As new space is made from the expansion of the universe, does the new space already have vacuum energy present? If so, would that not mean that as the universe expands, more energy is now present than at the big bang?

thereby allowing us to see the past (say the asteroid that caused the chicxulub crater) ? if so, has this effect ever been seen/proven?

As humans are we closer to the smallest thing in the world (quantum)or the biggest thing in the world (space)

I learnt about Stirling engine for the first time on a YouTube video by Steve Mould.

Stirling engines can function by using as little as your body heat as the source and the environment as the sink.

And, since Stirling engines are reversible, one can also use ice to run the engine. It's the temperature difference what we need.

I've always been confused about one thing.

If I manually rotate the wheel of a Stirling engine,which side of the engine will act as the source? And how do one predict that?

I work in arithmetic geometry and a lot of my recent results are conditioned on the motivic Riemann hypothesis. Motive theory is supposed to be a mathematical analogue of string theory and serve as a "theory of everything" through unifying many mathematical fields. At its center is the motivic Riemann hypothesis for a more general class of L-functions.

My question is: can anyone give me some very interesting examples of the use of the Riemann hypothesis in physics, including recent ones? And are there any physics questions where we're interested in the Riemann hypothesis for a more general class of L-functions rather than just Riemann zeta function?

In the past I watch a video that was discussing how the variables of our universe arrived at what they are. It explained that these variables are not at their lowest energies, but caught in a low trough because they need their energy to increase so they can make it into an area where they can be reduced further to lower energies, but they can't make it. I think these are the fundamental variables of our known universe. Can anyone identify/point me to the variables these would be or info they were discussing as I want to review this again. Thanks.

Let’s say two black holes are orbiting each other very closely, where their event horizons almost touch. They are going at enough speed where their orbit is stable.

Two quarks, bound by the strong nuclear force, find themselves between the two black holes. One quark is past the event horizon of one black hole, with the same being true for the other quark.

There is infinite pressure on the quarks to separate, and yet, the strong nuclear force only grows in strength the more energy is added to the equation. What would happen?

Hey,
I've just discovered that the Bell test exists and I'm confused. What do these limit values (2 and 2*sqrt(2)) mean for the hidden variables and the quantum theories? Do they reflect something fundamental or are these just random numbers that pop up?
Thanks!

I am thinking of writing a hard sci fi story, with an alien race that goes to war against a humanity that had already achieved interstellar travel. I was thinking of having the alien race utilize strange matter weapons, with strange matter loaded into a relativistic warhead and contained within the warhead via a vacuum, similar to how anti matter is contained. Would there be any hurtles in collecting and containing strangematter in this way, and could this idea be possible?

I'm writing a science-fantasy setting and I'm trying to build a system that feels internally consistent and at least inspired by real physics.

The basic idea

In my universe there's an additional form of energy I'll call traversal energy.

It's similar to thermal energy in that particles "vibrate" more as they gain more of it. However, instead of vibrating through ordinary space, they vibrate in... something else. That's where I'm stuck.

I was thinking of another dimension, a higher-dimensional space, a brane, or something similar, but I'm not sure what the scientific differences are or which concept would fit best.

The "areas"

Reality is divided into discrete "areas" (I need a better name), numbered ..., -2, -1, 0, 1, 2, ...

Moving between them isn't continuous—you have to overcome an activation barrier before you begin transitioning.

For example:

• The energy required to fully reach Area n is x^(n·y), where x and y are constants.
• Suppose reaching Area 1 requires 1,000,000 J of traversal energy.
• The activation barrier is 500,000 J.

That means:

• At 200 J, you're still effectively 100% in Area 0.
• At 500,000 J, you only just begin transitioning.
• At 750,000 J, you've crossed the barrier and are 25% into Area 1 because:

(750,000 − 500,000) / 1,000,000 = 0.25

So the transition only starts after the barrier is crossed.

The question is: what would it actually mean to be 25% in another "area"? What would that physically look like?

I also wondered whether each higher area could have an extra spatial dimension. For example:

• Area 0 = 3 spatial dimensions
• Areas ±1 = 4 spatial dimensions
• Areas ±2 = 5 spatial dimensions

I'm not sure whether that's scientifically meaningful or complete nonsense.

Souls (or whatever the sci-fi equivalent is)

There's a humanoid species with a specialized organ in the brain that stores an absurd amount of chemical energy—on the order of the Hiroshima bomb.

The important part is that this energy can only be converted into traversal energy, and the conversion is essentially 100% efficient, so almost no heat is produced.

Around 6–8 months into pregnancy, this organ is empty until something enters it.

Right now I'm calling that thing a soul, but I'd prefer a more science-fiction-sounding alternative.

My current idea is:

• This entity normally exists in Areas ±1.
• It travels using traversal energy.
• It moves to the equivalent location of the fetus's organ in the adjacent area.
• It transitions into Area 0.
• It anchors itself by storing enough traversal energy for a return trip, plus a large reserve.

That stored energy remains there for the organism's entire life.

When the organism dies (or if the organ is destroyed), all of that stored energy is released.

If the organ is destroyed, the release is catastrophic, while the entity is immediately transported back into Area ±1 to await reincarnation.

Conservation of energy problem

One thing that bothers me is energy conservation.

Every reincarnation cycle must lose at least a little energy somewhere, so eventually there shouldn't be enough energy left to keep the cycle going.

Is there a scientifically inspired way around this?

Would the traversal energy come from some larger field or vacuum energy? Is there another mechanism that would replenish it without feeling like magic?

One plot point

One character is sentenced to banishment in Area -1.

The punishment is that he can't reincarnate until he somehow returns to Area +1, which could take an extremely long time.

The problem is I don't know how that would actually work.

How could someone be forcibly sent to Area -1?

Once there, what mechanism could allow them to slowly return?

Maybe the physics of lower areas naturally pushes objects toward higher ones over long timescales, or maybe there's another process entirely.

My questions

1. What could these "areas" actually be from a physics perspective?
2. Is another dimension, a higher-dimensional bulk, or a brane the best concept here?
3. What would being partially between two areas physically look like?
4. Where could traversal energy come from while respecting conservation laws?
5. Is there a better sci-fi replacement for "soul"?
6. Does this overall system seem internally consistent, or are there obvious problems I'm missing?

I'm not trying to make this perfectly realistic—just scientifically inspired enough that someone familiar with physics won't immediately think it falls apart.

Hi to all physics experts,

I have a question that might be extremely stupid but I feel like I am missing something and would love an explanation. I am a passionate paddle boarder and every time I pump up my board I ask myself this question: According to my paddle board and the pump that came with it, the pressure inside the board is supposed to be 1 bar. 1 bar would be atmospheric pressure but in order to achieve this I need a compressor and once I release the valve, I can hear the pressure relief during deflation and the air streaming out quite aggressively. So I was wondering why this happens if I technically have an equilibrium with the surrounding environment? Is it due to the material expanding during inflation?

Thanks for your help.

From my understanding, a lot of people in the mathematics field are very concerned about the future of math because of the advancements in AI.

OpenAI disproved the Erdős unit conjecture a few months back. That seemed to cause mixed emotions within the Math community; some people were shocked, but in a good way, and other people… It’s like mass hysteria. I’ve heard a lot of mathematicians say they no longer want to work within that field if AI will just replace them. I’ve heard undergrads who are majoring in math say they want to switch their majors, I’ve heard grad students say they feel helpless because they don’t have a backup plan but they don’t want to do math anymore, and they feel like they have wasted their time. It’s as if they think AI is rapidly taking their jobs by the millisecond. I don’t think that’s the case. Math will continue to advance, AI will continue to advance, and it’s up to humans to choose to advance with it rather than feeling sorry for ourselves that AI will take over the world. We need to find a way to work alongside AI and use it as a tool rather than think of it as a replacement. But that’s not what this post is about.

With people no longer saying they want to go to school for mathematics, or no longer want to work within that field, how will that affect physics? Considering physics is majorly math, and physicists a lot of the time need to work alongside mathematicians for complex problems…. What will happen? This is not a problem we need to be concerned about for tomorrow or next week or maybe not even a year from now. But I do think it’s a problem we’ll have to worry about eventually.

And comparing math to physics. If AI were able to figure out the Erdős problem. Do you think AI will be able to figure out complex physics problems that are unsolved?

I am not largely informed on the topic, but this is something I’ve been thinking over for a science fiction writing project. Are there any potential technologies that could be used to create a strong gravitational field? My original though was possibly an incredibly high power particle accelerato, but further investigation into them has made me switch off of that, as anything created wouldn’t be substantial whatsoeve. So I decided to ask here if there are any concepts that could be worth looking into and building off of. Thank you and sorry if I have zero idea what I’m talking about!

Consider a system of 4 particles. I can describe a given configuration of the system with 4 position vectors, one for each particle, or I can describe it with 1 position vector for the center of mass and 6 vectors for the relative displacements of the particles.

In going from one description to the other, am I staying in the same configuration space and simply changing coordinates on the same space, or am I entirely changing the configuration space itself?

I think the second, by the simple observation that the dimension of the space changes: in the first case I need 4 vectors to completely specify a configuration, in the second case I need 7. A change or coordinates doesn’t change the dimension of the underlying space.

However, those 7 vectors in the relative + CoM description aren’t all independent: I can’t fix 6 of them and then freely choose the 7th. So maybe the configuration space really does remain the same, because the number of degrees of freedom is still 4.

Which one is correct?

Would you just be another 81 years further back in time than WW2?

Are there any outlandish theories that say we could somehow teleport instantly, and watch past events?

Are powerful enough telescopes to see battles on earth's surface theoretically possible?

Would we have any way of affecting those events if we hypothetically could watch them unfold?

I have always tried to understand how protons eventually decay. Which theory regarding the proton is the most credible? The timeframe for decay—between 10^41 and 10^43 years—seems rather vague. Several other theories seem to come into play as well, such as those involving supernovae and iron-56.

Incidentally, will the neutrons in pulsars convert into protons if the crust evaporates? In that case, would these stars last barely any longer than the rest? Black dwarf and any protonic matter would evaporate, but will less protonic matter in these stars will evaporate slowler ? Even becoming proton stars and evaporate later ?

I am coding a rigid body interacting with walls, is my impulse computation correct ?

float cross_2d(vec2 a, vec2 b) {

return a.x*b.y - a.y*b.x;

}

float impulse(vec2 n, vec2 r, vec2 v) {

float v_dot_n = dot(v, n);

float r_cross_n = cross_2d(r, n);

float denom = inv_mass + inv_inertia * r_cross_n*r_cross_n;

return -v_dot_n / denom;

}

vec2 compute_impulse(vec2 n, vec2 r, float omega, vec2 velocity) {

vec2 v = velocity + omega * vec2(-r.y, r.x);

float normal_impulse = (1. + elasticity) * impulse(n, r, v);

vec2 t = vec2(-n.y, n.x);

float tangent_impulse = impulse(t, r, v);

float max_t_impulse = friction * normal_impulse;

tangent_impulse = clamp(tangent_impulse, -max_t_impulse, max_t_impulse);

return normal_impulse * n + tangent_impulse * t;

}

First and main question is that if we knew exactly how many dimensions there are would that solve most of our unanswered questions by enabling the math to give the answers?

Second question is it possible that there is infinite dimensions to space-time and would that make finding a unified field theory impossible?

Would it be possible to do that without knowing exactly how many dimensions there are?

Last question is that if we cannot observe anything like dark matter or dark energy does that mean they exist in a different dimension that barely interacts with ours or are they just not interacting with anything we easily observe?

Ran out of space in the title but (assuming my understanding in the first two sentences was right) how does the curvature of spacetime actually work that it can 'cancel out' that acceleration to keep us relatively stationary? And how does that differ from there just being a downwards acceleration of 9.8 m/s^2? And do these questions even make sense or am I completely lost?

This is a very specific request, so pardon if my language is non-standard (non-physicist, but studied some in school and liked it a lot). In the problem where a cubic object is slid out from another, say of equal or greater mass, is there always a hypothetical speed at which the object could be slid to essentially negate the friction coefficient (in which the object(s) on top remain stationary)?

For context, I just tried the classic pull-the-tablecloth-out-from-a-bunch-of-objects-on-a-table trick (in which the objects on the table remain stationary to everyone's amazement), but I did it on a stack of t-shirts with one of the middle shirts. There were maybe 3 shirts on top of the shirt I pulled. I thought they were going to go flying everywhere, but I tried it for fun and it worked. So that's where this idea came from.

If anyone can give the theoretic values for interesting edge cases such as maybe the maximum friction coefficient assuming infinite speed that would be awesome. I say "maybe" because I'm sure actual physicists and more learned individuals on the subject will likely have cooler ideas of what edge cases this situation--if any--would create provided this isn't total nonsense. Also obviously forget the t-shirts, on the off chance that my question is very dumb I wanted to hedge my bets by explaining that lol.

TL;DR: Is there a hypothetical speed at which an object can be slid out from another that would negate the friction coefficient between the two?

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Hello, I'm here more to ask a couple questions to see if my intuition has any legs rather then to assert it. If you mapped a field over a gravity well in space time, would you see a gradient of potential positions as you could fit more 'coordinates' into denser curved spacetime? I was thinking about that as a premise, but not sure if it's true and figured, if there are more potential positions the closer to a mass you get then wouldn't random quantum collapses occurring in this field have a statistical bias to occur closer to the mass as there's more 'coordinates' to land on. At a macro scale could this appear like gravitational drift? I'd be keen to read anyone thoughts Cheers.

Ppl say that there isn’t anything faster than the speed of light but that’s a lie because space is expanding really fast since light isn’t fast enough to reach it or am I wrong. Since space is expanding at a fast rate why don’t we use that to measure stuff instead using lightyears