Physics Girl

WATCH: Why the death of black holes is such a problem for physicists

Someone really needs to solve this.

BEC CREW
3 FEB 2016
 

Of all the strange, colossal, and unknowable things out there in space, there's arguably none so confounding as the black hole - those deep, dark regions of extreme mass and gravity that are scattered throughout the Universe. While some have hypothesised that 'death by black hole' would involve a painful roasting, generally, physicists agree that if you get too close to the event horizon, your body would be 'spagettified' as the gravitational tidal forces stretched you apart. But what about the black hole itself - how does it die? And where do all those hypothetical spagettified human remains go then?

 

Just like most things in existence, black holes can't escape their own inevitable demise. Over a very long period of time, they'll evaporate into nothing, sort of like a puddle on a warm day. This occurs thanks to Hawking radiation leaking out all over the place, and our current understanding of the physics behind all that brings up a whole lot of problems, as the latest episode of Physics Girl explains.

So what makes a black hole so black? The fact that not even light can escape the gravitational pull of a black hole means it's completely imperceptible. You need some kind of light in order to see something, which means despite the fact that physicists have been studying black holes for decades, no one's ever actually directly detected one. 

While most of you probably already knew that even light can't escape a black hole, this was no easy task for scientists to initially explain. The laws of physics saw that light always travels at the speed of light, so how could you possibly capture it? Thanks to Einstein's general theory of relativity, we know that mass bends space itself, and we perceive the effects of this as gravity.

When you've got an object with incredible mass - like a black hole - warping space-time so drastically, light will continue to travel at the speed of light when the two meet, but in a special curved path that can never lead back out of the black hole. If that's hard to wrap your head around, the video above has got a simple animation to show you how it works.

While all this light is getting sucked into a theoretical black hole whirlpool, the black hole has its own problems - namely, the fact that it's dying an excruciatingly slow death. As Physics Girl explains, countless pairs of virtual, quantum entangled particles suddenly form on the event horizon, and the negatively charged one gets sucked in, while the particle with positive energy escapes. This phenomenon causes the black hole to be losing mass constantly, and one day, it'll be reduced to nothing.

"This picture is relatively simple and compelling, but it's misleading, and can lead to trouble if taken seriously," says Physics Girl. Why? I'll let the video above explain, because trust me, you're going to need some clever animations to get you through. Let's just say established laws of physics don't work like they should around black holes. If you suggest things go one way because of what one law says, that will mean another, equally established law must be wrong, and that's a problem no physicist has even gotten close to reconciling. 

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