Take a mind-bending plunge into a supermassive black hole
A new NASA simulation takes us on what might be one of the scariest trips in the universe — spiralling into a reality-warping black hole.
In recent years, astronomers have given us our first look at what a supermassive black hole really looks like — first revealing the one at the core of galaxy M87, and then showing us Sagittarius A-star, located in the centre of the Milky Way.
Now, Jeremy Schnittman and Brian Powell, two scientists at NASA's Goddard Space Flight Center, used a supercomputer to depict what it would be like to see one of these cosmic monsters from way too up close.
A supermassive black hole from over 600 million kilometres away. (NASA's Goddard Space Flight Center/J. Schnittman and B. Powell)
According to NASA, the camera starts off 640 million kilometres away, or a little over four times farther than Earth is from the Sun. As the black hole fills the camera's view, we encounter the warping of space-time due to its titanic gravity.
During the camera's journey completing nearly two full orbits, the black hole's disk, the bright photon rings surrounding it, and even the view of the cosmos beyond, become distorted by the strong gravitational lensing.
Warped space-time distorts our view of the black hole and the universe beyond (NASA's Goddard Space Flight Center/J. Schnittman and B. Powell)
This simulation depicts a one-way trip, though, because the camera eventually encounters a boundary around the black hole known as the event horizon.
Once that boundary is crossed, even light — the fastest thing in the universe — doesn't have enough speed to escape.
On the cusp of the event horizon, the dark void of the black hole looms beneath us. (NASA's Goddard Space Flight Center/J. Schnittman and B. Powell)
"Once the camera crosses the horizon, its destruction by spaghettification is just 12.8 seconds away," Schnittman said.
Spaghettification is the scientific term for what happens to something or someone that gets too close to the centre of a black hole. The intensity of its gravitational pull increases so quickly as you approach that you would feel it far stronger in your feet than in your head. The closer you got, the more you would become stretched by these tidal forces, like spaghetti.
"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."
For more on this, as well as a second simulation where the camera just skirts the edge of the black hole before escaping back into space, check out the NASA website.
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What is a black hole?
Every star we can see, including our Sun, exists in a careful balance: the immense weight of the star's outer layers presses inward, while the pressure resulting from fusing elements together in the star's core pushes outward. When the star's core can no longer produce enough fusion energy, the balance is disrupted and the star dies.
Exactly how the star dies depends on how massive it is. Smaller stars, like our Sun, simply cast off their outer layers, leaving behind their core as a white dwarf. More massive stars die in a much more dramatic way, producing a brilliant supernova as their outer layers crush the core. In some cases, the core can only be crushed down so far. This leaves behind a 10-kilometre-wide remnant at the centre of the explosion, known as a neutron star.
Stars of different masses follow different paths of evolution. Along the top of the image, a supermassive star quickly expends the nuclear fuel in its core, exploding in a supernova, and leaving behind a black hole. (©ESA)
For the most massive stars, though, nothing can prevent the complete collapse of their core. It gets crushed down into what astrophysicists call a singularity — an infinitesimally small point that still contains all the mass of the original core.
This results in a very strange situation unique to a black hole. See, the intensity of a star's gravity depends on two things — how much mass it has and your distance from it. So, the closer you get to it, the stronger you feel its gravity and the faster you need to go to escape its grasp.
Since a singularity has so much mass packed into such a small space, you can get very close to it — so close that you reach a point where not even light is going fast enough to escape. This distance is known as the event horizon, and since we can't see anything beyond it, this is technically the 'edge' of the black hole.
This artist's impression depicts a spinning supermassive black hole surrounded by an accretion disc. (ESO, ESA/Hubble, M. Kornmesser/N. Bartmann)
Supermassive black holes take all of this to an extreme. Rather than having the mass of several Suns compacted into a singularity, these monsters contain millions to billions of solar masses.
It's not known yet how supermassive black holes got their start. They may be the dead remnants of the very earliest stars, which have grown immense by consuming gas, dust and stars over billions of years. Or, they may have started out like this when the universe was far smaller and much more dense, and the galaxies just coalesced around them. What we do know is that nearly every galaxy we can see has one of these at their core.
