To solve the mysteries of black holes, man only take risks in one. However, there is a rather complicated catch: man can do this only if the respective black hole is supermassive and isolated and if the person entering the black hole does not expect to report the findings to anyone in the entire universe.
We are both physicists who study black holes, albeit from a very safe distance. Black holes are among the most abundant astrophysical objects in our universe. These interesting objects seem to be an essential ingredient in the evolution of the universe, from the Big Bang to the present day. They probably influenced the formation of human life in our own galaxy.
2 types of black holes
The universe is full of a vast zoo of different kinds of black holes.
They can vary in size and be electrically charged, just as electrons or protons are in atoms. Some black holes actually turn. There are two types of black holes that relate to our discussion. The first one does not rotate, is electrically neutral – so not positively or negatively charged – and has our solar mass. The second type is a supermassive black hole, with a mass millions to even billions of times larger than that of our Sun.
In addition to the massive difference between these two types of black holes, what also differentiates them is the distance from their center to their “event horizon” – radial distance. The event horizon of a black hole is the point of no return. Everything that passes this point will be swallowed up by the black hole and will forever disappear from our known universe.
At the event horizon, the gravity of the black hole is so powerful that no amount of mechanical force can overcome or counteract it. Even light, the fastest moving 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 key for a person to survive falling into one. For a black hole with a mass of our Sun (one solar mass), the event horizon will have a radius of just under 2 miles.
The supermassive black hole at the center of our galaxy, by contrast, has a mass of about 4 million solar masses, and has an event horizon with a radius of 7.3 million miles or 17 solar radii.
Thus, someone falling into a star-sized black hole will get much closer to the center of the black hole before passing the event horizon, as opposed to falling into a supermassive black hole.
This implies, due to the proximity of the center of the black hole, that the traction of the black hole on a human will differ by a factor of 1,000 billion times between head and toe, depending on who is leading the free fall. In other words, if the person falls feet first as they approach the event horizon of a stellar massive black hole, the gravitational pull on their feet will be exponentially greater compared to the pull of the black hole on their head.
The person would experience spaghetti and most likely will not survive being stretched into a long, thin noodle-like shape.
Now, a man falling into a supermassive black hole would reach the event horizon much farther from the central source of gravitational traction, which means that the difference in the gravitational pull between head and toe is almost zero. Thus, the person would cross the eventual horizon intact, would not be stretched into a long thin noodle, would survive and float painlessly beyond the horizon of the black hole.
Most black holes we observe in the universe are surrounded by very hot disks of material, mostly gas and dust or other objects such as stars and planets, that have come too close to the horizon and 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 traveling into the black hole extremely dangerous.
To enter one safely, you would need to find a supermassive black hole completely isolated and not feeding surrounding materials, gas, or even stars.
Now, if a person found an isolated supermassive black hole suitable for scientific study and decided to take a risk, everything observed or measured about the black hole interior would be limited within the event horizon of the black hole.
Remembering that nothing can prevent the gravitational pull beyond the event horizon, the falling person could not send any information about their findings outside this horizon. Their journey and finds would be lost to the rest of the entire universe for all time. But they would enjoy the adventure while they lived … maybe …
This article was originally published in The Conversation of Leo Rodriguez and Shanshan Rodriguez at UCL. Read the original article here.