black holes

Stars, planets, people and petunias: everything emits a special kind of radiation and will, if it sticks around long enough, evaporate into nothing. That’s the claim in a new study of physics effects that were previously thought to occur only near a black hole. In that extreme environment, the largest and smallest things in the universe rub up against one another. To describe events on such different scales, scientists must use both Einstein’s theory of relativity (rules governing the big stuff) and quantum mechanics…

A team of astrophysicists has determined through simulations that the debris shed by dying stars may be a source of gravitational waves—those ripples in spacetime predicted by Einstein over a century ago.First Full-Color Images From Webb Space TelescopeGravitational waves are predicted by the general theory of relativity; they are ripples in spacetime generated by massive accelerating objects. The waves are also produced by the interactions of such objects, like binaries of and mergers between neutron stars and black…

Hotta found, to his surprise, that a simple sequence of events could, in fact, induce the quantum vacuum to go negative—giving up energy it didn’t appear to have. “First I thought I was wrong,” he said, “so I calculated again, and I checked my logic. But I could not find any flaw.”The trouble arises from the bizarre nature of the quantum vacuum, which is a peculiar type of nothing that comes dangerously close to resembling a something. The uncertainty principle forbids any quantum system from settling down into a…

Astronomers have witnessed the largest explosion in space.  The explosive event labeled AT2021lwx was observed to be ten times brighter than any known supernova, the explosions that occur as massive stars die. And whereas supernova explosions only last a few months, this explosive event has been raging for at least three years.  AT2021lwx is also three times brighter than the light that is emitted as stars are ripped apart and devoured by supermassive black holes, occurrences called "tidal disruption events" or "TDEs."…

Gif: NASA’s Goddard Space Flight Center Conceptual Image Lab/GizmodoA video recently shared by NASA showcases just how big supermassive black holes can get. Supermassive black holes have masses greater than 100,000 Suns, and NASA’s new visualization shows the extent to which our local star pales in comparison. What Is Planet Nine and Why Can’t We Find It?The smallest of the lot is the relatively puny J1601+3113, a dwarf galaxy with a black hole at its center. NASA said in a release that even though J1601+3113 has 100,000…

In the movies, time travelers typically step inside a machine and—poof—disappear. They then reappear instantaneously among cowboys, knights or dinosaurs. What these films show is basically time teleportation. Scientists don’t think this conception is likely in the real world, but they also don’t relegate time travel to the crackpot realm. In fact, the laws of physics might allow chronological hopping, but the devil is in the details. Time traveling to the near future is easy: you’re doing it right now at a rate of one…

A team of researchers using the Global Millimeter VLBI Array, a network of radio telescopes around the world, has produced a new image of the black hole at the center of galaxy Messier 87.First Full-Color Images From Webb Space TelescopeThe new composite image resolves aspects of the black hole, including the structure of the superheated material surrounding it, the high-speed relativistic jet spewing from it, and (of course) the menacing shadow of the black hole itself.Radio telescopes like the GMVA and the Event Horizon…

A team of physicists mathematically built an exotic object that they believe could look like a black hole to Earth-based observers but is actually a star. First Full-Color Images From Webb Space TelescopeThe star is a topological soliton: a smooth, stable, albeit theoretical object. (Skyrmions are another type of topological soliton.) In this case, the vexingly complicated mathematics undergirding the hypothetical object show that it would distort space like a black hole, an object whose gravitational field is so intense…

Intriguingly, this kind of decoherence will occur anywhere there is a horizon that only allows information to travel in one direction, creating the potential for causality paradoxes. The edge of the known universe, called the cosmological horizon, is another example. Or consider the “Rindler horizon,” which forms behind an observer who continuously accelerates and approaches the speed of light, so that light rays can no longer catch up with them. All of these “Killing horizons” (named after the late-19th- and…

In the early 2000s, Phil Plait wrote his first book, Bad Astronomy, which debunked conspiracy theories and fallacies, like the idea that NASA faked the moon landings in the 1970s or that planetary alignments can affect life on Earth. Twenty years later, he’s continuing his quest to quash astronomical misconceptions while sharing his love for the cosmos. Plait, an astronomer and science writer, has spent his career sharing space news and explaining complex concepts to the public through his popular blog and newsletter,…