Are there reflections in the fourth dimension?

AI Thread Summary
The discussion centers on the concept of reflection in relation to dimensions, specifically the fourth dimension. A phase conjugate mirror is mentioned as a theoretical device that could reflect electromagnetic radiation backward in time, potentially rendering objects invisible. There is acknowledgment of military research into invisibility technology, though no significant breakthroughs have been reported. The definition of reflection is also explored, describing it as a linear transformation that alters one dimension while maintaining others. Overall, the conversation delves into the complexities of reflection in higher dimensions and its implications.
hydrostaticequil
Messages
0
Reaction score
0
If so what does the reflection look like?
 
Physics news on Phys.org
hydrostaticequil said:
If so what does the reflection look like?
Physicists refer to three dimensions of space and one of time usually. I am not sure what you mean by "reflection."
 
What do you mean by the fourth dimension?
 
Welcome to PF.
hydrostaticequil said:
If so what does the reflection look like?
How will you make the mirror?

A "phase conjugate mirror" might reflect EM radiation, back the way it came, in effect backwards in time. That would cause things that reflect light or radar to cancel with themselves, becoming invisible. There has been military research into the field of making things invisible, but I don't think there has been any real success.
https://en.wikipedia.org/wiki/Nonlinear_optics#Optical_phase_conjugation
 
hydrostaticequil said:
If so what does the reflection look like?
I would define a reflection as a linear map that changes the sign in one dimension and keeps all other dimensions fixed. This is independent of the number of dimensions.
 

Thread 'Predictions for the Nobel Prize in Physics 2025'

Similar to the 2024 thread, here I start the 2025 thread. As always it is getting increasingly difficult to predict, so I will make a list based on other article predictions. You can also leave your prediction here. Here are the predictions of 2024 that did not make it: Peter Shor, David Deutsch and all the rest of the quantum computing community (various sources) Pablo Jarrillo Herrero, Allan McDonald and Rafi Bistritzer for magic angle in twisted graphene (various sources) Christoph...
View full post »
Thread 'My experience as a hostage'

Thread 'My experience as a hostage'

I believe it was the summer of 2001 that I made a trip to Peru for my work. I was a private contractor doing automation engineering and programming for various companies, including Frito Lay. Frito had purchased a snack food plant near Lima, Peru, and sent me down to oversee the upgrades to the systems and the startup. Peru was still suffering the ills of a recent civil war and I knew it was dicey, but the money was too good to pass up. It was a long trip to Lima; about 14 hours of airtime...
View full post »

Similar threads

Interacting with the fourth dimension?
Replies
2
Views
983
Physics inserted in society
Replies
5
Views
156
I Not all reflections in 2D are 3D rotations?
Replies
9
Views
3K
I Are 1D Longitudinal Waves Reflected at an Open End?
Replies
11
Views
986
Mirror system in geometrical optics
Replies
9
Views
2K
I Some questions regarding Acoustic wave reflection
Replies
11
Views
1K
B Is imaginary time a fourth dimension?
Replies
13
Views
1K
Photo Contest - Total Reflection (11/17-11/23)
Replies
11
Views
2K
B What Is the Fourth Dimension and How Does It Work?
Replies
3
Views
2K
How does light interact with objects to create vision?
Replies
7
Views
1K

Hot Threads

Recent Insights

Back
Top