They will also be able to use single, on-street parking stalls to create pop-up patios or for retail uses during the warmer months, from March 1 to Oct. 31, 2021. 

Businesses with liquor licences will be pre-approved to have licences extended into the temporary spaces.

“Through the temporary outdoor commercial use program, the city is helping our community maintain physical distancing,” Mayor Victor Cumming said in a press release. “This program extension will also help businesses continue to adapt as we head into the colder months and plan ahead for spring and summer.”    

For information on the guidelines, visit vernon.ca/covid-19/.

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NASA spacecraft collects up to 4.5 pounds of asteroid to be sent to Earth – Global News

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A NASA spacecraft tucked more than two pounds of asteroid samples into a capsule for return to Earth after losing some of its precious loot because of a jammed lid, scientists said Thursday.

They won’t know the precise amount of the cosmic haul from asteroid Bennu, more than 200 million miles (322 million kilometres) away, until the capsule parachutes into the Utah desert in 2023.

Read more:
Scans reveal failed planet-turned-asteroid worth up to $10,000 quadrillion

“We’ve still got a lot of work to do” to get the samples back safely, said lead scientist Dante Lauretta of the University of Arizona.

The spacecraft Osiris-Rex won’t depart Bennu’s neighbourhood until March at the earliest, when the asteroid and Earth are properly aligned.

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Osiris-Rex collected so much material from Bennu’s rough surface on Oct. 20 that rocks got wedged in the rim of the container and jammed it open. Some of the samples were seen escaping into space, so flight controllers moved up the crucial stowing operation.






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NASA spacecraft gets sample from nearby asteroid Bennu


NASA spacecraft gets sample from nearby asteroid Bennu

Based on images, scientists believe Osiris-Rex grabbed 4 1/2 pounds (2 kilograms) of rubble, a full load. The minimum requirement had been 2 ounces (60 grams) — a handful or two.

“Just imagine a sack of flour at the grocery store,” Lauretta said of the initial haul.

But tens of grams of material were lost following the successful touch-and-go maneuver and again this week when the spacecraft’s robot arm moved to put the samples inside the capsule.

Read more:
NASA identifies ‘asteroid’ expected to become mini-moon next month as old rocket

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“Even though my heart breaks for the loss of sample, it turned out to be a pretty cool science experiment and we’re learning a lot,” Lauretta told reporters.

While collecting the samples, the container on the end of the robot arm pressed down nine to 19 inches (24 to 48 centimetres) during the six seconds of contact, indicating a sandy and flaky interior beneath the rough surface, Lauretta said.

The slow, tedious stowing operation took 36 hours. After each successful step, flight controllers cheered, saving the biggest and loudest response when the lid on the capsule finally was closed and latched, sealing the samples inside.


Click to play video 'Space Talk: Asteroid mining'



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Space Talk: Asteroid mining


Space Talk: Asteroid mining

It will be September 2023 — seven years after Osiris-Rex rocketed from Cape Canaveral — before the samples arrive here.

Rich in carbon, the solar-orbiting Bennu is believed to hold the preserved building blocks of the solar system. Scientists said the remnants can help explain how our solar system’s planets formed billions of years ago and how life on Earth came to be. The samples also can help improve our odds, they said, if a doomsday rock heads our way.

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Bennu — a black, roundish rock bigger than New York’s Empire State Building — could come dangerously close to Earth late in the next decade. The odds of a strike are 1-in-2,700. The good news is that while packing a punch, it won’t wipe out the home planet.

Japan, meanwhile, has retrieved samples from other asteroids twice in the past two decades, although just tiny amounts. The second batch is due to arrive in December.

© 2020 The Canadian Press

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