Connect with us

Science

Strangely Behaving Red Supergiant Betelgeuse Smaller and Closer Than First Thought – SciTechDaily

Published

 on


Betelgeuse illustration. Credit: NASA, ESA, and E. Wheatley (STScI)

It may be another 100,000 years until the giant red star Betelgeuse dies in a fiery explosion, according to a new study by an international team of researchers.

The study, led by Dr. Meridith Joyce from The Australian National University (ANU), not only gives Betelgeuse a new lease on life, but shows it is both smaller and closer to Earth than previously thought.

Dr. Joyce says the supergiant — which is part of the Orion constellation — has long fascinated scientists. But lately, it’s been behaving strangely.

“It’s normally one of the brightest stars in the sky, but we’ve observed two drops in the brightness of Betelgeuse since late 2019,” Dr. Joyce said.

“This prompted speculation it could be about to explode. But our study offers a different explanation.

“We know the first dimming event involved a dust cloud. We found the second smaller event was likely due to the pulsations of the star.”

The researchers were able to use hydrodynamic and seismic modeling to learn more about the physics driving these pulsations — and get a clearer idea of what phase of its life Betelgeuse is in.

According to co-author Dr. Shing-Chi Leung from The University of Tokyo, the analysis “confirmed that pressure waves — essentially, sound waves-were the cause of Betelgeuse’s pulsation.”

“It’s burning helium in its core at the moment, which means it’s nowhere near exploding,” Dr. Joyce said.

“We could be looking at around 100,000 years before an explosion happens.”

Co-author Dr. László Molnár from the Konkoly Observatory?in Budapest says the study also revealed how big Betelgeuse is, and its distance from Earth.

“The actual physical size of Betelgeuse has been a bit of a mystery — earlier studies suggested it could be bigger than the orbit of Jupiter. Our results say Betelgeuse only extends out to two thirds of that, with a radius 750 times the radius of the sun,” Dr. Molnár said.

“Once we had the physical size of the star, we were able to determine the distance from Earth. Our results show it’s a mere 530 light years from us — 25 percent closer than previously thought.”

The good news is Betelgeuse is still too far from Earth for the eventual explosion to have a significant impact here.

“It’s still a really big deal when a supernova goes off. And this is our closest candidate. It gives us a rare opportunity to study what happens to stars like this before they explode,” Dr. Joyce said.

The study was funded by The Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, and facilitated by the ANU Distinguished Visitor’s program. It involved researchers from the United States, Hungary, Hong Kong and the United Kingdom, as well as Australia and Japan.

The study has been published in The Astrophysical Journal.

Reference: “Standing on the Shoulders of Giants: New Mass and Distance Estimates for Betelgeuse through Combined Evolutionary, Asteroseismic, and Hydrodynamic Simulations with MESA” by Meridith Joyce, Shing-Chi Leung, László Molnár, Michael Ireland, Chiaki Kobayashi and Ken’ichi Nomoto, 13 October 2020, The Astrophysical Journal.
DOI: 10.3847/1538-4357/abb8db

Let’s block ads! (Why?)



Source link

Continue Reading

Science

New Research Provides Comprehensive Reconstruction of End-Permian Mass Extinction | Paleontology – Sci-News.com

Published

 on


The end-Permian mass extinction, also known as the Permian-Triassic extinction event and the Great Dying, is the largest mass extinction event in Earth’s history that peaked about 252.3 million years ago. The catastrophe killed off nearly 96% of all marine species and 70% of terrestrial vertebrate species on the planet over the course of thousands of years. Massive eruptions in a volcanic system called the Siberian Traps are thought to have played an important role, but the causational trigger and its feedbacks are yet to be fully understood. Now, a research team led by Dr. Hana Jurikova from the GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel and the Helmholtz Zentrum Potsdam has assembled a consistent biogeochemical reconstruction of the mechanisms that resulted in the end-Permian extinction.

An illustration depicting the onset of the end-Permian mass extinction. Image credit: Dawid Adam Iurino / PaleoFactory, Sapienza University of Rome / Jurikova et al, doi: 10.1038/s41561-020-00646-4.

Dr. Jurikova and her colleagues studied isotopes of the element boron in the calcareous shells of fossil brachiopods and determined the rate of ocean acidification over the Permian-Triassic boundary.

“These are clam-like organisms that have existed on Earth for more than 500 million years,” Dr. Jurikova said.

“We were able to use well-preserved brachiopod fossils from the Southern Alps for our analyses.”

“These shells were deposited at the bottom of the shallow shelf seas of the Tethys Ocean 252 million years ago and recorded the environmental conditions shortly before and at the beginning of extinction.”

Because the ocean pH and atmospheric carbon dioxide are closely coupled, the researchers were able to reconstruct changes in atmospheric carbon dioxide at the onset of the extinction from boron and carbon isotopes.

They then used an innovative geochemical model to study the impact of the carbon dioxide injection on the environment.

“With this technique, we can not only reconstruct the evolution of the atmospheric carbon dioxide concentrations, but also clearly trace it back to volcanic activity,” said co-author Dr. Marcus Gutjahr, a researcher at the GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel.

“The dissolution of methane hydrates, which had been suggested as a potential further cause, is highly unlikely based on our data.”

“Without these new techniques it would be difficult to reconstruct environmental processes more than 250 million years ago in the same level of detail as we have done now,” said co-author Professor Anton Eisenhauer, also from the GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel.

The team’s findings showed that volcanic eruptions in Siberian Traps released immense amounts of carbon dioxide into the atmosphere.

This release lasted several millennia and led to a strong greenhouse effect on the late Permian world, causing extreme warming and acidification of the ocean.

Dramatic changes in chemical weathering on land altered productivity and nutrient cycling in the ocean, and ultimately led to vast de-oxygenation of the ocean.

The resulting multiple environmental stressors combined to wipe out a wide variety of animal and plant groups.

“We are dealing with a cascading catastrophe in which the rise of carbon dioxide in the atmosphere set off a chain of events that successively extinguished almost all life in the seas,” Dr. Jurikova said.

“Ancient volcanic eruptions of this kind are not directly comparable to anthropogenic carbon emissions, and in fact all modern fossil fuel reserves are far too insufficient to release as much carbon dioxide over hundreds of years, let alone thousands of years as was released 252 million years ago.”

“But it is astonishing that humanity’s carbon dioxide emission rate is currently 14 times higher than the annual emission rate at the time that marked the greatest biological catastrophe in Earth’s history.”

The study was published in the journal Nature Geoscience.

_____

H. Jurikova et al. Permian-Triassic mass extinction pulses driven by major marine carbon cycle perturbations. Nat. Geosci, published online October 19, 2020; doi: 10.1038/s41561-020-00646-4

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Haunted houses find ways around COVID 19

Published

 on

Psychotic clowns. Axe murderers. Bedrooms possessed by poltergeists.

Many of the frights greeting visitors of horror attractions this Halloween will be familiar, but the thrill-creators behind them say one terrifying experience is squarely off-limits: the terrors of COVID-19.

Before the pandemic shook our lives, haunted houses sometimes dipped into the fears of contagion, splashing themed rooms with signs of a viral outbreak, hazmat suits and contamination warnings.

But with those experiences uncomfortably close to reality this year, horror masters like Shawn Lippert say reminding people of the virus is one line they’re not willing to cross.

“We use the analogy: Treat `COVID’ like the F-word in church,” said the owner of Scarehouse, an industrial-sized indoor haunted house in Windsor, Ont.

“It’s too real and so close to home. It’s almost like when you tell a joke and they say, `Too soon.”’

Lippert said that’s one of several rules he’s introduced at his haunt in order to keep people feeling safe and heath authorities satisfied. Ticketholders arrive at staggered times, and everyone is required to wear a mask.

Creepy objects that once brushed against visitors have been removed, and the giant airbags that evoke the feeling of claustrophobia have been stowed away to decrease the potential spread of germs.

Lippert describes those as small changes in a challenging year.

Many haunt operators were jittery about moving ahead with their usual Halloween festivities, considering health authorities could shut down the houses without much notice if the region experiences a surge in local cases. That would leave a brutal dent in their investments.

“If we can keep our doors open for the full run at this point, that would be a success for us,” Lippert said.

Several Toronto haunted houses decided the risk was too high. Casa Loma’s Legends of Horror and 28-year pillar Screemers at Exhibition Place were among the operators who decided to sit this year out, even before the city introduced tighter restrictions that would’ve closed them anyway.

Some organizers have used the pandemic to imagine ways to scare the living daylights out of people from a distance — often from the safety of their own vehicles.

The Pickering Museum Village put a historic spin on its spooky experience with a drive-thru tour that urged visitors to creep their cars along a roadway checkered with old houses, as ghost stories played on their FM radios.

Others have gone online with virtual group parties for kids or, for those of legal drinking age, what’s being sold as Canada’s first Virtual Halloween Cocktail Crawl.

Mentalist Jaymes White decided to embrace the digital world this year for his annual Halloween seances. His new Zoom experience, called Evoke, invites a small circle of friends to channel a spirit through video chat. He admits the idea goes against the traditions of a seance, where people usually hold hands around a table, but he’s confident the spirits will still be ready to unsettle his guests.

“They don’t care that we have a pandemic,” he said.

Paul Magnuson, one of the leaders at Calgary artist collective Big Art, will take over a downtown self-serve car wash for three days for a drive-in of the dead later this month.

Scare Wash is described as a trip to hell and back that begins when a wash attendee’s seemingly normal car rinse spirals into a nightmare.

Magnuson came up with the idea when it was clear plans for his usual neighbourhood spectacle wouldn’t be possible in the pandemic.

“Last year I turned my garage into a Dexter killer room where we did performances all night. In previous years I’ve had an interactive cemetery,” he said.

“I’m not going to let COVID take this holiday.”

Robby Lavoie felt a similar conviction for keeping Terror Train on track this year at the National Ontario Railroad Museum and Heritage Centre. The annual Halloween event draws thousands of people to Capreol, Ont., part of Greater Sudbury, and provides the museum with a healthy dose of revenue.

Lavoie said he drew inspiration from videos he saw of a Japanese zombie drive-in haunted house over the summer. He knew there was a way to tone down the gore and make the idea a bit more Canadian.

After speaking with museum organizers, Lavoie secured the board’s approval for “Inferno 6077,” an immersive drive-in horror experience inside the garage of the fire hall.

Pulling from his own knowledge of working in live theatre and movies, Lavoie began thinking on a grand scale. He hired a local writer who penned a story about townsfolk who seek revenge on an old man, and built rolling set pieces for the spectacle, which reaches its peak when the space is engulfed in flames, an illusion created with lights and projections.

“We’re putting you almost in an interactive movie, and it all came together within a month,” he said.

“I see myself doing this again next year, even if there isn’t COVID.”

Kathrine Petch understands the urge to keep Halloween on the calendar. As the general manager of Deadmonton Haunted House in Edmonton, she’s laid down strict COVID-19 precautions for their Area 51-themed haunt.

“The absolute, pure excitement of the customers is contagious to us,” she said.

“As long as we can pay the bills and have some money left over to make a different haunted house next year, I think we’ll be pretty happy.”

Petch said keeping Deadmonton open during the pandemic was important to everyone who runs the show.

“One of our biggest goals was to provide people with some kind of escape from all the crappiness that is 2020,” she said.

“And when they reach the end of our haunted house, at least they know the scares are done.”

Source: – CityNews Toronto

Source link

Continue Reading

Science

U.S. spacecraft touches asteroid to grab sample – CBC.ca

Published

 on


A NASA spacecraft descended to an asteroid Tuesday and, dodging boulders the size of buildings, momentarily touched the surface to collect a handful of cosmic rubble for return to Earth.

It was a first for the United States — only Japan has scored asteroid samples.

“Touchdown declared,” a flight controller announced to cheers and applause. “Sampling is in progress.”

Confirmation came from the Osiris-Rex spacecraft as it made contact with the surface of the asteroid Bennu more than 320 million kilometres away. But it could be a week before scientists know how much, if much of anything, was grabbed and whether another try will be needed. If successful, Osiris-Rex will return the samples in 2023.

“I can’t believe we actually pulled this off,” said lead scientist Dante Lauretta of the University of Arizona. “The spacecraft did everything it was supposed to do.”

Osiris-Rex took four and a half hours to make its way down from its tight orbit around Bennu, following commands sent well in advance by ground controllers near Denver.

Bennu’s gravity was too low for the spacecraft to land — the asteroid is just 510 metres across. As a result, it had to reach out with its 3.4-metre robot arm and attempt to grab at least 60 grams of Bennu.

‘Kissing the surface’

The University of Arizona’s Heather Enos, deputy scientist for the mission, described it as “kissing the surface with a short touch-and-go measured in just seconds.” At Mission Control for spacecraft builder Lockheed Martin, controllers on the TAG team — for “touch-and-go” — wore royal blue polo shirts and black masks with the mission patch. The coronavirus pandemic had resulted in a two-month delay.

Tuesday’s operation was considered the most harrowing part of the mission, which began with a launch from Cape Canaveral back in 2016.

A van-sized spacecraft with an Egyptian-inspired name, Osiris-Rex aimed for a spot equivalent to a few parking spaces on Earth in the middle of the asteroid’s Nightingale Crater. After nearly two years orbiting the boulder-packed Bennu, the spacecraft found this location to have the biggest patch of particles small enough to be swallowed up.

After determining that the coast was clear, Osiris-Rex closed in the final few metres for the sampling. The spacecraft was programmed to shoot out pressurized nitrogen gas to stir up the surface, then suck up any loose pebbles or dust, before backing away.

By the time flight controllers heard back from Osiris-Rex, the action already happened 18.5 minutes earlier, the time it takes radio signals to travel each way between Bennu and Earth. They expected to start receiving photos overnight and planned to provide an update Wednesday.

WATCH | A 3D animation of the asteroid Bennu:

The Canadian Space Agency’s OSIRIS-REx Laser Altimeter was crucial in mapping the asteroid Bennu ahead of its “touch-and-go” mission to collect samples that will be returned to Earth in 2023. Credit: Mike Daly, et. al 0:51

“We’re going to be looking at a whole series of images as we descended down to the surface, made contact, fired that gas bottle, and I really want to know how that surface responded,” Lauretta said. “We haven’t done this before, so this is new territory for us.”

Scientists want at least 60 grams and, ideally, closer to two kilograms of Bennu’s black, crumbly, carbon-rich material — thought to contain the building blocks of our solar system. Pictures taken during the operation will give team members a general idea of the amount of loot; they will put the spacecraft through a series of spins Saturday for a more accurate measure.

NASA’s science mission chief, Thomas Zurbuchen, likened Bennu to the Rosetta Stone: “something that’s out there and tells the history of our entire Earth, of the solar system, during the last billions of years.”

Another benefit: The solar-orbiting Bennu, which swings by Earth every six years, has a slight chance of smacking Earth late in the next century. It won’t be a show-stopping life-ender. But the more scientists know about the paths and properties of potentially hazardous space rocks like this one, the safer we’ll all be.

Osiris-Rex could make two more touch-and-go manoeuvres if Tuesday’s sample comes up short. Regardless of how many tries it takes, the samples won’t return to Earth until 2023 to close out the $800-plus million US quest. The sample capsule will parachute into the Utah desert.

“That will be another big day for us. But this is absolutely the major event of the mission right now,” NASA scientist Lucy Lim said.

Japan expects samples from its second asteroid mission — in the milligrams at most — to land in the Australian desert in December.

NASA, meanwhile, plans to launch three more asteroid missions in the next two years, all one-way trips.

The team at Lockheed Martin Space in Denver, which built the spacecraft, react as contact with the asteroid Bennu is announced. (NASA TV)

Let’s block ads! (Why?)



Source link

Continue Reading

Trending