Dec 12, 2023 07:05 PM
Cosmic nuclear fission seen for 1st time in 'incredibly profound' discovery
https://www.space.com/nuclear-fission-ne...ments-gold
INTRO: Scientists have discovered the first indication of nuclear fission occurring amongst the stars. The discovery supports the idea that when neutron stars smash together, they create "superheavy" elements — heavier than the heaviest elements of the periodic table — which then break down via nuclear fission to birth elements like the gold in your jewelry.
Nuclear fission is basically the opposite of nuclear fusion. While nuclear fusion refers to the smashing of lighter elements to create heavier elements, nuclear fission is a process that sees energy released when heavy elements split apart to create lighter elements. Nuclear fission is pretty well known, too. It's actually the basis of energy-generating nuclear power plants here on Earth — however, it had not been seen occurring amongst the stars before now.
"People have thought fission was happening in the cosmos, but to date, no one has been able to prove it," Matthew Mumpower, research co-author and a scientist at Los Alamos National Laboratory, said in a statement.
The team of researchers led by North Carolina State University scientist Ian Roederer searched data concerning a wide range of elements in stars to discover the first evidence that nuclear fission could therefore be acting when neutron stars merge. These findings could help solve the mystery of where the universe's heavy elements come from... (MORE - details)
Extra-long blasts challenge our theories of cosmic cataclysms
https://www.quantamagazine.org/extra-lon...-20231211/
INTRO: On December 11, 2021, a beam of gamma rays — the most energetic form of light — slammed into NASA’s Swift satellite. Within 120 seconds, the satellite had swiveled toward the blast and spotted the glowing embers of a cosmic catastrophe. Ten minutes later, alerts went out to astronomers around the world.
Among them was Jillian Rastinejad, a graduate student at Northwestern University. To Rastinejad and her collaborators, this gamma-ray burst looked oddly similar to an unusual burst from 2006. Rastinejad called up the Gemini Observatory in Hawai‘i and enlisted researchers there to stare deeply at the patch of sky where the burst had come from. A few days later, when clouds rolled in, a researcher at the MMT Observatory in Arizona took over, doing her best to keep the telescope trained on the fading spot of light a billion light-years away.
It was no small feat given that the weather was turning there too, Rastinejad said. “She found a hole in the clouds for us around 4 a.m. every day.”
By the time the chain of observations had wrapped up a week or so later, Rastinejad and her colleagues had a pretty good idea of what had fired those gamma rays across the universe. As they’d watched, the burst’s aftermath had turned redder and redder — an unmistakable sign that in the debris, heavy atoms like gold and platinum were being forged. The main source of such cosmic alchemy is collisions involving neutron stars, the unimaginably dense cores of dead suns.
The only problem was that such a conclusion seemed impossible. When neutron stars merge, astrophysicists suspect, it’s all over in a fraction of a second. But Swift had recorded a gamma-ray bombardment lasting a relatively interminable 51 seconds — normally the signature of a very different type of cosmic drama.
Along with her collaborators, Jillian Rastinejad, a graduate student at Northwestern University, solved the mystery of a perplexing gamma-ray burst that slammed into Earth in 2021.
Since then, astronomers have identified more events like this. The most recent occurred in March, when the second-brightest gamma-ray burst ever detected lasted for 35 seconds. Again, astronomers observed the ruddy aftermath of a neutron star collision. They also recruited the James Webb Space Telescope to study the bizarre burst and spotted signs of the heavy element tellurium in the settling dust.
Together, the string of observations brings a new mystery to an area of astronomy that most researchers had considered settled: What causes these supposedly quick, violent events to blast out gamma rays for so long? It’s a puzzle astrophysicists will have to solve if they want to achieve the more ambitious goal of understanding the origins of all the different elements in the universe, many of which are born from these violent outbursts.
“I’ve been really excited to see this,” said Daniel Kasen, an astrophysicist at the University of California, Berkeley who specializes in cosmic explosions. “It’s posed a real puzzle.” (MORE - details)
https://www.space.com/nuclear-fission-ne...ments-gold
INTRO: Scientists have discovered the first indication of nuclear fission occurring amongst the stars. The discovery supports the idea that when neutron stars smash together, they create "superheavy" elements — heavier than the heaviest elements of the periodic table — which then break down via nuclear fission to birth elements like the gold in your jewelry.
Nuclear fission is basically the opposite of nuclear fusion. While nuclear fusion refers to the smashing of lighter elements to create heavier elements, nuclear fission is a process that sees energy released when heavy elements split apart to create lighter elements. Nuclear fission is pretty well known, too. It's actually the basis of energy-generating nuclear power plants here on Earth — however, it had not been seen occurring amongst the stars before now.
"People have thought fission was happening in the cosmos, but to date, no one has been able to prove it," Matthew Mumpower, research co-author and a scientist at Los Alamos National Laboratory, said in a statement.
The team of researchers led by North Carolina State University scientist Ian Roederer searched data concerning a wide range of elements in stars to discover the first evidence that nuclear fission could therefore be acting when neutron stars merge. These findings could help solve the mystery of where the universe's heavy elements come from... (MORE - details)
Extra-long blasts challenge our theories of cosmic cataclysms
https://www.quantamagazine.org/extra-lon...-20231211/
INTRO: On December 11, 2021, a beam of gamma rays — the most energetic form of light — slammed into NASA’s Swift satellite. Within 120 seconds, the satellite had swiveled toward the blast and spotted the glowing embers of a cosmic catastrophe. Ten minutes later, alerts went out to astronomers around the world.
Among them was Jillian Rastinejad, a graduate student at Northwestern University. To Rastinejad and her collaborators, this gamma-ray burst looked oddly similar to an unusual burst from 2006. Rastinejad called up the Gemini Observatory in Hawai‘i and enlisted researchers there to stare deeply at the patch of sky where the burst had come from. A few days later, when clouds rolled in, a researcher at the MMT Observatory in Arizona took over, doing her best to keep the telescope trained on the fading spot of light a billion light-years away.
It was no small feat given that the weather was turning there too, Rastinejad said. “She found a hole in the clouds for us around 4 a.m. every day.”
By the time the chain of observations had wrapped up a week or so later, Rastinejad and her colleagues had a pretty good idea of what had fired those gamma rays across the universe. As they’d watched, the burst’s aftermath had turned redder and redder — an unmistakable sign that in the debris, heavy atoms like gold and platinum were being forged. The main source of such cosmic alchemy is collisions involving neutron stars, the unimaginably dense cores of dead suns.
The only problem was that such a conclusion seemed impossible. When neutron stars merge, astrophysicists suspect, it’s all over in a fraction of a second. But Swift had recorded a gamma-ray bombardment lasting a relatively interminable 51 seconds — normally the signature of a very different type of cosmic drama.
Along with her collaborators, Jillian Rastinejad, a graduate student at Northwestern University, solved the mystery of a perplexing gamma-ray burst that slammed into Earth in 2021.
Since then, astronomers have identified more events like this. The most recent occurred in March, when the second-brightest gamma-ray burst ever detected lasted for 35 seconds. Again, astronomers observed the ruddy aftermath of a neutron star collision. They also recruited the James Webb Space Telescope to study the bizarre burst and spotted signs of the heavy element tellurium in the settling dust.
Together, the string of observations brings a new mystery to an area of astronomy that most researchers had considered settled: What causes these supposedly quick, violent events to blast out gamma rays for so long? It’s a puzzle astrophysicists will have to solve if they want to achieve the more ambitious goal of understanding the origins of all the different elements in the universe, many of which are born from these violent outbursts.
“I’ve been really excited to see this,” said Daniel Kasen, an astrophysicist at the University of California, Berkeley who specializes in cosmic explosions. “It’s posed a real puzzle.” (MORE - details)