Did supernovae kill off large ocean animals at dawn of Pleistocene?

 

Cosmos by John Hussey

The effects of a supernova — and possibly more than one — on large ocean life like school-bus-sized Megalodon 2.6 million years ago are detailed in a new article.

A nearby supernova remnant. Credit: NASA

 

View the Cosmos – Video-eBook or Search for your Cosmos – Answer Here

 

About 2.6 million years ago, an oddly bright light arrived in the prehistoric sky and lingered there for weeks or months. It was a supernova some 150 light years away from Earth. Within a few hundred years, long after the strange light in the sky had dwindled, a tsunami of cosmic energy from that same shattering star explosion could have reached our planet and pummeled the atmosphere, touching off climate change and triggering mass extinctions of large ocean animals, including a shark species that was the size of a school bus.

The effects of such a supernova — and possibly more than one — on large ocean life are detailed in a paper just published in Astrobiology. “I’ve been doing research like this for about 15 years, and always in the past it’s been based on what we know generally about the universe — that these supernovae should have affected Earth at some time or another,” said lead author Adrian Melott, professor emeritus of physics & astronomy at the University of Kansas.

“This time, it’s different. We have evidence of nearby events at a specific time. We know about how far away they were, so we can actually compute how that would have affected the Earth and compare it to what we know about what happened at that time — it’s much more specific.” Melott said recent papers revealing ancient seabed deposits of iron-60 isotopes provided the “slam-dunk” evidence of the timing and distance of supernovae.

“As far back as the mid-1990s, people said, ‘Hey, look for iron-60. It’s a telltale because there’s no other way for it to get to Earth but from a supernova.’ Because iron-60 is radioactive, if it was formed with the Earth it would be long gone by now. So, it had to have been rained down on us. There’s some debate about whether there was only one supernova really nearby or a whole chain of them. I kind of favor a combo of the two — a big chain with one that was unusually powerful and close.

If you look at iron-60 residue, there’s a huge spike 2.6 million years ago, but there’s excess scattered clear back 10 million years.” Melott’s co-authors were Franciole Marinho of Universidade Federal de Sa?o Carlos in Brazil and Laura Paulucci of Universidade Federal do ABC, also in Brazil. According to the team, other evidence for a series of supernovae is found in the very architecture of the local universe. “We have the Local Bubble in the interstellar medium,” Melott said. “We’re right on its edge.

It’s a giant region about 300 light years long. It’s basically very hot, very low-density gas — nearly all the gas clouds have been swept out of it. The best way to manufacture a bubble like that is a whole bunch of supernovae blows it bigger and bigger, and that seems to fit well with idea of a chain.

When we do calculations, they’re based on the idea that one supernova that goes off, and its energy sweeps by Earth, and it’s over. But with the Local Bubble, the cosmic rays kind of bounce off the sides, and the cosmic-ray bath would last 10,000 to 100,000 years. This way, you could imagine a whole series of these things feeding more and more cosmic rays into the Local Bubble and giving us cosmic rays for millions of years.

” Whether or not there was one supernova or a series of them, the supernova energy that spread layers of iron-60 all over the world also caused penetrating particles called muons to shower Earth, causing cancers and mutations — especially to larger animals.

View the Cosmos – Video-eBook or Search for your Cosmos – Answer Here

View Sample Video – Cosmology – Universe – Beyond the Big Bang

Related Video Content

Cosmology – Universe – Beyond the Big Bang.mp4
Cosmology – Universe – Birth and Death of Stars.webm
Cosmology – Universe – Cosmic Calendar.mp4
Cosmology – Universe – Cosmic Inflation.webm
Cosmology – Universe – Dark Matter and Dark Energy.mp4
Cosmology – Universe – Death of the Universe.mp4
Cosmology – Universe – Death Stars and their Threat to Earth.mp4
Cosmology – Universe – Do You Know What Time It Is.mp4
Cosmology – Universe – God and the Universe.mp4
Cosmology – Universe – Gravity.mp4
Cosmology – Universe – How Large is the Universe.mp4
Cosmology – Universe – Is There An Edge To the Universe.webm
Cosmology – Universe – Journey Through the Milky Way.mp4
Cosmology – Universe – Journey To The Edge Of The Universe.mp4
Cosmology – Universe – Light Speed.webm
Cosmology – Universe – Mapping the Universe.flv
Cosmology – Universe – Milky Way Galaxy Formation – Simulation.webm
Cosmology – Universe – Most of the Universe is missing.mp4
Cosmology – Universe – Nebulae.webm
Cosmology – Universe – Our Place In The Milky Way.webm
Cosmology – Universe – Parallel Universes.webm
Cosmology – Universe – Pulsars and Quasars.webm
Cosmology – Universe – Seven Ages of Starlight.webm
Cosmology – Universe – Supernovae.webm
Cosmology – Universe – The Energy of Empty Space.mp4
Cosmology – Universe – The Multiverse Theory.webm
Cosmology – Universe – The Platonic Solids.mp4
Cosmology – Universe – The Riddle of Anti Matter.mp4
Cosmology – Universe – Voyager Golden Record.mp4
Cosmology – Universe – What happened before the beginning.webm
Cosmology – Universe – What happened before the Big Bang.mp4
Cosmology – Universe – What is Reality.mp4
Cosmology – Universe – What on Earth is Wrong With Gravity.mp4

View Sample Video – Cosmology – Universe – Supernovae

“The best description of a muon would be a very heavy electron — but a muon is a couple hundred times more massive than an electron,” Melott said. “They’re very penetrating. Even normally, there are lots of them passing through us.

Nearly all of them pass through harmlessly, yet about one-fifth of our radiation dose comes by muons. But when this wave of cosmic rays hits, multiply those muons by a few hundred. Only a small faction of them will interact in any way, but when the number is so large and their energy so high, you get increased mutations and cancer — these would be the main biological effects.

We estimated the cancer rate would go up about 50 percent for something the size of a human — and the bigger you are, the worse it is. For an elephant or a whale, the radiation dose goes way up.” A supernova 2.6 million years ago may be related to a marine megafaunal extinction at the Pliocene-Pleistocene boundary where 36 percent of the genera were estimated to become extinct.

The extinction was concentrated in coastal waters, where larger organisms would catch a greater radiation dose from the muons. According to the authors of the new paper, damage from muons would extend down hundreds of yards into ocean waters, becoming less severe at greater depths: “High energy muons can reach deeper in the oceans being the more relevant agent of biological damage as depth increases,” they write. Indeed, a famously large and fierce marine animal inhabiting shallower waters may have been doomed by the supernova radiation.

“One of the extinctions that happened 2.6 million years ago was Megalodon,” Melott said. “Imagine the Great White Shark in ‘Jaws,’ which was enormous — and that’s Megalodon, but it was about the size of a school bus. They just disappeared about that time. So, we can speculate it might have something to do with the muons. Basically, the bigger the creature is the bigger the increase in radiation would have been.” The KU researcher said the evidence of a supernova, or series of them, is “another puzzle piece” to clarify the possible reasons for the Pliocene-Pleistocene boundary extinction.

“There really hasn’t been any good explanation for the marine megafaunal extinction,” Melott said. “This could be one. It’s this paradigm change — we know something happened and when it happened, so for the first time we can really dig in and look for things in a definite way. We now can get really definite about what the effects of radiation would be in a way that wasn’t possible before.”  

 

Story Source:

Materials provided by University of Kansas.  

 

Cosmos by John Hussey  

https://www.sciencedaily.com/releases/2018/12/181211112941.htm

 

View the Cosmos – Video-eBook or Search for your Cosmos – Answer Here

Tangled magnetic fields power cosmic particle accelerators

 

Cosmos by John Hussey

New way to explain how a black hole’s plasma jets boost particles to the highest energies observed in the universe Magnetic field lines tangled like spaghetti in a bowl might be behind the most powerful particle accelerators in the universe. That’s the result of a new computational study that simulated particle emissions from distant active galaxies. SLAC researchers have found a new mechanism that could explain how plasma jets emerging from the center of active galaxies, like the one shown in this illustration, accelerate particles to extreme energies. Computer simulations (circled area) showed that tangled magnetic field lines create strong electric fields in the direction of the jets, leading to dense electric currents of high-energy particles streaming away from the galaxy. Credit: Greg Stewart/SLAC National Accelerator Laboratory

View the Cosmos – Video-eBook or Search for your Cosmos – Answer Here

Magnetic field lines tangled like spaghetti in a bowl might be behind the most powerful particle accelerators in the universe. That’s the result of a new computational study by researchers from the Department of Energy’s SLAC National Accelerator Laboratory, which simulated particle emissions from distant active galaxies. At the core of these active galaxies, supermassive black holes launch high-speed jets of plasma — a hot, ionized gas — that shoot millions of light years into space. This process may be the source of cosmic rays with energies tens of millions of times higher than the energy unleashed in the most powerful human-made particle accelerator. “The mechanism that creates these extreme particle energies isn’t known yet,” said SLAC staff scientist Frederico Fiúza, the principal investigator of a new study that will publish tomorrow in Physical Review Letters. “But based on our simulations, we’re able to propose a new mechanism that can potentially explain how these cosmic particle accelerators work.” The results could also have implications for plasma and nuclear fusion research and the development of novel high-energy particle accelerators. Simulating cosmic jets Researchers have long been fascinated by the violent processes that boost the energy of cosmic particles. For example, they’ve gathered evidence that shock waves from powerful star explosions could bring particles up to speed and send them across the universe. Scientists have also suggested that the main driving force for cosmic plasma jets could be magnetic energy released when magnetic field lines in plasmas break and reconnect in a different way — a process known as “magnetic reconnection.”

View the Cosmos – Video-eBook or Search for your Cosmos – Answer Here

View Sample Video – Cosmology – Universe – Beyond the Big Bang

Related Video Content
Cosmology – Universe – Beyond the Big Bang.mp4
Cosmology – Universe – Birth and Death of Stars.webm
Cosmology – Universe – Cosmic Calendar.mp4
Cosmology – Universe – Cosmic Inflation.webm
Cosmology – Universe – Dark Matter and Dark Energy.mp4
Cosmology – Universe – Death of the Universe.mp4
Cosmology – Universe – Death Stars and their Threat to Earth.mp4
Cosmology – Universe – Do You Know What Time It Is.mp4
Cosmology – Universe – God and the Universe.mp4
Cosmology – Universe – Gravity.mp4
Cosmology – Universe – How Large is the Universe.mp4
Cosmology – Universe – Is There An Edge To the Universe.webm
Cosmology – Universe – Journey Through the Milky Way.mp4
Cosmology – Universe – Journey To The Edge Of The Universe.mp4
Cosmology – Universe – Light Speed.webm
Cosmology – Universe – Mapping the Universe.flv
Cosmology – Universe – Milky Way Galaxy Formation – Simulation.webm
Cosmology – Universe – Most of the Universe is missing.mp4
Cosmology – Universe – Nebulae.webm
Cosmology – Universe – Our Place In The Milky Way.webm
Cosmology – Universe – Parallel Universes.webm
Cosmology – Universe – Pulsars and Quasars.webm
Cosmology – Universe – Seven Ages of Starlight.webm
Cosmology – Universe – Supernovae.webm
Cosmology – Universe – The Energy of Empty Space.mp4
Cosmology – Universe – The Multiverse Theory.webm
Cosmology – Universe – The Platonic Solids.mp4
Cosmology – Universe – The Riddle of Anti Matter.mp4
Cosmology – Universe – Voyager Golden Record.mp4
Cosmology – Universe – What happened before the beginning.webm
Cosmology – Universe – What happened before the Big Bang.mp4
Cosmology – Universe – What is Reality.mp4
Cosmology – Universe – What on Earth is Wrong With Gravity.mp4

View Sample Video – Cosmology – Black Holes – Super Massive Black Hole at the Center our Galaxy

However, the new study suggests a different mechanism that’s tied to the disruption of the helical magnetic field generated by the supermassive black hole spinning at the center of active galaxies. “We knew that these fields can become unstable,” said lead author Paulo Alves, a research associate working with Fiúza. “But what exactly happens when the magnetic fields become distorted, and could this process explain how particles gain tremendous energy in these jets? That’s what we wanted to find out in our study.” To do so, the researchers simulated the motions of up to 550 billion particles — a miniature version of a cosmic jet — on the Mira supercomputer at the Argonne Leadership Computing Facility (ALCF) at DOE’s Argonne National Laboratory. Then, they scaled up their results to cosmic dimensions and compared them to astrophysical observations. From tangled field lines to high-energy particles The simulations showed that when the helical magnetic field is strongly distorted, the magnetic field lines become highly tangled and a large electric field is produced inside the jet. This arrangement of electric and magnetic fields can, indeed, efficiently accelerate electrons and protons to extreme energies. While high-energy electrons radiate their energy away in the form of X-rays and gamma rays, protons can escape the jet into space and reach Earth’s atmosphere as cosmic radiation. “We see that a large portion of the magnetic energy released in the process goes into high-energy particles, and the acceleration mechanism can explain both the high-energy radiation coming from active galaxies and the highest cosmic-ray energies observed,” Alves said. Roger Blandford, an expert in black hole physics and former director of the SLAC/Stanford University Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), who was not involved in the study, said, “This careful analysis identifies many surprising details of what happens under conditions thought to be present in distant jets, and may help explain some remarkable astrophysical observations.” Next, the researchers want to connect their work even more firmly with actual observations, for example by studying what makes the radiation from cosmic jets vary rapidly over time. They also intend to do lab research to determine if the same mechanism proposed in this study could also cause disruptions and particle acceleration in fusion plasmas. This work was also co-authored by Jonathan Zrake, a former Kavli Fellow at KIPAC, who is now at Columbia University. The project was supported by the DOE Office of Science through its Early Career Research Program and an ALCC award for simulations on the Mira high-performance computer. ALCF is a DOE Office of Science user facility.   Story Source: Materials provided by DOE/SLAC National Accelerator Laboratory. Original written by Manuel Gnida.   Cosmos by John Hussey   https://www.sciencedaily.com/releases/2018/12/181213131242.htm  

View the Cosmos – Video-eBook or Search for your Cosmos – Answer Here