Sorry for my english its my second language but i its my first time trying to ask about physics with it

Newton law described almost everything about any action that is happening, and ofc this included everything on this universe. Now if i run full human speed and hit someone standing, the same power will affect me too but on the opposite direction and will stop me too, the poor guy will also be affected by the power and will move in the same direction i was moving.

Lights ( with its being an electromagnatic energy and its weight is actually the momentom proportional of its frequance) travels with the highest speed that can break into the 4th dimension, and it hits everything with no regard of the Newton law, i know it might be stupid but bare with me, the fusion power is created by hitting atoms with eachother with high speed. Despite Its speed, light is also effected by the known physics, it can be reflected and curved around huge mass forces like the sun or the black hole, it can be transform into other forms of energy...etc

This question i have been trying to have an answer for the past 3 days: If i run with my body asfast as light speed( i will be dead half the way there but lets say im an astronaut in space with no air resistance) and i hit another astronaut with light speed, what will happened then?

Is Newton law gonna do the same energy reflection aganist me, stopping me right at that person place and sending him at light speed?

Or

Is the Newton law gonna be ineffective ? And in that case, what will happened to him with that huge 60kg light speed human hitting him? Is he gonna disintegrated?

Whether it's from your undergraduate or graduate days, can you recall a particularly memorable final exam? Maybe it was extremely challenging, or perhaps you left the exam room feeling triumphant, like a champ. I'm surrounded by my own study chaos (there's a kid that keeps pressing one of those annoying buttons) and am curious to hear about others' experiences

Any thoughts on this response to the investigation into the high-Tc superconductivity claims concerning the C-S-H and Lu-N-H compounds?:

Response by Prof. Dias to Rochester Investigation

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For background here, I'm a high school student.

I've recently been reading a lot about how it's like to solve math problems at the research level. They just pick interesting questions in their field and work on them. It's just problem solving but a pretty high level. However, it's been very hard to find a physics equivalent answer to this question. All the posts I have been reading about are about experimentation and collecting data and no seems to discuss what it's like to solve problems at the research level. What do you theoretical physicists work on?

I read Walter Isaacson's biography on Albert Einstein and from what I saw, he was doing much the same thing in physics too. He was asking what are the implications if speed of light is constant in any frame? Is this a special case or is research level theoretical physics the same?

I would really love it if you guys could explain with an example which you have worked on.

P.S : If there are any sources where I could read more about this I would be grateful :) .

This is a dedicated thread for you to seek and provide advice concerning education and careers in physics.

If you need to make an important decision regarding your future, or want to know what your options are, please feel welcome to post a comment below.

A few years ago we held a graduate student panel, where many recently accepted grad students answered questions about the application process. That thread is here, and has a lot of great information in it.

Helpful subreddits: /r/PhysicsStudents, /r/GradSchool, /r/AskAcademia, /r/Jobs, /r/CareerGuidance

I was doing a campus visit recently where another perspective student was handing out puzzles from her undergrad research project. 1000 pieces, 20"x30", and all the black swirly portions really sucked to put together. It is truly a testament to my commitment to silly things.

This is the actual puzzle fully assembled. The picture has more of a red tint than the real thing, but shows the glossiness well.

A digital picture and an accompanying article can bee seen here with more details on the research project. Along with some more info on SOFIA specifically. She's essentially a telescope strapped to a 747 and flown around the globe, taking measurements of the near, mid, and far-infrared radiation coming from different sources.

I'm going to build a frame for this and hang it in my office, so let me know if you have any ideas on the frame design/color!

Hi all, first post here and I am not sure if it is appropriate or not. I am a lecturer/researcher in a not so advanced uni in some 3rd world country, with background in control engineering > pivoted to Density Functional Theory for material simulations in masters > currently working on functional surfaces (liquid on hydrophobic surface) for PhD. Due to possible focus on national research interest, I most likely will have to pivot again to Computational Fluid Dynamics and related stuffs. I have tried reading on the current state of the field, but since I do not really have extensive background in Fluid Dynamics, I might have miss quite a bit of things, especially with the requisite maths needed for it.

One bit of puzzle that intrigues me at the moment is one of so called Navier-Stokes existence and smoothness problem. I am aware that the problem is currently more of a Mathematics problem than Physics problem, but I am not sure to what extent. A lot of literature suggests that since we do not have a proper solution to Navier-Stokes smoothness, a computational fluid simulation may blow-up some times. Is there any way to predict on when a simulation will blow-up, and parameters that help to avoid it. I presume there would be some kind of "best practices" in the community that with some kind parameters/setups to avoid or to use. If I allude to some similarities in DFT simulations it would be the choice of basis sets (plane wave or Gaussians), exchange-correlation functions for different type of materials, adding van der Waals parameters/terms and so on which reasons are not exactly intuitive to someone who is new to the field. I wonder if it will be the same for Fluid Dynamics due to Navier-Stokes smoothness issue, or is it an issue that only happen on the edge cases? Sorry if my exposition is not succinct enough to explain my case.

This thread is a dedicated thread for you to ask and answer questions about concepts in physics.

Homework problems or specific calculations may be removed by the moderators. We ask that you post these in /r/AskPhysics or /r/HomeworkHelp instead.

If you find your question isn't answered here, or cannot wait for the next thread, please also try /r/AskScience and /r/AskPhysics.

This is a thread dedicated to collating and collecting all of the great recommendations for textbooks, online lecture series, documentaries and other resources that are frequently made/requested on /r/Physics.

If you're in need of something to supplement your understanding, please feel welcome to ask in the comments.

Similarly, if you know of some amazing resource you would like to share, you're welcome to post it in the comments.

Just saw a post about what equation you liked most. I wonder which one you use most on an everyday basis and which ones you've used alot in the past.

A student asked me about Cherenkov Radiation and the speed of light, and how it is similar to a sonic boom and if something could travel faster then the speed of light, could it create a light boom.

Nasa article on Cherenkov Radiation that I think led him to this.

Yes, it traveled faster then light in water, but it didn't travel faster than light as in actual light in the universe. We are working on diffraction and they should understand how that changes the properties of light, Snell's law, etc. I'm having trouble finding the words to explain.

Please help me explain to a high school junior why it exceeded the 'speed of light' in water, but it's not faster than the speed of 'regular' light. ELI ... I dunno, 16 years old.

Hey everyone, my question is directed to those who have completed a bachelor's degree in Physics. What career paths did you pursue afterwards? I'm about to finish my bachelor's degree in physics in approximately a year, and I'm becoming increasingly anxious about finding employment in this field

This is a dedicated thread for you to seek and provide advice concerning education and careers in physics.

If you need to make an important decision regarding your future, or want to know what your options are, please feel welcome to post a comment below.

A few years ago we held a graduate student panel, where many recently accepted grad students answered questions about the application process. That thread is here, and has a lot of great information in it.

Helpful subreddits: /r/PhysicsStudents, /r/GradSchool, /r/AskAcademia, /r/Jobs, /r/CareerGuidance

Dr. Sudhir Kumar from the ETH Institute who will be presenting the following topic:

Overcoming intrinsic light outcoupling limit in perovskite quantum dots LEDs using low refractive index anisotropic nanocrystals

Date & Time: Tue, April 9, 10:00 AM - 11:00 AM (CET)

Joining Dr. Sudhir will be Dr. Balthsar Blülle from Fluxim who will be presenting a talk on Angular luminescence spectroscopy to explore novel emitter and light conversion materials.

https://events.teams.microsoft.com/event/b474ae6f-91ea-4ad5-a761-9a341f4cc68d@edaecfd0-eb6b-4e07-b7ed-3a0e8fbf5d0c

Original post with proper formatting

Text version with bad formatting:

Shower thought

When you are in the shower, watching the million billion molecules of water spray from the showerhead every nanosecond, take a moment to reflect on how, despite their innumerable multitude, each molecule has traveled a completely unique and remarkable journey for billions of years over and through the Earth to you.

Except, it's not true. None of the water molecules in your showerhead will last long enough to reach you.

At room temperature, pure liquid water is ionized at a ratio of about 2.8 parts per billion: for every billion water molecules, there are 2.8 H+ ions and 2.8 OH- ions. Lone protons are never found in liquid water, but rather are associated with water molecules to make hydronium H3O+, and frequently bigger associations (H5O2+ "Zundel ion", H9O4+, etc). The bonds in hydronium are very weak, not much stronger than hydrogen bonds, and have similarly short lifespan: hydronium typically lasts around a picosecond before one of the hydrogens jumps ship to sign on with a new water molecule. This is the Grotthuss process which causes protons to diffuse very rapidly in water:

https://upload.wikimedia.org/wikipedia/commons/d/d3/Proton_Zundel.gif

Thus, for every H+ ion (by which we mean H3O+, etc, collectively) in a mass of water, there are about one trillion hydrogen swaps between nearby water molecules each second. This comes to around 400 swaps per water molecule: every water molecule in liquid water changes one of its hydrogen atoms on average 400 times per second.^[This figure is super approximate, and could easily be more than an order of magnitude off.]

If it takes, say, 140 ms for water in the showerhead to reach you, that is 100 times the half-life of a water molecule, and only 1 in $2^{100}$ water molecules (about 10000 liters) last that long.

(There is some nuance; liquid water forms large-scale networks or clusters of molecules connected by hydrogen bonds, which are constantly shifting and rearranging, but the timescale at which molecules turn and move is slightly longer than the timescale of the Grotthuss process. Thus when H+ moves from one water molecule to another, the most likely next place for it to go is back where it just came from, and the above calculation will modestly over-estimate the diffusive rate of H+.)

In the whole lifetime of the visible universe, no water molecule has ever persisted intact for a minute in liquid water at room temperature through chance alone.^[It is possible that there is some stabilizing process that I don't know about -- water is complicated -- but that would not be through chance.]

Perhaps, one might think, although water molecules are rapidly intermixed, some water molecules might reform from the same constituents as at some point previously; if a billion H+ are shuffled between a billion water molecules, on average one of them will end up where it started. This would be reasonable if water molecules had one hydrogen, but with two hydrogens this would require both to return to the same starting molecule at the same time. The probability of this falls rapidly as the number of molecules involved increases; and as more time passes, there are more opportunities for the body of water to be mixed with other bodies, and the original constituents of a water molecule to be separated forever.

Let us relax our expectations a bit and ask whether any arrangement of an oxygen atom and two hydrogen atoms has ever recurred. Out of $N$ water molecules there are $N^3$ possible such arrangements. By the birthday problem, you need to sample about $\sqrt{N^3} = N^{3/2}$ random arrangements to have even odds of having sampled the same arrangement twice. 400 times a second, $N$ new such arrangements are made.

Recall that deep in the mantle of the Earth, crystals are frequently found to have small pockets of water which may have been sealed for billions of years. If such an inclusion had a milligram of water, which is $10^{19}$ molecules, it would need $10^{9.5} / 400$ seconds, or 3 months, for some water molecule configuration to have occurred more than once.^[Or maybe not: "Recent research, however, has shown that water can sometimes be gained or lost from minerals at magmatic temperatures (>1000 C) in a matter of minutes. If this is true, then the fidelity of mantle xenoliths is questioned."] This remarkable coincidence will last for perhaps a millisecond (or, if a little unlucky, only a picosecond) before dissolving away.