Physics of Black Holes...Or Lack Thereof

Isabella Jacavone

To comprehend how the universe works, we must dwell into the most basic building blocks of existence; matter, energy, space, and time. NASA's Physics of the Cosmos program involves cosmology, astrophysics, and fundamental physics intended to answer questions about the elusiveness of complex concepts such as black holes, neutron stars, dark energy, and gravitational waves.

In this blog post, I'd like to elaborate on a subject that is very intriguing to me; Black holes. And more specifically, what would happen if we got near one.

A black hole is anything but a hole, but rather an immense amount of matter compacted into an extremely small area. A black hole is caused when, hypothetically, a star four times more massive than our sun collapses into a sphere no bigger than 600 square km. To put that in perspective, that's about the size of New York City. Black holes were predicted by Einstein's theory of general relativity, which showed that when a massive star dies, it leaves behind a small, dense core. If the core's mass is more than three times the mass of the collapsed star, its gravitational force overwhelms all other forces and produces a black hole.

That being said, what would happen if we got near a black hole? Keeping in mind that not even light and electromagnetic radiation can escape the pull of a black hole, I'd assume that we'd have a slim chance of survival. Nevertheless, let's find out! 

When we float across a black hole's outer boundary, or commonly known as the event horizon or point of no return, the same physics that causes Earth's tides take affect. Near a black hole the size of Earth, forces are magnified an incomprehensible amount. Under the circumstance that we dove head first into the black hole, nearly immediately the top of your head would considerable much more gravitational pull than the tips of your toes. You would stretched longer and longer, or a victim of 'spaghettification,' [Sir Martin Rees] where you'd eventually become a stream of nothing more than subatomic particles. 

Sad right? Maybe we got lucky. If we truly wanted to have a first hand observation of the universe's most strange phenomenon, we'd have to visit a bigger black hole. The bigger a black hole is, the less extreme the pull of the event horizon is. As we approach the event horizon of a black hole the size of our solar system, we experience something called time dilation. Time dilation happens when we approach the speed of light as we are hurdling towards the black hole, and the faster we move, the slower we move through time.

 

So why write about black holes for a physics blog? As we approach the infinitely dense center, or the singularity, black holes completely disregard the laws of physics. It's black holes and other unexplainable phenomena such as wormholes that stump astrophysicists today. Infinity is a concept that we only see on paper and truly never witness in nature, yet a black hole's center is infinitely dense. 

Black Holes defy the laws of physics as we know them, and maybe, just maybe, in the future... we can modify the laws of physics to fully comprehend black holes. Until then, black holes are the most elusive occurrences in our universe, and although we'd love to get a first hand look at one, it probably isn't the best idea.