What is Hawking radiation?
In the 1970s, physicist Stephen Hawking attempted to answer a seemingly simple question: Do black holes have a temperature? His analysis led to the development of the concept that now bears his name: Hawking radiation. Not only did Hawking show that black holes radiate energy, he showed that they contract very slowly and eventually explode with a flash of gamma rays.
The idea of Hawking radiation is based on the fact that empty space is not actually empty. This concept may be difficult to comprehend. Although empty space contains no mass, particles, or quantum energy, the quantum fields that define them exist in the vacuum of space. The usual explanation is that these fields, given that they are not required to be of zero energy, can exist pairs of “virtual particles, usually a pair of particle and antiparticle that annihilate each other quickly, but near the black hole, according to the explanation, One of these particles could disappear into a black hole and be lost forever, while the other escaped in the form of Hawking radiation.
This interpretation, although commonly used, is not entirely complete. Hawking radiation is actually a result of how gravity affects spacetime, as described by general relativity. Quantum fields in empty space are subject to Heisenberg’s uncertainty principle, which means that there is a limit to the certainty by which we can know their energy, or the time at which a certain energy can be assigned to them. Since the gravitational field bends spacetime, and affects the passage of time locally, this means that regions of spacetime with different gravitational curvatures cannot agree on the energy of the quantum fields. It is this difference in vacuum energy at different locations in the black hole’s gravitational field that generates “virtual particles” as they are called.
Can we detect Hawking radiation?
Hawking was able to answer his original question about whether a black hole has a temperature, and the answer is yes, but these temperatures are very small. Moreover, Hawking showed that the amount of energy that a black hole emits is a ring, and therefore, surprisingly, the greater the mass of the black hole, the less energy it emits and its temperature. A black hole with a mass of one solar (one solar mass equal to the mass of our sun) may have a temperature of about 10 K, while a black hole with a mass of one million solar masses will be about 10 K, these temperatures are only slightly higher than absolute zero and are small compared to At the temperature of the cosmic microwave background (CMB), the residual radiation from the Big Bang that spreads throughout space. It also appears that the universe cannot routinely produce black holes smaller than about 25 solar masses, so finding very small, hot black holes is not an option, so detecting the Hawking ray is likely nearly impossible.
There is one possibility though. Some astronomers hypothesize the existence of primitive black holes, which may have formed due to density fluctuations in the early universe, and may be responsible for some of the mysterious dark matter that astronomers are still confused about. The important thing is that primordial black holes are not restricted by their size, so there is a possibility that low-mass black holes may emit enough Hawking radiation to detect them, and because their life is short compared to large black holes, they can reveal themselves in a flash of gamma rays when they breathe.