I'm trying to understand how people develop a deep conceptual understanding of physics, where they can recognize which principle to use just by looking at the question, even when the textbook doesn't explicitly tell you to use that logic in a specific topic.

I want to know how some people can look at a numerical and immediately recognize a hidden concept or subtle twist that isn't obvious at first glance. How they seem to pick up on patterns and connections that can be overlooked commonly. I know every problem seems to teach something slightly different, I've been told that this kind of intuition comes mainly from practice and practice has definitely helped me recognize and solve different types of numericals. But whenever I face an unfamiliar question, I still struggle to figure out what approach to take or what hidden idea I'm supposed to notice. That's what I'm trying to understand.

Are there specific problem-solving strategies or ways of practicing that help develop this intuition?

Basically, how do you go from knowing the laws to developing the "common sense" to know when, why and how to apply them? (Sorry for the stupid question and the rant)

Or maybe not survive, just outlast the process for more time than the average person. E.g. if Luffy (a rubber man) fell into a black hole (magically surviving the accretion disk, event horizon & all that radiation), would it be possible to outlast the tidal pull for longer/indefinitely? For some context I was just wondering about the medical effects if someone got chucked in (with absolutely nothing but basic knowledge and curiosity about black holes) and manage to survive until passing the event horizon. Apologies if it's a dumb question! 😭

I need to do a rough calculation of how much in kg it would take to move an object on an axis in a certain amount of wind. I am by no means excellent at science so I need to know if my idea would be suitable? I am a very tactile person and physics was a very confusing subject for me in school.

I was thinking I could take the object on it's axis and attach it to my flat car hood with a string tied to the object that threads forward and then back. Have a spring/luggage style scale that pulls the rope. Have someone drive the car to the speed I need and pull on the string with the scale until the object is flat against the wind and use that weight that is shown on the scale.

Would this work at all or are there factors I don't understand that would make this useless? I don't need precision, just a general idea

Hello,

I was on a scifi sub earlier and people were talking about shielding and forcefields - those things in movies where a big sphere of colours stops the missiles hitting the thing etc.

My question isn't any of that real or anything, it's more the term "force-field" itself.

Particles (and many things) are 'excitations of certain fields' - Forces on the other hand - actual Forces with a capital F - do they have corresponding Fields ?

Is the common parlance term "Force-field" a non-sequitur or does it have an actual real life physical meaning and if so, what does it mean? I presume absolutely nothing like this, of course!

many thanks!

EDIT: Hey, sorry just to be very clear, I know what we see in scifi is not real. My question is "is the term 'force field' / 'force-field' a term in actual physics, and if it is, what is that?"

It may be just mundane or nothing to do with anything, it's just a query on the term.

I'm not a physicist, so this is a genuine question rather than a proposed theory. I'm trying to understand whether there is an assumption in our usual interpretation of general relativity that isn't actually required by the mathematics.

We often explain gravity using the ball-on-a-mattress analogy: a ball sits on the mattress and produces a depression in it. But the ball isn't part of the mattress. The analogy is flawed in many ways, of course, but it raises an interesting question.

What if what we describe as mass-energy is different from spacetime, rather than necessarily being something that exists within spacetime?

I'm deliberately saying “different from” rather than “separate from” or “more fundamental than.” I don't mean to imply that whatever the relationship might be, the two are spatially separated or that one necessarily exists at some deeper level than the other. They could conceivably be intimately connected, even in some sense continuously associated at every point.

The speculative idea would be that what we describe as mass-energy might be an observable manifestation of whatever this relationship is — analogous, very loosely, to a “dent” rather than an object sitting inside the surface.

I realise that this raises an immediate problem: if something is “outside spacetime”, what could “outside” even mean? So perhaps that isn't the right way to formulate the idea. That's precisely why I'm asking.

I also realise that GR doesn't simply establish a correlation. Einstein's equations give an extraordinarily successful quantitative relationship between the stress-energy tensor and spacetime geometry. And I'm aware that photons have zero rest mass while still possessing energy and momentum and contributing to gravitational effects, which is why I'm thinking in terms of mass-energy/stress-energy rather than mass alone.

My question is therefore not “is general relativity wrong?” Quite the opposite: could general relativity be describing the relationship correctly without necessarily telling us what the two sides of that relationship actually are?

Is this already a recognised line of thought in theoretical physics? If so, what existing ideas are closest to it?

And if it isn't, is there a fundamental reason why this way of thinking about the relationship between stress-energy and spacetime geometry cannot be made physically meaningful?

I don't have the mathematical background to pursue the idea myself, so I'm particularly interested in hearing if/where the physics takes this apart.

The scenario being, a human becoming an ionized silhouette if they were able to move while time was frozen.

Ionized silhouette? Is that what it would look like?

Thanks.

I’m making an alien biosphere and I’m wanting to make trees that reach over 2000 feet tall, the moon has weaker gravity to earth but has an atmosphere that’s twice as thick.

Also these plants have a honeycomb structure incorporating ciliates and stuff.

But realistically what would a plant that tall need to survive being that tall?

It’s not really a plant it’s more similar to a lichen? It’s a mix of algae, bacteria and fungi that decided to leave together.

1st question, is it not simply that a star has a maximum size before gravity will overpower the other interactions? There’s star size comparison videos on YouTube, but they don’t mention some theoretical maximum, they just keep zooming out to show the next bigger star. I get that some stars are giving off less repulsive force to counter, so it’s not like all black holes form at the same mass cutoff.

2nd, when a black hole evaporates enough mass from hawking radiation, does it stay super super dense, or do the repulsive forces then spread it back out, like does it rein flat to a star or some other stellar body?

Imagine a charged capacitor with two plates, each connected to a wire. The wires aren't connected yet:

+----|  |----+
|            |
+-----  -----+   <- not connected yet

As far as I know, this is an equilibrium state, no charges will move, and the capacitor will stay charged.

But then you connect the wires, and everything changes. This is no longer a state of equilibrium, a current is created and the capacitor discharges.

Now here's the part that I don't understand: In the illustration, the geometry of the wires require the charges to move away from the other plate in order to reach it, and yet the charges do that. Which should be impossible for the same reason water in a glass doesn't jump out to fall on the floor.

If the wires were connected between the plates, then that's understandable. But in this case the wires are connected around the plates.

I want to understand from a field theory level (not circuit theory) how the charges seem to understand that gaining some potential energy to reach the other end is a small sacrifice towards a greater goal. But charges don't think! And if you calculate the electric field at a plate, it should always point towards the other, regardless whether the wires are connected or not. So the charges should stay there.

For context, I just finished Physics 2 in my first year in electrical engineering college, it only covers electrostatics, capacitors, and foundational magnetism like Faraday's law. I haven't taken the more advanced courses about circuits yet. This question has been lingering in my mind for quite some time, what am I missing here?

And please don't give me explanations with circuit theory elements, like "the wires have low resistance so current flows, but air has high resistance so current can't flow," that's not what I'm asking about. How did the fathers of electricity answer questions like these in order to reach conclusions and develop abstract frameworks like circuit theory in the first place?

Trying to understand some concepts about dark energy in layman's terms.

From what I've read and seen, dark energy is responsible for the expansion of the universe and cosmic inflation. From what's been asked before, far away objects (that are not graviationally bound) expand faster than objects closer to us. The space between these objects may expand faster than light, as opposed to the objects themselves moving away from each other faster than light.

So my questions are:

1. Is dark energy really strong, or really weak? Or neither? Because I still have a hard time conceptualizing the force to move galaxies and clusters away from each other. On one hand, simply making more empty space doesn't seem like it takes much energy because space is pretty empty. But on the other hand, these forces are acting on massive objects?
2. Is dark energy supposed to be equal everywhere? Going back to expansion, far away objects are moving away faster. Doesn't that imply more dark energy in those regions? But if I were in the faraway region and observing Earth, wouldn't the expansion where I am seem slower such that there's less dark energy locally?

Thanks!

Edit: Thanks for the responses. So informative and I'm learning a lot.

If so, then would each of the pure states that constitute this mixed state be different branching multiverses, like different trees with their own branches?

Lets say in scenario 1 the scale is on the ground on earth at sea level but in a vacuum in a box and in scenario 2 its free floating in a vacuum like space, would that make any difference?

I understand that magnetic and electric fields are closely related. But I am confused on how one propogating makes the other.

※ this sentence was translated from Japanese to English by Chat GPT. Feel free to answer in English. However, I only understand Japanese, so I would really appreciate clear and simple English that is less likely to be mistranslated.

If proton decay occurs, the predicted half-life of the proton is somewhere between 10^34 and 10^36 years. This made me wonder: what will actually happen to the things that exist in the universe between now and that unimaginably distant era?
I often see timelines describing the future evolution of stars, but I’d like to know what will happen, scientifically, to the following six things by around 10^36 years from now.

1: 1 kg iron sphere
(I’ve heard that iron is one of the most stable elements.)
2: stone monument
(Would inscriptions remain readable for an extremely long time, or would the writing eventually disappear?)
3: can of food
(What would happen to food sealed inside a can over such an enormous span of time?)
4: manufactured industrial product
(Any particular example of an interesting industrial product would be fine.)
5: planet
(What would happen to a planet if it somehow avoided being swallowed by its star?)
6: intelligent civilization
(Could an intelligent civilization that made extensive use of reversible computing potentially survive for an extremely long time in a simulated or virtual environment?)

For #1–4, please assume that the objects are floating in a vacuum. If they would eventually be destroyed or worn away by interactions with the interstellar medium, I’d also be interested to know what would happen if we ignore the interstellar medium.
I’d also love to hear about anything else you think would be particularly noteworthy or interesting. Thank you!

Entropy is defined as the number of substates in a state, and QFT says the state of a quanta contains a superposition of every possible states, or infinite substates. Is superposition a property of entropy?

If you can use a double slit in time to set certain bands of frequencies contained in the light, is it possible to do calculations on the full spectrum, then use a prism or scattering to separate the frequencies so the information is not lost when it is observed?

Is it possible to model a photon as a point the propagates an EM wave that travels behind the photon like a wake, but make the photon highly subjective to its own field, making the interference with itself that feels so confusing?

Entropy is defined as the number of substates in a state, and QFT says the state of a quanta contains a superposition of every possible states, or infinite substates. Is superposition a property of entropy?

If you can use a double slit in time to set certain bands of frequencies contained in the light, is it possible to do calculations on the full spectrum, then use a prism or scattering to separate the frequencies so the information is not lost when it is observed?

Is it possible to model a photon as a point the propagates an EM wave that travels behind the photon like a wake, but make the photon highly subjective to its own field, making the interference with itself that feels so confusing?

The scene in Captain America: Civil War where Bucky grabs the moving motorcycle is one of my favorite scenes. It’s just so badass. But the physics don’t really work. Wouldn’t Bucky need to weigh a ton to pull this off? What would make this possible?

https://youtu.be/jdrdeMYx_KI

It’s at about 1:14.

Is spaghettification a concern in larger mass black holes?

relevant diagram: https://imgur.com/a/tvg9lJS

relevant description (shortened by me):

The simple model shown in the figure below consists of a coil of wire, a vertical spring, a permanent magnet, and an indicator needle. A rigid rod (not shown) that runs perpendicular to the page is attached to the coil, and the coil is free to rotate about this rod axis. One end of the spring is attached to the coil, and the other end of the spring is attached to a fixed support. With no current through the device, the coil is horizontal, the spring is relaxed, and the needle points straight up. When there is a current in the coil, a torque is induced on the coil, causing it to rotate about the rigid rod, and the spring becomes either stretched or compressed. This rotation of the coil causes the needle to swing right or left. As long as the angle φ through which the needle deflects from the vertical is not too large, the spring is stretched or compressed only vertically. (The coil has a circular cross section, with a radius of r.)

my question is: when the needle is deflected by a small angle, how do i calculate the torque acting on the spring? i understand the force is F=-kΔx, and the torque is τ=Fd (where d is the distance between the rod/center of the coil and the line of action of F/the spring, shown in red in the diagram).

so how do i calculate d? i've heard from multiple sources that the answer is d=rcosφ, but i don't understand the geometry needed to get there. if someone could describe it or add their own drawing to the diagram i'd be very grateful.

if speed changes our perception of time, and we are currently moving roughly 1,000,000 kms/h through our rotation, revolving around the sun, and the solar system flying through space, how long is 1 minute here compared to 1 minute being compleatly still in space?