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In December 2024, a planet-wide network of telescopes silently gazed up at a single point of light. For almost 50 days, they remained fixed upon this glittering dot in the dark, watching as it grew brighter and brighter. Before long, it outshone all of its host galaxy. This was a super-luminous supernova, a rare and highly energetic event. But something about this one was different. It didn't just fade away. It pulsed, coming back to life over and over again. And no one knew where this power was coming from.
What made it so much brighter than the death rows of other stars? How did it remain so bright for so long? What kind of cosmic beast had just been created here? I'm Alex McConaughey, and you're watching Astrium. Join me as we unravel this mysterious signal, peering deep into the scorching clouds of dust and gas to explore one of the most extreme magnetic environments in the universe. A place where we might just be witnessing the birth of a new cosmic object, a magnetar. In 2024, a network of four telescopes called the Asteroid Terrestrial Impact Last Alert System, or ATLAS, was scouring the skies for asteroids that
might threaten life here on Earth. Each night, they scan the entire sky four times, looking out for objects so faint that it would be like standing in San Francisco and trying to spot a match being lit in New York. In space terms, that's spotting a 100-m diameter asteroid 40 million kilometers away from the earth, as far away from us as Venus is at its closest. Once an object has been found, the next job is to track its path. And to do that, ATLAS takes four exposures of the same patch of sky every hour. Since asteroids are fast-moving when close to earth, they should appear in a different
patch of sky with each exposure, whooshing through each frame. But on the 12th of December, near the constellation of Corvus, they saw something that did not follow this pattern. It was an object that stayed quite motionless in all four frames. This was no asteroid. Having confirmed that Earth was safe, for now at least, the team was curious as to what this might be. So, they passed their findings on to Joseph Farah and his team at Las Cumbres Observatory Global Telescope for closer investigation. As the name suggests, this is a truly global network of telescopes, 27 of them in fact, scattered across the planet at locations from Texas all the way to South Africa and even Australia.
Las Cumbres is fully robotic, allowing it to run around the clock. Its global spread makes it brilliant at studying what we call transient events, temporary phenomena lasting anywhere from mere seconds to several years, with each telescope passing the observation baton to the next as the Earth spins, causing an object to pass across and then out of their fields of view. And so, for another 200 straight days, all 27 telescopes watched the single distant point ATLAS had found. It was thanks to this combined power of Las Cumbres that astronomers were able to observe something that mankind had never seen before, something incredibly powerful.
Now, 27 telescopes might be a little difficult to carry around with you, but by following the event across a global network, they could trace subtle changes in its brightness over time that no single snapshot could reveal. And combining multiple observations to reveal more information is also one of the strengths of another telescope, one compact enough to take almost anywhere, the Dwarf Mini. Brought to you by the sponsor of today's video, Dwarf Lab. The Dwarf Mini is an approachable, portable smart telescope that takes breathtaking images of some of the most beautiful galaxies and nebulae of deep space, drawing additional details to the fore by taking and compiling multiple images
in a process known as live stacking. It's really simple to set up. I just attach it to its tripod, calibrate the telescope, and select a target with its automatic go-to, whereby using the stars to orient itself, the Dwarf Mini swivels to whatever target you select for it. Then, it was just a matter of leaving it for a few minutes and seeing the incredible images it produced in the app by the end. It's a great way to get into stargazing for yourself and with others. Less lugging around and setting up a heavy kit, and more seeing some of the wonders space has on offer. And speaking of offers, if you scan my QR code or follow the link in the description below, Dwarf Lab is running a 5% discount for my viewers if you use the
code Astro at checkout. It's a great way to support the channel, so go check them out. Now, back to that powerful object witnessed by the Las Cumbres telescope that was shining so brightly. The transient event the Las Cumbres telescopes were watching was called super luminous supernova. You might be able to guess from the name that this is a particularly bright supernova. A billion light-years from Earth, a star with a mass around 25 times that of our sun was dying, going out in a final blaze of glory. And what a blaze. This mighty beacon of light was one of the brightest events anywhere in the universe, and they
casually named it SN2024afav. We've been occasionally spotting superluminal supernova for the last 20 years, but they're not common. In fact, we've only confirmed sightings of around 100 of them in that time. Standard supernovae derive much of their power from radioactive elements like nickel 56 formed during their explosion. It is the decay of these elements that we can see lighting up the expanding clouds of stellar debris surrounding them. Superluminal supernovae, on the other hand, are truly dazzling explosions, usually between 10 and 100 times brighter than typical supernovae. In fact, the brightest supernova-like event that we've ever seen was not only 570
billion times brighter than our own sun, but outshone the entire Milky Way galaxy. And therein lies the mystery that has plagued astronomers since these immense explosions of light were first discovered 20 years ago. What is it about these dying stars in particular that makes them shine so bright? Frustratingly and tantalizingly, superluminal supernovae are one of those pesky space phenomena that are particularly hard to see. As they explode, waves of dust and gas hurtle away from their fiery center, creating a huge opaque wall of superheated material that our telescopes cannot penetrate.
The difficulty is that the cloud of dust surrounding the exploding star is so dense and hot that it forms a wall of plasma. All light trying to escape becomes trapped, bouncing around the cloud of ions and electrons, often for days or weeks, only eventually escaping when the plasma cools enough for light to be able to escape. And that means we cannot see and do not know what is happening at the heart powering these vastly bright explosions. Instead, for 20 years astronomers have been forced to speculate. That is until we found this super luminous supernova, SN2024afav.
You see, by trolling through the 255 days worth of data from Las Cumbres, the analysis team discovered that SN2024afav did not follow any of the usual supernova brightness patterns. Day after day, the supernova became brighter and brighter until, around day 46, it reached its dazzling peak and began to fade. But the show wasn't over. About 40 days later, the supernova brightened again, then sharply faded, only to briefly brighten again 32 days later. Finally, after another 22 days of gentle fading, its brightness undulated four more times, getting brighter and dimmer again in the same fashion, only less dramatically than with the first three peaks.
It was only then that the supernova truly continued to fade away. The astronomers had never seen anything like this before. On occasion, they'd seen a couple of bumps, possibly produced by shock waves as layers of gas collide during the epic explosion, but never anything quite as distinctive as these four clear, increasingly rapid oscillations or chirps, which swept upwards in frequency like a rising birdsong. So, what exactly had we just witnessed? Across the US, a team of astrophysicists spent months building and testing models. Central to one of the most interesting ones was the promise of a new cosmic monster being born. A theory that had been waiting 16 years to
be tested. It was the brainchild of Dan Kasen, a theoretical astrophysicist at University of California, Berkeley. Dan had a thought. What if, hiding at the heart of these violent cataclysms, empowering their violent explosions, was a magnetar? Of all the weird and wonderful things that populate our universe, magnetars are some of my favorites. They are a rare, exotic, and extreme type of neutron star. Each magnetar has a diameter of just under 20 km, roughly the length of Manhattan, but contains more mass than the sun. And boy, do they spin, whipping around thousands of times every second at their peak. But the feature that makes them really
special is their titanic magnetic field. Each magnetar has more than a trillion times more magnetic strength than the sun. Or, to put it another way, that's more than 10 trillion times stronger than one of the novelty magnets attached to your refrigerator door. Let's not underestimate what that means. Get close enough to a magnetar, and the very atoms inside you will rip you apart, shredded by its magnetic pull. Despite their extreme nature, however, we haven't actually known about magnetars for that long. The story of magnetars began in 1979 when three disconnected events occurred in the same year. Each one a powerful and unexplainable burst of gamma rays.
The second event, which took place on the 5th of March, lasted only 0.2 seconds but released as much energy as the sun emits in a thousand years. Astronomers first assumed that they were looking at simple gamma-ray bursts, but as time went on, they ruled that out. A gamma-ray burst is a one-time event, whereas these peculiar objects would flash brightly on and off over a week, stop for weeks or years, and then flash again. Instead, it was quickly realized that these three objects were connected, and since they were all very compact and releasing huge amounts of energy with each burst, they were good candidates to be neutron stars.
The next time there was an outburst, a team of astronomers led by Dr. Chryssa Kouveliotou of George Washington University set out to take two measurements. The speed at which the object was slowing and the rate that the spin was slowing down. This way, they had hoped to predict the neutron star's magnetic field strength. How? Well, a magnetic field acts like a cosmic brake, and the stronger it is, the faster it slows the spin of a neutron star. The object that they saw exploding on the 5th of March was estimated to have a magnetic field strength somewhere between 100 trillion and a quadrillion or 10 to the power of 15 gauss.
One of the strongest ever seen or predicted in the universe. In 1992, Dr. Robert Duncan of the University of Texas at Austin and Dr. Christopher Thompson of the University of South Carolina at Chapel Hill proposed that it was possible that these incredibly powerful magnetic fields could theoretically be generated by a newborn neutron star spinning as fast as it can without breaking apart. They coined the term magnetar for these super magnetically powerful neutron stars. Then in 1998, astronomers picked up steady x-ray pulses from a mysterious object and found that its spin was
slowing down. From those measurements, they inferred a magnetic field around 100 times stronger than those of ordinary radio pulsars, giving us the first compelling observational confirmation that magnetars really existed. But the evidence was still indirect. Scientists had calculated the field strength from the object's behavior, rather than measured it outright. It wasn't until 2002 that scientists, using NASA's Rossi X-ray Timing Explorer, managed to measure the magnetic field strength of a potential magnetar directly, rather than as a ratio of the spin and spin down speed. Todd Strohmayer and Alaa Ibrahim from NASA Goddard captured a key measurement from SGR 1806-20, the fourth magnetar ever discovered.
They teased out a line in the magnetar's absorption spectrum that was at an energy of 5 kilo electron volts, consistent with the energy of a proton spiraling in a magnetic field of a quadrillion gauss, just as the earlier teams had predicted. Even today, we have only confirmed 24 of them with a handful more candidates in contention. And Dan's idea was that perhaps these super luminous supernova events were showing us not just the death of a star, but the birth of a magnetar. He proposed that as these wild neutron stars spin, their magnetic fields would accelerate charged particles, hurtling them into the debris expanding around the supernova. The force of these particles colliding with the debris field that would heat the already
boiling hot debris up even further, supercharging the supernova's glow and making it far brighter than a typical supernova. But, he'd never been able to conclusively link the two. And that brings us back to the 2024 super luminous supernova and those mysterious luminous chirps in signal SN2024afav. Joseph Faira at the Las Cumbres Observatory Global Telescope managed to link those chirps to Dan Kasen's idea about magnetars being born. It wasn't straightforward, though. As his team ran model after model to try and find one that perfectly fit the data and explained exactly what they had seen over that 255 days of observations, it became clear that something wasn't right.
Using classic Newtonian mechanics wasn't producing simulations that matched what they had detected with their telescopes. And that was because they were missing one more crucial link. Something that has become one of the most revolutionary ideas of the 20th century. The team ran their models again, but this time they accounted for space-time and general relativity. Given we know its effects become dominant in really extreme environments, it seemed worth a try. Instead of picturing an invisible force pulling between two objects, general relativity describes a four-dimensional fabric that is warped by object with mass, familiar to us as space-time. That picture changes how we calculate
the influence of objects very close to a dense mass, like the debris around a magnetar. When we take the effects of general relativity into consideration, all sorts of new and surprising effects are predicted. Faira and his team shifted gears, beginning to include general relativity into their models, and suddenly everything began to click into place, including the changes in its brightness. The picture that began to emerge looked like this. A star with a very powerful magnetic field dies. As it collapses into a neutron star, it spins ever more rapidly. If the dying star's initial magnetic field is strong enough, this rapid rotation
creates a magnetohydrodynamic dynamo, amplifying that magnetic field by trillions of times. In this case, out of the catastrophic explosion, a brand new magnetar is born. During the collapse, huge amounts of dust and gas are propelled out into the cosmos by vastly powerful shock waves. Much of it is carried away from the dying star, but not all. Some of the material falls back, unable to escape the pull of the magnetar's great gravitational field. It instead forms a flat accretion disk, spinning around the magnetar. But the accretion disk and the magnetar are spinning along different axes. And this is where things start to get really weird. Thanks to general
relativity, spinning objects like these dense, newly forming magnetars drag space-time with them. Theoreticians refer to this as frame dragging, which in this case causes a motion known as Lense-Thirring precession, where a new magnetar is warping its space-time sheet around it as it spins. The result is that the accretion disk wobbles, and every now and again blocks and reflects the light from the magnetar. This creates an almost strobing effect, a blinking in the light traveling to us on Earth. Since the space-time around the magnetar is being dragged faster and faster the closer you get, as the disc is pulled inward towards the giant spinning mass,
its wobbles get faster and faster, too, matching the increased speed of the oscillating brightness that the researchers spotted as the supernova began to fade. The team say this is actually the first time general relativity has been needed to describe the behavioral mechanics of a supernova. And what's really special about this is that it provides a really strong, clear link between two remarkable phenomena, super luminous supernovae and the birth of magnetars, and ties them together with Einstein's theory of general relativity.
Two birds with one very weird stone. If they are right, and it is indeed the birth of a magnetar at the center of this super bright space explosion, then Farrah and his colleagues estimate that the magnetar has a spin period of 4.2 milliseconds and a magnetic field about 300 trillion times the strength of Earth's. But of course, saying that magnetars are at the heart of some super luminous supernovae doesn't mean they are at the heart of all of them. No other supernova has been found to have a chirp, and the team are very clear that this is only one part of a bigger picture.
Other possibilities are still being explored, and you'll be pleased to hear that they are equally epic. We won't delve into them too much here, but if it's something you'd be interested in another video, then let me know in the comments. But one option is that they could still be an exploding star's ejector racing out in a shock wave. The shock wave collides with peripheral, slower moving shells and material that the progenitor star had cast off before dying, and dramatically increases the luminosity as it turns dust into seething hot plasma, thus causing the blips in luminosity. And another option is that it could be a black hole forming, and what we're seeing is the wobbles of a newborn
accretion disk. And who wouldn't want to see that? As I said, more on that another time. But personally, I like the magnetar theory best. There is something about those powerful magnetic fields distorted by space and time, ready to shred anything that gets too close to them that captures the mind. And what I find most exciting is that this is only the start. Given that before now, no one had combined the explosive power of a supernova with general relativity, who knows what future observations will find. I really hope they go back and use these same principles on other supernova events, as there could be a whole world of new physics just waiting to be uncovered. If you've ever watched an Astron video
and found yourself pausing just to take in the beauty of space, you're not alone. The colors, the motion, the scale, they remind us how vast and awe-inspiring the universe really is. Have you ever had your breath taken away when seeing these videos of our sun, Milky Way, or perhaps Venus? Well, now Patreon members have access to these wallpapers for your phone and laptop. Sign up with the link below. It's a simple way to bring that sense of wonder into your daily life while supporting future Astron creations.
