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> Okay but fundamentally speaking, if I say rotate a magnet continually, it actually emits radio waves?

Yup! The connection between magnets and light is one of the most surprising parts of physics. If it were intuitive, it wouldn’t have taken us centuries to figure out!

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Let's start here:

>my math teacher told me I had no chance to ever learn the math necessary to do Physics, and it's just be a waste of my tuition money

What a horrible teacher! I don't care how hopeless it looks, a teacher should never, ever discourage our curiosities! I don't care if you were struggling with basic algebraic principles, you can learn the math necessary if you are truly curious about physics!

>everybody has told me that I just have to take a bunch of math and make sure I'm 100% on that before I ever even look at a physics book, but I just can't do it. I hate math so much).

Also not the best advice for everybody. We all have areas of strengths and natural curiosities and other things are just work. This advice amounts to "you can never play an instrument if you don't learn nusic theory and how to read sheet music." It's just not true. You should try to learn the formal rules and principles, and respect the wisdom and truth they contain, but if you love to play music and can do it without reading sheet music, then do it! This is kind of the same thing, although you can't completely disregard the math in science, whereas you can have a successful career playing music even if you never learn to read a musical note.

>I was trying to figure out what Maxwell's equations mean, and that took me to Stack Exchange, where somebody said that if we have a wave passing through the magnetic field, it induces an electrical field, and then that re-induces a magnetic field, which then self-propagates as the electrical wave makes a magnetic wave, and so on and so forth. We can this endless propagation a photon.

Oof. I don't like that explanation at all. They might have some truth in some of it, but it is safe to just ignore this explanation. Also, Maxwell's equations are very difficult to understand intuitively. I'm an electrical engineer by profession, I have an undergrad degree in that and one in business, and I am deeply interested in the physics, I should have double majored or at least minored in physics. I also may later pursue a PhD in physics, but for now my career is to be an engineer, which I do enjoy.

Maxwell's equations describe basically the totality of the electromagnetic force. It helped einstein to come up with special relativity and it also provided clues to quantum theory. These equations described the electromagnetic force better than Newton described classical mechanics. Quantum theory doesn't blow up Maxwell's equations the way quantum mechanics blow up Newtonian physics. It's amazing. But it's also not very intuitive and I have no idea how I would even go about summarizing Maxwell's equations to a lay person. So don't sweat it if you don't "understand" these equations!

Now, here's a story.

Me, an EE who graduated with a 3.3 GPA from a top 50 school, loved math in high school but didn't love science. I struggled badly with my second semester of physics in college for my business degree. Then, after graduation, I read this book because I thought it would just be good general knowledge:

https://press.princeton.edu/books/hardcover/9780691135045/physics-and-technology-for-future-presidents

This book completely changed my perspective on physics principles that I never could grasp before. You can read the entirety while ignoring some of the math he presents. It's a textbook but reads very conversationally most of the time, and is meant to be very approachable for people who aren't necessarily STEM majors.

Now, I ask you before we go farther, what exactly do you want? Do you want to just gain a better layman's understanding of physics, or are you exploring going to college or a career change?

Because how we talk about this I think depends on your goals.

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Honestly, zero. When I was in high school, I wanted to be a physics major in college, but I my math teacher told me I had no chance to ever learn the math necessary to do Physics, and it's just be a waste of my tuition money, so I abandoned that plan because I couldn't afford to fail my first year as a physics major and then need to change to a different program.

I've always kind of regretted my decision, and now I'm trying to self-study. I've been going through Taylor's Classical Mechanics, and basically picking up Calc and differential equations along the way as I go (I know, this is all a bad idea. Believe me, everybody has told me that I just have to take a bunch of math and make sure I'm 100% on that before I ever even look at a physics book, but I just can't do it. I hate math so much).

Taylor's Classical Mechanics is not exactly easy, but I felt like I was making some level of progress. I bought a used copy of Griffith's Electrodynamics because I found a used book store selling it for a really low price.

I'm confused now because I was trying to figure out what Maxwell's equations mean, and that took me to Stack Exchange, where somebody said that if we have a wave passing through the magnetic field, it induces an electrical field, and then that re-induces a magnetic field, which then self-propagates as the electrical wave makes a magnetic wave, and so on and so forth. We can this endless propagation a photon.

So then I thought, well wait that doesn't make sense. Because then moving a magnet through space would just make magnetic waves, and that would create photons? That makes no sense at all. But another comment said that photons are created by wave excitations in the EM field. Which sounds similar?

At that point I decided, okay I have no idea what is going on, I'd better ask.

And here we are.

That's all there is to it. I have no formal education at all. I'm just a humanities person who's in way over his head.

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So I'm just a sentient culmination of quadrillions of field disturbances interacting with each other

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can you give me a source on all of this?

A field in quantum field theory (QFT), which is what this is about, is something that has a value at each point at space time. This value can be 0 but not null. More specifically every point in space is a quantum object that is a harmonic oscillator and according to QFT this is actually what everything is. Everything is emergent from these values, for example a particular wavelength of light is a particular value of these oscillators in the electromagnetic field of oscillators and its movement through space is just this value propagating through these oscillators like a wave. Objects can have values from multiple fields. For example a neutrino interacts with the Higgs field and the weak field but not the electromagnetic field so it is famously hard to detect. It also means that light literally does not exist to it.

In my head they are kind of loosely analogous to splines where one dimensional values can control the motion or path of an object through space.

What are these oscillators and do they actually exist? We don’t know. Maybe? Probably? I believe the current consensus is they may be fundamental as in they aren’t made of anything and are irreducible but in physics every time we have thought this we were shown to be wrong. The thing is it seems to be correct, very correct. This model has made predictions that turned out to be experimental verified later.

The problem is it’s essentially a purely mathematical construct and we’re getting into the realm of philosophy asking if it’s real or not. It depends on what math actually is/describes. It might be that at the very basic level of everything all there really is is math. All we can say for sure is QFT works very well.

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It's worth noting, in addition to u/Jason-_B's excellent comment, that the placenta is not unique to mammals - it's seen in fish, lizards, and snakes as well. More importantly, unlike mammals, the intermediate states are still around, and plentifully represented.

In species with internal fertilization, the egg has to spend at least some time in the female regardless, just to add yolk and a shell. But more time in the female also lets her more precisely control the egg's environment, especially temperature, so keeping them interally has advantages (as well as the disadvantage of not being able to ditch them to escape a predator, and being "weighed down"). So a lot of species have variable time before laying, all the way up to laying right before hatching. Oxygen, CO2 and water can transfer, but it helps to ditch the shell in that case. However, no nutrient transfer occurs. At the very highest extreme, this is ovoviviparity - where the eggs entirely lack calcified shells, and the mom "lays" them immediately before or as the offspring are "hatching". From an outside perspective, this looks just like viviparity, but the key is the lack of nutrients - they need a yolk.

But if you've got eggs interally for a while, why not transfer some nutreints? There are lots of ways to do this, with the most bizarre probably being some species of caecilians (long, worm-like, burrowing amphibians) in which the mother grows nutritive lining in her uterus, which the young scrape from the walls and eat. However, a common way is to vascularize the yolk sac, squish it up against the uterus, let them fuse, and transfer nutrients across - bingo, you've got a placenta. Some of these are every bit as complex and specialized as mammal placentas.

The most useful thing is we have numerous independent evolutions of the placenta outside of mammals (who only evolved it once, as far as we know), as well as living examples of every intermediate you could ask for. There are even species (three-toed skinks) where some populations give live birth and others lay eggs.

Even crazier is the exception - Archosaurs (crocodiles, birds, dinosaurs, and their relatives) cannot ever evolve live birth. Unlike other species, the Archosaur embryo uses the calcium in the eggshell for bone calcification and, if the shell is removed, the hatchling is basically a gummy-bird or gummy-gator (obviously non-viable). This means they can never ditch the shell, and never take those first steps. And not a single Archosaur has ever evolved live birth, despite hundreds of millions of years of opportunities, and literally ruling the planet for most of that time.

Do we have any fossil examples of any intermediates between egg-laying mammals and placental mammals?

That's because it is. What is your formal level of education on the topic? We have to begin with where you are correct. You seem to be confusing a magnetic field with photons themselves.

Is radio long-distance crosstalk, then?

>You're trying to make sense of black holes before you make sense of the basic properties of the EM force. You need to slow down and try to get a better understanding of the basics before trying to understand what happens near a singularity.

Yeah, I'm sorry. I'm trying to make sense of EM force, but I'm finding it really, really confusing.

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>I am correct to say that if I have a permanent magnet it will emit EM radiation all the way down?

No. Not at all. I thought that specific part was pretty clear. A magnet does not simply emit EM radiation, moving it doesn't change that either. Moving it in the vicinity of free charged particles can induce a current, but that is not the same as light either.

Light - i.e. a photon - is a quantized packet of energy. You're not just flinging around energy by waving a magnet, no matter how fast it moves.

>Could I (theoretically) detect a magnet falling into a black hole by observing the radio waves it emits, and infer that a magnet must be falling into the black hole?

No, because it isn't emitting radio waves this way.

>What happens to a black hole that's rotating if it has charge? Does it emit EM radiation? Intuitively, I think the answer is "no" because a black hole can't emit anything. So I think I'm misunderstanding things. Where am I going wrong?

You're trying to make sense of black holes before you make sense of the basic properties of the EM force. You need to slow down and try to get a better understanding of the basics before trying to understand what happens near a singularity.

A really rough estimate: We have ~500,000 km^3 of global precipitation per year (1 meter averaged over the surface). If we put all of the 10,000 tonnes of aluminium into that, ignoring chemistry or what happens afterwards, we get an average of 20 ng/liter. For scale, the US EPA recommends no more than 0.05-0.20 mg/liter or 50,000 to 200,000 ng/liter for drinking water.

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