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Can any nearby supernova cause a mass extinction?

Paul Sutter
Universe Today
Tue, 18 Mar 2025 03:41 UTC
The Veil Nebula Supernova Remnant.
© NASA/ESA/Hubble Heritage TeamThe Veil Nebula Supernova Remnant.
The most dangerous parts of a supernova explosion are the outputs like X-rays and gamma rays. Even though they only share a small fraction of a supernova's power, they are extremely dangerous. But they're not going to disintegrate the Earth. We are simply too far away from any potential supernova for that to ever be a problem.

What can happen is that these forms of radiation pack enough energetic punch that they can tear apart molecules. Elements like nitrogen and oxygen prefer to float around as molecules in our atmosphere. But then once they get hit by x rays, gamma rays, and cosmic rays, they get broken apart. And then they recombine in interesting and fascinating ways like various nitrogen oxides, including everybody's favorite nitrous oxide AKA laughing gas. And while everyone's laughing and having a good time, our ozone layer gets stripped away.

That's the danger of a too-close supernova: it breaks up our ozone layer. And without an ozone layer, it means the Earth is vulnerable to ultraviolet radiation from the Sun. Our ozone layer protects us from the vast majority of ultraviolet radiation. There are a couple specific bands of wavelengths that do sneak through, which is why we need to wear sunscreen here on the surface, so we don't get nasty tans and sunburns and skin cancer and all that.

But imagine no ozone layer, then you get all the UV radiation, the full output, and it's bad. And it's not just a matter of quicker tans and faster burns and higher rates of skin cancer. The problem is that photosynthetic microorganisms like algae become vulnerable. They get cooked and then they die. And since they form the very base layer of the food chain, you end up with whole ecosystem collapse and a mass extinction.
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Attention

128 new Saturn moons just announced

Michelle Starr
Science Alert
Wed, 12 Mar 2025 01:45 UTC
Saturn's Moons
© NASA/JPL-Caltech/Space Science InstituteFive of Saturn's moons, from left: Janus, Pandora, Enceladus, Rhea, and Mimas.
The race between Jupiter and Saturn for the most moons in the Solar System may have just finally come screeching to a halt.

A team of scientists has found a whopping 128 previously unknown moons hanging around Saturn, in a discovery officially recognized by the International Astronomical Union. This brings the planet's total number of known moons to 274, leaving Jupiter, with its mere 95 moons, in the dust.

The first hint that there were more moons awaiting discovery came between 2019 and 2021, when 62 such objects were identified. Other small objects were also spotted at the time that couldn't yet be designated.

"With the knowledge that these were probably moons, and that there were likely even more waiting to be discovered, we revisited the same sky fields for three consecutive months in 2023," says astronomer Edward Ashton of Academia Sincia in Taiwan.

"Sure enough, we found 128 new moons. Based on our projections, I don't think Jupiter will ever catch up."
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Cassiopaea

Astronomers investigate the evolution of a newly detected supernova

Tomasz Nowakowski
Phys Org
Tue, 11 Feb 2025 15:38 UTC
SN 2024jlf
© arXiv (2025). DOI: 10.48550/arxiv.2501.18686Multi-band light curve of SN 2024jlf and best fit model light curves.
An international team of astronomers has investigated a newly detected Type II supernova designated SN 2024jlf. The new study, detailed in a paper published Jan. 30 on the arXiv pre-print server, yields important information regarding the evolution of this supernova and the nature of its progenitor.

Type II supernovae (SNe) are the results of rapid collapse and violent explosion of massive stars (with masses above 8.0 solar masses). They are distinguished from other SNe by the presence of hydrogen in their spectra.

Based on the shape of their light curves, they are usually divided into Type IIL and Type IIP. Type IIL SNe show a steady (linear) decline after the explosion, while Type IIP exhibit a period of slower decline (a plateau) that is followed by a normal decay.

SN 2024jlf was first spotted on May 28, 2024 using the Zwicky Transient Facility (ZTF), with a brightness of 15.88 mag. The supernova occurred in NGC 5690 — an edge-on spiral galaxy at a redshift of 0.0058.

Subsequent observations of SN 2024jlf after its discovery have revealed that its spectrum shows a blue continuum with weak flash features, indicating a young core-collapse supernova of Type II. A search for the progenitor of SN 2024jlf has also been conducted. However, no source has been identified in the location of this supernova.
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Potentially deadly 'chirping waves' detected in baffling location near Earth, and scientists are stumped

Ben Turner
Live Science
Thu, 23 Jan 2025 17:47 UTC
Chorus waves are mysterious, chirping signals produced by spiraling plasma inside our planet's magnetic field. But a new detection suggests scientists may understand less about them than first thought.
The northern lights
© Courtesy of NASA/Mokko StudioThe northern lights as seen from the International Space Station.
Scientists have detected strange chirping waves — which resemble the dawn chorus of birds — thousands of miles from Earth, and they could pose big problems for future spaceflight.

Chorus waves, named because of their resemblance to birdsong when converted to audio signals, are perturbations in Earth's electromagnetic field capable of accelerating particles to potentially deadly speeds for spacecraft and astronauts.

Yet while these mysterious waves have been spotted coming from Earth and other planets since the 1960s, scientists previously assumed they only occurred nearby.

Now, in a discovery that challenges existing theories, a new team of researchers has spotted the waves at a distance of 100,000 miles (165,000 kilometers) from Earth, roughly three times further than they were detected before. The researchers published their findings Jan 22. in the journal Nature.

Chorus waves (or whistler-mode chorus waves) are bursts of energy lasting just a few tenths of a second that ping across Earth's magnetosphere, the magnetic field that envelops our planet. The waves were first detected by World War I radio operators who heard them while listening for enemy signals.

In the decades since, chorus waves have been picked up by radio receivers, as well as by NASA's Van Allen Probe spacecraft, which detected the chirrups coming from Earth's radiation belts. The waves have also been spotted surrounding Mercury, Jupiter, Saturn, Uranus and Neptune (all planets with global magnetic fields) as well as Mars and Venus, which do not have magnetic fields.
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Astronomers thought they understood fast radio bursts. A recent one calls that into question.

Robert Sanders
University of California - Berkeley
Tue, 21 Jan 2025 20:40 UTC
The new ability to pinpoint sources of fast radio bursts places one recent burst in a surprising location.
The CHIME telescopes in British Columbia
© CHIME, Andre Renard, Dunlap Institute for Astronomy & Astrophysics, University of TorontoThe CHIME telescopes in British Columbia detected the unusual fast radio burst, dubbed FRB 20240209A, in February 2024.
Astronomer Calvin Leung was excited last summer to crunch data from a newly commissioned radio telescope to precisely pinpoint the origin of repeated bursts of intense radio waves — so-called fast radio bursts (FRBs) — emanating from somewhere in the northern constellation Ursa Minor.

Leung, a Miller Postdoctoral Fellowship recipient at the University of California, Berkeley, hopes eventually to understand the origins of these mysterious bursts and use them as probes to trace the large-scale structure of the universe, a key to its origin and evolution. He had written most of the computer code that allowed him and his colleagues to combine data from several telescopes to triangulate the position of a burst to within a hair's width at arm's length.

The excitement turned to perplexity when his collaborators on the Canadian Hydrogen Intensity Mapping Experiment (CHIME) turned optical telescopes on the spot and discovered that the source was in the distant outskirts of a long-dead elliptical galaxy that by all rights should not contain the kind of star thought to produce these bursts.

Instead of finding an expected "magnetar" — a highly magnetized, spinning neutron star left over from the core collapse of a young, massive star — "now the question was: How are you going to explain the presence of a magnetar inside this old, dead galaxy?" Leung said.

The young stellar remnants that theorists think produce these millisecond bursts of radio waves should have disappeared long ago in the 11.3-billion-year-old galaxy, located 2 billion light years from Earth and weighing more than 100 billion times the mass of the sun.
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Cassiopaea

Hubble captures a pale blue supernova in galaxy LEDA 22057


European Space Agency
Fri, 03 Jan 2025 17:41 UTC
Supernova in LEDA 22057
© ESA/Hubble & NASA, R. J. Foley (UC Santa Cruz), CC BY 4.0 INT or ESA Standard License
This NASA/ESA Hubble Space Telescope Picture of the Week features the galaxy LEDA 22057, which is located about 650 million light-years away in the constellation Gemini. Like the subject of a previous Picture of the Week, LEDA 22057 is the site of a supernova explosion.

This particular supernova, named SN 2024PI, was discovered by an automated survey in January 2024. The survey covers the entire northern half of the night sky every two days and has cataloged more than 10,000 supernovae.

The supernova is visible in the image: Located just down and to the right of the galactic nucleus, the pale blue dot of SN 2024PI stands out against the galaxy's ghostly spiral arms. This image was taken about a month and a half after the supernova was discovered, so the supernova is seen here many times fainter than its maximum brilliance.
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Galaxy

M87's powerful jet unleashes rare gamma-ray outburst


Nagoya City University
Fri, 13 Dec 2024 17:03 UTC
M87 Gamma Outburst
© EHT Collaboration, Fermi-LAT Collaboration, H.E.S.S. Collaboration, MAGIC Collaboration, VERITAS Collaboration, EAVN CollaborationLight curve of the gamma-ray flare (bottom) and collection of quasi-simulated images of the M87 jet (top) at various scales obtained in radio and X-ray during the 2018 campaign. The instrument, the wavelength observation range and scale are shown at the top left of each image.
Also known as Virgo A or NGC 4486, M87 is the brightest object in the Virgo cluster of galaxies, the largest gravitationally bound type of structure in the universe. It came to fame in April 2019 after scientists from EHT released the first image of a black hole in its center. Led by the EHT multi wavelength working group, a study published in Astronomy and Astrophysics Journal presents the data from the second EHT observational campaign conducted in April 2018, involving over 25 terrestrial and orbital telescopes. The authors report the first observation of a high-energy gamma-ray flare in over a decade from the supermassive black hole M87, based on nearly simultaneous spectra of the galaxy spanning the broadest wavelength range ever collected.

"We were lucky to detect a gamma-ray flare from M87 during this Event Horizon Telescope's multi-wavelength campaign. This marks the first gamma-ray flaring event observed in this source in over a decade, allowing us to precisely constrain the size of the region responsible for the observed gamma-ray emission. Observations — both recent ones with a more sensitive EHT array and those planned for the coming years — will provide invaluable insights and an extraordinary opportunity to study the physics surrounding M87's supermassive black hole. These efforts promise to shed light on the disk-jet connection and uncover the origins and mechanisms behind the gamma-ray photon emission." says Giacomo Principe, one of the paper coordinators, a researcher at the University of Trieste associated with INAF and INFN. The article has been accepted for publication in Astronomy & Astrophysics.

The relativistic jet examined by the researchers is surprising in its extent, reaching sizes that exceed the black hole's event horizon by tens of millions of times (7 orders of magnitude) - akin to the difference between the size of a bacterium and the largest known blue whale.
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Galaxy

Rare, ultra-luminous nova spotted in the Small Magellanic Cloud

Sam Sholtis
Penn State Eberly College of Science
Wed, 16 Oct 2024 15:53 UTC
The X-ray outburst from the nova, observed by the Neil Gehrels Swift Observatory, is one of the brightest ever produced by a white dwarf star.
Small Magellanic Cloud
© Space.comSmall Magellanic Cloud
A rare, extremely luminous X-ray outburst has been observed in the Small Magellanic Cloud, a dwarf galaxy that is a close neighbor of our own Milky Way galaxy. The observations, made by the Neil Gehrels Swift Observatory and other telescopes, were described by an international team of astronomers led Penn State scientists on the Swift team. The researchers attribute the outburst to a nova eruption produced by a white dwarf binary star system. The researchers attributed the outburst to one of the most luminous nova eruptions ever produced by a white dwarf binary star system.

The observations were described in a paper recently published in the Monthly Notices of the Royal Astronomical Society.

"This is only the second time that we have observed such a bright outburst from this type of white dwarf binary system," said Thomas Gaudin, a graduate student at Penn State and the first author of the paper. "We hope that this event will provide more insight into how these outbursts are produced and help us to better understand this mysterious class of binary."

The system that produced this outburst is referred to as CXOU J005245.0-722844. It was recently identified by members of the Einstein Probe team and confirmed by the Swift team as the seventh-known example of a Be/White Dwarf X-ray binary. Be/White Dwarf binaries are binary systems in which a white dwarf star orbits a hot young star surrounded by a disk of stellar material. Astronomers expect these binaries to be commonly observed, Gaudin said, and the lack of known examples is a mystery.
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Cassiopaea

Northern Lights shimmer over UK in stunning photos

Simon King, Ian Aikman and Hafsa Khalil
BBC
Fri, 11 Oct 2024 10:07 UTC
MMMM
© REUTERSAngel of the North, Gateshead
The Northern Lights have splashed vivid colour across UK night skies once again, with stunning images captured all across the country.

The lights, also known as aurora borealis, were expected to be seen only as far south as the Midlands, but on Wednesday night, according to BBC Weather was the strongest and most widespread showing of the phenomenon in the UK since May.

As solar activity weakens, it might still be possible for those in some Northern areas to see the lights on Friday, but elsewhere, the chances are low.

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Question

James Webb telescope watches ancient supernova replay 3 times — and confirms something is seriously wrong in our understanding of the universe

Ben Turner
Live Science
Thu, 03 Oct 2024 15:37 UTC
The James Webb Space Telescope has zoomed in on an ancient supernova, revealing fresh evidence that a crisis in cosmology called the Hubble tension isn't going anywhere soon.
Ancient Supernova
© NASAAn ancient supernova from the early universe is magnified and duplicated three times (circled dots) through the phenomenon of gravitational lensing.
The James Webb Space Telescope (JWST) has discovered yet another troubling sign that there's something very wrong with our model of the universe.

Depending on which part of the universe astronomers measure, the cosmos seems to be growing at different rates — a problem scientists call the Hubble tension. Measurements taken from the distant, early universe show that the expansion rate, called the Hubble constant, closely matches our best current model of the universe, while those taken nearer to Earth threaten to break it.

Now, a new study using the gravitationally-warped light of a 10.2 billion light-year distant supernova has revealed that the mystery could be here to stay. The researchers released their findings in a series of papers in The Astrophysical Journal. The Hubble tension calculations have also been accepted for publication in the journal, and are posted in a paper on the pre-print database arXiv.

"Our team's results are impactful: The Hubble constant value matches other measurements in the local universe, and is somewhat in tension with values obtained when the universe was young," co-author Brenda Frye, an associate professor of astronomy at the University of Arizona said in a statement.
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