Available research on the theory is contradictory. More research is required to make a further judgement.
In 1974, theoretical physicist Stephen Hawking claimed that black holes are not black but slowly emit thermal radiation, ScienceAlert reported. Hawking radiation is the hypothetical particles believed to be released spontaneously by black holes' event horizon. It is caused by the continuous conversion of quantum vacuum fluctuations into pairs of particles. Stephen claimed that black holes could shrink as they radiate energy, which reduces their mass. Moreover, Hawking radiation has not yet been observed.
According to NASA, "the enormous tidal forces in the black hole's vicinity cause nearby matter to heat up to millions of degrees and emit radio waves and X-rays. Some material orbiting even closer to the event horizon may be hurled out, forming jets of particles moving at near-lightspeed and emitting radio, X-rays, and gamma rays".
On November 23, 2020, NASA said that a black hole captures anything that passes through the event horizon. However, as gas and dust get closer to the event horizon, the black hole's gravity causes it to spin extremely fast, resulting in a large amount of radiation.
A study published by the Japan Aerospace Exploration Agency shows that the gravity from a black hole sucks in everything near it. It also emits energy into surrounding space. Because the gas density in a galaxy cluster is so high, X-rays emit a lot of radiation energy. The gas should usually cool down when energy is released, which stops the production of X-rays. However, X-ray emissions continue in the center of a galaxy cluster. Continuous X-ray emissions require a heat source, which could be the heavy mass of a black hole. It is believed that a massive black hole at the center of a galaxy emits energy that heats the surrounding gas.
An article published by Event Horizon Telescope reported that a black hole does not emit radiation. It captures everything that falls onto it. Event Horizon Telescope (EHT) revealed that the gas that surrounds the EHT's observational targets does indeed radiate; therefore, by viewing this area, the EHT may be able to discover structures caused by the black hole's tremendous gravity.
There is no clarity on how radiation emits from an event horizon nor evidence to prove whether it radiates from the inner horizon. More scientific studies are required to confirm Stephen Hawking's radiation theory. However, we can't objectively verify the claim unless it is proven. Hence, we are marking this claim as unverifiable.