Scientists have found what they call a “cow” 180 million light-years away. But this isn’t bovine in space—it’s a giant explosion that’s trickier than experts imagine.
Stars often explode in a spherical shape, but in 2018, scientists noticed an unusual stellar explosion deep in space that was “the most aspherical ever seen.” news release from the University of Sheffield. Justin Mound, a lecturer in astrophysics at the university, was the lead author of the latest study on the observations, which was published Monthly Bulletin of the Royal Astronomical Society.
Scientists accidentally – and fortunately – observed a flash of polarized light in June 2018 that was captured by a telescope in Hawaii. A 2019 news release from Northwestern University, whose researcher Raffaella Margutti was part of the initially reported results, said the explosion, dubbed AT2018cow, was a “spectacularly bright anomaly” 10 to 100 times brighter than supernovae. Scientists also noticed that the explosion released particles flying at 10% of the speed of light.
“We knew right away that this source went from inactive to peak light in a matter of days,” Margutti said. “That was enough to get everyone excited because it was unusual and, by astronomical standards, it was very close.”
In Mound’s study, the researchers measured the polarization of that flash, which allowed them to identify the shape of the burst, and through that, they found that it was the size of Earth’s solar system in a galaxy about 180 million light-years away.
They determined that the burst was a rare fast blue optical transient, a type of burst that astronomers refer to as a “cow.” The latest discovery is the fifth such starburst ever seen.
“Very little is known about FBOT explosions — they don’t behave like exploding stars, they’re very bright and they evolve very quickly,” Maund said. “Generally speaking, they’re weird, and this new observation makes them even weirder. … We never thought explosions could be so volatile.”
He proposed two possible reasons why this method might explode. The first is that stars that explode can form a disk shape just before they die. the other? The star collapses into a black hole and eats the rest of its structure, an event known as a failed supernova.
“What we know for sure is that the recorded anomaly levels are a key part of understanding these mysterious explosions,” Maund said, “and it challenges our preconceived notions of how they might explode in the universe.”
