Is Classical Physics Wrong

  • Thread starter Albeaver
  • Start date
  • #1
5
0

Main Question or Discussion Point

Basically the title. Take relativity it has the Lorenz factor 1/sqrt(1-(v/c^2)) and if v is not zero it's something that isn't accounted for in classical mechanics. Does that make classical mechanics wrong?
 

Answers and Replies

  • #2
Stephen Tashi
Science Advisor
7,124
1,301
It only makes it "wrong" if you consider an approximation that applies to some situations ( v small relative to c) to be "wrong". If you consider approximations "wrong" then most physics is wrong. Mathematical solutions to real life problems are usually approximations.
 
  • Like
Likes Chestermiller and Dale
  • #3
11,707
5,292
No, its not wrong, I would say its imcomplete. As we extend our understanding of the very small, the very large, and the very fast we discover that there are things CM can't explain.

This causes us to extend our theories to explain the discovered anomalies and predict new things. The guiding principle is that the new theories must in the limit of everyday experience predict the same outcomes as Classical Mechanics.

Relativity is a good example when we consider everyday velocities the v^2/c^2 term becomes zero and the equations reduce to classical ones.
 
  • #4
8
0
SR is just incomplete, or rather it's a simplification, but in a some different way.

In the classical physics the (v/c)^2 is usualy omited only, and this is a simplicity also, and that's all story.
 
  • #5
362
26
Classical kinetic energy is the lowest series expansion of gamma,.
Classical mechanics is correct up to and including the second order in v.
 
  • #6
Nugatory
Mentor
12,708
5,298
  • Like
Likes nsaspook, DrClaude and jedishrfu
  • #7
8
0
Classical kinetic energy is the lowest series expansion of gamma,.
Classical mechanics is correct up to and including the second order in v.
But, and unfortunately for such improvised claims, the gamma is a simple classical thing, because easily derivable, for example using the light clock, which is a completely classical entity.
 
  • #9
Nugatory
Mentor
12,708
5,298
But, and unfortunately for such improvised claims, the gamma is a simple classical thing, because easily derivable, for example using the light clock, which is a completely classical entity.
Sometimes the word "classical" is used to mean Newtonian/Galilean, so that relativity and QM are both non-classical. Other people prefer to treat SR as a classical theory because it is a logical extension of classical electrodynamics, and reserve "non-classical" for QM. You appear to be using the word in the latter sense while my2cts is using it in the former sense.

The historical accident that QM and relativity were both shaking up the comfortable Galilean/Newtonian world at the same time may have contributed to the conflicting uses of the word.

Please don't start an argument over this..... :)
 
  • #10
Khashishi
Science Advisor
2,815
493
All physical laws are approximations of reality. Most of physics is finding the appropriate approximations that simplify the problem enough to be solvable, but not too much that the answer is meaningless. So is all physics wrong? Classical mechanics are a great approximation in many situations.
 
  • #11
phinds
Science Advisor
Insights Author
Gold Member
2019 Award
16,099
6,091
Basically the title. Take relativity it has the Lorenz factor 1/sqrt(1-(v/c^2)) and if v is not zero it's something that isn't accounted for in classical mechanics. Does that make classical mechanics wrong?
All of the bridges and skyscrapers ever built and all of the moon landing made so far are just two sets of examples of VAST number of things that show just how right classical physics is. As has been stated in the thread several times, it DOES fail under conditions that are outside normal human experience but that just makes it incomplete, not wrong.
 
  • #12
362
26
Physics is right. The absolute proof is the destruction of two cities by weapons created purely from physical theory.
 
  • #13
362
26
A horrible proof, yet a proof.
 

Related Threads on Is Classical Physics Wrong

Replies
142
Views
8K
Replies
43
Views
6K
  • Last Post
Replies
8
Views
2K
  • Last Post
Replies
12
Views
2K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
3
Views
5K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
1
Views
3K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
8
Views
2K
Top