Insights Blog
-- Browse All Articles --
Physics Articles
Physics Tutorials
Physics Guides
Physics FAQ
Math Articles
Math Tutorials
Math Guides
Math FAQ
Education Articles
Education Guides
Bio/Chem Articles
Technology Guides
Computer Science Tutorials
Forums
Trending
Log in
Register
What's new
Latest activity
Register
Menu
Log in
Register
Navigation
More options
Style variation
System
Light
Dark
Contact us
Close Menu
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
PeroK's latest activity
PeroK
reacted to
Gavran's post
in the thread
B
Onto set mapping is the surjective set mapping, and into injective?
with
Like
.
To be on the set means occupying the whole set in a particular way and the word “onto” follows the definition of a surjective function...
Sep 5, 2025
PeroK
reacted to
berkeman's post
in the thread
EMF (Electromagnetic Field) & EHS (Electromagnetic Hyper Sensitivity)
with
Like
.
Those are very tiny signals, and not likely to cause any physical effects. Folks here at PF have lots of experience with EM shielding...
Sep 5, 2025
PeroK
reacted to
Baluncore's post
in the thread
EMF (Electromagnetic Field) & EHS (Electromagnetic Hyper Sensitivity)
with
Like
.
Welcome to PF. The observations you report are inconsistent with what we know about the physical world. While it is possible to screen...
Sep 5, 2025
PeroK
replied to the thread
Introductions
.
I thought that sounded familiar: https://m.imdb.com/title/tt0067355/
Sep 5, 2025
PeroK
reacted to
PeterDonis's post
in the thread
A
Gravitational Analysis of Wide Binaries
with
Like
.
I don't think that's a fair description of the paper you referenced. For example, consider these items from the abstract: "[W]e are...
Sep 4, 2025
PeroK
reacted to
ojitojuntos's post
in the thread
I
Question about discussions around quantum interpretations
with
Like
.
I understand that the world of interpretations of quantum mechanics is very complex, as experimental data hasn't completely falsified...
Sep 4, 2025
PeroK
replied to the thread
A
How does time derivative commute from one variable to another?
.
That's the hand-waving way to do it. If you want to justify it more formally, then you need a sound mathematical basis for what is a...
Sep 4, 2025
PeroK
replied to the thread
A
How does time derivative commute from one variable to another?
.
The definition of a differential that I use is: If ##x = f(t)## then ##dx = f'(t)dt##, where ##f'(t) = \frac{df}{dt}##. So, as ##\dot...
Sep 3, 2025
PeroK
replied to the thread
I
Quantum behaviour of an electron around a positively charged sphere
.
I'm not sure what you mean by really occurs. The hydrogen atom satisfies the relevant Schrodinger equation. That gives a sequence of...
Sep 3, 2025
PeroK
replied to the thread
I
Quantum behaviour of an electron around a positively charged sphere
.
No, it doesn't. QM applies for a hydrogen atom. And classical electromagnetism does not apply.
Sep 3, 2025
PeroK
reacted to
PeterDonis's post
in the thread
B
How can a black hole absorb matter?
with
Like
.
Wrong. For someone falling into the black hole, time passes normally. Their clocks read one second per second, just as ours do. We see...
Sep 2, 2025
PeroK
reacted to
Dale's post
in the thread
B
How can a black hole absorb matter?
with
Like
.
That is only a small part of the trick, not even close to the whole trick. Other parts of the trick include 1) we can use any...
Sep 2, 2025
PeroK
reacted to
weirdoguy's post
in the thread
I
Quantum behaviour of an electron around a positively charged sphere
with
Like
.
Why? Positively charged sphere is something way different than proton. Real world sphere would consist of milions of atoms itself!
Sep 2, 2025
PeroK
replied to the thread
I
Quantum behaviour of an electron around a positively charged sphere
.
How are you going to model a charged sphere in QM? If you replace the hydrogen nucleus with a greater positive charge, then the lowest...
Sep 2, 2025
PeroK
reacted to
Ibix's post
in the thread
B
How can a black hole absorb matter?
with
Like
.
No. As I said, intuitive reasoning in curved spacetime is a mistake. Your objection turns out to be similar to claiming that you can't...
Sep 2, 2025
Forums
Back
Top