Einstein Definition and 788 Threads

I keep reading things like the following (for me not correct) on different websites like researchgate (coming from supposedly phd.), so I wanted to make sure there is no flaw in my thinking. One example of a comment I've read was: "TIME is an ILLUSION according to EINSTEIN - (the space-time...

Hello everybody, my question may sound stupid, especially speaking of such a mind-blowing and important theory... but here I am! I'm 17 and I'm reading a fabulous book by Stephen Hawking, "A Brief History of Time", and it introduced me to relativity theories... I literally started looking the...

$$Q_{(\alpha, \beta)} = \sum_{N=0}^{\infty} e^{\alpha N} Z_{N}(\alpha, \beta) \hspace{1cm} (3.127)$$ Where ##Q## is the grand partition function, ##Z_N## is the canonical partition function and: $$\beta = \frac{1}{kT} \hspace{1cm} \alpha = \frac{\mu}{kT} \hspace{1cm} (3.128)$$ In the case of an...

Is concept of inertial vs non inertial frame inveted in Einsten theory of relativity or Newton knows that we can see on same object from different perspective? (Newton set 3 laws for inertial frame,so did he knew for realitivtiy when view object form different perspective/frame and did he...

Here is the Code File in an txt. I can on request provied the whole Program, which includes the PSE, AtomFunctions and many useful but not all implemented Funtions to solve the Many Worlds Problem in C#. Please feel free to ask questions via here or email [e-mail address deleted by Mentors] I...

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Below is my attempted solution: $$\epsilon_{ij \ell} \, \epsilon_{km \ell} \, \epsilon_{ijm} \, a_k$$ $$\Rightarrow (\delta_{ik} \, \delta_{jm} - \delta_{im} \, \delta_{jk}) \epsilon_{ijm} \, a_k$$ $$\Rightarrow \delta_{ik} \, \delta_{jm} \, \epsilon_{ijm} \, a_k - \delta_{im} \, \delta_{jk}...

Attempted Solution: $$a_i \, b_j \, c_k \, \epsilon_{ij \ell} \, \epsilon_{3k \ell}$$ $$a_i\, b_j\, c_k\, (\delta_{i3} \, \delta_{jk} - \, \delta_{ik}\, \delta_{j3})$$ Beyond this, though, I am quite lost. I know I am very close to the answer, but seeing this many terms can become fairly...

For finding n, I believe that directly applying the above formula gives the results. But I am confused whether I have to put the value of given temperature T = 100K or the actual temperature Tc for Rb-87 at which BE Condensation occurs (i.e. 100 nK, which I got from a quick Google search)? Or do...

Hello, everyone. I am trying to find an aberration of light formula in Einstein's writings that is given in terms of tangents. I did a fairly thorough internet search and all I could find was the formula he wrote in terms of cosines. Yet I have a vague memory that somewhere he did give the...

For ##q >> N ##. ##\Omega \approx \left( \frac{eq}{N} \right)^N \text{ } (2)## (Schroeder, An introduction to thermal physics (2.21)). Can we argue that: ##\Delta I = - \Delta S \text{ } (3)?## How large can ##\Delta N##, be? Thank you for your time.

I was looking at the images of Einstein rings in a recent press release. https://hubblesite.org/contents/media/images/2020/05/4613-Image?news=true And in these images as well as others I have seen in the past, i.e. https://www.space.com/28744-cosmic-lens-4-supernova-views-photo.html there...

A short historical paper gives evidence that Einstein was not the first who discovered ##E=mc^2##. https://arxiv.org/abs/physics/0608289

I bought the book "The principle of Relativity" by Einstein et al. and was really surprised by the (low) level of explanation by Lorentz regarding the compression of rods on the experiment carried out by Michelson & Morley. I reproduce part of it below: Well, he gave absolutely no arguments to...

I read these lines from the book Ideas and Opinions by Albert Einstein- "Gradually the conviction gained recognition that all knowledge about things is exclusively a working-over of the raw material furnished by the senses." what I interpret from is that knowledge is obtained by observing...

If I was looking at a self-luminous object, and all of a sudden a great pass appeared directly between me and the object, in the line of sight between me and it, I could potentially see an Einstein ring. Q: If that mass then started moving radially towards me (distance to self-luminous source...

I am interested in whether or not Bose Einstein condensates have been realized for spin zero stable oxygen isotopes and if so, the maximum density achieved for these condensates. I understand that the quantum spins of oxygen 16 and oxygen 18 are both zero so such condensates would seem to be...

If I see ##f(x_ie_i)## I assume it means ##f(\Sigma x_ie_i)## (summing in the domain of f) but what if I instead wanted to write ##\Sigma f(x_ie_i)## (summing in the range)? Is there a way to distinguish between these in Einstein’s summation notation?

I am very new to such ideas but was wondering if there is any connection to what I am asking. Taking two events, let's say at opposite ends of the globe. Would even A, only have a potential on event B, if light could travel between these event in the given time frame of these event occurring...

At the risk of sounding stupid, this question has always perplexed me. Einstein theorized that mass can not travel faster than the speed of light. I don't really understand it, I assume it has something to do with mass just being energy. Anyway imagine two objects in orbit of something with...

Hi All. Given that we may write And that the Stress-Energy Tensor of a Scalar Field may be written as; These two Equations seem to have a similar form. Is this what would be expected or is it just coincidence? Thanks in advance

If you’re traveling at the speed of light TOWARDS a mirror, will you be able to see yourself?

I have seen people using Einstein's comments on the geometrical description of spacetime to mean that he didn't believe in the curvature of spacetime. While I do not think this is true I cannot fully understand what his remarks mean.When reviewing a book on relativity by Emile Meyerson: La...

<Moderator’s note: forked from https://www.physicsforums.com/threads/proper-and-coordinate-times-re-the-twin-paradox.915212/page-13#post-6215675 > Thank you, that is very interesting and I can understand much of it. :smile: But can someone tell me if it was the application of hyperbolic...

This thread is supposed to be about finding flaws in General Relativity, but the way these people talk they sound like they have no real knowledge of GR. I was just curious if any of you guys could explain further.

https://link.springer.com/article/10.12942/lrr-2005-6 https://en.wikipedia.org/wiki/Exact_solutions_in_general_relativity http://www.numdam.org/article/SEDP_1989-1990____A15_0.pdf A moderator removed this off-topic discussion from another thread. Does anyone on the Physics Forums have...

I find this subject fascinating. Einstein said the distinctions between past, present and future is just a persistent illusion. I was watching a special with Brian Greene and other Physicist who think we do live in a Block Universe and they explained it very well. Here's my question. Say there...

Hello Everyone! I am interested in examining the case of an isolated Einstein Solid (ES) with a decreasing number of oscillators. The total amount of energy of the ES is considered fixed. Whenever an oscillator abandons our model, it "leaves behind" the amount of energy it contained, so that the...

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Just wondering if I'm going to be in over my head here, as I'm not sure what to expect. A notoriously "difficult" professor as my school is teaching a senior level undergraduate course "Introduction to General Relativity Physical consequences of Einstein's equations, including the principle of...

Im reading a book called “Quantum” the deabate between Einstien and Bohr. I’ve read reviews on it and this one particular review said the book doen’t delve into the “epistimological paradox” theat caused the two debaters to take their stand in their arguement. My question is, what was their...

Hi, I have been reading and watching a lot of physics lately but I have come across this problem. I have the basics of special relativity down, and it all seems clear to me. This is not in question to me. For example, I am reading a book on string theory by Brain Greene, and in it he covers...

Hello, I am trying to find in which book Albert Einstein wrote something. I will appreciate any help. The adage i am trying to find is: Education is not the learning of things , but the education of the mind so that it can think. Thank.you

Not sure where best to post. Local paper has had a couple of articles about the black hole image over the past couple of days. They quote Walter Isaacson “Einstein did not believe, then or later, that these results actually corresponded to anything real,” . Is that true? I couldn't imagine...

My question is generated by a an unsuccessful attempt to construct the einstein system with limited knowledge. The first part the counter flow of different gasses (See attachment No1) The main part is the simplified Einstein is what prevents counter flow in this system. I think that perhaps...

At least three items around March 14: new documents from Einstein a coin commemorating Hawking Pi-Day https://todayinsci.com/3/3_14.htm Albert Einstein was born on March 14, 1879. Among various documents of Einstein (acquired by Hebrew University to update their collection of his documents...

Using Newton's equation for gravity and assuming a corpuscular theory of light, one can calculate the angle that light would bend in a gravitational field. General relativity predicts a bend that is twice as large. In the Newtonian limit of GR (which includes weak gravity), does the GR...

by this quote "If A is a success in life, then A equals x plus y plus z. Work is x; y is play; and z is keeping your mouth shut." i wonder if "z" means "say nobody about your results until they are published" or "work and do not gab on empty"

I graduated from high school last year, and I didn't have the class rank that I wanted (I was stupid number 2 in the class) after lots of hard work. It all turned out that my hard work was wasted to get some stupid title, but it got me thinking that I probably wasn't genius enough to be ranked...

I've always wondered how we came to come up with such an idea. Was he one day sitting around and thinking, then made a random assumption and go "ah hah!". Or did his idea come up through his calculations on the nature of how gravity should cause interaction? Is their a literal fabric of space...

I just finished watching this biographical drama on Einstein's life. I found it quite good. Has anyone else here seen it?

NOVA presents a show on Einstein and Quantum Entanglement:

I am confident that there are scientific nut cases in every country (there certainly are in the US) but usually they are fringe people or just crackpots. It has long amazed me the extent to which seemingly responsible people in India subscribe to ridiculous theories. I've had a couple of direct...

I've seen quotes by Einstein along the lines that he was well aware he didn't have all the answers, that his knowledge related to the workings of the universe was quite limited. Having trouble re-finding these quotes - looking to get pointed toward them. Thanks.

I was reading a document from the time of Einstein where the metric is referred to as "the fundamental tensor". That made me wonder if it's possible to derive all concepts of tensor field, scalar product, connectivity etc. starting from the requirement that the metric is invariant under change...

In Einstein summation convention, the summation occurs for upper indices and its repeated but lower indices. However I have some confusion 1) $${\displaystyle v=v^{i}e_{i}={\begin{bmatrix}e_{1}&e_{2}&\cdots &e_{n}\end{bmatrix}}{\begin{bmatrix}v^{1}\\v^{2}\\\vdots \\v^{n}\end{bmatrix}},\ \qquad...

I am collecting ways to visualize the curvature of spacetime -- and movement of objects affected by gravity -- as per Einstein's GR. Alternatives to the bowling ball / trampoline image so often used in the popular press. Images that show the similarities / differences between Newton & Einstein...

I was surprised recently to learn that one of the reasons both Newton and Einstein were so revolutionary was that they performed a neat mathematical trick. For Newton, it was the mathematical derivation of Kepler's laws from Newton's laws of gravitation and motion. For Einstein, it was the...

Homework Statement I am reading through Griffiths' Electrodynamics, and I have come to the scenario in the Relativity chapter where in an inertial reference frame ##S##, we have a wire, with positive charges (linear density ##\lambda##) moving to the right at speed ##v##, and negative charges...

1. Homework Statement [/B] This is a problem that was in my Physics HW. Two powerless rockets are on a collision course. The rockets are moving with speeds of 0.800c and 0.600c and are initially ## 2.52 × 10^{12} ## m apart as measured by Liz, an Earth observer, as shown in Figure P1.59. Both...