Out of the mouths of young people!

A young man aged eight asks a very deep question.

Now the answer, that I am about to republish, is written to Tristan, aged 8. But frankly I have no doubt that the answer will be keenly read by persons of all ages. Certainly, this 75-year-old found the answer of great interest.

But to the question:

How can a Big Bang have been the start of the universe, since intense explosions destroy everything? – Tristan S., age 8, Newark, Delaware

And the answer:

ooOOoo

How could an explosive Big Bang be the birth of our universe?

April 30, 2020
By Michael Lam, Assistant Professor of Physics and Astronomy, Rochester Institute of Technology

Pretend you’re a perfectly flat chess piece in a game of chess on a perfectly flat and humongous chessboard. One day you look around and ask: How did I get here? How did the chessboard get here? How did it all start? You pull out your telescope and begin to explore your universe, the chessboard….

What do you find? Your universe, the chessboard, is getting bigger. And over more time, even bigger! The board is expanding in all directions that you can see. There’s nothing that seems to be causing this expansion as far as you can tell – it just seems to be the nature of the chessboard.

But wait a minute. If it’s getting bigger, and has been getting bigger and bigger, then that means in the past, it must have been smaller and smaller and smaller. At some time, long, long ago, at the very beginning, it must have been so small that it was infinitely small.

Let’s work forward from what happened then. At the beginning of your universe, the chessboard was infinitely tiny and then expanded, growing bigger and bigger until the day that you decided to make some observations about the nature of your chess universe. All the stuff in the universe – the little particles that make up you and everything else – started very close together and then spread farther apart as time went on.

Our universe works exactly the same way. When astronomers like me make observations of distant galaxies, we see that they are all moving apart. It seems our universe started very small and has been expanding ever since. In fact, scientists now know that not only is the universe expanding, but the speed at which it’s expanding is increasing. This mysterious effect is caused by something physicists call dark energy, though we know very little else about it.

A visualization of tiny energy fluctuations in the early universe. ESA, Planck Collaboration, CC BY

Astronomers also observe something called the Cosmic Microwave Background Radiation. It’s a very low level of energy that exists all throughout space. We know from those measurements that our universe is 13.8 billion years old – way, way older than people, and about three times older than the Earth.

If astronomers look back all the way to the event that started our universe, we call that the Big Bang.

Many people hear the name “Big Bang” and think about a giant explosion of stuff, like a bomb going off. But the Big Bang wasn’t an explosion that destroyed things. It was the beginning of our universe, the start of both space and time. Rather than an explosion, it was a very rapid expansion, the event that started the universe growing bigger and bigger.

This expansion is different than an explosion, which can be caused by things like chemical reactions or large impacts. Explosions result in energy going from one place to another, and usually a lot of it. Instead, during the Big Bang, energy moved along with space as it expanded, moving around wildly but becoming more spread out over time since space was growing over time.

Back in the chessboard universe, the “Big Bang” would be like the beginning of everything. It’s the start of the board getting bigger.

It’s important to realize that “before” the Big Bang, there was no space and there was no time. Coming back to the chessboard analogy, you can count the amount of time on the game clock after the start but there is no game time before the start – the clock wasn’t running. And, before the game had started, the chessboard universe hadn’t existed and there was no chessboard space either. You have to be careful when you say “before” in this context because time didn’t even exist until the Big Bang.

You also have wrap your mind around the idea that the universe isn’t expanding “into” anything, since as far as we know the Big Bang was the start of both space and time. Confusing, I know!

Astronomers aren’t sure what caused the Big Bang. We just look at observations and see that’s how the universe did start. We know it was extremely small and got bigger, and we know that kicked off 13.8 billion years ago.

What started our own game of chess? That’s one of the deepest questions anyone can ask.

ooOOoo

Before the Big Bang then there was “no space and there was no time.” Michael Lam says that is confusing. I think that’s a gigantic understatement.

There there’s Dark Energy!

I wonder if we humans will ever come to the point where it is all understood!

10 thoughts on “Out of the mouths of young people!

  1. I wonder if we humans will ever come to the point where it is all understood!

    I doubt that, very much. We’re not smart enough, and we lack a sense of perspective.

    Not only is the Universe stranger than we think, it is stranger than we can think. — Werner Heisenberg

    Liked by 1 person

    1. Thanks for reminding me of that quote by Heisenberg, he of the Heisenberg Principle, Colin. I hope he is wrong but I also anticipate that he is not. It is stranger than we can think! Perfect!

      From Wikipedia:

      Werner Karl Heisenberg, 5 December 1901 – 1 February 1976, was a German theoretical physicist and one of the key pioneers of quantum mechanics.

      Liked by 1 person

  2. A complex Answer that I think none of us will ever truly know the true answer to… As it’s far too complex for us ever to grasp the concept of… Because within our Human minds we perceive everything as having a beginning and an end.. So my question now is…. Before this expansion…. How did that get there…. 🙂 And what occupies Space! …. Energy! … and what is Energy???? The questions can go on and on and on and on… Much like the Universe and the next universe and the next… 🙂
    So if there was no space…. In our minds something must have created the space for space to occupy it… It is all so mind blowing!!!!…… Infinity is!….
    That little eight year old asked a great Question Paul.. ….
    None of us I doubt, not even those great scientific minds can ‘really’ Know the answer… Its all based upon what they Think happened because of mans calculations within his understanding of mathematics and equations …

    Hoping you and Jean are keeping well my friend…
    Lots of earth digging happening here.. 🙂
    Take care.. Sue 🙂

    Like

    1. Dear Sue, thank you for your many wonderful responses. So far as this post is concerned, Tristan asked the most fundamental question of all questions. I sincerely hope he will continue asking deep questions, possibly becoming a scientist when he is a little older, because he has already shown a propensity to explore this strange world.

      Liked by 1 person

    2. And, yes, Jeannie and I are also keeping well and also plenty of gardening. We are expecting today for rain and thunderstorms but it will still be a particularly dry few months; the period January-April 2020 gave us only 50% of the rainfall of the same period 2019. I presume you and your husband are also keeping fit and well; the world is very uncertain at the present time.

      Liked by 1 person

      1. The watering of our plot throughout a dry April kept us fit… Thankfully we too have had a few thunder showers and so our arms have been given a rest from watering these past two days.. 🙂

        Like

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