Experts don’t know everything. Often, they only know how to look things up, and how to understand what they find. If you’ve ever seen physicists answering a physics FAQ, those answers took a lot of effort to get right. Some common questions are in fact really complicated, or hard, or maybe they just aren’t about the things that physicists normally think about.
With humorous intent, I’m going to answer a bunch of frequently asked questions, sampled from this physics FAQ by John Baez. And I’m doing it without preparation, so the answers will be bad.
Why is the sky blue?
I believe that’s because you’re seeing scattered light, and Raleigh scattering is stronger for higher frequencies of light. I learned that from reading physics FAQs, I did not learn it from taking physics courses. I think Raleigh scattering was covered somewhere in electromagnetism? And I don’t quite remember what it was? I feel like if you don’t know what Raleigh scattering is, or what distinguishes it from other kinds of scattering, it’s hardly a real answer.
Why are golf balls dimpled?
Gosh, I don’t know. I have to guess that this is the result of experimenting with different shapes to find the one that goes farthest. Perhaps later, some aerodynamics expert studied the question and came up with an explanation that they understood but we mortals do not.
Why do mirrors seem to reverse left and right, but not up and down?
Mirrors don’t do either of those things. They reverse front and back. If you mentally rotate your reflection around, it seems to reverse left and right; but if you mentally flip your reflection on its head, it reverses up and down. The former rotation is more intuitive because you do it on a daily basis, whereas flipping yourself on your head is a less common activity.
How is the speed of light measured?
One way to think about it is that you send light off to a mirror, and time how long it takes to make a round trip. But the more accurate way to understand it is that you just create a standing wave between two mirrors. At least, that’s how I would do it, maybe it’s not the historical way.
If you go too fast, do you become a black hole?
Uh, I never thought about it. I can imagine two possible answers. First, everything is a black hole in some reference frames but not others. Second, an object only becomes a black hole when it’s dense enough in the reference frame where it’s at rest. I’m guessing the second answer is correct, because I don’t see how gravity could crush you into a singularity only in one reference frame but not another.
Why are there more protons than antiprotons?
I get the sense that this question was asked by a physicist, and not a lay person. Perhaps the hope is that lay people will take an interest and ultimately support more funding for research investigating this question.
Does antimatter fall up or down?
An easy one! Down. *Checks Baez* …Well sure I guess it’s hard to experimentally verify that, but come on. If you’re so interested in testing that one, you gotta be one of those physicists.
What is negative temperature?
You know what would be a better question? What is positive temperature? Sure, people have direct experience with positive temperature, but they don’t really know how to define it. I assert that if you understand how to define positive temperature, then you would also know what negative temperature is.
Is it possible to go faster than light?
Sure, if you slow down light by putting it through a medium. Otherwise no. But I have a feeling that some physicist is going to describe an edge case if you look at it funny and oh god I just glanced at Baez’s answer my worst fears are realized.
What is the mass of a photon?
Photons don’t have mass, but they do have energy. This contradicts the popularly known principle that mass is energy. The thing is, Einstein said mass is energy and all, but then there was no reason to call the same thing by two names. Since then, mass and energy have been repurposed to refer to different things. Now, instead of that other equation, we have E2 = (mc2)2 + (pc)2, spread the word.
Why are there eight gluons?
I don’t know. When gluons were first explained to me by a cartoon anthropomorphic quark (my memory of this may not be accurate), it claimed that each gluon is a combination of one positive charge and one negative charge. The strong force has three distinct types of charges (known as red, blue, and green), and each type of charge can be either positive or negative. The natural conclusion is that there are 9 distinct gluons. But instead, there are only 8 gluon for reasons that the grinning quark hand-waved away.
If I had to guess, each of the 8 gluons is actually a quantum superposition of the 9 that you’d initially guess, and there’s a ninth superposition that is impossible for some reason.
Can you take the logarithm of a dimensioned quantity?
Yeah, go crazy you mathematical rebel. Of course, if you take log(3 m), you get log(3) + log(1 m), and the latter component is an uninterpretable quantity that you better hope cancels out before you arrive at your final answer. Maybe keep it hush hush off the record.
Is energy conserved in general relativity?
Hell if I know. I think that’s one of those questions where it depends on how you look at it. It’s probably ultimately conserved but only if you include a term for “energy lost to physics’ bullshit”.
What is Hawking Radiation?
This is another one of those questions that I only know about through popular physics, and not through my formal education. I’ve of course heard Hawking’s popular explanation, that it has to do with virtual particle pairs forming at the event horizon. I have been informed that this explanation is a lie, and that it really has something to do with the quantum fluctuations of the vacuum in curved space. Hawking’s fake explanation is what you get when a science popularizer pretends that physics FAQs can be effortlessly answered in a simple and satisfying way.
Which way will my bathtub drain?