Ask Ethan: Do Black Holes Grow Faster Than They Evaporate? (Synopsis) [Starts With A Bang]

“Maybe that is our mistake: maybe there are no particle positions and velocities, but only waves. It is just that we try to fit the waves to our preconceived ideas of positions and velocities. The resulting mismatch is the cause of the apparent unpredictability.” -Stephen Hawking

So, you’ve got a black hole in the Universe, and you want to know what happens next. The space around it is curved due to the presence of the central mass, with greater curvature occurring closer to the center. There’s an event horizon, a location from which light cannot escape. And there’s the quantum nature of the Universe, which means that the zero-point-energy of empty space has a positive value: it’s greater than zero. Put them together, and you get some interesting consequences.

Particle-antiparticles pairs pop in-and-out of existence continuously, both inside and outside the event horizon of a black hole. When an outside-created pair has one of its members fall in, that’s when things get interesting. Image credit: Ulf Leonhardt of the University of St. Andrews.

One of these is Hawking radiation, where radiation is created and moves away from the black hole’s center. It occurs at a specific rate that’s dependent on the black hole’s mass. But another is black hole growth from the mass and energy that falls through the event horizon, causing that black hole to grow. At the present time, realistic black holes are all growing faster than they’re decaying, but that won’t be the case for always.

As a black hole shrinks in mass and radius, the Hawking radiation emanating from it becomes greater and greater in temperature and power. Once the decay rate exceeds the growth rate, Hawking radiation only increases in temperature and power. Image credit: NASA.

Eventually, all black holes will decay away. Come find out the story on when evaporation will win out on this week’s Ask Ethan!

from ScienceBlogs http://ift.tt/2vbieSP

“Maybe that is our mistake: maybe there are no particle positions and velocities, but only waves. It is just that we try to fit the waves to our preconceived ideas of positions and velocities. The resulting mismatch is the cause of the apparent unpredictability.” -Stephen Hawking

So, you’ve got a black hole in the Universe, and you want to know what happens next. The space around it is curved due to the presence of the central mass, with greater curvature occurring closer to the center. There’s an event horizon, a location from which light cannot escape. And there’s the quantum nature of the Universe, which means that the zero-point-energy of empty space has a positive value: it’s greater than zero. Put them together, and you get some interesting consequences.

Particle-antiparticles pairs pop in-and-out of existence continuously, both inside and outside the event horizon of a black hole. When an outside-created pair has one of its members fall in, that’s when things get interesting. Image credit: Ulf Leonhardt of the University of St. Andrews.

One of these is Hawking radiation, where radiation is created and moves away from the black hole’s center. It occurs at a specific rate that’s dependent on the black hole’s mass. But another is black hole growth from the mass and energy that falls through the event horizon, causing that black hole to grow. At the present time, realistic black holes are all growing faster than they’re decaying, but that won’t be the case for always.

As a black hole shrinks in mass and radius, the Hawking radiation emanating from it becomes greater and greater in temperature and power. Once the decay rate exceeds the growth rate, Hawking radiation only increases in temperature and power. Image credit: NASA.

Eventually, all black holes will decay away. Come find out the story on when evaporation will win out on this week’s Ask Ethan!

from ScienceBlogs http://ift.tt/2vbieSP