If You Fell Into a Black Hole, You'd Be Frozen in Space and Time Forever

Black holes are the universe's boogeyman: always lurking somewhere out there, but nearly impossible to spot.

First theorized to exist by Albert Einstein and eventually discovered by Stephen Hawking, black holes are objects so immensely dense and with gravity so strong that not even light can escape from them. They have remained mostly a mystery to science for a long time, and only now are we starting to understand exactly what they are, and how they work in terms of physics.

Black holes, according to astrophysicist and science communicator Dr. Becky Smethurst, are neither black nor holes. She is the author of A Brief History of Black Holes: And why nearly everything you know about them is wrong.

"They're more like mountains of matter than holes," she told Newsweek. "There's no other side of them that they lead somewhere. It's literally just you've taken a star and you've crushed it down."

"They are [also not] black," she said. "They are some of the brightest objects in the entire universe. It's not necessarily the black hole itself, because they're these prisons for light and you can't get any light from the black hole, but the region around the black hole."

"You have material that is spiraling inwards towards it, that is accelerated to huge speeds, which heats up and starts to glow like iron heating on a forge. It doesn't just start to glow in optical light, it's also X-ray light, UV light, and you also get some radio emission as well from it. So they light up like Christmas trees," Smethurst said.

Black holes have an event horizon, which is the point of no return for all matter and energy: once you've passed that, there is no escape from gravity. Beyond the event horizon is eventually the singularity, the inconceivable single point where the immense mass of the black hole is located.

If you somehow fell into a black hole, on the journey between these places, something called spaghettification would happen to your body.

"Spaghettification essentially means that the gravity at your feet would be stronger than [at] your head, and you would get stretched out like spaghetti as you fall closer and closer to the black hole. It's a rather morbid picture."

What you experience and witness as someone falling into a black hole would be very different to what a bystander, safely away from the event horizon, would see.

"[Approaching the event horizon], you would see the black hole getting bigger and bigger and bigger. Black holes do this sort of weird warping of light that makes them look bigger than they appear," Smethurst explained.

"As you fall beyond the event horizon, you will have all the light of the universe bent into your eye, one brief moment. And then beyond that, we don't know what you would see at all—whether it would be incredibly bright in there, whether it would be complete darkness, or whether you'd see some other form of matter that we just don't know. Because at the minute, under our understanding of laws of physics, we have no idea what's beyond the event horizon," she said.

Your friend watching you fall in, though, wouldn't see that at all.

"Say you had a little beacon on your spacecraft that was like a little lighthouse flashing every 30 seconds. The light signals from that would actually take longer and longer to get to you between each flash because of the force of gravity, essentially almost like slowing down the light as it got closer and closer to the black hole. And so [the observer] would never actually see you cross that event horizon. You would appear frozen forever in space and time," said Smethurst.

The amount of time between crossing the event horizon and spaghettification may not be as short as you might expect, however. Depending on the size of the black hole, the distance between the event horizon and the singularity may be immense: the largest black hole we have discovered so far, TON 618, is more than 40 times wider than the distance from Neptune to the Sun.

"There is a chance that someone falling into that black hole and working their way down this gradient of gravity could live their entire human lifetime traveling from relative safety [inside the black hole]," Smethurst said.

"But it's interesting to see how your concept of time would change: as soon as you're past the event horizon, any direction in space is also the future. There is no past because you can never get out."

Correction, 09/07/2022, 8:45 a.m. ET: This article has been amended to correct the spelling of Stephen Hawking's name.