Space
Editorial of the Technological Innovation Website – 05/07/2024
Diving into a black hole
Have you ever wondered what would happen if you intentionally fell, or dived, into a black hole?
Thanks to a new immersive visualization produced on a NASA supercomputer, it’s now possible to get a glimpse of what theories tell us about what it would be like to plunge into the event horizon, the point of no return of a black hole.
Here are two videos, one just showing the window of your ship, and another more educational, explaining (in English) each step of the viewing and diving, with the effects of general relativity making everything twist and bend.
“People often ask about this, and simulating these hard-to-imagine processes helps me connect the mathematics of relativity to real consequences in the real Universe,” said Jeremy Schnittman, an astrophysicist at the Goddard Space Flight Center who created the visualizations. “So I simulated two different scenarios, one in which a camera – a stand-in for a daring astronaut – misses the event horizon and shoots back, and another in which it crosses the boundary, sealing its fate.”
To create the visualizations, Schnittman teamed up with his colleague Brian Powell and used the supercomputer Discover at the NASA Climate Simulation Center. The project generated about 10 terabytes of data – equivalent to about half the estimated text content of the Library of Congress. It took about 5 days running on 0.3% of the supercomputer’s 129,000 processors – it could be done on a typical laptop, but it would take about a decade.
The destination of the trip is a supermassive black hole with 4.3 million times the mass of our Sun, equivalent to Sagittarius A*, located in the center of our galaxy, the Milky Way.
“Stellar-mass black holes, which contain up to about 30 solar masses, have much smaller event horizons and stronger tidal forces, which can destroy approaching objects before they reach the horizon,” explained Schnittman. “If you have a choice, you’ll want to fall into a supermassive black hole.”
This occurs because the gravitational pull on the end of an object closest to the black hole is much stronger than on the other end. Falling objects stretch like noodles, a process astrophysicists call spaghettification. Other simulations have shown that it may be possible to survive a fall into a black hole.
Like the trip to a black hole
The event horizon of the simulated black hole spans about 25 million kilometers, or about 17% of the distance from Earth to the Sun. A flat, swirling cloud of hot, glowing gas, called an accretion disk, surrounds it and serves as a visual reference during diving. The same happens with bright structures, called photon rings, that form closer to the black hole from light that has orbited it one or more times.
As the chamber approaches the black hole, reaching speeds increasingly close to the speed of light, the brightness of the accretion disk and background stars becomes amplified, much like the sound of a racing car accelerating. approaching increases in intensity. Its light appears brighter and whiter when we look in the direction of travel.
The films begin with the camera located nearly 400 million miles away, with the black hole quickly filling the field of view. Along the way, the black hole’s disk, photon rings, and night sky become increasingly distorted, and even form multiple images as their light passes through the increasingly distorted space-time.
In real time, the camera would take about 3 hours to fall to the event horizon, completing almost two full 30-minute orbits along the way. But to anyone watching from afar, she would never get there. As spacetime becomes increasingly distorted near the event horizon, the camera image slows down and appears to freeze a little earlier. This is why astronomers originally referred to black holes as “frozen stars.”
At the event horizon proper, even spacetime itself flows inward at the speed of light, the limit of cosmic speed. Once inside, both the camera and the space-time in which it moves race toward the center of the black hole – a one-dimensional point called the singularity, where the laws of physics as we know them cease to make sense.
Other animations are available at https://svs.gsfc.nasa.gov/14576.
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