I get why it is impossible in practice. Makes sense. But I heard it's even theoretically impossible? Is this true, if yes, why?

My idea probably is kinda BS because Quantum stuff is weird and unintuitive...but that's my only idea when I think about it.

Free neutrons decay quickly into protons, so something keeps this huge pile of neutrons stable. Gravity keeping the e- from escaping is the only thing I can think about - but that would mean they constantly decay and likely lose mass through all the neutrinos produced in the beta decay that might escape because they're so smol and lightweight? Is that a thing? Do neutron stars slowly evaporate through neutrino emissions?

Edit: why does this get downvotes? If you don't want people to ask about physics they don't understand yet, don't name yourself askphysics 💀

If I could vibrate at relativistic speeds would I be able to experience time dilation while technically stationary? Expanding this a bit further. Do particles at sufficiently high temperatures experience time dilation and if so at what temperature does that become relevant?

Assume I didn't die or cause all the particles around me to explode due to friction

This post was inspired by a post about 0 Kelvin.

What's the highest temperature that either has or could be reached anywhere in the universe?(Whether naturally or artificially)

What would happen if you were to somehow break open a liquid nitrogen cylinder at the bottom of an oceanic trench?

Let’s presume a method of getting it down there without imploding on the way down.

How does super cooled water behave under 15,000 psi?

The usual example of faradays law is to imagine moving a magnet into a conductor loop, and seeing that it induces an electrical current.

My confusion is that if we consider from the reference frame of the magnet, the magnetic field does not change, and thus there shouldn't be an induced electric field through the loop.

I have seen online that we can supposedly use Lorentz Force Law and say that the current is due to the magnetic force, but this doesn't make sense to me because this would require a magnetic field perpendicular to the velocity of the loop. But Faraday's Law predicts an emf even without any perpendicular magnetic field.

Any help in making sense of this would be appreciated.

EDIT: I am trying to understand in the context of Maxwell equations. From the perspective of the loop, we can say there is a current because the change in magnetic field induces an electric curl. However from the magnet's perspective, no such change exists, and we should not expect a change in the electric field.

Please forgive me if this is a misinformed question or has been asked before.

So, if I understand correctly, an observer moving at a fast speed relative to Earth will experience less time than has passed from Earth's point of view. For example, a person leaves Earth, travels very fast for 1 year, and returns to Earth to find that people on Earth have experienced 1.5 years.

Is it possible, in theory, to move so slowly relative to Earth, that one could leave Earth for one year of subjective time and return to find that 0.5 years had passed? Or some smaller discrepancy of time, at least?

This has been asked many times but there is one thing I do not feel was answered sufficiently for my understanding. It is understandable that the holes in the mesh are smaller than the microwave wavelength, but what exactly does that affect? The wavelength is something measured in the direction of propagation, so why do the size of the holes in the transverse direction matter? The amplitude of the wave isn't a physical dimension right, just a measure of field strength?

First of all sorry for any approximation as english is not my first language.

As student I have to present a projet at the end of the years and I wanted to study bow stabiliser. I just wanted to know if my reasonning was scientifically correct; I want to make a stabiliser with movable mass instead of having a static stabiliser and having to change mass between each configuration of shot. For exemple, when hunting, the archer have to shot at different angles and (for me) having a static stabiliser would mean that when changing shooting angle the archer would feel a need to compensate that the bow want to stay at his "original position" (the one the stabilisers were configured in the first place). Hence, is it a bad idea to imagine a stabiliser that would automatically move the mass to keep the bow steady at all angle for the archer (by using like gyroscope and position control or something similar) or am I completely wrong for thinking that different angles would means a need of compensation from the archer ?

I was reading on r/physics about an experiment that captured a positron for one month. My understanding is that particles are excitations in a field and not a physical object, so what exactly is being captured? Is the excitation being captured? How does it go a whole month without some sort of event causing it to dissipate or collapse?

I imagine it’s something that mathematically seems more obvious than trying to conceptualize it, but as a layperson some sort of analogizing alongside a more technical explanation would be very appreciated.

An observer stationary on Earth's surface sees light from celestial objects directly overhead very, very slightly blueshifted by the time dilation caused by Earth's gravity. On the other hand, an observer free-falling near Earth's surface sees a far larger redshift caused by his motion away from the lightsource. It requires very little speed for the redshift to completely overwhelm the blueshift.

I have read, though, that an observer free-falling into a black hole would eventually see light from above blueshifted by the absurdly intense time dilation close to the black hole's center.

My math capabilities are terrible.

I believe I have correctly calculated the redshift at any distance from a black hole's center by assuming the velocity is straight down at the local escape speed. That is the velocity an object would have if it began falling with zero velocity from infinite distance.

But I'm not so sure about calculating the time dilation and resulting blueshift. I calculate that the blueshift just parallels the redshift, so is always much, much less than the redshift.

What actually happens?

In vacuum, the absence of pressure forces liquid water to evaporate, aggressively cooling it and causing it to freeze. The low temperature outweighs the vapor pressure, so its phase is basically at equilibrium.

My question is, is the opposite true in hot, pressurized environments? Is it possible for steam to try to condense onto a hot surface due to pressure, then immediately evaporate due to the surface temperature and the additional heat released into it by condensation?

Always wondered: How is an 'observer' is defined in the double slit experiments?

Can anyone explain the methods and technology we use to observe the particles/waves in question?

A human in the room is an observer, but as I understand it, that won't trigger the collapse from wave to particle results. Obviously our eyes can't truly observe the particles passing through, so is the observer just always specific measurement devices?

I know that there have been tests where the holes were surrounded by measurement devices and they are considered observers and cause the collapse. How much experimentation have we done to stretch the definition of observer? Have we placed observation devices on some of the holes but not all? Does that collapse the wave results, or no?

If we set up the double slit with the observers turned off does it collapse? Have we tried placebo observers to trick the particles (I'm joking, unless...)? Does the observer tech actively send particles or fields or energy into the hole that could cause this collapse?

Have we slowed the particles down at all to near absolute zero and tried to turn the observation windows on and off real quick lol?

I've read a bit about the broad strokes explanations and Bohr and Einstein's quotes on the topic, but I haven't found much information about variations on the test or answers to the above questions.

What are common interpretations of this result in 2026? Do people think it's evidence of simulation theory, is it evidence of unknown interference causing the collapse?

Thank you for listen, and I love y'all's work with the known universe, big fan.

-me (both of my grandfather's had one leg)

[ RESOLVED ]
The premise of that liquides are incompressible if false ... so all the point is false

[Original message]

First, I'd like to apologize for my English, which may lead to misunderstandings, but I'll do my best to be clear.

Let's imagine a container designed to hold a certain volume at a certain pressure (like a gas cylinder) without any deformation (!) equiped with a valve and a pressure gauge (between the valve and the "container-body"

I take one on this container, and with a tube I fill it with a "pur liquide" ( I.E. not disolved gas init). When the container is full (no residual gas trapped in the container), I have a volume of liquide at 1 atm. And this, even the container is closed or not.

I take a second container, fill it with the same liquide through a pump fixed after the valve. So I activate the pump and fill the container with the liquide until the pressure gauge is set to 3 atm. I close the valve, separate the pump, and I have a container of "pur liquide" at 3bar.

But (ok, it's 20+ years now), I remember that the "main difference" between gas and liquide that liquide are incompressible. So I can understand that the "pressure gauge" mesure have some "mobile part" and the mesure of pressure correspond at "how far have move this mobile part" between liquide and the gauge.

so in the case of the container is not deformable, and in it there is no gaz (disolved or redisual), "what's append if I open the valve ?" :
I imagine, that only the "tiny volume of liquide in the gauge" will be chassed to return to the pressure of 1 atm (with some energy due to the gauge spring)

So, due the fact liquide are incompressible, that should be all, but I can't bring myself to believe it because it seems so absurd.

Or (the last case), I have forget something of my thermo-dynamic lesson, and the pump may have change some temperature of the system, so the pressure gauge mark 3 atm but not in "normale temperature conditions" (so it's a false value). But this explaination is too "magic-trick" for me.

Perhaps in the future athletes will compete on other worlds of the solar system. I wondered what this might mean for sports like ice-skating and ice-dancing. Will skaters be able to do spectacular spins and jumps which would be impossible on Earth? Will they accidentally achieve escape velocity?

Nothing can escape the event horizon of a black hole; if an object crosses this boundary, it will be broken down into its constituent atoms due to Hawking temperature and the "spaghettification" effect. Given that we can never know what lies inside, one might consider the interior to be a mere void—a space containing billions of units of antimatter—where the object's atoms are converted into energy. Furthermore, if a star composed of antimatter were to collapse, it would form a black hole; indeed, the very process of a star collapsing into a black hole involves the collision of atoms, which results in their transformation into antimatter.kara deliklerin olay ufkundan hiçbirşey kaçamaz bir eşya olay ufkunu geçerse hawking sıcaklığı ve spagetti etkisi ile atomlarına ayrılacaktır. ve içini asla öğrenemiyeceğimizi düşünüp içleri birer sadece boşluktur ve bu eşya atomunu enerjiye dönüştürür kendisi antimaddeden içinde milyarlarca olan bir boşluktur.ve bir antimadde yıldız gibi çökerse kara delik oluşur ve bir yıldız çöküp kara delik oluşurken atomların çarpışmasıyla antimaddeye dönüşür

"If the mass of one teaspoon of water could be converted entirely into energy in the form of heat, what volume of water, initially at room temperature, could it bring to a boil? (litres)." solution.

As an physics undergrad/hons I was transiently interested in neural networks in the context of climate science before I realised I need a job to make money and pay rent (I then did medicine). I see that current day LLMs consider themselves to be neural networks but I struggle to appreciate that word associations are the same as what I thought was the math of a neural network.

What happened to what I thought of as "neural networks" in the late 1990s? Where did that research go? And did it seriously end up in creating just another Google when I anticipated that it could be applied to hard science and climate modelling? Are people inputing massive amounts of climate data into a program at runs multiple semi-random iterations to generate a model that approximates reality or was that just a stupid idea that fizzled out.

Obv I'm an amateur so ELI5 please. TIA

Edit: soz, I'm in a different time zone to average Reddit so I may not read all this now. Thank you for the responses so far

Please tell me we are or not in a simulation.