The Black Hole Information Paradox
By Mila Patrick
Information is one of the constituent parts of the universe—so what happens to information if it falls into a black hole?
One of the most intriguing as-yet-unsolved mysteries for the scientific community is known as the black hole information paradox. First, what is meant by the term information? In this context, information describes quantum information. This refers to the properties of the individual particles that build physical material. The law of conservation of information states that the total amount of information in the universe must be conserved: new information cannot be created, nor can existing information be destroyed.
So, what does this have to do with black holes? Black holes contain massive amounts of information, as they have consumed vast amounts of material. In 1974, physicist Stephen Hawking discovered that black holes evaporate. This occurs over extremely long periods of time, by giving off particles now known as Hawking radiation. But this radiation is seemingly unrelated to the information within the black hole, thus indicating that a black hole and all information it contains could be destroyed entirely. This presents a serious problem for scientists. If information truly is destroyed through Hawking radiation, it would mean rewriting all of quantum physics. If it is not destroyed, how is it conserved?
There have been many theories as to how this could work. One early idea suggested is that the information is sent through a wormhole to an entirely different universe. However, I believe—along with many noted physicists—that information actually escapes black holes through Hawking radiation and remains in this universe; unfortunately, it is simply not yet known how that information affects Hawking radiation.
There are alternative speculations. Physicist Gerard t’Hooft discovered that information does not freeze on the event horizon, but instead forms a distortion that contains information. He suggested that these distortions could influence Hawking radiation, causing the information they contain to be carried out into the universe. Hawking himself has proposed another solution: that quantum tunneling within the black hole could be a mechanism by which information escapes. These seem to be plausible explanations for how information is imprinted on Hawking radiation, but they do not account for the fact that the concept itself also breaks the law of conservation of quantum information. The reason for this is simple. When an object approaches a black hole, it appears to freeze on the event horizon, though it does in fact cross it. The object’s quantum information is thus duplicated—one copy is seen on the horizon, and one copy is inside the black hole. But as mentioned earlier, conservation of information requires that no new information be created, so another paradox results.
This does not mean the end of the theory, however. Physicist Leonard Susskind contends that the law is not violated, because the two copies of information do not actually occur on the same timeline: i.e., they do not truly exist at the same time. This theory is known as black hole complementarity, and it provides a legitimate way to keep the laws of physics intact. However, this brings forth yet another paradox! Namely, it breaches the principle of monogamy of quantum entanglement, which states that a particle may be entangled with only one other at a time (quantum entanglement is a specific type of relationship between particles). Black hole complementarity suggests that every particle of Hawking radiation ought to be entangled with both the interior of the black hole it escapes, and all past Hawking radiation. No credible solution has yet been found to this problem by scientists.
Psalm 8:3-4 says, “When I look at your heavens, the work of your fingers, the moon and the stars, which you have set in place, what is man that you are mindful of him, and the son of man that you care for him?” The black hole information paradox is certainly an example of this. As I learn more about the cosmos, I realize how much I don’t know—each new answer opens up endless new questions to be explored. The more I study, the more I am humbled by God’s majesty and the vastness of His creation. I can’t wait to delve deeper into this paradox as I continue my education and begin my career in astrophysics.
Mila Patrick is a 14-year-old junior at Rivendell Academy Homeschool in Muncie, IN. She enjoys reading, drawing, and astronomy, and plans to study physics in college.
Page photograph of the Orion Nebula, taken by Bryan Goff, used from Wikipedia under a CC BY-SA 4.0 license.