Questions tagged [soft-question]

Questions that ask about some aspect of physics research or study which doesn't involve the actual physics. In general, soft questions can be answered without using physical reasoning.

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18
votes
3answers
12k views

Why does the lake surface appear darker in some areas?

What causes the surface of the lake to appear darker in some places? Firstly, I know that it's not fishes that cause it. Secondly, the dark surfaces move from time to time and thus are not ...
11
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4answers
804 views

What is an interpretation of quantum mechanics?

In the sense of "Copenhagen Interpretation", what exactly is an interpretation? What purpose does an interpretation serve? Can an interpretation be tested or even be correct or incorrect independent ...
8
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3answers
4k views

Popular books on QM

After some discussions with my friend about some "popular" aspects of quantum mechanics, my friend asked me whether there exist any books that could convey the basic ideas in a non-technical way (my ...
8
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2answers
308 views

Is symplectic form in Hamiltonian mechanics a physical quantity?

Is symplectic form $dp_i \wedge dq_i$ in Hamiltonian mechanics a physical quantity? It feels to me to be something different than say energy, momentum or mass. Like just certain structure. The real ...
6
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5answers
5k views

Do perfect spheres exist in nature?

Often in physics, Objects are approximated as spherical. However do any perfectly spherical objects actually exist in nature?
5
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2answers
9k views

If I move a long solid stick can I send message fastest than light? [duplicate]

Possible Duplicate: Is it possible for information to be transmitted faster than light? I mean by using a perfect solid stick long enough and moving it forward and backward can I send information ...
3
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4answers
1k views

Is it possible to restart formal higher education in physics at a later age? [closed]

I would begin by apologizing for a soft question. Reading the FAQ, I have tried to formulate my question precisely in the last paragraph and you may skip the following paragraph where I make ...
1
vote
1answer
345 views

Are there any good audio recordings of educational physics material?

I am studying to return to school in physics and would like to start spending as much time as possible on that task. Most of my small amount of free time, however, I am either doing house work or ...
-1
votes
2answers
447 views

What causes the expansion of space? [closed]

What is causing space to expand? Is it due to some kind of innate property or is it due to some force? I did a google search on this and found lots of articles explaining that space is expanding ...
27
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15answers
5k views

Learning physics online?

I'm thinking of following some kind of education in physics online. I have a master degree in Computer Science and have reasonable good knowledge in physics. I would like a program of 1-2 years and I'...
25
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11answers
7k views

Books that develop interest & critical thinking among high school students

I heard about Yakov Perelman and his books. I just finished reading his two volumes of Physics for Entertainment. What a delightful read! What a splendid author. This is the exact book I've been ...
16
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5answers
20k views

What does it take to understand Maxwell's equations? [closed]

Assume I want to learn math and physics enough to reach a level where I understand Maxwell's equations (The terms and reasoning in the equations I.e. why they "work"). What would I have to learn in ...
26
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5answers
28k views

Difference between theoretical physics and mathematical physics?

I'm a huge fan of mathematical physics and I know what the formal definitions of those two areas are, I've seen them. But I still get completely baffled when someone asks me to explain it simply. The ...
28
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6answers
3k views

Are there two theories that are mathematically identical but ontologically different?

I have no background in physics but there is a question that has been bothering me, so I'm asking you. Are there at least 2 physical theories that are : Mathematically identical, which means that ...
38
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1answer
3k views

Why is the partition function called ''partition function''?

The partition function plays a central role in statistical mechanics. But why is it called ''partition function''?
16
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4answers
6k views

What are the best open-access journals in physics?

I would like to support open-access journals by choosing to publish in journals which allow readers free online access. Ideally I would also like to retain copyright instead of signing it over to ...
8
votes
2answers
642 views

Understanding Cherns-Simons-Witten Theory

I want to read about Wittens work, on Cherns-Simons theory, and relations to knots and jones polynomials. I am extremely motivated to read his paper: Quantum Field Theory and Jones polynomial. What ...
6
votes
3answers
897 views

An operator on the other side of the Schrödinger equation

A form of the Schrödinger equation is $$ \left[-\frac{\hbar^2}{2m} \nabla^2 + V(\vec{r}, t)\right]\Psi = i\hbar \frac{\partial}{\partial t} \Psi $$ The bracketed term is of course the ...
19
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3answers
3k views

Can we tell when an established theory is wrong?

I was reading the following answer from this question: In physics, you cannot ask / answer why without ambiguity. Now, we observe that the speed of light is finite and that it seems to be the ...
15
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9answers
3k views

Is it possible to work on physics independently outside academia? [closed]

The traditional physics career is an academic job at some university, with the eventual goal of becoming a tenured professor. Is it possible for a mostly self-educated outsider working outside ...
11
votes
1answer
277 views

What strategies can a researcher use when confronted with a long and complicated symbolic expression?

When doing research in theoretical physics, a frequent task one encounters is trying to express some physical quantity as a function of other quantities. A lot of times this can't be done analytically,...
6
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9answers
3k views

What are the most important discoveries/breakthroughs in physics recently?

Can you provide a list of the most important discoveries/breakthroughs in physics recently? By recent, I mean the past decade or so. All branches of physics are welcome. Basically, I am interested in ...
17
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4answers
4k views

What does Peter Parkers formula represent?

Okay, so the trailer for the new Spider Man movie is out and appearently our friendly physicist from the neightborhood came up with something. However I can't find out what this is. Transcription: $...
9
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5answers
2k views

How to learn celestial mechanics?

I'm a PhD student in math and am really excited about celestial mechanics. I was wondering if anyone could give me a roadmap for learning this subject. The amount of information about it on the ...
8
votes
2answers
44k views

Differences between astronomy, astrophysics and cosmology? [closed]

What is the main difference between Astronomy, Astrophysics, and Cosmology? I have the impression that astronomy is a subject that runs parallel to physics but it is outside the physics field. This ...
8
votes
4answers
3k views

Textbook on group theory to be able to start QFT [duplicate]

I am very enthusiastic about learning QFT. How much group theory would I need to master? Please could you recommend me a textbook on group theory, which would help me to start QFT?
9
votes
2answers
327 views

Why is there no need in extra knowledge to go from the classical to the quantum desctiption of a system?

Take, for example, the hydrogen atom. Both the classical and the quantum models are based on the same Hamiltonian, describing the Coulomb potential. The classical model however misses a lot of ...
8
votes
9answers
5k views

Should I begin to study quantum mechanics or wait until I have a stronger base on easier topics? [closed]

I apologize if this is off topic since it does not relate directly to the study of physics, but I could not think of a better place to ask. I am a high school student graduating in a few days and ...
8
votes
1answer
939 views

Why is a dipole moment called a dipole moment?

The General Formula for a moment is the following one: $$ \vec{M} = \vec{r} \times \vec{F}. $$ However the formula for a dipole moment is this one: $$ \vec{p} = Q \vec{d}. $$ How comes this is still ...
7
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3answers
524 views

Supersymmetry in Quantum Mechanics

I was reading Supersymmetry in Quantum Mechanics and got stuck in the various mathematical terminology like "Graded-Lie Algebra", "Super Algebra". Is there any good lecture notes concerning these ...
2
votes
1answer
3k views

Classical Mechanics for Mathematician [duplicate]

Possible Duplicate: Which Mechanics book is the best for beginner in math major? I am looking for suitable ways to learn mechanics in mathematician's perspective. I went through: multivariable ...
10
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5answers
1k views

How would I go about detecting monopoles?

A question needed for a "solid" sci-fi author: How to detect a strong magnetic monopole? (yes, I know no such thing is to be found on Earth). Think of basic construction details, principles of ...
13
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4answers
1k views

What does it mean to say that the electron is a near-perfect sphere?

It's announced that researchers at Imperial College London has found that the electron is almost a perfect sphere. The popular articles all have a nice photo of a billiard ball, etc. It is reported ...
5
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2answers
8k views

Mathematics needed for string theory [duplicate]

I'm interested in cutting edge string theory studied by research physicist. I'm wonder what mathematics is needed and how far am I in terms of mathematics background needed and how much more ...
1
vote
2answers
3k views

What is a good introductory text to astronomy [closed]

What is a good and easy to read introductory text for an adult with limited basic scientific knowledge to astronomy for someone without a telescope and lives in a big city and why do you think that ...
1
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3answers
4k views

Prerequisites for classical mechanics by Susskind

So I am an undergraduate in Electrical Engineering. We had a course on Physics in our freshman year which is equivalent to Classical Mechanics I as taught in MIT. I am interested in studying advanced ...
9
votes
1answer
2k views

Meaning of the word “Moment”?

This question is more of a question about the origin of a physical term moment used in many contexts. My question is about the linguistic or historical meaning of the word "moment". Please don't ...
4
votes
2answers
777 views

Why “Dark Energy” is called energy instead of force?

The overly simplified explanation I'm giving myself right now is dark energy causes the opposite of what gravity does, that's why the universe is expanding. Now where gravity is a force, why dark ...
3
votes
3answers
501 views

Would a sea level rise (on the other side of the Earth) if you would dip your finger into the ocean?

(I'm not a physicist & I hope this question isn't too basic/lame) The question says it all & assuming: No atmosphere No Earth rotation Not a single object in the ocean(s) Ignore all other ...
2
votes
1answer
2k views

Is it possible to take a QFT class knowing only basic quantum mechanics? [closed]

I'm in grad school and notice there are no prerequisites required for QFT in the physics department. In fact, the system allows me to sign up for the course just fine as a technical elective. But... ...
1
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4answers
1k views

Matrix mechanics for those with wave mechanics background

Just curious: Is there any book or resource that teaches matrix mechanics (quantum mechanics) only without wave mechanics stuff - meaning that the book assumes wave mechanics background.
1
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2answers
125 views

What does a unit like $C^{1/5}$ or $kg^{1/2}$ physically mean?

I'm more of a math guy than a physics guy so bear with me.... In fractal geometry, fractals are considered to have fractional dimension. For instance an object such as the Koch curve has a fractal ...
0
votes
1answer
378 views

Order of magnitude

When finding out the order of magnitude of quantities, as said in my textbook, we compare the numerical part with $3.2$ (approximately $\sqrt{10}$ or rounded off version of $3.162$) Thus, $9.12 \...
9
votes
2answers
15k views

What is the meaning of this “let there be light” joke?

Someone across the restaurant is wearing this shirt, and I certainly don't get it. Update Related: What does this quote about the four dimensional divergence of an antisymmetric tensor mean?
8
votes
10answers
468 views

Are there websites or programmes that permit a simulation of the night sky in the past and the future on an ordinary computer?

Are there websites or programs that permit a simulation of the night sky in the past and the future on an ordinary computer? (For the past, I would be content with objects visible to the naked eye.)
8
votes
5answers
2k views

What is the term for hose fluctuating movements during flow?

What do we call it when water flowing through a flexible hose causes it to act like snake movements if the hose were disturbed? Can this movement be explained by the Coriolis force?
6
votes
2answers
4k views

What causes charge buildup in a cloud before a lightning storm?

I am curious what causes the charge build up in a cloud before lightning occurs. I have seen in a few places such as this, that the process is not fully understood. Is this some form of static ...
6
votes
1answer
2k views

Does “finite” include zero?

Infinity, is clearly not finite. But there is some dissent on whether or not zero is finite. I have seen authors use "finite" to indicate the value of $0$ is excluded as well as infinity. Is there ...
5
votes
5answers
1k views

Regarding string theory: how to refute the argument “if it cannot be tested experimentally then it is not science”? [duplicate]

Possible Duplicate: What differs string theory from philosophy or religion? I find a lot of people disbelieve in string theory, saying that since it cannot be tested experimentally then it is not ...
4
votes
2answers
4k views

Is Hubble's constant really constant? [duplicate]

How does Hubble's constant resembles age of universe? Isn't universe getting old each day? How can a constant be a reciprocal of age of universe? Hubble's value must be variable, isn't it?