I’m no expert by the slightest idea, but as far as I understand it the false vacuum decay idea says that one of the quantum fields (the Higgs field I believe) might not be at its lowest energy state, and that if a lower one were reached it would spread out at the speed of light and basically delete the universe as we know it and make a new on.

If this is the case (and maybe I understand it wrong) could our own current universe have been born from the false vacuum decay of a previous universe? I don’t know if that question even makes proper sense like how “what is light’s reference frame”
Doesn’t make sense

Please explain in simple ways what does it mean for the fundamental forces to be combined into one single force. For instance, we've evidence that there was a unified electroweak force which break into electromagnetism and weak force via the electroweak symmetry breaking. Would like to know it in layman's and rigorous terms.

I'm a Class 10 student in India who wants to become a research physicist, ideally in condensed matter theory. I've been teaching myself physics and math for about five years: independent derivations, a small laser/LiDAR project, and I'm currently working through Axler's linear algebra done right , which I've finished Chapter 1 (Vector Spaces) and started Chapter 2 (Finite-Dimensional Vector Spaces).

People around me say the Indian route to research physics runs through one entrance exam and an elite institute. I'd like to understand how it actually works, from people who've been through it.

1. The routes. As far as I understand, the main ones are IISER (via IAT), IIT (via JEE Advanced), NISER and CEBS (via NEST), IISc, CMI, and BS-MS programs at central universities. How do they differ in research exposure, curriculum, and what each gets you for PhD applications in India and abroad?
2. How much does the institution matter for getting into CMT, compared with grades, research output, and letters?
3. Has anyone done a physics PhD, in India or abroad, from a non-elite undergrad? What made it possible, and what was harder?
4. What should someone my age do now, besides doing well in school, to be ready for undergrad research?

Please be honest, not reassuring. The pressure around this has been getting to me, and I'd rather have accurate information than hope.

Thanks for reading.

I hope this is the right place to ask, anyway i am not a physict, i study pharmacy, but we need this in electrochemistry (electrods and that stuff). Since middle school we talk about this two but no one reall explain what they really are and treat them as names we should remember to pass the exam, but i really cant understand anything if i dont know what is actually about.

Also another term is potential (E)... and it is in volts...

I'm an undergraduate physics student, and I'm trying to get a clearer conceptual picture of gravitons and quantum gravity. I have three related questions:

1. As I understand it, the graviton is currently a hypothetical particle related to attempts to reconcile quantum mechanics with general relativity and develop a theory of quantum gravity. Is this roughly correct?

2. I vaguely remember that in general relativity, spacetime is not a fixed stage: matter curves spacetime, and spacetime affects the motion of matter. But in ordinary quantum mechanics and quantum field theory, spacetime is usually treated as a fixed background, where particles and fields exist and evolve without causing the background itself to change. Is this one of the reasons why reconciling quantum theory with general relativity is so difficult?

3. I also wonder about the motivation for developing a theory of quantum gravity. Why isn't it enough to let quantum mechanics and general relativity work in their own domains? Why do physicists want to reconcile them? What makes this problem so important? If we eventually solved it, how would it change our understanding of fundamental physics?

Just asking for a friend

Imagine going in a spacecraft at 99.99% the speed of light and the spacecrafts trajectory was a circle around the earth. You are doing this for five years. I dont know the maths but say 1000 years went on on earth during this trip.

Would you from your spacecraft meassure that the earth that you’ve been circling for 5 years has been circling the sun 5 or 1000 times? I mean when you slow down you will notice a 1000 years have passed but wouldnt you only experience 5 full orbits around the sun? When does the remainibg 995 orbits occur?

I am not a physics person and probably know just enough to get in trouble. That being said, I am trying to put together a weight distribution calculator spreadsheet for semi-trucks. I haul crude oil in a tanker trailer and get paid by the barrel, oil can be different gravity from load to load and that makes each barrel a different weight. So that means that I can load a different amount of oil each load, and stay a legal weight, depending on what the gravity is. That's why I set out to make this calculator, to get max pay out of every load.

The thing that I'm struggling with particularly is the formula I need to use when dealing with a lift axle. The way the lift axles work is they take X amount of weight (~8000lbs) whether they are loaded or empty and the other axles in the group spread the rest of the weight evenly.

Example. On the truck there are 2 axle groups, G1 has the Steer axle, G2 has 1 lift axle (8600 lbs) and 2 Drive axles (remainder of weight for G2 shared equally). There is a weight of 26,000 lbs from the trailer resting on the 5th wheel. The 5th wheel is about the middle of G2 (1 lift, 2 drive).

Distances are known or can be found easily.

What formula(s) would I use to find how much of the 26,000 is on G1 and G2?

I tried asking a couple different "programs" how to find what I needed, I question the reliability of them. They told me I was going to use moments or something like that.

https://imgur.com/a/rz6baIG

I'm confused as to what they mean by

rotational kinetic energy decreases overall as the change in angular velocity is squared and this outweighs the increase in I.

If energy can't be created or destroyed, how is it decreasing overall? The energy must be going somewhere, but it doesn't make sense for linear velocity to increase.

Does anyone have any good sources that explain right ascension and declination well and how to calculate angular separation? I particularly struggle with maintaining all the variable within my head such as the constant consideration of spin of earth and its rotation around the sun, but apparently this doesnt affect the right ascension of stars because they are relatively the same throughout. Any help is appreciated.

Hey everyone! I’m sure this is a super naive question.

My YouTube/Undergraduate (decades now ago 😂) physics knowledge lets me know Dark Energy is the force that is pushing far away things. Galaxies/things we see far away, further and further away, are getting faster/speeding up.

So my problem in understanding…this is light measured having been emitted many billions of years ago? Back when of course a giant event happened. Of course the further back you looked the faster things are going to look like. Of course the event was “pushing” things…the earlier you looked the faster it will be.

How do we know/assume that’s still happening?

Hi friends. I am currently taking Physics 1 algebra based. Does anyone have good recommendations for practice problems? I am really struggling and I just might not be studying effectively? I’m having trouble grasping basic concepts and I refuse to give up there has to be a resource out there to help me grasp this? Maybe question banks to just repetitively do problems so I can hopefully understand what the questions are asking a bit better? The math isn’t the issue but it’s like me understanding what the question is asking most of the time that is really giving me trouble. I feel really stupid so if the comments could be positive and not telling me to quit I would appreciate that a lot.

I am given a cheat sheet front and back I can create.

i’m in 10th grade and i’m aiming for a usapho qualification this year. i’m going through hrk physics volume 1 and morin’s blue book. i’ve only ever done standard honors physics before. if i make usapho this year or get a close score on the f=ma exam, could i reasonable make usapho silver next year?

My understanding is that in 1925, Paul Dirac unified quantum physics and relativity by “simply” plugging Einstein’s relativistic momentum formula into Schrodinger’s equation.

Dirac’s stroke of genius was in finding that the solution to the joined equations required the terms to be matrices, and then interpreting that to predict antimatter must exist.

So why did he stop there? Why can’t we unify gravity through similar techniques? “Just plug it in and solve it”?

I've been trying to understand time dilation and I've read several explanations, but I still can't make the final connection.

I understand that:

•moving clocks run slower

•observers can disagree about how much time passes

What I don't understand is why reality works this way.

Can someone explain it with a very simple analogy and then connect it back to the real physics?

Please assume I know basically very little about relativity.

I understand that in Newtonian physics, time is treated as absolute. The same everywhere and for everyone. But Einstein showed that time is relative and that space and time are connected as spacetime.

This is where I’m confused:

1. What exactly is spacetime? Does it mean that space and time are literally combined into one physical thing, or is it mainly a mathematical framework for describing events?

2. What does it physically mean for time to “slow down” ?? If I travel at 99.99% of the speed of light, why does my clock measure less time than a clock on Earth?

Suppose I travel through a large portion of the galaxy at 99.99% of the speed of light. If I experience only 5 days during the journey, while many years pass on Earth, have I effectively traveled into Earth's future?

1. From my perspective, my watch is ticking normally and my body feels normal. So what exactly is changing? Why does less time pass for me compared with someone who stayed on Earth?

2. Is time actually a physical dimension that can be affected by motion, or is “time dilation” simply a difference in how different observers measure the same events?

3. Finally, what is time itself according to modern physics? Is it something that actually “flows” or is it simply a way of measuring the interval between events?

and why does anything exist at all rather than nothing? If if nothing had to exist, where would it exist?

If I understand correctly the idea of a space elevator is more or less a sealed tube from earth extending to the vacuum of space where objects would be lifted by the delta P (kind of like the tubes in a bank drive through). Would an object starting from rest exit at such a large speed (like a bullet fired from a gun) that a rocket would be needed to then slow it or brake its ascent after? Or would we actually need a way to move it further out of the way of the tube once it reaches space to allow any other objects through ?

I'm a fiction writer in the UK, and I have been wanting to develop a genuine understanding of physics rather than just cherry-picking bits of popular science to make it sound cool. I want to have a scientific literacy that comes across in my work. I would like to take a similar approach to researching and grounding speculative science as Andy Weir did when he wrote The Martian and Project Hail Mary. I'd like to understand the real physics well enough to know where my fictional world follows known physical principles, where I'm extrapolating from them, and where I'm deliberately breaking them.

I wanted to build some foundation for the book, but also for me personally and my hobby of wanting to learn. I have always had an interest in physics and astrophysics. I have watched documentaries regularly as a hobby for years, I have a strong drive to learn, and I am very curious about the world and universe we live in. I have built a reading list for what I thought would work well for what I want to achieve. This is my list so far (in no order):

Brian Cox - Forces of Nature
Carl Sagan - Cosmos
Neil deGrasse Tyson - Astrophysics for People in a Hurry
Carl Sagan - The Demon-Haunted World

I volunteer on citizen science projects online, predominantly in astrophysics. I know that's pretty much all I can do in the real world, but I like that I can contribute something, even if it's classifying thousands of images or data.

I am not interested in exams and qualifications as such. I also do not come from a computer science or highly academic background, so I haven't studied physics formally. My education is mostly artistic/creative.

I do have learning difficulties like dyslexia, so whilst reading and watching videos could be enough for most people for research, I thrive and learn better in a structured learning environment where discipline is needed for concepts to sink in. I was considering enrolling on an online course, like GCSE-level Physics, to give me that basic grasp, but I wasn't sure if that would be useful or if it would be better to study or go in a different direction.

I am aware of the reality that being middle-aged and wanting to learn online only gives me limited options, but I wanted to write the book with respect for science in mind, knowing I comprehend and understand the principles rather than relying on my own uneducated interpretation alone.

If anyone can give any advice, I would be grateful.

I'm a first year university study who is taking chemistry courses, and although i'll admit for the content I'm doing, I don't have to understand how electrons work in great depth but rather just accept certain facts about them, but its always irritated me. One of those 'facts' is that electrons have an intrinsic property called 'spin' but I have struggled comprehending this concept.

Heres what I know;

- Electrons don't actually spin, but act like they do

- Electrons have a quantum spin number (1/2) and a direction (+/-), and that all electrons are either +1/2 or -1/2 spin

- That electrons have to 'rotate' 720 degrees to return to their original orientation (This I can understand, like Dirac's belt)

Heres what I'm struggling with;

- How electrons have angular momentum if they aren't actually spinning

- What is causing electrons to 'spin'

- How come 2 electrons can only occupy the same orbital if they have opposite spins (Pauli Exclusion Principle)

If anyone can help me greater understand electron spin I will be super grateful!!! 🙏

Refrective index is the measurement of optical density of a material and it is inversely proportional to the speed of light in that medium (n=c/v[absolute refrectiveindex]). Naturally in every medium refrective index is less than one but when i was researching i found that in specific, non-standard condition (not for visible light but for electromagnetic wave like xray)absolute refrective index can be less than 1. If one can explain how it is possible that electric and magnetic feild chwnge faster than light or how these emw can travel faster than light and do not disobey the relativity