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Name: Alex
Status: student
Grade: 9-12
Location: MA
Country: USA
Date: Summer 2013


Question:
This is kind of an intricate question that involves multiple questions in multiple fields:

1. Is there randomness in the universe? If you knew absolutely everything about a given scenario, will you know what the result will be (will one event lead to only one possible outcome)?

2. If yes, then during the Big Bang, would the information for the whole Universe, both present, past, and future, be encoded in that first moment?

3. If yes, would it be possible to relate this to data compression in computers? If you were able to take a huge amount of information (like the whole Universe) and collapse it into a single, small piece of data (the Big Bang), and supply the computer with equations to simulate that small piece of data into the big piece of data (how the universe evolved), could you possibly be able to collapse huge amounts of data into one small package?

Replies:
"Randomness" is a tricky topic and much of what your asked is still up for debate. On the topic of knowing all the outcomes I once had a physics professor explain his idea like this: Even though one can predict motion of objects such as some pool balls using Newton's laws, at the quantum mechanical level, (i.e. subatomic particles such as electrons) there will always be some uncertainly as to the location and speed of said particles. Since all matter is composed of these subatomic particles is this therefore not possible to predict everything with absolute certainty.

I know this topic is difficult to wrap one's head around but I hope this explanation helps. Like I said earlier, a lot of this topic is still up for debate. Cheers

Ben Sirota


Alex,

This is one of the strangest results of quantum mechanics that there seems to be a fundamental randomness to the universe. When you get down to the smallest sizes, such as atoms and particles, you enter the world where quantum mechanics must be used to calculate behavior. Simple, classical, particle physics breaks down. You must use a “wave function” to describe the behavior of matter, and this function is probabilistic (random) in nature. This feature of fundamental randomness has been studied, debated, and tested quite extensively, and it seems to be true. Many scientists believe that this randomness indicates that something is missing in the current understanding of the universe; however, if we stick to what is supported by current evidence, we would have to conclude that you could not predict the unfolding of the universe exactly. If you knew everything about a scenario, you could not say it would progress with one outcome simply because the outcome is probabilistic in nature. Another problem is that quantum mechanics, by its nature, will not allow you to know all the information of a scenario. The only way to determine the state of every particle is to measure it. The Heisenberg Uncertainty Principle shows that any measurement changes the state of what you are measuring. You cannot know simultaneously, for example, the precise velocity and location of a particle. Saying that somehow you even know the exact state of every particle at some particular time is cheating, in some way. If you tried to measure every position and velocity of every particle in the universe, you would end up changing the state of the universe, and you would again be left with an unknown initial state. Given our current understanding, it is likely that the answer to your question #2 is no. The third question is quite insightful, and I would say that you should rethink it leaving out the words, “if yes...” We know that we cannot plug in bits into a computer and simply simulate what will happen in the universe from start to finish. Nevertheless, information is contained in the universe, and there is an entire field called “Information Theory” that sprung out of similar questions you ask (data compression, transmission, etc.). Some physicists have even asked the question, “what happens to information as it collapses in a black hole? Is it retrievable somehow?”

Kyle J. Bunch, PhD, PE


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