Hawking Radiation: Exploring Mass & Temperature Changes

In summary, the conversation discusses exponential growth and decay in nature and specifically focuses on the effects of Hawking Radiation on black holes. The speaker is seeking help in understanding how the mass and temperature of black holes change over time and how to calculate them. The Bekenstein-Hawking formula is mentioned, along with the equations for calculating mass and temperature in relation to entropy. The conversation also mentions the Stefan-Boltzmann law for understanding the changes in mass and temperature over time.
  • #1
James Way
3
0
Hello, I am rather new to Physics and for a class project on exponential growth and decay in nature and I chose the effects Hawking Radiation on black holes. If anyone could help explain how the mass and temperature change over time and how to calculate them(this one especially) that would be wonderful
 
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  • #2
Simplified, why are these decreases(in mass) and increases(in heat) expoenential.
 
  • #3
*exponential
 
  • #4
James Way said:
how the mass and temperature change over time and how to calculate them
According to the Bekenstein–Hawking formula in black hole thermodynamics, $$S=\frac{kAc^3}{4G\hbar}$$ Consider a Schwarzschild black hole, we know that $$r_{\rm g}=\frac{2GM}{c^2},\ A=4\pi r_{\rm g}^2$$ Therefore, we can get $$M^2=\frac{\hbar c^3}{4\pi k_{\rm B} G}S$$ From thermodynamics, we learn that ##{\rm d}M=T{\rm d}S##, so we have $$T=\frac{{\rm d} M}{{\rm d} S}=\frac{\hbar c^3}{8\pi k_{\rm B}G}\frac{1}{M}$$I believe this is what you want.

By the way, according to the Stefan-Boltzmann law, $$\frac{{\rm d}M}{{\rm d}t}=-\sigma AT^4$$ and thus you can know how the mass and temperature change over time.
 

1. What is Hawking Radiation?

Hawking Radiation is a theoretical concept proposed by physicist Stephen Hawking in 1974. It suggests that black holes emit radiation due to quantum effects near the event horizon, resulting in a gradual loss of mass over time.

2. How does Hawking Radiation affect the temperature of a black hole?

The temperature of a black hole decreases as it emits Hawking Radiation, since the radiation carries away energy from the black hole. This is known as the Hawking temperature, and it is inversely proportional to the mass of the black hole.

3. Can Hawking Radiation ever cause a black hole to completely evaporate?

Yes, according to Hawking's theory, black holes with a very small mass will eventually evaporate completely due to Hawking Radiation. However, the time scale for this process is incredibly long, on the order of 10^67 years for a black hole with the mass of the sun.

4. How does Hawking Radiation challenge our understanding of black holes?

Hawking Radiation challenges the idea that black holes are completely "black" and do not emit any radiation. It also raises questions about the conservation of energy and information in the universe, as the radiation carries away energy and information from the black hole.

5. Is there any experimental evidence for Hawking Radiation?

Currently, there is no direct experimental evidence for Hawking Radiation. However, indirect evidence has been observed through observations of black holes and their surroundings, as well as theoretical calculations that align with Hawking's predictions.

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