livescience--2020-10-20--'Challenge study' to infect healthy volunteers with the coronavirus will begin in early 2021

Researchers in the U.K. will begin the first challenge study to deliberately expose volunteers to the novel coronavirus early next year , according to a statement .
And the first participants in this trial will not receive an experimental vaccine before being exposed the virus .
In typical vaccine trials , volunteers are given an experimental vaccine and then followed for months until a subset of them are naturally exposed to the virus .
But by exposing every participant in a trial to SARS-CoV-2 , challenge studies can shave months , if not years , off of the typical vaccine @ @ @ @ @ @ @ risky , as COVID-19 does n't have a cure if things go wrong , Live Science previously reported .
Still , challenge studies are n't new and they have been an important tool for learning more about diseases such as malaria and yellow fever .
The new human challenge study will be led by researchers from the Imperial College London in partnership with the Department for Business , Energy and Industrial Strategy , clinical company hVIVO and the Royal Free London NHS Foundation Trust , according to the statement .
The U.K. government @ @ @ @ @ @ @ million pounds ) in the study , according to NPR .
In the study , the researchers will recruit healthy volunteers between the ages of 18 to 30 with no history of COVID-19 and no underlying health conditions or known risk factors for COVID-19 such as heart disease , diabetes or obesity .
If given approval , the study will begin in January 2021 in London 's Royal Free Hospital , where volunteers will be quarantined and given a lab-grown SARS-CoV-2 strain , according to NPR .
In the first part of this @ @ @ @ @ @ @ the smallest amount of virus that a person would need to be infected with in order to develop COVID-19 , according to the statement .
Study authors will start by exposing participants to a tiny number of virus particles and then slowly increase the viral dose .
Following this stage , the researchers will test a number of promising experimental vaccines to compare them and see how effectively they work to prevent COVID-19 ; they also plan to study potential treatments and the immune response , according to the statement .
The study @ @ @ @ @ @ @ candidates they will test .
`` Deliberately infecting volunteers with a known human pathogen is never undertaken lightly , '' Peter Openshaw , study co-investigator and director of the Human Challenge Consortium at Imperial College London , said in the statement .
`` However , such studies are enormously informative about a disease , even one so well studied as COVID-19 . ''
More than 38,000 people from around the world have already expressed interest in participating in such challenge studies , according to the `` 1Day Sooner '' website , which is @ @ @ @ @ @ @ people willing to participate .
Before any volunteers are enrolled , the human challenge study will be reviewed by an ethics committee and approved by a regulatory agency , according to the statement .

Researchers in the U.K. will begin the first challenge study to deliberately expose volunteers to the novel coronavirus early next year, according to a statement. And the first participants in this trial will not receive an experimental vaccine before being exposed the virus.
In typical vaccine trials, volunteers are given an experimental vaccine and then followed for months until a subset of them are naturally exposed to the virus. But by exposing every participant in a trial to SARS-CoV-2, challenge studies can shave months, if not years, off of the typical vaccine trial timeline. Such trials can be risky, as COVID-19 doesn't have a cure if things go wrong, Live Science previously reported. Still, challenge studies aren't new and they have been an important tool for learning more about diseases such as malaria and yellow fever.
Related: Coronavirus live updates
The new human challenge study will be led by researchers from the Imperial College London in partnership with the Department for Business, Energy and Industrial Strategy, clinical company hVIVO and the Royal Free London NHS Foundation Trust, according to the statement. The U.K. government will invest $43.4 million (33.6 million pounds) in the study, according to NPR.
In the study, the researchers will recruit healthy volunteers between the ages of 18 to 30 with no history of COVID-19 and no underlying health conditions or known risk factors for COVID-19 such as heart disease, diabetes or obesity. If given approval, the study will begin in January 2021 in London's Royal Free Hospital, where volunteers will be quarantined and given a lab-grown SARS-CoV-2 strain, according to NPR.
In the first part of this study, researchers will try to quantify the smallest amount of virus that a person would need to be infected with in order to develop COVID-19, according to the statement. Study authors will start by exposing participants to a tiny number of virus particles and then slowly increase the viral dose.
Following this stage, the researchers will test a number of promising experimental vaccines to compare them and see how effectively they work to prevent COVID-19; they also plan to study potential treatments and the immune response, according to the statement. The study designers haven't yet announced which vaccine candidates they will test.
"Deliberately infecting volunteers with a known human pathogen is never undertaken lightly," Peter Openshaw, study co-investigator and director of the Human Challenge Consortium at Imperial College London, said in the statement. "However, such studies are enormously informative about a disease, even one so well studied as COVID-19."
More than 38,000 people from around the world have already expressed interest in participating in such challenge studies, according to the "1Day Sooner" website, which is keeping a tally of the number of people willing to participate.
Before any volunteers are enrolled, the human challenge study will be reviewed by an ethics committee and approved by a regulatory agency, according to the statement.
Originally published on Live Science.


livescience--2020-10-21--Black holes could become massive particle accelerators

Black holes are powerful engines of pure , capable of pulling on objects so intensely that they ca n't possibly escape .
When those objects near the event horizon , they 're accelerated to incredible velocities .
Now , some physicists are suggesting harnessing the gravitational pull of black holes to create ferocious particle accelerators .
The trick , the new study finds , is to carefully set everything up so that do n't get lost forever in the insatiable black hole .
This new insight may help us identify black holes from the streams of particles blasting away from @ @ @ @ @ @ @ objects in the universe Let 's say a particle starts falling into a black hole .
As it gets closer to the black hole , it speeds up , just like a ball speeds up as it rolls down a hill .
In fact , it 's much worse than a ball rolling down a hill , because the gravity of a black hole is so strong that particles can fall in faster than the speed of light The event horizon — the distance from the black hole where infalling particles reach the @ @ @ @ @ @ @ of the black hole .
Related : What would happen if you fell into a black hole ?
If a particle falls in , it is lost forever , locked behind the event horizon with no hope of escape .
When thinking about making a particle accelerator , that region is a no-go , as an accelerator that never spits out particles would n't be any fun .
But that 's the story of just one lonely particle .
When two or more particles are involved , things can get interesting .
Going @ @ @ @ @ @ @ a black hole , they each receive a huge boost in energy .
Our current particle colliders accelerate heavy particles to over 99 % of the speed of light , but it takes a lot of work ( and in the case of the world 's largest atom smasher , the Large Hadron Collider , a ring of superconducting channels nearly 17 miles , or 27 kilometers , long ) .
Black holes create this kind of insane acceleration simply by existing .
As the two particles approach the event horizon , their @ @ @ @ @ @ @ just so happen to have the right combination of incoming speed and direction , they can ricochet off each other , sending one of them plummeting to its doom , as the other skirts the edge of the event horizon before flying off to safety .
These events are rare , but previous research has found that the particles are capable of smashing together with arbitrarily high energies — it all depends on how close they can get to the event horizon ( and how close they get to the speed of light @ @ @ @ @ @ @ This rimshot particle accelerator would work even better for rotating black holes .
Due to their extreme spin , these types of black holes can rotate space-time around the event horizon , allowing more particles to reach the vicinity of the event horizon before flying off to infinity .
There is one catch to this story , however .
Due to the complex nature of the mathematics involved , this black-hole-as-particle-cannon scenario has only been explored in the case of what 's known as `` extremal '' black holes .
These are theoretical @ @ @ @ @ @ @ mass that can rotate at a given speed .
In real life , scientists think that almost all ( if not absolutely all ) black holes are much more massive than they strictly need to be .
This would make real-life black holes `` non-extremal , '' which means that until now , physicists were n't sure if they could act as particle colliders or not .
It turns out , they do , thanks to new research published on Oct. 1 in the preprint database arXiv and set to publish in the @ @ @ @ @ @ @ found that more realistic black holes — including massive , rotating black holes and electrically charged black holes can still accelerate particles usefully .
It 's not a generic particle gun , however .
In order to get the high-speed kick required , the incoming particles have to be rushing in at already high speeds , which kind of negates the point .
But the researchers found that multiple , low-speed collisions can take place near the event horizon , leading to the desired high-energy output .
Unfortunately , since the collisions have @ @ @ @ @ @ @ order to reach such insane energies , when they escape the black hole they have to fight against all that almost-overwhelming gravity , slowing them down before they reach true freedom in interstellar space .
Thankfully , the researchers found a solution for that problem too , showing that high-energy collisions can occur around rotating black holes without getting too close to the event horizons — meaning that particles can shoot off in a blaze of glory .

Black holes are powerful engines of pure gravity , capable of pulling on objects so intensely that they can't possibly escape.
When those objects near the event horizon, they're accelerated to incredible velocities. Now, some physicists are suggesting harnessing the gravitational pull of black holes to create ferocious particle accelerators. The trick, the new study finds, is to carefully set everything up so that particles don't get lost forever in the insatiable black hole. This new insight may help us identify black holes from the streams of particles blasting away from them.
Related: The 12 strangest objects in the universe
Falling together
Let's say a particle starts falling into a black hole. As it gets closer to the black hole, it speeds up, just like a ball speeds up as it rolls down a hill. In fact, it's much worse than a ball rolling down a hill, because the gravity of a black hole is so strong that particles can fall in faster than the speed of light
The event horizon — the distance from the black hole where infalling particles reach the speed of light — defines the boundary of the black hole.
Related: What would happen if you fell into a black hole?
If a particle falls in, it is lost forever, locked behind the event horizon with no hope of escape. When thinking about making a particle accelerator, that region is a no-go, as an accelerator that never spits out particles wouldn't be any fun.
But that's the story of just one lonely particle. When two or more particles are involved, things can get interesting.
Going to the extreme
If two particles approach a black hole, they each receive a huge boost in energy. Our current particle colliders accelerate heavy particles to over 99% of the speed of light, but it takes a lot of work (and in the case of the world's largest atom smasher, the Large Hadron Collider, a ring of superconducting channels nearly 17 miles, or 27 kilometers, long). Black holes create this kind of insane acceleration simply by existing.
As the two particles approach the event horizon, their speeds ratchet up. And if they just so happen to have the right combination of incoming speed and direction, they can ricochet off each other, sending one of them plummeting to its doom, as the other skirts the edge of the event horizon before flying off to safety.
Related: The biggest black hole findings
These events are rare, but previous research has found that the particles are capable of smashing together with arbitrarily high energies — it all depends on how close they can get to the event horizon (and how close they get to the speed of light) at the moment of collision.
This rimshot particle accelerator would work even better for rotating black holes. Due to their extreme spin, these types of black holes can rotate space-time around the event horizon, allowing more particles to reach the vicinity of the event horizon before flying off to infinity.
There is one catch to this story, however. Due to the complex nature of the mathematics involved, this black-hole-as-particle-cannon scenario has only been explored in the case of what's known as "extremal" black holes. These are theoretical black holes that are the smallest possible mass that can rotate at a given speed. In real life, scientists think that almost all (if not absolutely all) black holes are much more massive than they strictly need to be.
This would make real-life black holes "non-extremal," which means that until now, physicists weren't sure if they could act as particle colliders or not.
Making it all work
It turns out, they do, thanks to new research published on Oct. 1 in the preprint database arXiv and set to publish in the journal Physics Review D. The new research found that more realistic black holes — including massive, rotating black holes and electrically charged black holes can still accelerate particles usefully.
It's not a generic particle gun, however. In order to get the high-speed kick required, the incoming particles have to be rushing in at already high speeds, which kind of negates the point. But the researchers found that multiple, low-speed collisions can take place near the event horizon, leading to the desired high-energy output.
Unfortunately, since the collisions have to occur near the event horizon in order to reach such insane energies, when they escape the black hole they have to fight against all that almost-overwhelming gravity, slowing them down before they reach true freedom in interstellar space. Thankfully, the researchers found a solution for that problem too, showing that high-energy collisions can occur around rotating black holes without getting too close to the event horizons — meaning that particles can shoot off in a blaze of glory.
Originally published on Live Science.


livescience--2020-10-21--The strange story of 2020 SO: How an asteroid turned into rocket junk and the NASA scientist who fig

The strange story of 2020 SO: How an asteroid turned into rocket junk and the NASA scientist who figured it out

As soon as he saw the data , Paul Chodas knew something was strange about the near-Earth object that had been designated 2020 SO .
It should have been just another of the tens of thousands of space rocks that astronomers have spotted breezing through our neighborhood in space .
This solar system rubble is mostly harmless , but scientists identify and track all they can in case an object appears to be on a collision course with Earth .
As head of NASA 's Center for Near-Earth Object Studies at the Jet Propulsion Laboratory in California , Chodas evaluates @ @ @ @ @ @ @ And to Chodas , did n't look like an asteroid .
Instead , it looked like something much rarer : an abandoned rocket body that had once ferried a spacecraft to the moon .
`` Even on the night it was announced , I said , ' I think this is such-and-such rocket stage .
That 's my guess , all circumstantial evidence points to that , ' '' Chodas told Space.com in late September .
Related : See the dramatic increase in near-Earth asteroids NASA has discovered ( video ) Now , @ @ @ @ @ @ @ confirmed that 2020 SO is moving more like a spent rocket stage than a space rock , buffeted by simply the sunlight hitting it .
`` Our latest orbit calculations for this object clearly show that it is being affected by non-gravitational forces , presumably solar radiation pressure , '' he wrote in an email update , calling those calculations `` very strong evidence '' that the object is not a space rock .
`` An is not easily pushed around , '' Chodas told Space.com during his original interview .
`` But @ @ @ @ @ @ @ stage , would be pushed around . ''
But he did n't need the ongoing observations to suspect that the erstwhile space rock was actually human debris , the spent Centaur upper stage of the rocket that , in 1966 , sent a NASA mission called to the moon .
Chodas is one of the scientists who have had their eyes peeled for just such an object for more than a decade now .
`` We 've kind of mused about whether [ or ] when this would this happen , '' he @ @ @ @ @ @ @ years looked at asteroid orbits to see if any of them was in an orbit around the sun that was likely to have been associated with a launch . ''
And 2020 SO is the best match to date .
Two characteristics in particular stand out about the object 's journey : its slow speed and how closely its trajectory around the sun aligns with Earth 's own orbit .
Asteroids do n't tend to behave that way — they travel much more quickly and without regard to Earth 's own path around @ @ @ @ @ @ @ , 2020 SO 's orbit shouts that it 's a rocket body from a mission to .
`` It was clearly not from a launch to Mars or Venus or any of the others because they would be in orbits that would carry them out toward those planets , '' Chodas said .
`` It has all of the hallmarks of a lunar mission , '' he said of the object 's orbit .
In particular , 2020 SO looks like an object that was trying to land a spacecraft on the moon @ @ @ @ @ @ @ fast .
`` The spacecraft had to slow down , you want to approach the moon fairly slowly , '' Chodas said .
`` So the rocket body missed the moon and went into orbit around the sun , just barely . ''
( Meanwhile , the Surveyor 2 spacecraft itself botched the soft landing and . )
That 's what caused the slow , near-Earth orbit that so stuck out to Chodas .
`` That 's why I was suspicious in the first place that this could be a rocket body , @ @ @ @ @ @ @ he said .
Chodas was thenable to rewind the orbit , so to speak , to determine when 2020 SO might have left the Earth-moon system .
The answer ?
Late 1966 .
But the '60s , of course , were the height of the moon-bound , and between the U.S. and the Soviet Union , 10 missions launched to the moon that year .
But between the later launch date , the details of the trajectory needed to land softly on the moon rather than simply orbit it , and the relative @ @ @ @ @ @ @ play , Chodas was soon confident that 2020 SO is actually the used to launch NASA 's Surveyor 2 mission on Sept. 20 , 1966 .
That identification is n't confirmed , he noted in his update email , although it 's `` looking increasingly likely , '' he wrote .
He and his colleagues are still analyzing the forces that would have acted on the object over the past half century .
But the initial data is compelling circumstantial evidence , he said .
`` This orbit is known so accurately that @ @ @ @ @ @ @ energy with which the rocket left the moon back in 1966 , and the direction and geometry , '' Chodas said during the original interview .
`` Everything fits the Surveyor 2 mission — the velocity , the nearness to the moon , the date — everything matches to that launch , and it does n't match to the other launches . ''
Email Meghan Bartels at mbartels @ space.com or follow her on Twitter @ meghanbartels .
Follow us on Twitter @ Spacedotcom and on Facebook .

As soon as he saw the data, Paul Chodas knew something was strange about the near-Earth object that had been designated 2020 SO.
It should have been just another of the tens of thousands of space rocks that astronomers have spotted breezing through our neighborhood in space. This solar system rubble is mostly harmless, but scientists identify and track all they can in case an object appears to be on a collision course with Earth. As head of NASA's Center for Near-Earth Object Studies at the Jet Propulsion Laboratory in California, Chodas evaluates observations of these objects every day.
And to Chodas, 2020 SO didn't look like an asteroid. Instead, it looked like something much rarer: an abandoned rocket body that had once ferried a spacecraft to the moon.
"Even on the night it was announced, I said, 'I think this is such-and-such rocket stage. That's my guess, all circumstantial evidence points to that,'" Chodas told Space.com in late September.
Related: See the dramatic increase in near-Earth asteroids NASA has discovered (video)
Now, nearly a month of ongoing observations have confirmed that 2020 SO is moving more like a spent rocket stage than a space rock, buffeted by simply the sunlight hitting it.
"Our latest orbit calculations for this object clearly show that it is being affected by non-gravitational forces, presumably solar radiation pressure," he wrote in an email update, calling those calculations "very strong evidence" that the object is not a space rock.
"An asteroid is not easily pushed around," Chodas told Space.com during his original interview. "But an empty can, like a rocket stage, would be pushed around."
But he didn't need the ongoing observations to suspect that the erstwhile space rock was actually human debris, the spent Centaur upper stage of the rocket that, in 1966, sent a NASA mission called Surveyor 2 to the moon.
Chodas is one of the scientists who have had their eyes peeled for just such an object for more than a decade now. "We've kind of mused about whether [or] when this would this happen," he said. "I've over the years looked at asteroid orbits to see if any of them was in an orbit around the sun that was likely to have been associated with a launch."
And 2020 SO is the best match to date. Two characteristics in particular stand out about the object's journey: its slow speed and how closely its trajectory around the sun aligns with Earth's own orbit. Asteroids don't tend to behave that way — they travel much more quickly and without regard to Earth's own path around the sun.
Instead, Chodas said, 2020 SO's orbit shouts that it's a rocket body from a mission to the moon . "It was clearly not from a launch to Mars or Venus or any of the others because they would be in orbits that would carry them out toward those planets," Chodas said. "It has all of the hallmarks of a lunar mission," he said of the object's orbit.
In particular, 2020 SO looks like an object that was trying to land a spacecraft on the moon — gently, and therefore not particularly fast. "The spacecraft had to slow down, you want to approach the moon fairly slowly," Chodas said. "So the rocket body missed the moon and went into orbit around the sun, just barely." (Meanwhile, the Surveyor 2 spacecraft itself botched the soft landing and crashed into the lunar surface .)
That's what caused the slow, near-Earth orbit that so stuck out to Chodas. "That's why I was suspicious in the first place that this could be a rocket body, and from a lunar mission," he said.
Chodas was thenable to rewind the orbit, so to speak, to determine when 2020 SO might have left the Earth-moon system. The answer? Late 1966. But the '60s, of course, were the height of the moon-bound space race , and between the U.S. and the Soviet Union, 10 missions launched to the moon that year.
But between the later launch date, the details of the trajectory needed to land softly on the moon rather than simply orbit it, and the relative size of the potential rocket bodies at play, Chodas was soon confident that 2020 SO is actually the Centaur upper stage used to launch NASA's Surveyor 2 mission on Sept. 20, 1966.
That identification isn't confirmed, he noted in his update email, although it's "looking increasingly likely," he wrote. He and his colleagues are still analyzing the forces that would have acted on the object over the past half century.
But the initial data is compelling circumstantial evidence, he said.
"This orbit is known so accurately that I can be very sure of the energy with which the rocket left the moon back in 1966, and the direction and geometry," Chodas said during the original interview. "Everything fits the Surveyor 2 mission — the velocity, the nearness to the moon, the date — everything matches to that launch, and it doesn't match to the other launches."
Email Meghan Bartels at mbartels@space.com or follow her on Twitter @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook.


livescience--2020-10-21--The closest black hole to Earth may not actually be a black hole after all

An object identified earlier this year as the closest black hole we 've ever discovered may have just been demoted .
After reanalyzing the data , separate teams of scientists have concluded that the system in question , named HR 6819 , does not include a black hole after all .
Instead , they have found that it 's likely just two stars with a slightly unusual binary orbit that makes it difficult to interpret .
HR 6819 , located around 1,120 light-years away , has been a bit of a puzzle for some time .
Initially , it was @ @ @ @ @ @ @ the Be spectral type .
This is a hot , blue-white star on the main sequence whose spectrum contains a strong hydrogen emission line , interpreted as evidence of a disc of circumstellar gas ejected by the star as it rotates at an equatorial velocity of around 200 kilometers per second .
In the 1980s , astronomers noticed that the object seemed also to be exhibiting the light signature of a second type of B-type star , a B3 III star .
This was found in 2003 to mean that HR 6819 was @ @ @ @ @ @ @ although they could not be individually resolved .
Further analysis revealed that the B3 III star , clocking in at an estimated 6 solar masses , had a roughly 40-day orbit - but the Be star , also estimated to be around 6 solar masses , seemed to be motionless .
If the two stars comprised an equal mass binary , they should orbit a mutual centre of gravity , not one star orbiting the other .
After conducting careful calculations , a team of astronomers concluded that the B3 III star could @ @ @ @ @ @ @ one that could n't be seen .
A black hole .
But , other astronomers argue , that 's far from the only possibility .
What if we have miscalculated the masses of the stars ?
`` The presence of a Be star component in the spectrum of HR 6819 suggests another interpretation of the system , '' wrote astronomers Douglas Gies and Luqian Wang of Georgia State University in their paper .
`` It is possible that the B3 III stellar component is actually a low mass , stripped down star that @ @ @ @ @ @ @ In this case , the Be star would be the companion in the 40-day binary instead of a black hole . ''
In other words , the much lower-mass B3 III star would whizz around the Be star .
If this were the case , that orbital motion could be detectable in the hydrogen gas surrounding the Be star - it would move almost imperceptibly as it was tugged by the smaller star .
This is what Gies and Wang went looking for .
They carefully studied the hydrogen emission in the system @ @ @ @ @ @ @ hydrogen disc around the Be star did indeed display a 40-day periodicity in both Doppler shift and emission line shape .
This is consistent with the B3 III star 's orbit - just as would be expected if the system were an unequal-mass binary .
`` This indicates , '' they wrote , `` that HR 6819 is a binary system consisting of a massive Be star and a low-mass companion that is the stripped down remnant of a former mass donor star in a mass transfer binary . ''
In other words @ @ @ @ @ @ @ whole bunch of material from the B3 III star , leaving it much smaller .
There is , the team noted , recent evidence that suggests many Be stars are the product of this process .
According to their calculations , the Be star would be about 6 solar masses , as previously found ; but the B3 III star would be between 0.4 and 0.8 solar masses .
But it gets more interesting .
Gies and Wang were not the only researchers looking into this idea .
In a second paper , @ @ @ @ @ @ @ Bodensteiner of KU Leuven in Belgium independently examined the hydrogen emission of the Be star , and performed an orbital analysis of the system .
She and her colleagues came to almost exactly the same conclusion .
`` We infer spectroscopic masses of 0.4 [ solar masses ] and 6 [ solar masses ] for the primary and secondary , '' they wrote in their paper .
`` This indicates that the primary might be a stripped star rather than a B-type giant .
Evolutionary modelling suggests that a possible progenitor system would @ @ @ @ @ @ @ experienced conservative mass transfer… In the framework of this interpretation , HR 6819 does not contain a BH . ''
And , in a third paper , currently in preprint , astronomers Kareem El-Badry and Eliot Quataert of UC Berkeley also independently analysed the system 's spectra , obtaining masses of 0.47 and 6.7 solar masses for the B3 III and Be stars respectively .
`` We argue that the B star is a bloated , recently stripped helium star with mass ≈ 0.5 solar masses that is currently contracting to become a @ @ @ @ @ @ @ wrote .
`` The orbital motion of the Be star obviates the need for a black hole to explain the B star 's motion .
A stripped-star model reproduces the observed luminosity of the system , while a normal star with the B star 's temperature and gravity would be more than 10 times too luminous . ''
So the future looks grim for the black hole interpretation , although it 's not settled quite yet .
Future observations could help resolve any lingering questions .
But , Gies and Lang argue , @ @ @ @ @ @ @ than a black hole .
`` The luminous and low-mass companion in the HR 6819 system may represent a rare and important case in which the companion has recently completed mass transfer and has yet to descend to the white dwarf cooling stage of evolution , '' they wrote .
So , either way , we have not yet heard the last from HR 6819 .
Gies and Lang 's research was published in The Astrophysical Journal Letters .
Bodensteiner et al .
's research was published in Astronomy & Astrophysics .
El-Badry @ @ @ @ @ @ @ to the Monthly Notices of the Royal Astronomical Society and is available on arXiv .
This article was originally published by ScienceAlert .
Read the original article here .

This artist's impression shows the orbits of the objects in the HR 6819 system. The system was thought to consist of a binary star pair in which one star (orbit in blue) orbits a black hole (orbit in red), as well as another star with a wider orbit (also in blue). Now, scientists say that black hole might not be that at all.
An object identified earlier this year as the closest black hole we've ever discovered may have just been demoted. After reanalyzing the data, separate teams of scientists have concluded that the system in question, named HR 6819, does not include a black hole after all.
Instead, they have found that it's likely just two stars with a slightly unusual binary orbit that makes it difficult to interpret.
HR 6819, located around 1,120 light-years away, has been a bit of a puzzle for some time. Initially, it was thought to be a single star of the Be spectral type.
This is a hot, blue-white star on the main sequence whose spectrum contains a strong hydrogen emission line, interpreted as evidence of a disc of circumstellar gas ejected by the star as it rotates at an equatorial velocity of around 200 kilometers per second.
In the 1980s, astronomers noticed that the object seemed also to be exhibiting the light signature of a second type of B-type star, a B3 III star. This was found in 2003 to mean that HR 6819 was not one, but two stars, although they could not be individually resolved.
Further analysis revealed that the B3 III star, clocking in at an estimated 6 solar masses, had a roughly 40-day orbit - but the Be star, also estimated to be around 6 solar masses, seemed to be motionless. If the two stars comprised an equal mass binary, they should orbit a mutual centre of gravity, not one star orbiting the other.
After conducting careful calculations, a team of astronomers concluded that the B3 III star could be orbiting another, third object, one that couldn't be seen. A black hole.
But, other astronomers argue, that's far from the only possibility. What if we have miscalculated the masses of the stars?
"The presence of a Be star component in the spectrum of HR 6819 suggests another interpretation of the system," wrote astronomers Douglas Gies and Luqian Wang of Georgia State University in their paper.
"It is possible that the B3 III stellar component is actually a low mass, stripped down star that is still relatively young and luminous. In this case, the Be star would be the companion in the 40-day binary instead of a black hole."
In other words, the much lower-mass B3 III star would whizz around the Be star. If this were the case, that orbital motion could be detectable in the hydrogen gas surrounding the Be star - it would move almost imperceptibly as it was tugged by the smaller star. This is what Gies and Wang went looking for.
They carefully studied the hydrogen emission in the system's spectrum, and found that the hydrogen disc around the Be star did indeed display a 40-day periodicity in both Doppler shift and emission line shape. This is consistent with the B3 III star's orbit - just as would be expected if the system were an unequal-mass binary.
"This indicates," they wrote, "that HR 6819 is a binary system consisting of a massive Be star and a low-mass companion that is the stripped down remnant of a former mass donor star in a mass transfer binary."
In other words, the Be star slurped up a whole bunch of material from the B3 III star, leaving it much smaller. There is, the team noted, recent evidence that suggests many Be stars are the product of this process. According to their calculations, the Be star would be about 6 solar masses, as previously found; but the B3 III star would be between 0.4 and 0.8 solar masses.
But it gets more interesting. Gies and Wang were not the only researchers looking into this idea. In a second paper, a team of astronomers led by Julia Bodensteiner of KU Leuven in Belgium independently examined the hydrogen emission of the Be star, and performed an orbital analysis of the system. She and her colleagues came to almost exactly the same conclusion.
"We infer spectroscopic masses of 0.4 [solar masses] and 6 [solar masses] for the primary and secondary," they wrote in their paper. "This indicates that the primary might be a stripped star rather than a B-type giant. Evolutionary modelling suggests that a possible progenitor system would be a tight B+B binary system that experienced conservative mass transfer… In the framework of this interpretation, HR 6819 does not contain a BH."
And, in a third paper, currently in preprint, astronomers Kareem El-Badry and Eliot Quataert of UC Berkeley also independently analysed the system's spectra, obtaining masses of 0.47 and 6.7 solar masses for the B3 III and Be stars respectively.
"We argue that the B star is a bloated, recently stripped helium star with mass ≈ 0.5 solar masses that is currently contracting to become a hot subdwarf," El-Badry and Quataert wrote.
"The orbital motion of the Be star obviates the need for a black hole to explain the B star's motion. A stripped-star model reproduces the observed luminosity of the system, while a normal star with the B star's temperature and gravity would be more than 10 times too luminous."
So the future looks grim for the black hole interpretation, although it's not settled quite yet. Future observations could help resolve any lingering questions. But, Gies and Lang argue, the binary system could be more interesting than a black hole.
"The luminous and low-mass companion in the HR 6819 system may represent a rare and important case in which the companion has recently completed mass transfer and has yet to descend to the white dwarf cooling stage of evolution," they wrote.
So, either way, we have not yet heard the last from HR 6819.
Gies and Lang's research was published in The Astrophysical Journal Letters. Bodensteiner et al.'s research was published in Astronomy & Astrophysics. El-Badry and Quataert's paper has been submitted to the Monthly Notices of the Royal Astronomical Society and is available on arXiv.
This article was originally published by ScienceAlert. Read the original article here.


livescience--2020-10-21--Ghostly 'UFO cloud' hovering over mountains wows judges in weather photo contest

A ghostly white saucer hovers over the peaks of El Chaltén in southern Argentina .
As wind thrashes the nearby clouds , the saucer remains fixed above the craggy summit , anchored in the sky like a mothership surveying the hills below .
It 's not aliens .
( Sorry … ) .
It 's just a friendly neighborhood `` UFO cloud '' — better known in meteorological circles as a .
This eerie weather phenomenon is relatively common in mountainous regions like El Chaltén , or the in the U.S. , where high-speed winds ricochet over a tall peak @ @ @ @ @ @ @ cloud formation high in the sky .
Still , photographer — whose photo above is a finalist in the Royal Meteorological Society 's ( RMS ) 2020 Weather Photographer of the Year contest — had to wait the better part of a day to capture the cloud in its mysterious glory .
`` An hour before taking this photograph I was walking along the trails that surround the beautiful rock formation … [ but ] the day was very cloudy .
Apparently , luck was not with me on this adventure , '' @ @ @ @ @ @ @ Only for a moment , the clouds allowed me to see El Chaltén — and to my surprise , there was a spectacular and brilliant lenticular cloud with a beautiful and perfect figure that I had never seen . ''
This forms when strong wind blows into the side of a mountain , skyscraper or other tall obstruction , according to the .
The mountain deflects the wind , forcing it into a wave that crests over the mountaintop , dips down on the other side , then rises up again .
In @ @ @ @ @ @ @ the air cools until it condenses into clouds .
When the air descends again on the downward-moving side of the wave , the cloud evaporates .
The result is a spooky , stationary cloud perched atop the crest of the wave , sculpted into a saucer shape by the wind constantly rising and falling within it .
Negroni Rodriguez 's photo joins 25 other finalists in the RMS contest , which is co-sponsored by AccuWeather .
While the alien cloud was not one of the three grand-prize winners announced on Oct. 17 , @ @ @ @ @ @ @ more than 7,700 entries , according to the RMS .
To see some of the other stunning finalists — including the big winners — click through this gallery .

A ghostly white saucer hovers over the peaks of El Chaltén in southern Argentina. As wind thrashes the nearby clouds, the saucer remains fixed above the craggy summit, anchored in the sky like a mothership surveying the hills below.
It's not aliens. (Sorry … it's never aliens ). It's just a friendly neighborhood "UFO cloud" — better known in meteorological circles as a standing lenticular cloud .
This eerie weather phenomenon is relatively common in mountainous regions like El Chaltén, or the Rocky Mountains in the U.S., where high-speed winds ricochet over a tall peak, creating a distinct lens- or saucer-shaped cloud formation high in the sky. Still, photographer Francisco Javier Negroni Rodriguez — whose photo above is a finalist in the Royal Meteorological Society's (RMS) 2020 Weather Photographer of the Year contest — had to wait the better part of a day to capture the cloud in its mysterious glory.
Another contest runner-up shows this 'monster' storm rearing its head over Umag, Croatia. (Image credit: Maja Kraljik)
Related: Gallery: Reading the clouds
"An hour before taking this photograph I was walking along the trails that surround the beautiful rock formation … [but] the day was very cloudy. Apparently, luck was not with me on this adventure," Negroni Rodriguez told the RMS. "Only for a moment, the clouds allowed me to see El Chaltén — and to my surprise, there was a spectacular and brilliant lenticular cloud with a beautiful and perfect figure that I had never seen."
This type of cloud forms when strong wind blows into the side of a mountain, skyscraper or other tall obstruction, according to the National Weather Service . The mountain deflects the wind, forcing it into a wave that crests over the mountaintop, dips down on the other side, then rises up again. In the upward-moving parts of the wave, the air cools until it condenses into clouds. When the air descends again on the downward-moving side of the wave, the cloud evaporates. The result is a spooky, stationary cloud perched atop the crest of the wave, sculpted into a saucer shape by the wind constantly rising and falling within it.
This contest finalist captures a tornado tearing through rural Colorado. Photographer Tori Jane Ostberg calls it "the red terror." (Image credit: Tori Jane Ostberg)
Negroni Rodriguez's photo joins 25 other finalists in the RMS contest, which is co-sponsored by AccuWeather. While the alien cloud was not one of the three grand-prize winners announced on Oct. 17, it nevertheless rose to the top of more than 7,700 entries, according to the RMS. To see some of the other stunning finalists — including the big winners — click through this gallery.
Originally published on Live Science.


livescience--2020-10-21--'Monster' storms and frozen bison: The most spectacular weather photos of 2020

On October 17 , the Royal Meteorological Society announced the winners of its annual weather photographer of the year contest , co-sponsored by AccuWeather .
The judges picked 26 images from among more than 7,700 , highlighting some of the most epic storms , glorious rainbows and living wonders of nature to cross a camera lens over the last year .
Below are some of our favorite submissions .
Tourists shudder on the Brooklyn Bridge in New York City during a strong blizzard .
According to photographer Rudolf Sulgan , the powerful blizzard was amplified by climate change .
`` @ @ @ @ @ @ @ during a strong blizzard as El Nino ’ s periodic warming of water often disrupts normal weather patterns , '' Sulgan told the RMS .
`` My main concern and inspiration is that my images hopefully do a small part in combating climate change . ''
This photo was awarded the top prize in the 2020 RMS photo contest .
Lightning cracks the sky over Mallorca Spain .
According to photographer Marc Marco Ripoll , `` I tried many times to catch a good lightning strike behind this rock called Sa Foradada , @ @ @ @ @ @ @ conditions were not so good .
This night I knew that a big storm was approaching Mallorca and all the conditions were perfect .
I do n't remember if the moon was full , but I remember that it was very big .
This was perfect , because the moon was going to illuminate all the land and the sea and gives more color to the scene .
I chose my composition , and I shot many pictures until the storm fell on me .
To see the storm and the lightning that @ @ @ @ @ @ @ tea hills of Phu Tho Province , Vietnam bask in morning light .
Photographer Vu Trung Huan says : `` Long Coc tea hill has mysterious and strange features when the sun is not yet up .
Hidden in the morning mist , the green color of tea leaves still stands out .
Early in the morning , holding a cup of tea , taking a breath of fresh air , Watching the gentle green stretches of green tea hills .
It is true that nothing is equal ! ''
Photographer Alessandro Cantarelli @ @ @ @ @ @ @ the Italian Dolomite mountains on a sunny morning , but was soon flooded with fog .
Late that night , he beheld something marvelous .
Cantarelli writes : `` At about 23:00 the fog curtain lifted to what I can consider one of the most beautiful shows I have ever seen in my life , the madness of the Three Peaks of Lavaredo illuminated by a powerful moon , with Jupiter on his right , above the highest peak , where I could see the headlights of climbers who climbed quickly to enjoy @ @ @ @ @ @ @ of the rocky shores of the Isle of Lewis in Scotland .
Photographer Richard Fox Writes : `` My wife and I visited the Isle of Harris and Lewis on holiday for a week .
One evening , after a day out on Lewis , we stopped off at Mangersta sea stacks one evening .
It was pretty windy on the cliff tops , making long exposures quite challenging .
All of a sudden a few rain showers passed over as the late evening light broke though , providing an amazing set of @ @ @ @ @ @ @ fearsome head over Umag , Croatia .
Photographer Maja Kraljik writes : `` This monster shelf cloud was perhaps the most beautiful structure and size over my area .
I was waiting for two hours for the cloud to arrive and then it made a real mess . ''
Photographer Tori Jane Ostberg writes : `` An incredible EF2 tornado tears through a rural Colorado field after destroying a home .
This tornado marked my very first day of my very first great plains storm chase adventure , and it was only a @ @ @ @ @ @ @ . ''
The winner of this year 's young weather photographer category shows a leaf frozen in a lake in Russia .
Photographer Kolesnik Stephanie Sergeevna , age 17 , writes : `` The photo is of a leaf stuck in the ice .
Figurally , this is a print of summer on winter .
I wanted to take this shot because… It looks like frozen life .
Time seems to have stopped for this leaf '' An epic dust storm bears down on Phoenix , Arizona .
Photographer Tina Wright Writes : @ @ @ @ @ @ @ two largest haboobs ( dust storms ) ever recorded in the state of Arizona .
At the point of this photo it was fully mature , towering over a mile high with winds in excess of 80 miles per hour .
The sun was setting , giving the dust wall it 's deep pink hue .
It was a truly incredible sight to see ! ''
Water cascades down the dam wall of Wet Sleddale reservoir near Cumbria , UK after a period of heavy rainfall .
Photographer Andrew McCaren writes : `` @ @ @ @ @ @ @ of March 2019 , Wet Sleddale dam came to mind .
I have driven past Wet Sleddale dam many times and seen it dry even after prolonged rainfall , but thought I would take a chance .
After a 4:30am start and a 2-and-a-half-hour drive from my home in Leeds to Cumbria , I made it to the location an remember shouting 'yes , yes , yes , ' as I saw the water pouring down the spillway . ''
Ghostly trees dance out of the fog in Colorado 's Medicine Bow-Routt National @ @ @ @ @ @ @ `` On the morning after a bitterly cold night in December , I left Steamboat Springs in search of frost and any winter weather I could find .
I wandered the roads and forests near the edge of the morning snow showers to find where interesting transitions in weather might be seen .
This was the last photo of many taken that morning and my favorite by far .
The fog bank behind the frosted trees isolates the small grove and creates a wonderfully minimalistic scene . ''
On a foggy day in @ @ @ @ @ @ @ the Lakhta Center ( Europe 's largest skyscraper ) and sent a drone high into the air .
Stolypin writes : `` I wanted to take a photo of the tallest skyscraper in Europe , shrouded in morning fog .
I regularly monitored the weather and looked into the city cameras to make sure that all shooting conditions were favorable for the intended shot , since I live very far from the shooting location .
When everything coincided , early in the morning I called a taxi , arrived at the skyscraper , @ @ @ @ @ @ @ and took this picture .

On October 17, the Royal Meteorological Society announced the winners of its annual weather photographer of the year contest, co-sponsored by AccuWeather. The judges picked 26 images from among more than 7,700, highlighting some of the most epic storms, glorious rainbows and living wonders of nature to cross a camera lens over the last year. Below are some of our favorite submissions.
Blizzards
(Image credit: Rudolf Sulgan)
Tourists shudder on the Brooklyn Bridge in New York City during a strong blizzard. According to photographer Rudolf Sulgan, the powerful blizzard was amplified by climate change. "I made this image in 2018, during a strong blizzard as El Nino’s periodic warming of water often disrupts normal weather patterns," Sulgan told the RMS. "My main concern and inspiration is that my images hopefully do a small part in combating climate change." This photo was awarded the top prize in the 2020 RMS photo contest.
Sa Foradada storm
(Image credit: Marc Marco Ripoll)
Lightning cracks the sky over Mallorca Spain. According to photographer Marc Marco Ripoll, "I tried many times to catch a good lightning strike behind this rock called Sa Foradada, but every time I tried, the conditions were not so good. This night I knew that a big storm was approaching Mallorca and all the conditions were perfect. I don't remember if the moon was full, but I remember that it was very big. This was perfect, because the moon was going to illuminate all the land and the sea and gives more color to the scene. I chose my composition, and I shot many pictures until the storm fell on me. To see the storm and the lightning that night was something amazing."
Frosty bison
(Image credit: Laura Hedien)
Tea hills
(Image credit: Vu Trung Huan)
The tea hills of Phu Tho Province, Vietnam bask in morning light. Photographer Vu Trung Huan says: "Long Coc tea hill has mysterious and strange features when the sun is not yet up. Hidden in the morning mist, the green color of tea leaves still stands out. Early in the morning, holding a cup of tea, taking a breath of fresh air, Watching the gentle green stretches of green tea hills. It is true that nothing is equal!"
Lavaredo's gloria
(Image credit: Alessandro Cantarelli)
Photographer Alessandro Cantarelli ascended the Three Peaks of Lavaredo in the Italian Dolomite mountains on a sunny morning, but was soon flooded with fog. Late that night, he beheld something marvelous. Cantarelli writes: "At about 23:00 the fog curtain lifted to what I can consider one of the most beautiful shows I have ever seen in my life, the madness of the Three Peaks of Lavaredo illuminated by a powerful moon, with Jupiter on his right, above the highest peak, where I could see the headlights of climbers who climbed quickly to enjoy this magic."
Pinnacles of light
(Image credit: Richard Fox)
Rainbows slant out of the rocky shores of the Isle of Lewis in Scotland. Photographer Richard Fox Writes: "My wife and I visited the Isle of Harris and Lewis on holiday for a week. One evening, after a day out on Lewis, we stopped off at Mangersta sea stacks one evening. It was pretty windy on the cliff tops, making long exposures quite challenging. All of a sudden a few rain showers passed over as the late evening light broke though, providing an amazing set of rainbows!"
Cloud Attack
(Image credit: Maja Kraljik)
A storm rears its fearsome head over Umag, Croatia. Photographer Maja Kraljik writes: "This monster shelf cloud was perhaps the most beautiful structure and size over my area. I was waiting for two hours for the cloud to arrive and then it made a real mess."
The red terror
(Image credit: Tori Jane Ostberg)
Photographer Tori Jane Ostberg writes: "An incredible EF2 tornado tears through a rural Colorado field after destroying a home. This tornado marked my very first day of my very first great plains storm chase adventure, and it was only a sign of the incredible things to come."
Frozen life
(Image credit: Kolesnik Stephanie Sergeevna)
The winner of this year's young weather photographer category shows a leaf frozen in a lake in Russia. Photographer Kolesnik Stephanie Sergeevna, age 17, writes: " The photo is of a leaf stuck in the ice. Figurally, this is a print of summer on winter. I wanted to take this shot because… It looks like frozen life. Time seems to have stopped for this leaf"
Final stand
(Image credit: Tina Wright)
An epic dust storm bears down on Phoenix, Arizona. Photographer Tina Wright Writes: "This was one of the top two largest haboobs (dust storms) ever recorded in the state of Arizona. At the point of this photo it was fully mature, towering over a mile high with winds in excess of 80 miles per hour. The sun was setting, giving the dust wall it's deep pink hue. It was a truly incredible sight to see!"
Dam wet
(Image credit: Andrew McCaren)
Water cascades down the dam wall of Wet Sleddale reservoir near Cumbria, UK after a period of heavy rainfall. Photographer Andrew McCaren writes: "Whilst trying to visualize the heavy rainfall of March 2019, Wet Sleddale dam came to mind. I have driven past Wet Sleddale dam many times and seen it dry even after prolonged rainfall, but thought I would take a chance. After a 4:30am start and a 2-and-a-half-hour drive from my home in Leeds to Cumbria, I made it to the location an remember shouting 'yes, yes, yes,' as I saw the water pouring down the spillway."
Trees and fog
(Image credit: Preston Stoll)
Ghostly trees dance out of the fog in Colorado's Medicine Bow-Routt National Forest. Photographer Preston Stoll writes: "On the morning after a bitterly cold night in December, I left Steamboat Springs in search of frost and any winter weather I could find. I wandered the roads and forests near the edge of the morning snow showers to find where interesting transitions in weather might be seen. This was the last photo of many taken that morning and my favorite by far. The fog bank behind the frosted trees isolates the small grove and creates a wonderfully minimalistic scene."
Steel star
(Image credit: Yuriy Stolypin )
On a foggy day in Saint-Petersburg, photographer Yuriy Stolypin arrived at the Lakhta Center (Europe's largest skyscraper) and sent a drone high into the air. Stolypin writes: "I wanted to take a photo of the tallest skyscraper in Europe, shrouded in morning fog. I regularly monitored the weather and looked into the city cameras to make sure that all shooting conditions were favorable for the intended shot, since I live very far from the shooting location. When everything coincided, early in the morning I called a taxi, arrived at the skyscraper, raised the drone as high as possible and took this picture.
Originally published on Live Science.


livescience--2020-10-21--Coronavirus outbreak: Live updates

Coronavirus outbreak: Live updates

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90-year-old woman in the UK receives first dose of Pfizer vaccine, FDA review confirms vaccine is safe and effective A 90-year-old woman (who will turn 91 next week) became the first in the world to be given Pfizer's coronavirus vaccine outside of clinical trials, according to the BBC. Margaret Keenan, who is originally from Northern Ireland, was given the vaccine at the University Hospital in Coventry, England. She received the first of 800,000 doses expected to be administered in the U.K. in the coming weeks, according to the BBC. "I feel so privileged to be the first person vaccinated against Covid-19," Keenan said, according to the BBC."It's the best early birthday present I could wish for because it means I can finally look forward to spending time with my family and friends in the new year after being on my own for most of the year." "My advice to anyone offered the vaccine is to take it. If I can have it at 90, then you can have it too," she added. Up to four million doses of Pfizer's vaccine is expected to be given to people in the U.K. by the end of the month. Meanwhile, a 53-page Food and Drug Administration (FDA) review published Tuesday (Dec. 8) confirmed that Pfizer's vaccine is safe and effective, according to The Washington Post.
Pfizer's COVID-19 vaccine starts to work just 10 days after 1st dose Pfizer's new COVID-19 vaccine starts to protect people from the novel coronavirus just 10 days after the first dose, according to new documents from the U.S. Food and Drug Administration (FDA). The documents were released on Tuesday (Dec. 8), two days before a meeting of the FDA's vaccine advisory panel, which will vote on whether to recommend authorization of the vaccine in the U.S, Live Science reported . The FDA analyzed data from Pfizer's phase 3 clinical trial, which included some 44,000 people in the United States, Brazil, Argentina, Germany and Turkey, about half of whom received the vaccine while the other half received a placebo. Both groups received two shots, 21 days apart. About 10 days after the first dose, there was a noticeable drop-off in new COVID-19 cases in the vaccine group compared with the placebo group, indicating that even one dose provides some protection, the report said. However, scientists don't know how long the protection from a single dose will last, so it will still be important for people to receive two shots, according to The New York Times . Overall, the vaccine was 52% effective after the first dose and 95% effective after the second dose, the report said.
People with significant allergies should avoid Pfizer vaccine, UK warns The U.K.'s Regulatory Agency is advising people with a history of "significant" allergic reactions to avoid Pfizer's coronavirus vaccine, after two National Health Service members developed severe allergic reactions to it on Tuesday (Dec. 8), Live Science reported. "As is common with new vaccines the MHRA (Medicines and Healthcare products Regulatory Agency) have advised on a precautionary basis that people with a significant history of allergic reactions do not receive this vaccination after two people with a history of significant allergic reactions responded adversely yesterday," Stephen Powis, the national medical director for England's National Health Service said in a statement on Wednesday (Dec. 9). Both workers have a history of severe allergies and carry adrenaline auto injectors (such as EpiPens) around with them, according to The Guardian. Shortly after receiving the vaccine, both NHS workers developed anaphylaxis-like symptoms, or severe allergic reactions, but have recovered after receiving treatment. The MHRA will investigate further and Pfizer and BioNTech will support their investigation, according to Reuters. "Allergic reaction occurs with quite a number of vaccines, and perhaps even more frequently with drugs. So it is not unexpected," Stephen Evans, a professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine said in remarks to journalists published by Britain's Science Media Center. “What would be wise, as the MHRA have already advised, would be for anyone who has known severe allergic reaction such that they need to carry an EpiPen, to delay having a vaccination until the reason for the allergic reaction has been clarified," he said. For the general population this does not mean that they would need to be anxious about receiving the vaccination, he added. "One has to remember that even things like marmite [a quintessential British food spread] can cause unexpected severe allergic reactions.”
Canada approves Pfizer's COVID-19 vaccine Canada has authorized Pfizer's new COVID-19 vaccine, with the first doses expected to be administered there as early as next week. Health Canada, the country's health regulatory agency, said in a statement on Wednesday (Dec. 9) that it had determined that the vaccine "meets the Department's stringent safety, efficacy and quality requirements for use in Canada," according to CTV News . "We expect vaccines to arrive maybe as early as Monday [Dec. 14]. It takes time to prepare the vaccine," said Maj.-Gen. Dany Fortin, the top military general leading the vaccine rollout for the Public Health Agency of Canada, according to CTV News. The first doses could be administered by the middle of next week, he said. Canada is the third country in the world to authorize the Pfizer vaccine, following the United Kingdom and Bahrain. The country should receive up to 249,000 doses of the vaccine by the end of December, and has purchased 20 million doses total, with the option to purchase more, CTV News reported.
Daily COVID-19 death toll in the U.S. reaches record-high, surpassed 9/11 On Wednesday (Dec. 9), the U.S. recorded 3,124 new COVID-19 deaths, the highest daily death toll to date, according to CNN . In comparison, 2,977 people were killed in the 9/11 attacks. The U.S. has now recorded 280,488 deaths related to the virus, according to The COVID Tracking Project . A forecast from the U.S. Centers for Disease Control and Prevention predicts that the total death toll can increase to between 332,000 and 362,000 by January 2, according to CNN. There are currently 106,671 people hospitalized with the virus in the U.S.; 20,903 of them are currently in the ICU and 7,621 are currently on a ventilator, according to the COVID Tracking Project. On Thursday (Dec. 10), the Vaccines and Related Biological Products Advisory Committee is set to meet to discuss an emergency use authorization for the Pfizer-BioNTech coronavirus vaccine.
FDA panel recommends authorization of Pfizer's COVID-19 vaccine A panel of experts for the Food and Drug Administration (FDA) has recommended that the agency authorize Pfizer's new COVID-19 vaccine in the United States. On Thursday (Dec. 10), the panel voted 17 to 4 to recommend that the vaccine receive emergency use authorization (EUA) for people ages 16 and older, according to The New York Times . The FDA typically follows the advice of its panels, and so today's vote is an important step towards the vaccine's authorization. It is anticipated that the agency will officially authorize the vaccine on Saturday (Dec. 12), the Times reported. Several countries have already authorized Pfizer's vaccine, including Canada, the United Kingdom and Bahrain.
Vaccine approval could come this weekend, as U.S. continues to record high daily death tolls On Thursday (Dec. 10), the U.S. recorded another 2,902 COVID-19 deaths, a day after the country set a record of 3,253 deaths, according to Reuters . “Probably for the next 60 to 90 days, we’re going to have more deaths per day than we had on 9/11 or we had at Pearl Harbor,” Dr. Robert Redfield, the director of the U.S. Centers for Disease Control and Prevention, told the Council on Foreign Relations on Thursday, according to Reuters. "The reality is the vaccine approval this week is not going to really impact that, I think, to any degree for the next 60 days." On Thursday, the Vaccines and Related Biological Products Advisory Committee discussed, voted and recommended that the Food and Drug Administration (FDA) should grant an emergency use authorization for Pfizer's coronavirus vaccine. The Pfizer vaccine has already been approved in the U.K. and in Canada, and FDA approval for use in the U.S. could come this weekend.
Australia abandons local COVID-19 vaccine after it caused false-positive HIV tests An Australian COVID-19 vaccine that had shown promising results in early trials is being abandoned after researchers found that the shot caused false-positive results on HIV tests. On Friday (Dec. 11), Australian officials said they had canceled an order for some 51 million doses of the vaccine, which was being developed by The University of Queensland and CSL Ltd., a local biotech company, according to The New York Times . In an early trial with 216 participants, the vaccine appeared to be safe and to produce a robust immune response against COVID-19, according to a statement from CSL . But some volunteers falsely tested positive for HIV, which officials feared would undermine trust in the vaccine, the Times reported. The vaccine contained small fragments of an HIV protein, which helped stabilize the vaccine. Some of the participants developed antibodies against these fragments, and these antibodies triggered false positive results on some HIV tests. It's important to note that there is no way for the vaccine to cause an HIV infection, because it contains harmless fragments of the virus.
ICU nurse in New York becomes first person in the US to receive a coronavirus vaccine outside of clinical trials New York, the worst-hit state at the start of the pandemic, just became the first to administer a coronavirus vaccine outside of clinical trials, kicking off a long, massive effort to vaccinate the American people, Live Science reported. Around 9 a.m. E.T. on Monday (Dec. 14), the very first dose of Pfizer and BioNTech's coronavirus vaccine was given to Sandra Lindsay, an intensive care nurse in Long Island Jewish Medical Center in Queens, New York, according to The New York Times. This comes as the U.S. continues to battle a massive wave of the virus that has more than 109,000 people currently hospitalized, according to The COVID Tracking Project. Since the start of the pandemic, New York has recorded more than 780,000 cases of COVID-19 and more than 35,100 deaths, according to The Times. "This vaccine is exciting because I believe this is the weapon that will end the war," Gov. Andrew Cuomo said during a live broadcast of the first vaccination. "It's the beginning of the last chapter of the book, but now we just have to do it."
FDA analysis confirms Moderna's vaccine is safe and effective, emergency authorization is likely to come Friday A new briefing document from the Food and Drug Administration (FDA) released on Tuesday (Dec. 15) confirmed that Moderna's COVID-19 vaccine is safe and effective, according to NPR . Moderna's COVID-19 vaccine is 94% effective and has "a favorable safety profile," according to the document. A panel of experts is set to meet on Thursday (Dec. 17) to discuss the effectiveness and safety of the vaccine and vote on whether or not the FDA should grant emergency approval to the vaccine. Last week, the same panel voted that the FDA should grant emergency approval to Pfizer's coronavirus vaccine; the authorization came a day late and the first doses were given on Monday (Dec. 15). The FDA will likely approve Moderna's vaccine for emergency use on Friday (Dec. 18), according to The New York Times .
FDA authorizes first over-the-counter COVID-19 test The U.S. Food and Drug Administration (FDA) has authorized the first over-the-counter COVID-19 test, which can be done at home and does not need a prescription. The test, made by the Australia-based company Ellume, provides results in as little as 20 minutes, according to a statement from the FDA . It is a "lateral flow antigen test," meaning it works in a similar way to a home pregnancy test, by running a "liquid sample along a surface with reactive molecules," the FDA said. The test works in conjunction with a smartphone app. Users take a nasal swab and place their sample in an analyzer, which communicates to the smartphone app via Bluetooth. The results are delivered through the app, and also reported to public health authorities (based on a user's zip code) through a secure cloud connection, the company said . Ellume is ramping up production of its test, and expects to produce three million tests in January 2021, and 20 million within the first half of 2021.
A wild mink tested positive for the coronavirus, it may be the first wild animal to have a confirmed case A wild mink in Utah may be the first "free-ranging, native wild animal" confirmed to be infected with SARS-CoV-2, according to the U.S. Department of Agriculture (USDA), Live Science reported. The mink was found near a mink farm and likely picked up the infection from the farmed mink. There's no evidence that the virus spread to other minks or wild animals; but if the virus does begin circulating in wild animals, it could pick up mutations that COVID-19 vaccines may not protect well against if it spreads back to humans, according to the report. "If it does [establish a reservoir], then we've got a long-term issue here, where this virus has the potential to be with us for millennia," Sarah Olson, associate director of the health program at the Wildlife Conservation Society, told Vox. The U.S. Department of Agriculture's Animal and Plant Health Inspection Service has screened other animal species for the virus near mink farms in Utah, Michigan and Wisconsin, but all of them have tested negative so far, according to a statement.
An FDA advisory panel will meet today to vote on whether to recommend Moderna's coronavirus vaccine for emergency approval On Thursday (Dec. 17), a Food and Drug Administration (FDA) advisory committee will meet to determine whether to recommend that Moderna’s coronavirus vaccine for emergency approval, according to The New York Times . This panel, composed of independent experts, will vote on whether to recommend the vaccine after hearing from the company, FDA scientists and the public, according to The Times. Last week, the same panel of experts met to discuss Pfizer’s coronavirus vaccine and voted to recommend emergency authorization; the authorization came the next day. There have now been more than 16.9 million cases of COVID-19 in the U.S. and more than 307,000 deaths, according to the Johns Hopkins dashboard . There are currently 113,090 people hospitalized across the country with more than 21,900 of them in the ICU and 7,778 on a ventilator, according to The COVID Tracking Project .
California becomes new epicenter of COVID-19 in U.S. California, once praised for its early pandemic response, is now the new U.S. hotspot for COVID-19 infections. The state has reported an alarming surge in cases, breaking previous records for daily cases. On Thursday (Dec. 17), the state reported some 50,000 COVID-19 infections in 24 hours, and nearly 100,000 in 48 hours, according to The Washington Post . That's more than the daily cases reported in many countries, including India, Germany and Britain, the Post reported. The state also set a record for daily deaths on Thursday, with 379 fatalities reported, up from the previous high of 293. Capacity in intensive care units has also dropped dramatically, with hospitals in Southern California reporting zero percent capacity on Thursday. "I want to be very clear: Our hospitals are under siege, and our model shows no end in sight," said Christina Ghaly, director of Los Angeles County's Department of Health Services, the Post reported.
FDA expected to authorize Moderna's vaccine on Friday The U.S. Food and Drug Administration is expected to authorize Moderna's COVID-19 vaccine on Friday (Dec. 18). Once authorized, it will be the second coronavirus vaccine to get the green light from the agency in just a week, with Pfizer's vaccine gaining authorization on Dec. 11. Moderna is expected to begin shipping 5.9 million doses of its vaccine on Sunday (Dec. 20), with the first deliveries arriving Monday (Dec. 21), according to The New York Times . Unlike the Pfizer vaccine, Moderna's vaccine does not require storage in extremely cold temperatures, and states are hoping to distribute the vaccine to rural hospitals and community health centers, the Times reported.
COVID-19 cases continue to surge across the U.S. There have now been more than 17 million cases of COVID-19 in the U.S. and more than 300,000 deaths, according to The COVID Tracking Project . There are currently 114,237 people hospitalized across the country and 21,900 people in the ICU. California is facing a massive surge in cases; the state reported 41,012 new COVID-19 cases and 300 new deaths on Thursday (Dec. 17), according to the state's COVID-19 dashboard . By comparison, at the start of November, California was reporting a seven-day average of 4,183 cases, compared to an average of 38,774 on Thursday, according to CNN . "We're experiencing an explosive and very deadly surge," Dr. Barbara Ferrer, Los Angeles County Public Health Director said, according to CNN. Intensive care unit beds are rapidly filling up across the state; there are only 1,234 ICU beds left available in California, according to the dashboard. Current closures across California are impacting around 98% of the state's population, according to CNN.
London and southeast England are under an emergency lockdown Following concerns of a new version of the coronavirus that might be more transmissible, London and most of southeast England are now under an emergency lockdown, according to The New York Times . Prime Minister Boris Johnson announced the lockdown on Saturday (Dec. 19) citing concerns that the mutated virus — which was detected a couple of weeks ago in southeast England — may be as much as 70% more transmissible than previous versions, according to the Times. The new version of the coronavirus is detected in more than 60% of new infections in London and have also been detected in several other countries, according to the Times. But it's not yet clear if this coronavirus version is any more infectious than the last and thorough analyses will need to be conducted before conclusions are made, scientists cautioned. In South Africa, a similar version of the virus has been found in up to 90% of new cases detected since mid-November, according to The Times . It's common for viruses to mutate, and this particular coronavirus has mutated many times since the start of the pandemic. But experts told The Times that it would take years for the virus to mutate enough such that it would make the current vaccines developed to fight COVID-19 ineffective.
Biden gets Pfizer's COVID-19 vaccine President-elect Joe Biden received a dose of Pfizer's new COVID-19 vaccine on Monday (Dec. 21), according to The New York Times . He received the shot on camera at the Christiana Hospital in Newark, Delaware. "I'm doing this to demonstrate that people should be prepared when it's available to take the vaccine. There's nothing to worry about," Biden said.
Antarctica has its 1st COVID-19 outbreak The first COVID-19 cases have been reported in Antarctica , meaning the disease has now spread to every continent in the world. On Tuesday (Dec. 22), Chilean officials reported an outbreak of 36 COVID-19 cases at the Chilean research base General Bernardo O'Higgins Riquelme on the Antarctic Peninsula, according to the BBC . Of these, 26 cases were military personnel and 10 were maintenance workers, the BBC reported. All of these cases have been evacuated from Antarctica to Punta Arenas, Chile, according to The Guardian . Antarctica had been COVID-19 free up until the current outbreak. The continent has no permanent residents, but about 1,000 people, including scientists and other workers, stayed there this past winter, The Guardian reported.
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livescience--2020-10-21--1-minute encounters may add up to spread COVID-19

Having `` `` with COVID-19 is usually defined as being near an infected person for at least 15 consecutive minutes .
But a new report suggests that even very brief exposures — a minute or less — could spread the disease , if those exposures happen frequently .
The report , from the Centers for Disease Control and Prevention ( CDC ) , describes a correctional officer in Vermont who caught COVID-19 after exposure to infected prisoners , even though he was never around the infected people for more than a minute at a time .
The exposure likely happened @ @ @ @ @ @ @ were transferred to the Vermont prison from an out-of-state facility , according to the report , published today in the CDC journal .
None of the inmates showed , but all of them underwent routine upon arrival ; and all six inmates received positive results the next day .
After learning of the positive results , officials went back to see who had close contact with the inmates the day before .
The team reviewed video footage and found one correctional officer who did come within 6 feet ( 1.8 meters ) of @ @ @ @ @ @ @ a close contact because he was not around the infected people for 15 consecutive minutes .
Related : 20 of the worst epidemics and pandemics in history The officer continued to work as usual , but on Aug. 4 ( one week after the infected inmates arrived ) , he developed loss of smell and taste , runny nose , cough , shortness of breath , headache and other symptoms of COVID-19 , the report said .
The next day , the officer tested positive for the disease .
As a result of @ @ @ @ @ @ @ reviewed the video surveillance footage from July 28 .
Though the correctional officer never spent 15 minutes straight close to the infected inmates , he had multiple brief encounters with them .
Specifically , during his 8-hour shift , the officer had 22 brief encounters ( between 10 and 60 seconds each ) with the inmates , totaling 17 minutes of cumulative exposure .
The correctional officer wore a and goggles during his encounters , but the inmates were not always masked .
The officer had no other known contacts with COVID-19 and @ @ @ @ @ @ @ the 2 weeks before his illness .
In addition , the rate of new COVID-19 infections in Vermont was low at the time , meaning the officer was unlikely to catch the disease through community spread .
The findings suggest that `` at least one of the asymptomatic [ inmates ] transmitted SARS-CoV-2 [ the virus that causes COVID-19 ] during these brief encounters , '' the report authors said .
The findings have implications for , which usually defines `` close contact '' with a person infected with the novel coronavirus as @ @ @ @ @ @ @ 15 minutes .
Additional factors may also be considered , such as how close the individuals came to each other , whether the infected person was doing something like singing or exercising , which generates a lot of and whether the environment was crowded or adequately ventilated , the report said .
In the current case , `` although the initial assessment did not suggest that the officer had close contact exposures , detailed review of video footage identified that the cumulative duration of exposures exceeded 15 minutes , '' the authors wrote @ @ @ @ @ @ @ encounters between inmates and facility staff members are necessary , the authors said , and `` public health officials should consider transmission-risk implications of cumulative exposure time within such settings , '' they concluded .

Having " close contact " with COVID-19 is usually defined as being near an infected person for at least 15 consecutive minutes. But a new report suggests that even very brief exposures — a minute or less — could spread the disease, if those exposures happen frequently.
The report, from the Centers for Disease Control and Prevention (CDC), describes a correctional officer in Vermont who caught COVID-19 after exposure to infected prisoners, even though he was never around the infected people for more than a minute at a time.
The exposure likely happened on July 28, when six inmates were transferred to the Vermont prison from an out-of-state facility, according to the report, published today in the CDC journal Morbidity and Mortality Weekly Report . None of the inmates showed symptoms of COVID-19 , but all of them underwent routine testing for COVID-19 upon arrival; and all six inmates received positive results the next day.
After learning of the positive results, officials went back to see who had close contact with the inmates the day before. The team reviewed video footage and found one correctional officer who did come within 6 feet (1.8 meters) of the inmates, but was not considered a close contact because he was not around the infected people for 15 consecutive minutes.
Related: 20 of the worst epidemics and pandemics in history
The officer continued to work as usual, but on Aug. 4 (one week after the infected inmates arrived), he developed loss of smell and taste, runny nose, cough, shortness of breath, headache and other symptoms of COVID-19, the report said. The next day, the officer tested positive for the disease.
As a result of this positive test, officials once again reviewed the video surveillance footage from July 28. Though the correctional officer never spent 15 minutes straight close to the infected inmates, he had multiple brief encounters with them. Specifically, during his 8-hour shift, the officer had 22 brief encounters (between 10 and 60 seconds each) with the inmates, totaling 17 minutes of cumulative exposure.
The correctional officer wore a cloth mask and goggles during his encounters, but the inmates were not always masked. The officer had no other known contacts with COVID-19 and hadn't traveled outside of Vermont in the 2 weeks before his illness. In addition, the rate of new COVID-19 infections in Vermont was low at the time, meaning the officer was unlikely to catch the disease through community spread.
The findings suggest that "at least one of the asymptomatic [inmates] transmitted SARS-CoV-2 [the virus that causes COVID-19] during these brief encounters," the report authors said.
The findings have implications for contact tracing , which usually defines "close contact" with a person infected with the novel coronavirus as being within 6 feet for at least 15 minutes.
Indeed, following publication of the report on Wednesday, the CDC updated its definition of a close contact, according to The Washington Post . The agency now defines close contact as "someone who was within 6 feet of an infected person for a cumulative total of 15 minutes or more over a 24-hour period," the CDC's website says.
Additional factors may also be considered, such as how close the individuals came to each other, whether the infected person was doing something like singing or exercising, which generates a lot of respiratory aerosols and whether the environment was crowded or adequately ventilated, the report said.
In the current case, "although the initial assessment did not suggest that the officer had close contact exposures, detailed review of video footage identified that the cumulative duration of exposures exceeded 15 minutes," the authors wrote. In correctional settings, frequent close encounters between inmates and facility staff members are necessary, the authors said, and "public health officials should consider transmission-risk implications of cumulative exposure time within such settings," they concluded.
Editor's note: This article was updated on Thursday (Oct. 22) to include information on the CDC's expanded definition of a close contact.
Originally published on Live Science.


livescience--2020-10-21--US is a week away from 'rapid acceleration' of COVID-19 cases

The U.S. is bracing for a third wave of COVID-19 infections as it moves into the frigid winter months .
The country is only about a week away from a `` rapid acceleration '' in COVID-19 cases , Dr. Scott Gottlieb , former commissioner of the Food and Drug Administration said on CNBC on Monday ( Oct. 19 ) .
Coronavirus cases have increased in the U.S. by 36 % in the past two weeks , with an average of 60,160 new cases per day over the past week , according to a New York Times analysis .
Coronavirus case @ @ @ @ @ @ @ and hospitalizations are increasing in 42 , Gottlieb said .
`` We 're facing a tough circumstance right now , '' he said .
`` It 's going to be a difficult fall and winter . ''
New waves of the virus have also taken hold elsewhere .
In Europe , COVID-19 cases have been rising exponentially , and governments have once again resorted to lockdowns — some of these lockdowns are as strict as the ones put in place in the spring .
Ireland will enact a six-week long nationwide shutdown starting @ @ @ @ @ @ @ `` firebreak '' lockdown that will require everyone to remain at home for two weeks starting on Friday , according to CNN .
The U.S. is about two or three weeks behind Europe in terms of an increase in cases , Gottlieb said .
`` So we 're about a week away from starting to enter a period where we 're going to see a rapid acceleration of cases and I think November and December are going to be tough months . ''
Especially as the holidays approach , and people want to @ @ @ @ @ @ @ `` we ca n't let our guard down , '' he added .
Public health experts have been saying since nearly the start of the pandemic that COVID-19 cases may worsen in the fall and winter months .
One reason experts are worried is that as the weather cools , people will gather in close quarters inside , allowing the virus easily spread from person to person , .
And the dryer air that 's common in the winter months might allow the virus to remain viable in the air for longer , @ @ @ @ @ @ @ threaten to provide a double-whammy with the onset of the flu season , according to another Live Science report .
The U.S. has now reported more than 8.2 million cases of COVID-19 and more than 221,400 deaths , according to the Johns Hopkins dashboard .
With the prospect of a potential coronavirus vaccine looming on the horizon , `` we can look to happier days , '' Gottlieb said .
`` But these are going to be some tough months ahead of us . ''

The U.S. is bracing for a third wave of COVID-19 infections as it moves into the frigid winter months. The country is only about a week away from a "rapid acceleration" in COVID-19 cases, Dr. Scott Gottlieb, former commissioner of the Food and Drug Administration said on CNBC on Monday (Oct. 19).
Coronavirus cases have increased in the U.S. by 36% in the past two weeks, with an average of 60,160 new cases per day over the past week, according to a New York Times analysis . Coronavirus case counts are going up in 45 states and hospitalizations are increasing in 42, Gottlieb said. "We're facing a tough circumstance right now," he said. "It's going to be a difficult fall and winter."
New waves of the virus have also taken hold elsewhere. In Europe, COVID-19 cases have been rising exponentially, and governments have once again resorted to lockdowns — some of these lockdowns are as strict as the ones put in place in the spring. Ireland will enact a six-week long nationwide shutdown starting tomorrow, according to NPR . Wales will enact a "firebreak" lockdown that will require everyone to remain at home for two weeks starting on Friday, according to CNN.
Related: Coronavirus live updates
The U.S. is about two or three weeks behind Europe in terms of an increase in cases, Gottlieb said. "So we're about a week away from starting to enter a period where we're going to see a rapid acceleration of cases and I think November and December are going to be tough months." Especially as the holidays approach, and people want to gather indoors to see their families, "we can't let our guard down," he added.
Public health experts have been saying since nearly the start of the pandemic that COVID-19 cases may worsen in the fall and winter months. One reason experts are worried is that as the weather cools, people will gather in close quarters inside, allowing the virus easily spread from person to person, according to NBC12 . And the dryer air that's common in the winter months might allow the virus to remain viable in the air for longer, Live Science previously reported . Of course, winter months also threaten to provide a double-whammy with the onset of the flu season, according to another Live Science report .
The U.S. has now reported more than 8.2 million cases of COVID-19 and more than 221,400 deaths, according to the Johns Hopkins dashboard . With the prospect of a potential coronavirus vaccine looming on the horizon, "we can look to happier days," Gottlieb said. "But these are going to be some tough months ahead of us."