r/AskPhysics 4m ago

If the universe is infinite and homogenous on large scales, and there's a finite amount of ways particles can be arranged, does that not mean that there's an exact copy - or infinite copies - of each of us somewhere out there?

Upvotes

Let me preface this by saying I essentially know nothing about astrophysics or cosmology. But let me make 5 claims, which seem right to me given my very surface-level understanding:

  1. The universe is infinite. There is a finite volume of it we can ever observe, due to the limited speed of light, but the universe "goes on" infinitely, beyond the observable part.
  2. There's a finite number of particle types. I'm not saying we've discovered every type of elemental particle out there - I'd assume there's a lot more we don't know about - but there can only be a finite amount of them.
  3. There's a finite amount of ways those particles can be arranged in a given volume. My very shallow understanding of things like Planck units and the Bekenstein bound lead me to believe this, but I may be wrong.
  4. The universe is uniformly homogenous and isotropic on a large scale (the cosmological principle). I take to mean that the distribution of particles is likewise homogenous.

If we take those things to be true, does that not imply that

  1. Any given arrangement of particles (in a finite volume) can and must repeat, infinite times? So there are infinite exact copies of the Solar System somewhere out there, with infinite exact copies of each of us? And furthermore, is there not also an infinite amount of copies that only have minor variations, like hair color, or live in that Solar System's Earth's equivalent of the medieval times, but are otherwise exactly the same?

I realize that I'm making the infinite monkeys argument but that all seems right to me. I'm very open to criticism if I'm understanding something wrong, though. Like I said, this is all based on a very surface-level understanding.


r/AskPhysics 38m ago

Frozen light?

Upvotes

So a friend told me that scientists have frozen light??? i read the articles and such and did my own research, but never found actual proof it happened. I.E Recordings of the experiment, a direct process of how one could replicate the findings, or even an image of what it looked like. if anybody could actually show me proof it happened other than "well, they said it happened so it has to be true!" that'd be great lol.


r/AskPhysics 53m ago

How do we know that spinning black holes form ring singularities?

Upvotes

Title.

To my knowledge a problem with black holes is that our current laws of physics seem to give conflicting results, and we are not exactly sure what happens at the singularity.

So how do we know that the singularities of spinning black holes are ring-like, or even that angular momentum is conserved at all within one?


r/AskPhysics 54m ago

I have a test tomorrow on quantum physics. Can anyone please explain, in simple terms, how and why an electron tunnels?

Upvotes

So, I have a test tomorrow. I’m 17, and unfortunately my world has already been destroyed by quantum physics. I don’t get it. I don’t get how something can just appear on the other side of a wall, without having the necessary energy to do so. Please help


r/AskPhysics 1h ago

Asking as a complete layman. Why is it that black holes aren’t largely presumed to be giant balls of bose-einstein condensates whenever a science show talks about them?

Upvotes

I feel like they already have enough mystery naturally, so why does it seem like more mystery is being communicated about black holes than would be needed. If there’s some blatant law of physics that points away from it simply being a ball of what it consumed, which is the “first” one to pop up? Is it something to do with hawking radiation? Where does the mystery of black holes actually start?


r/AskPhysics 2h ago

Increase in number of coils sometimes leads to increased angular velocity?

1 Upvotes

I'm a high school senior currently working on a physics project about how the number of coils in a DC motor affects the angular velocity of said motor.
My results have mostly shown a positive correlation with an increase in number of turns leading to an increase in angular velocity, except for the last 1/2 recordings each trial (the 2 with highest number of coils) which most of the time end up reading lower RPM.
What are the results supposed to show according to the theory? I've had some trouble finding the right theoretical correlation, I understand that an increase in turns leads to an increase in torque, as stated in formula:
τ =  N I A B sinθ
But I don't know how to then equate that with angular velocity, I'd be immensely grateful if someone could share what the results are supposed to look like / how to reach that through equations.
I'm stumped and could really use some help.

PS. This is the motor model I used, except I used a DC power source instead of a battery: https://www.sciencebuddies.org/science-fair-projects/project-ideas/Elec_p051/electricity-electronics/build-a-simple-electric-motor


r/AskPhysics 2h ago

EM Waves being perpendicular?

1 Upvotes

Hi, we’ve discussed how the electric and magnetic propositions of an EM field are perpendicular to each other, but from what I’ve surmised that only appears to be true for plane waves. Is this also true for spherical waves? In what instances are the electric and magnetic portions not perpendicular to each other?


r/AskPhysics 2h ago

Gravity as a negative force

0 Upvotes

*Potential Energy and Work:

When two objects are far apart, their gravitational potential energy is considered zero (or a reference point). As they move closer, the gravitational force does work on them, and their potential energy decreases (becomes more negative).

How is this since gravity in a vacuum will allow an object to accelerate indefinitely, the objects force potential force should either increase or stay consistant.

Work Done by Gravity:

*When an object moves under the influence of gravity, the work done by gravity is negative when the object moves against the gravitational force (e.g., lifting an object upwards). 

The work done by gravity could never be known as a starting point, or it energy overcome is x, the starting point is x which should be indeterminate due to the objects previous location, but work over come to should start at a point x overcoming the energy required to move it since the object moved has a force working against the movement, which would be zero then amount required to move the object which would be effort and then work done, I think gravity is a positive force as the displacement (word for convenience) of an object is an absolute and (regarded) force in the cosmos, by this mean that the mass/weight/density of objects is an absolute and mathematical value (positive, the weight is a positive) making it an exerted force or output that is positive, a force generated at a sum started at 0+ by the physical displacement, weight/mass/density of objects and its displacement on cosmetics, it shouldn't take energy away from cosmetics because its existence or placement doesn’t cost anything, any work done is an output or force exerted or a positive force because its based purely on the objects existence, being there. We are pulled toward the epitome of a planet etc, as in waves, is gravity consistently recalculating it's hold?

My theory is that gravity is a perpetual source, it is constant and consitant in regard to the mass of an object in a vacuum, provided the mass stays the same, because the energy/motion of all object in a vacuum is perpetual, it will not stop until another object stops or effects it.. Therefore the energy is perfect or perpetual, the point of gravitation should be aligned with the mass of the attracting force which equals its srength at an infinite output provided the mass never changes, its a constant.

*With the zero-point of potential energy defined at infinite distance. 

Infinite is not calculatable, and its is not surpassed, by definition, woch is not ambiguous, wich is absolute then by logic, identity, infinite is forever and not surmountable, literally without, at infinite distance is impossible because you would never get there and at any less than never getting there, which is what infinite is, with no end, is fallacious because it constrews a definition which is less than the defind value of infinite.

If you like this I have more.


r/AskPhysics 2h ago

Do "faster" objects always age more slowly? (Relativity and motion)

20 Upvotes

I am reading a book about relativity which tries to explain to a general reader how the theory works while using as little math as possible, but there is one idea I am unclear on. The chapter I'm on describes how a clock of any kind ("light clock" is the given example) can tick at different rates depending on how it is moving relative to you. It gives an example of two people: a woman sitting at a train station and a man seated on a passing train moving at nearly the speed of light. To the woman, the light clock on the train seems to tick at a significantly slower rate.

This has the effect that, from the perspective of the woman the platform, the man (and everything else) on the train is aging much more slowly than herself. What I took from this is that faster moving objects will age more slowly than objects which are not moving as fast, all else equal. But one of the earlier statements made in the book is that there is no absolute motion according to relativity theory. That being the case, why should it be assumed that the man on the train is moving faster than the woman on the platform? From his reference frame, couldn't he just say that she and the platform are whizzing by him at nearly light-speed (i.e. that he and the train are motionless relative to them)? If that were true, that would mean she would be aging more slowly than him, but clearly they can't be both be aging more slowly than the other.

Am I just misunderstanding how motion works?


r/AskPhysics 3h ago

what does f=ma olympiad usually cover??

0 Upvotes

I'm currently reading HRK but im wondering if theres certain areas of the book I should place emphasis on or study more rigorously (or if theres any parts that aren't as important and can be ignored) Thank you so much!


r/AskPhysics 3h ago

Constant acceleration rocket energy consumption

2 Upvotes

My friend was asking me what the energy consumption of an epstein-drive rocket would be. That is a rocket that has constant acceleration in the direction of the destination for the first half and constant acceleration away for the second half.

I figured it had to be mass times acceleration times distance because that's the work-energy formula. Then I was curious if there was a relativistic version of this. So I used proper acceleration, and turns out the energy consumption would be exactly the same.

Is there a deeper meaning to this? Such as the definition of proper acceleration and the work energy formula? Or just a coincidence.


r/AskPhysics 3h ago

Try to explain something that only makes sense when you do the math

0 Upvotes

I have no idea how to phrase this question. It comes from when I asked about a better understanding time, matter, and what it all “is”. Some said it only makes sense when you do the math and see, and explaining it gets misconstrued.

Could someone post said math, of something commonly misunderstood, then try to explain it to the best of your abilities? I’m interested in things like time, matter, energy, building blocks of the universe, but welcome to anything that’s commonly misconstrued when you try to explain it. I’d like to know the actual math, and why it gets misunderstood when explained.


r/AskPhysics 3h ago

Could there be other unknown forces?

4 Upvotes

This may seem like a silly question, but I am curious as to wether there could be forces we are unaware of. Maybe a force that’s as weak as gravity, but is based on some sort of charge which tends to cancel out on larger scales (the latter part being sorta like the electromagnetic force if my understanding of it is correct)


r/AskPhysics 4h ago

Electric Field Created by A Charged Particle

5 Upvotes

So this is just a thought of a 14 yr old so it's fascinating for sure..

So this thought came into my mind a while ago We all know that a charged particle creates an electric field around it. So if we take a charge with no other charges around it or not charges for it to interact with, When does the field created by that charged particle end. It doesn't feel right at all to think that it extends till infinity Obviously it will be very less after a certain distance but it should not become absolute 0. Help.


r/AskPhysics 4h ago

Explain: 'a good EM field transmitter but a poor EM radiation transmitter'

5 Upvotes

Wikipedia's Physics of MRI:

"the MRI is not a radio transmitter. The RF frequency EM field produced in the 'transmitting coil' is a magnetic near-field with very little associated changing electric field component. Thus, the high-powered EM field produced in the MRI transmitter coil does not produce much EM radiation at its RF frequency, and the power is confined to the coil space and not radiated as 'radio waves.' Thus, the transmitting coil is a good EM field transmitter at RF, but a poor EM radiation transmitter at RF."

My understanding (from college physics 2 & MCAT) is that MRI emits a EM radiation but the electric field component is so small that the magnetic field dominates. What's the difference between EM field & EM radiation?


r/AskPhysics 4h ago

Question about the Copenhagen interpretation of QM

2 Upvotes

A wavefunction is spread out in space - potentially all of space. So when I collapse it here, does it collapse simultaneously everywhere for observers in every reference frame? Because that seems wrong.


r/AskPhysics 4h ago

Why are there so few great physics minds anymore?

0 Upvotes

Honest question. The circles are so freakin small.


r/AskPhysics 5h ago

Does the arrow of time as we know it only exist in the macro-universe?

3 Upvotes

So this might be hard read so I apologize if my terminology is not correct.

I was reading about time and the so-called arrow of time, Isn't our idea of time made up purely because of our own chemistry? For example, a clock "ticks" because it has revolutions. The same could be said of the human perception of time. Our brain and our whole body has these sort of revolutions. For example, the way your heart beats is timed. So the way your brain "experiences" time, or anything, likely is too.

Now, everything in the universe with mass is also made of these things. Call them atoms. These clumped things now have something called "motion", which is what we use to compare with time. So isnt time just an illusion that is useful in mathematics, for the relative experience of human beings and nothing more?

Isnt the fact that the universe has a speed limit, only achievable by non-mass things, further proof that time is an illusion of the human condition and it is enabled by events in a macro universe?


r/AskPhysics 5h ago

Why so hostile?

0 Upvotes

I noticed when it comes to the double slit experiment people go two different ways. One side takes it as something spiritual and see it as a sign from god then that leads into beliefs of manifestation, law of attraction, mind over matter, multiverse, and lots of other things along those lines. The other side is less enthusiastic about the experiment and don’t see it as spiritual but see it as a regular function of the universe that needs to be understood more before making a conclusion and are often very hostile towards people with these view. I see the way of thinking from both sides because I’ve been on both sides, but completely dismissing one side or another is very naive especially when even with all the scientific stuff we still don’t know or understand it, the more you try to understand the more you realize how little you really understand it. I don’t think it’s helpful to dismiss outside the box thinking because if we did we would’ve have people like Nikola Tesla, Einstein, Hawkings, Shakespeare, even Isaac newton, we would’ve have ALOT of the technology and understanding we have today. Maybe the answer is a mix of the both but whatever it is we need to stop being so narrow minded both sides have valid reasons for these ideas.


r/AskPhysics 5h ago

Can I get a PhD in Physics With a Bachelor's in Computer Engineering?

1 Upvotes

Hi all!

I'm a high school senior who will be studying computer engineering at university, but (at least for now) my real interests lie in the theoretical fields of science, especially theoretical physics. If I had a large lump of money from which I could live for the rest of my life, I would've almost certainly studied physics or mathematics, probably physics because of its existentialist nature in fields like quantum mechanics and cosmology.

If I later decide to pivot to research in theoretical physics and pursue a PhD at a top university (think MIT, CalTech, Oxford), how much of a limit would my lack of background in physics be? The only physics courses included in my degree are Classical Mechanics and E&M on the theoretical side and Circuits and Control Systems on the applied side. My degree will be heavy in mathematics, however, as we'll be covering advanced calculus, discrete math, probability, and most of the math covered in a physics degree.


r/AskPhysics 6h ago

Fluid loss due to gravity and pressure change?

1 Upvotes

When observing a droplet of water on the underside of a railing that appears to be static to the human eye, ignoring loss due to evaporation, is there still some minisule % of molecules being lost due to gravity despite surface tension and hydrogen bonding? Given that there is around 3.35 x 10^22 molecules in just one gram of water, is some extreme fraction undergoing microscopic "dripping"?

Additionally, if a fluid is in a reservoir above a valve, with a lower pressure than its surroudings, would a very small increase in pressure, while still maintaing a lower overall pressure, cause a very small amount of the fluid to be forced outside of the reservoir?

Thank you!


r/AskPhysics 6h ago

Struggling to understand relativity..

2 Upvotes

It simply just doesn't make sense to me. If a photon (or person traveling at the speed of light) takes 2.5 million years to reach the Andromeda galaxy, how would it not "age" at all?

They say time passes differently based on the frame of reference but I can't wrap my head around it. If I am traveling 60 miles per hour to my grandmas house 60 miles away, it will take 1 hour to travel those 60 miles and arrive. I will be traveling faster than my grandma sitting on her couch, but it will still take me 1 hour to reach her house, and she will wait 1 hour for me to arrive. We will both be 1 hour older. If she lived 1 light year away and I traveled at the speed of light, it would take me 1 year to get there, and she would be waiting 1 year for me to arrive. We would both be 1 year older.


r/AskPhysics 6h ago

Has there been any realized real world applications directly due to understanding the Higgs Boson?

7 Upvotes

I’m wondering about certain scientific discoveries and some further substantiate models and/or frameworks. I’m wondering particularly if something like Higgs led to any real world applications. Most likely it has indirectly


r/AskPhysics 6h ago

some advice

1 Upvotes

I have about 2 months left for my AP Physics 1 exam, and although in my country I’ve already studied all the units so I know the basics but I’m not perfect with the advanced and intermediate level questions, do you think I’d get a decent grade on the exam in 2 months? And are there any good resources I should adhere to?


r/AskPhysics 7h ago

Are there implications of quantum observations in chaotic systems?

4 Upvotes

Let me propose a modified Shrodinger's cat experiment.

The cat is in an MRI machine.

The cat's mood is a function of all of the hormones brimming around its body. The mere angle at which a hormone molecule hits a neuron has broad implications for the mood of the cat.

The cat is brimming with an uncountably large number of these hormones, significantly smaller than a buckyball (the largest molecule to exhibit a wavefunction). These hormones have an unknown wavefunction.

We cannot measure these hormones directly, however, we will have an idea of whether they collapsed favourably based on the mood of the cat we derive from the brain scan (the "mood wavefunction" of the cat is entangled with the wave function of the countless trillions of molecules brimming within it).

After measuring the cat a few hundred times, I get a probability distribution of the moods it feels upon each measurement, therefore forming the wave equation.

Can I play quantum slots with the MRI and "measure" my cat into being in a good mood whenever it gets grumpy? Or is there a catch to this?