Science
Researchers show magnetic fields around black hole in image for first time – Alaska Highway News
A team of international scientists that includes a Canadian researcher said it has mapped, for the first time, the magnetic fields surrounding a black hole.
The Event Horizon Telescope Collaboration team produced an image that shows electromagnetic fields that look like a “crisp swirl” of light around the black hole as it appears in polarized light.
The discovery will help astrophysicists better understand black holes and their profound effects on galaxies, said Avery Broderick, one of the team’s researchers who works at Perimeter Institute for Theoretical Physics in Waterloo, Ont.
“We’re watching this astrophysical drama, this twisting up of magnetic fields, building that spring at the bottom that’s going to launch this jet out into this large universe and rule the fates of galaxies,” Broderick said in an interview.
The polarized image allows researchers to learn more about the magnetic fields surrounding the black hole in the M87 galaxy, he said.
They believe the research helps its understanding of how magnetic fields allow the black hole to “eat” matter and eject powerful energetic jets.
Two years ago the same team released the first-ever image of a black hole.
The international collaboration is composed of more than 300 researchers who compiled the image from eight Earth-based telescopes positioned around the world.
The new image is part of two related papers published Wednesday in The Astrophysical Journal.
The scientists have been working on the new project the past two years, Broderick said, ensuring what they were seeing was, in fact, real.
He said he and his team devised a new radioimaging method that helped show the electromagnetic fields.
There were five other teams that were using different methods to show the polarization, some tried and true, others novel.
“All six of these achieved very similar results,” he said.
“Only when we have this kind of replication across this many teams that we feel confident we’re seeing something that’s really in the sky and not an artifact of our analysis.”
What the team produced is comparable, in a sense, to the old high school experiment where students drop iron filings around a magnet bar, he explained.
The filings will line up in a unique fashion around the poles and illustrate the invisible magnetic field.
“What we have shown is those magnetic fields are not random, not just angled up in random directions, but very much like that bar magnet,” said Broderick, who is also a professor at the University of Waterloo.
He said the teams produced four images between on April 5 and 11 in 2017.
“In some sense we have a polarized movie,” he said. “But the movie only has four frames.”
There is a difference between the first two images and the last two, he said.
“From the beginning of the week to the end of the week, the high polarization moves a bit,” Broderick said.
“That’s interesting — we don’t have a lot to say about it other than that’s interesting.”
The image researchers captured is not of the black hole closest to Earth, however, but of one at the centre of neighbouring galaxy Messier 87 that was easier to observe by telescope. It is about six billion times the mass of our sun and located about 53 million light years from Earth. One light-year is equal to 9.5 trillion kilometres.
“The newly published polarized images are key to understanding how the magnetic field allows the black hole to ‘eat’ matter and launch powerful jets,” said Andrew Chael, part of the team and a NASA Hubble Fellow at the Princeton Centre for Theoretical Science.
For Broderick, it’s not that different than building a fence.
“It’s a lot of work, a lot of sweat and frustration digging the post holes and screwing the whole thing together and making sure everything is plum, and while you’re doing that you’re focused on the mundane and onerous tasks,” he said.
“But then you get to step back when you’re finished and you have a nice looking fence that’s not too crooked and you feel an immense measure of pride and that’s where we are today.”
This report by The Canadian Press was first published March 24, 2021.
Liam Casey, The Canadian Press
Science
Giant prehistoric salmon had tusk-like teeth for defence, building nests
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The artwork and publicity materials showcasing a giant salmon that lived five million years ago were ready to go to promote a new exhibit, when the discovery of two fossilized skulls immediately changed what researchers knew about the fish.
Initial fossil discoveries of the 2.7-metre-long salmon in Oregon in the 1970s were incomplete and had led researchers to mistakenly suggest the fish had fang-like teeth.
It was dubbed the “sabre-toothed salmon” and became a kind of mascot for the Museum of Natural and Cultural History at the University of Oregon, says researcher Edward Davis.
But then came discovery of two skulls in 2014.
Davis, a member of the team that found the skulls, says it wasn’t until they got back to the lab that he realized the significance of the discovery that has led to the renaming of the fish in a new, peer-reviewed study.
“There were these two skulls staring at me with sideways teeth,” says Davis, an associate professor in the department of earth sciences at the university.
In that position, the tusk-like teeth could not have been used for biting, he says.
“That was definitely a surprising moment,” says Davis, who serves as director of the Condon Fossil Collection at the university’s Museum of Natural and Cultural History.
“I realized that all of the artwork and all of the publicity materials and bumper stickers and buttons and T-shirts we had just made two months prior, for the new exhibit, were all out of date,” he says with a laugh.
Davis is co-author of the new study in the journal PLOS One, which renames the giant fish the “spike-toothed salmon.”
It says the salmon used the tusk-like spikes for building nests to spawn, and as defence mechanisms against predators and other salmon.
The salmon lived about five million years ago at a time when Earth was transitioning from warmer to relatively cooler conditions, Davis says.
It’s hard to know exactly why the relatives of today’s sockeye went extinct, but Davis says the cooler conditions would have affected the productivity of the Pacific Ocean and the amount of rain feeding rivers that served as their spawning areas.
Another co-author, Brian Sidlauskas, says a fish the size of the spike-toothed salmon must have been targeted by predators such as killer whales or sharks.
“I like to think … it’s almost like a sledgehammer, these salmon swinging their head back and forth in order to fend off things that might want to feast on them,” he says.
Sidlauskas says analysis by the lead author of the paper, Kerin Claeson, found both male and female salmon had the “multi-functional” spike-tooth feature.
“That’s part of our reason for hypothesizing that this tooth is multi-functional … It could easily be for digging out nests,” he says.
“Think about how big the (nest) would have to be for an animal of this size, and then carving it out in what’s probably pretty shallow water; and so having an extra digging tool attached to your head could be really useful.”
Sidlauskas says the giant salmon help researchers understand the boundaries of what’s possible with the evolution of salmon, but they also capture the human imagination and a sense of wonder about what’s possible on Earth.
“I think it helps us value a little more what we do still have, or I hope that it does. That animal is no longer with us, but it is a product of the same biosphere that sustains us.”
This report by The Canadian Press was first published April 24, 2024.
Brenna Owen, The Canadian Press
Science
Giant prehistoric salmon had tusk-like spikes used for defence, building nests: study
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A new paper says a giant salmon that lived five million years ago in the coastal waters of the Pacific Northwest used tusk-like spikes as defense mechanisms and for building nests to spawn.
The initial fossil discoveries of the 2.7-metre-long salmon in Oregon in the 1970s were incomplete and led researchers to suggest the fish had fang-like teeth.
The now-extinct fish was dubbed the “saber-tooth salmon,” but the study published in the peer-reviewed journal PLOS One today renames it the “spike-toothed salmon” and says both males and females possessed the “multifunctional” feature.
Study co-author Edward Davis says the revelation about the tusk-like teeth came after the discovery of fossilized skulls at a site in Oregon in 2014.
Davis, an associate professor in the department of earth sciences at the University of Oregon, says he was surprised to see the skulls had “sideways teeth.”
Contrary to the belief since the 1970s, he says the teeth couldn’t have been used for any kind of biting.
“That was definitely a surprising moment,” Davis says of the fossil discovery in 2014. “I realized that all of the artwork and all of the publicity materials … we had just made two months prior, for the new exhibit, were all out of date.”
Science
SpaceX sends 23 Starlink satellites into low-Earth orbit
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April 23 (UPI) — SpaceX launched 23 Starlink satellites into low-Earth orbit Tuesday evening from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida.
Liftoff occurred at 6:17 EDT with a SpaceX Falcon 9 rocket sending the payload of 23 Starlink satellites into orbit.
The Falcon 9 rocket’s first-stage booster landed on an autonomous drone ship in the Atlantic Ocean after separating from the rocket’s second stage and its payload.
The entire mission was scheduled to take about an hour and 5 minutes to complete from launch to satellite deployment.
The mission was the ninth flight for the first-stage booster that previously completed five Starlink satellite-deployment missions and three other missions.
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