![]() A black hole time machine could allow an astronaut to find out what the world will be like in the future. An astronaut could take a short trip near a black hole and return to Earth after years, decades, or even centuries had passed there. Someday humans might be able to use black holes to time travel forward. When the spacewalker returned to the spaceship after an hour-long spacewalk, years would have passed for those aboard the spacecraft. But if anyone back on the spacecraft could observe the astronaut’s watch from far away, they’d see its hands slow down as the spacewalker got closer to the black hole. If an astronaut left his spacecraft to explore a black hole up close, he’d see the hands on his watch ticking at normal speed. The intense gravity near a black hole makes time behave in strange ways. (A* is scientist-code for “A-star.”) The most common type of black holes, stellar black holes, are only up to 20 times more massive than our sun. This is the kind of black hole that’s at the center of our galaxy, the Milky Way it’s called Sagittarius A*. A black hole has a gravitational pull that is so intense that nothing, not even light, can escape it once inside a certain region, called the event horizon. They’re up to one million times more massive than our sun. Supermassive black holes are the largest type of black hole. Though astronomers can’t see black holes, they know they’re there by the effect they have on objects that get too close. That’s why we can’t see black holes in space-they've gobbled up all the light. This includes light, the fastest thing in the universe. Nothing can move fast enough to escape a black hole’s gravity. They're extremely dense, with such strong gravitational attraction that not even light can escape their grasp. The giant star is eventually squashed into a supersmall dot you can’t see.Ī black hole’s gravity, or attractive force, is so strong that it pulls in anything that gets too close. Black holes are some of the strangest and most fascinating objects in space. This causes an explosion called a supernova. The star implodes, and its center collapses under its own weight. Most black holes, regardless of their size, are born when a giant star runs out of energy. At that time, he had considered this TDE unremarkable.At the center of most galaxies is one of the strangest and deadliest things in the universe: a black hole. Study co-author Sebastian Gomez, a postdoctoral fellow at the Space Telescope Science Institute in Baltimore, studied AT2018hyz in 2018 with visible-light telescopes such as the 1.2-meter (3.9 feet) telescope at the Fred Lawrence Whipple Observatory in Arizona. "But in AT2018hyz there was radio silence for the first three years, and now it's dramatically lit up to become one of the most radio-luminous TDEs ever observed." "We have been studying TDEs with radio telescopes for more than a decade, and we sometimes find they shine in radio waves as they spew out material while the star is first being consumed by the black hole," Berger said. The team studied the event in multiple wavelengths of light and with a range of telescopes - including the VLA, the MeerKAT radio telescope in South Africa, and the Atacama Large Millimeter/submillimeter Array in Chile - and found that the most striking observations of AT2018hyz were in radio frequencies. "All the applications were immediately accepted." "We applied for Director's Discretionary Time on multiple telescopes, which is when you find something so unexpected, you can't wait for the normal cycle of telescope proposals to observe it," Cendes said. This finding encouraged them to investigate AT2018hyz further. Data they collected in radio waves with the Very Large Array in New Mexico showed that this black hole had mysteriously burst back to life in June 2021. ![]() The astronomers spotted this event as they were searching for signs of TDEs that have occurred over the past few years. "This is the first time that we have witnessed such a long delay between the feeding and the outflow," study co-author Edo Berger, an astronomy professor at Harvard University, said in the statement. Why it took so long for this black hole to burp out its last meal is also a mystery. For comparison, TDEs usually spit out this material at about 10% the speed of light. ![]() "It's as if this black hole has started abruptly burping out a bunch of material from the star it ate years ago."Ĭendes and her team determined that this material is being ejected from the black hole at around 300 million mph (480 million kph) - about half the speed of light. "This caught us completely by surprise - no one has ever seen anything like this before," Yvette Cendes, an astronomer at the Harvard & Smithsonian Center for Astrophysics who led the research, said in a statement. ![]()
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