xkcd #2933: Elementary Physics Paths
xkcd #2933: Elementary Physics Paths
Alt text:
=COSMOLOGY==> 'Uhhh ... how sure are we that everything is made of these?'
63 comments
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What is this author for XKCD’s background? He seems to know a lot about a lot of complex subjects. I’m always impressed.
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I never seriously studied physics. A few years back I decided that it was time to push myself a little and start reading up. I started with some articles on string theory and suddenly remembered why I didn't want to study physics.
Looks like I saved twice as much time as I thought I had.
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I started with some articles on string theory
Yeah, that's a mistake.
Unless you understand the working theories out there, you gain nothing by going deep into speculative ideas.
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You could try reading Feynman's lectures, he was a very passionate teacher, and he used intuition a lot, so you don't need to grind on equations to follow. https://en.wikipedia.org/wiki/The_Feynman_Lectures_on_Physics
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String theory is barely a scientific theory, it's an untestable (experimentally) mathematical framework.
I'm far from an expert on this, but I don't think this is the best introduction to physics.
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If strings are just a theory then how do you explain shoelaces? 😏
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According to the article it's no longer a credible theory
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It's not untestable. It gives predictions and there has been tests for those predictions. The unfortunate part is that the predictions are often not very concrete, and the range of a lot of these predictions lies far beyond our capabilities. But people are looking to measure them indirectly in various ways. So it's not like it is untestable by design or anything like that.
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I did a semester of physics in high school and loved it. One of the few classes I actually enjoyed. I joined the nuclear program in the Navy and still loved it. I got to college and brought along all my ACE credits so I got to skip some math, physics, early chemistry, and thermodynamics.
We got to experimental physics and it broke my brain. I barely walked away with my BS and even though I could have made good money I never ended up using the degree because I ended up hating the whole field. It hangs on the wall next to my certificate from a two week bartending school.
I ended up with a long and fruitful IT career where I've never had to apply even a little knowledge I gained from that degree.
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Thanks for the story.
Nice to know I'm not the only one.
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Half-expected to see a wumbo boson in that article as a reason for "that" SpongeBob episode
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Per the alt text: How do we know that particles are the smallest bits? Let's zoom in even further.
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These are the questions that make me feel such an insane sense of wonder and awe.
How deep does it go?
How high does it go the other way? How big does existence get?
Why is there something rather than nothing?
What is nothing made of?
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Cosmology you put enough mass in a small enough area it becomes a singularity.
Quantum mechanics information can't be destroyed to an unrecoverable state so singularities are impossible.
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A big bang could recover it, you don't know. It's statistically possible and that's all that counts
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Crazy thing is very similar mathematical structures is used to define the behavior of a single particle in QFT and of a huge collection of particles in condensed matter physics
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It’s not crazy when you think they are both trying to model the same universe.
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When you section off a small part of the universe and try to model it, there's little reason your model should look like a model for a completely different small part of the universe. Not unless they share fundamental characteristics that you're trying to model. The math that describes permanent deformation looks nothing like fluid dynamics.
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Neither of them is trying to model the universe (that is the purview of cosmology). We are trying to model very particular phenomenon happening in the universe and there is no reason to expect them to modeled using the mathematical structure. The fact that they are is very fascinating.
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Quantum field theory really aligns with my fap roulette kink.
63 comments
Somewhat related, back in highschool I was really enjoying chemistry class. Super fun stuff, definitely a career path. Then when we were doing the math practices, I got a question wrong that I knew I combined correctly.
I asked the teacher and she said "oh yeah that one just doesn't follow the rules" instantly killed my enjoyment of chemistry.
Aw that's too bad. That response I'm sure you're paraphrasing, but "that one doesn't follow the rules" is the best part of science.
It means our rules aren't good enough, or we don't understand that one well enough. Figuring it out can be an entire career of discovery. And the reasons why can be fascinating and inspiring to more discoveries!
In this case, it was probably the teacher not being knowledgeable enough to explain a more advance theory that goes beyond the simple model he was teaching. What's sad is that the teacher didn't take the opportunity to dig deeper with the student, it could have been very motivating for the student to feel like he found something that went beyond the normal curriculum.
High school chemistry felt less like imperfect modeling and more like alchemy that sometimes yields tangible results. I can't remember specifics anymore but there were many moments where I was like "you're using too many shortcuts and this doesn't make any damn sense mathematically or dimensionally anymore". I know real chemistry is too complex to fit a high school program, but the way it was taught really was like a soft science cosplaying as a hard science.
Also chemists would use any pressure units before they used Pa. mmHg as a unit suffers from congenital defects I can only assume stem from repeated inbreeding.
or it's ochem
At school, I thought our understanding of chemistry was really good. Years later, I realized that complicated solutions aren’t covered by any of the equations we have. You’re can do fancy calculations, but you’re always stuck with simple solutions and standard conditions. In real life, you have to deal with super messy non-standard stuff all the time.
Top scientists end up developing semi-empirical models, or even particle simulations, and that’s the best we can do right now. Nobody fully trusts those predictions, so we’re still going to need lab experiments before making any big decisions.
The good news is that there’s still so much to discover.
You aren't following the rules! You're supposed to nonchalantly get the correct answer and thus discover a new rule that we nowadays know as the Galapagon Principle.
One of my great regrets in high school chemistry was that I was born too late to discover some pattern and have it called Liz 's Formula or whatever.
It's similar to what I felt learning organic chemistry. That's why I ended pursuing a career in math.