What happens if you fly too close to a black hole?

Let's say that you're part of an expedition to investigate the supermassive black hole that's in the center of the Milky Way galaxy. This massive object is 26,000 light years away in the region known as Sagittarius A. The supermassive black hole there has a mass of at least 4 million solar masses and has a radius 4 billion miles (this is an estimate based on the volume and mass). There are several different parameter values for this black hole, so your job is to find out what the values really are.

One of the main problems with approaching a supermassive black hole is the fact that it's rotating like mad and dragging a massive accretion disk around it at nearly the speed of light. In fact, the dust and gas in this accretion disc is heated to very high temperatures because of friction and it's hot enough to emit strong X-rays. The other main problem is that the black hole is actually bending space near it so much so that it's being twisted around the black hole at the speed of light.

As the spacecraft you're in approaches this massive object, it will not be dragged into the black hole. This is not the way it works. Since the space is curved radially around the event horizon, your ship will be swept into an orbit around the black hole just like the dust and gas in the accretion disk. This dust and debris continues to rotate around and around. Eventually, friction causes dust to get pulled into the even horizon. The same fate would await the spacecraft that you're in.
Time slows almost to a stop when your ship gets caught up in the accretion disk. Strangely enough, your ship doesn't heat up. However, you never notice the time slowing. It's just seems normal to you. Someone watching this at a distance sees your ship flying around and then dropping into the event horizon. For you, this takes forever, or so it seems. This is based on Einstein's general theory of relativity.
Time and space are curved and compressed or stretched by a massive object. It's the speed of light that remains constant.

No one really knows what's inside the event horizon. We can't see anything inside because light can't get out. Once you go in you never come out. So, what does happen when your ship enters the event horizon? Well, for one thing it would seem to take a long time. Your ship would be stretched into a long thin object, a process that's called spaghettification. This happens because the intense gravity of the core of the black hole twists space and curves it into the center. I have no idea what that would feel like, but it might not be very pleasant.

Some scientists believe that there's a firewall directly inside the event horizon because all of the energy is trapped and heats up to extremely high temperatures. If this were true, then you would be toast. Otherwise, you could end up in a different universe and be spit out from a white hole, which is the opposite of a black hole. Or, you could end up never being seen or heard from again.

One thing must be made clear. When a huge star goes supernova because it creates too much iron in its core, fusion stops and the core collapses very quickly, so quickly that the core causes an explosion that blasts the outer layers of the star away.  The reason for this is because the core collapse reaches 70,000 kilometers per second, resulting in extreme heat and pressure that has to go somewhere. If the star is 90 times the mass of our Sun, the core collapse forms a black hole.

However, the black hole's core is no longer composed of ordinary matter as we know it. Remember how I said that atoms are mostly empty. When you take away the electrons and smash neutrons down together, the density rises to unbelievable values, but in this case it goes even further and creates a singularity. This singularity is no longer matter but it remains gravitational, and the gravity around it is outrageously high. That's the reason that light cannot escape a black hole.

Surprisingly, a supermassive black hole has a density that's about that of water. So, there is a lot of space inside the event horizon. What this would be like is anyone's guess, but one thing is for sure, you're not coming back out the way you went in.

So, good luck.

Thanks for reading.