No human being will ever encounter a black hole. But we can’t stop wondering what it would be like to fall into one of these massive, beguiling, physics-defying singularities.
NASA created a simulation to help us imagine what it would be like.
Jeremy Schnittman is an astrophysicist at NASA’s Goddard Space Flight Center and he created the visualizations.
“People often ask about this, and simulating these difficult-to-imagine processes helps me connect the mathematics of relativity to actual consequences in the real universe,” he said.
“So I simulated two different scenarios, one where a camera — a stand-in for a daring astronaut — just misses the event horizon and slingshots back out, and one where it crosses the boundary, sealing its fate.”
In one, the viewpoint plunges directly into the black hole like a free-falling astronaut, with explanatory text to guide us through what we’re seeing. The other is a 360-degree view of the black hole.
Schnittman created them with a NASA supercomputer called Discover in only five days, generating about 10 terabytes of data. The computer used only about 0.3% of its power. The same visualization would’ve taken more than a decade to create on an average laptop computer.
The black hole in the visualization is the same size as Sagittarius A star, the supermassive black hole (SMBH) at the heart of the Milky Way.
It has 4.3 million solar masses and dominates the galaxy’s inner regions. Its event horizon reaches about 25 million km (16 million miles).
That’s about 17% of the distance from Earth to the Sun. The event horizon is surrounded by an accretion disk, a swirling disk of superheated material drawn in by the black hole’s overpowering gravity.
Another type of black hole, the stellar-mass black hole, is much less massive. Schnittman says that if you’re going to fall into a black hole, you’d rather fall into the supermassive one.
“If you have the choice, you want to fall into a supermassive black hole,” Schnittman explained. “Stellar-mass black holes, which contain up to about 30 solar masses, possess much smaller event horizons and stronger tidal forces, which can rip apart approaching objects before they get to the horizon.”
Powerful gravity is the reason. The SMBH’s gravity is so strong that it pulls harder on the end of the object nearest it. That stretches the object and elongates it. Stephen Hawking was the first to call this ‘spaghettification,’ and the name has stuck. Presumably, you’d get a better look if you fall into an SMBH.
In the movies, the camera begins at a distance of 640 million km (400 million miles.) Since space-time is warped around a black hole, so are the images of the sky, the black hole’s disk, and the photon ring.
It takes the camera three hours of real-time to fall into the event horizon, and it completes almost two 30-minute orbits as it falls. A distant observer would never see an object ever reach the black hole. From a distance, the object would freeze at the event horizon.
When a falling object reaches the event horizon, it and space-time itself reach the speed of light. After crossing the horizon, the object and the space-time around it surge toward the singularity, a point of infinite density and gravity.
“Once the camera crosses the horizon, its destruction by spaghettification is just 12.8 seconds away,” Schnittman said.
In the second video, the camera never crosses the event horizon and instead escapes. But the powerful black hole still has an effect.
Imagine if the camera were an astronaut, and they flew this six-hour roundtrip while a separate astronaut stayed far away from the SMBH. The astronaut would return and be 36 minutes younger than the astronaut who never approached the black hole.
“This situation can be even more extreme,” Schnittman noted. “If the black hole were rapidly rotating, like the one shown in the 2014 movie ‘Interstellar,’ she would return many years younger than her shipmates.”
The bottom line is, don’t fall into a black hole. In fact, resist your fascination and don’t even approach one.
Leave them for the physicists.
Written by Evan Gough/Universe Today.
