Could a human enter a black hole to study it and survive on the event horizon?

To solve the mysteries of black holes, a human would simply have to venture into them. However, there is a rather complicated capture: a human can only do this if the black hole is supermassive and isolated, and so the person entering the black hole does not expect to report the results to anyone in the entire universe.

We are both physicists who study black holes, albeit at a very safe distance. Black holes are among the most abundant astrophysical objects in our universe. These intriguing objects appear to be an essential ingredient in the evolution of the universe, big Bang till today. They probably had an impact on the formation of human life in our own galaxy.

Two types of black holes

The universe is littered with a vast zoo of different types of black holes.

They can vary in size and be electrically charged, in the same way that electrons or protons are in atoms. Some black holes are actually spinning. There are two types of black holes which are relevant to our discussion. The former does not rotate, is electrically neutral – that is, not positively or negatively charged – and has the mass of our Sun. The second type is a supermassive black hole, with a mass of millions or even billions of times that of our Sun.

Besides the mass difference between these two types of black holes, what also differentiates them is the distance from their center to their “event horizon” – a measure called radial distance. The event horizon of a black hole is the point of no return. Anything that passes this point will be swallowed by the black hole and will disappear forever from our known universe.

On the event horizon, the black hole’s gravity is so powerful that no mechanical force can overcome or thwart it. Even light, which moves the fastest in our universe, cannot escape – hence the term “black hole”.

The radial size of the event horizon depends on the mass of the respective black hole and is essential for a person to survive by falling into one. For a black hole with a mass of our Sun (a solar mass), the event horizon will have a radius of just under 2 miles.

The supermassive black hole at the center of our Milky Way the galaxy, on the other hand, has a mass of about 4 million solar masses, and it has an event horizon with a radius of 7.3 million miles or 17 solar rays.

So someone who falls into a stellar-sized black hole will get much, much closer to the center of the black hole before passing the event horizon, instead of falling into a supermassive black hole.

This implies, due to the proximity to the center of the black hole, that the attraction of the black hole on a person will differ by a factor of 1000 billion times between the head and the toes, depending on which one is leading the free fall. . In other words, if the person falls with their feet first, as they approach the event horizon of a stellar mass black hole, the gravitational pull on their feet will be exponentially greater than the tugging of the black hole on his head.

The person would undergo spaghettification and likely not survive a long, thin noodle shape.

Now, a person falling into a supermassive black hole would reach the event horizon much further from the central source of gravitational pull, meaning the difference in gravitational pull between the head and toes is almost zero. Thus, the person would cross the event horizon unaffected, not stretched into a long, thin noodle, survive, and float painlessly beyond the horizon of the black hole.

Other considerations

Most of the black holes we see in the universe are surrounded by very hot discs of matter, mostly made up of gas and dust or other objects like stars and planets that have come too close to the horizon and are fallen into the black hole. These disks are called accretion disks and are very hot and turbulent. They are certainly not hospitable and would make the trip to the black hole extremely dangerous.

To get into it safely, you will need to find a supermassive black hole that is completely isolated and does not feed on surrounding materials, gas, and or even stars.

Now, if a person discovered an isolated supermassive black hole suitable for scientific study and decided to venture into it, anything that was observed or measured inside the black hole would be confined to the black hole’s event horizon.

Keeping in mind that nothing can escape the gravitational pull beyond the event horizon, the falling person would not be able to send information about their findings beyond that horizon. Their journey and discoveries would be lost to the rest of the entire universe forever. But they would enjoy the adventure, as long as they survived… maybe….

Written by Leo Rodriguez, Assistant Professor of Physics, Grinnell College and Shanshan Rodriguez, Assistant Professor of Physics, Grinnell College.

Originally posted on The Conversation.