yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Is the Universe Discrete or Continuous?


2m read
·Nov 3, 2024

You said that we went from atoms in the time of Democritus down to nuclei, and from there to protons and neutrons, and then to quarks. It's particles all the way down. To paraphrase Feynman, we can keep going forever, but it's not quite forever. Right at some point, you run into the Planck length. There's the Planck time, there's the Planck length, there's even the Planck mass, which is actually quite a large mass.

These things don't have any physical significance. It's not like the Planck time is the shortest possible time, and it's not like the Planck length is the shortest possible length. The reason for that is because these Planck things are part of quantum theory, but length is not described by quantum theory. It's described by the general theory of relativity, and in that theory, space is infinitely divisible.

There is no smallest possible length or time. This illuminates an ancient tension between the discrete and the continuous because quantum theory seems to suggest that things are discrete. For example, there's a smallest possible particle of gold—the gold atom. There's a smallest possible particle of electricity—the electron. There's a smallest possible particle of light—the photon.

In quantum theory, we have this idea of discreteness—that there is a smallest possible thing from which everything else is built. But in general relativity, the idea is the opposite. It says things can continuously vary, and if the mathematics requires that things be continuously variable, so they can be differentiated and so on.

The idea there is that you can keep on dividing up space, and you can keep on dividing up time. So physicists understand that there is this contradiction at the deepest level of our most foundational explanations in physics. It's one of the reasons why there are these attempts to try and unify quantum theory and general relativity.

Because what is the fundamental nature of reality? Is it that things can be infinitely divisible? Or is it that we must stop somewhere or other? Because if it's infinitely divisible, then quantum theory might have to be subservient to general relativity. But we just don't know.

More Articles

View All
Infiltrating the Illegal Wildlife Trade: A Trafficker’s Downfall | Nat Geo Live
Anson Wong is a wildlife trafficker. He’s also a guy who was trafficking at the time all the things we care about when we think about precious wildlife. He was offering snow leopard pelts, rhino horn, and he was moving live elephants. He had a tiger farm …
10 TRAITS OF PEOPLE WHO SPEAK LESS | STOICISM INSIGHTS
“In the midst of chaos, there is also opportunity.” A profound statement by the ancient strategist Sun Tzu, yet it resonates deeply with the stoic philosophy we’re about to explore today. Imagine standing unflinchingly as the world whirls around you, find…
P-values and significance tests | AP Statistics | Khan Academy
Let’s say that I run a website that currently has this off-white color for its background, and I know the mean amount of time that people spend on my website. Let’s say it is 20 minutes, and I’m interested in making a change that will make people spend mo…
Sine equation algebraic solution set | Trigonometry | Precalculus | Khan Academy
The goal of this video is to find the solution set for the following equation, so all of the x values. And we’re dealing with radians that will satisfy this equation. So I encourage you, like always, pause this video and see if you can work through this o…
Queens of the High Seas | Podcast | Overheard at National Geographic
Did you ever play a video game that sucked you in and took over your life? I mean, if you have, you can relate, but if you haven’t, it’s similar to that feeling of reading an amazing book and staying up late to read just one more chapter. And then before …
Warren Buffett is BUYING! Pharmaceuticals in, banks out? (Berkshire Q3 13F)
So last quarter, Warren Buffett certainly, uh, shocked a lot of us with the sheer amount of selling that he did from his portfolio. I remember he sold out of seven positions entirely, which is very unlike Warren Buffett. Four of those positions were the b…