Why Is the Universe Not Symmetrical?

  • Context: Graduate 
  • Thread starter Thread starter Ozgen Eren
  • Start date Start date
  • Tags Tags
    Universe
Click For Summary

Discussion Overview

The discussion revolves around the non-symmetrical nature of the universe, exploring why it appears asymmetrical despite the assumption that scientific laws are uniform throughout. Participants examine concepts related to symmetry, homogeneity, isotropy, and the implications of initial conditions from the Big Bang.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants question how the universe can be non-symmetrical if scientific laws are the same everywhere and if there was "nothing" at the beginning.
  • Others reference the cosmological principle, suggesting that on large scales, the universe is homogeneous and isotropic, which contrasts with local asymmetries.
  • There is a discussion about different types of symmetries, with some arguing that if the universe began uniformly, it should exhibit symmetry in particle distribution at equal distances from the Big Bang.
  • Some participants mention that minor differences in the early universe led to the formation of structures like galaxies, implying that these differences were crucial for the current state of the universe.
  • One participant introduces the concept of spontaneous broken symmetry, suggesting that phase transitions in the universe lead to local asymmetries.
  • Another viewpoint posits that if there is no symmetry, it could imply different physical laws in different directions, although this is contested by others who argue that the same laws can lead to asymmetrical outcomes due to initial conditions.
  • Participants discuss the analogy of a needle balanced on its tip to illustrate how symmetry can be broken by small perturbations, raising questions about the role of randomness and quantum effects in symmetry breaking.

Areas of Agreement / Disagreement

Participants express differing views on the nature of symmetry in the universe. While some agree on the homogeneity and isotropy on large scales, others emphasize the lack of symmetry on smaller scales due to initial fluctuations and interactions. The discussion remains unresolved regarding the implications of these observations.

Contextual Notes

Participants acknowledge that the discussion involves complex concepts such as phase transitions, symmetry breaking, and the influence of quantum mechanics, which may not be fully resolved or agreed upon. The assumptions regarding initial conditions and the nature of physical laws are also points of contention.

  • #31
Ozgen Eren said:
Is there an archive of experiments led scientists to claim randomness?
As far as I'm aware, ALL experiments at the quantum level demonstrate randomness. It is, for example, the basis of Heisenberg's Uncertainty Principle which says that if you make EXACTLY the same setup, you'll get different results. All this randomness was severely disliked by men like Einstein ("god does not roll dice with the universe") and others but they all got past that some 80 or 90 years ago.

As Feynman was fond of saying, the predictions of QM have been equivalent to predicting the width of the United States and getting it right to within the width of one human hair. I think we've only been able to confirm them to that degree of precision because measurement instrumentation doesn't get any better, not because they are actually wrong by that amount.
 
Space news on Phys.org
  • #32
phinds said:
ALL experiments at the quantum level demonstrate randomness

Where are the most significant ones are published? Is there a physics magazine or a website? Where can I at least find their titles?
 
  • #33
phinds said:
The most obvious non-symmetry is between matter and anti-matter. Had there been perfect symmetry, we would not be here.

Phinds got me there...

In fact the question should be why is universe so symmetric [looking at CMB]? Which leads to inflation...
 
  • #34
Ozgen Eren, we've already had a fairly extended discussion of quantum randomness in this thread:

https://www.physicsforums.com/threads/a-very-basic-question-about-heisenberg-uncertainty.786473/

There's not much point in rehashing that discussion again; you're going to get the same answers here that you did in the other thread.

Ozgen Eren said:
Where are the most significant ones are published?

Try Googling these for a start: double slit experiment, Stern-Gerlach experiment (this is probably the simplest one, I'll discuss it a bit below), Airy experiment, Aspect experiment (the last one was a test of Bell's Theorem so it shows nonlocality, not just randomness).

The basic fact is that you can take a bunch of quantum systems that were all prepared in exactly the same way, put them through exactly the same experimental apparatus, and get different results. For example, in the Stern-Gerlach experiment, they took a bunch of electrons (actually they were silver atoms with one electron having its spin unpaired in the original, I believe it's now been redone with single electrons) which had all been prepared in exactly the same way (I'll go into that a bit more below), and put them through the same magnetic field. The electrons came out in two beams, which we can call "up" and "down". All the electrons were identical going in, yet they came out in two beams. That's quantum randomness.

Now you might zero in on that "prepared the same way" bit, because how can we know for sure that the electrons really were identical going in? Maybe there were some slight differences (the usual term in the QM literature is "hidden variables") that were too small for us to measure beforehand but which caused the electrons to split into two beams. In this particular case, the obvious "hidden variable" is the precise direction of the electron's spin axis. (Note that even on this view, the classical prediction for what should happen was still wrong: classical EM predicted that the electrons should come out in a whole range of directions, with a peak in the middle, depending on the exact orientation of the electron's spin relative to the magnetic field. There is no way to get a prediction of two separate beams from classical EM. So something has to change; the question is what.)

However, we can eliminate the above factor too, by simply forcing all the electrons going into have exactly the same spin orientation. The simplest way to do that is to take the electrons from one output beam of a previous Stern-Gerlach device, oriented in a different direction, for example left-right instead of up-down. All the electrons in the left output beam of this device have their spins pointing to the left--and we can verify this by passing them all through a second left-right Stern-Gerlach device and seeing that they all come out in a single beam, the left beam. In other words, we can execute a preparation procedure for the electrons that, by a simple test, gives us a beam of electrons that are, indeed, identical, because we can test them to be identical by re-running the preparation procedure on them and seeing that it leaves them unchanged.

And yet, even then, if we take this beam of spin-left electrons and put it through a Stern-Gerlach device oriented up-down, we still get two output beams, an up beam and a down beam. That is quantum randomness.
 
  • #35
Ozgen Eren, I strongly suggest that you pay close attention to Peter's post and even perhaps read up a bit on the Stern-Gerlach polarization experiment yourself (not that doing so will really tell you anything Peter didn't already tell you but reading about the experiment may further dispel your lack of belief in quantum randomness).

You are in good company finding quantum randomness hard to take, but I suggest you study the experiments, get past it and move on to learn something new instead of dwelling on a point of view that isn't going to take you anywhere.
 
  • #36
Because there is Higgs Boson
 
  • #37
LeilaTesla said:
Because there is Higgs Boson
In what way does that statement make sense to you? Do you think the existence of the Higgs solves the mystery of why matter and antimatter did not totally annihilate each other? Do you have any references to support that?
 
Last edited:
  • #38
LeilaTesla said:
Because there is Higgs Boson
Maybe it could during the Electroweak Phase Transition, but this doesn't work for the Standard Model because a strong 1st order phase transition can't occur.
 
  • #39
http://profmattstrassler.com/articl...known-particles-if-the-higgs-field-were-zero/

I think he's referring to the asymmetric effect of a zero higgs field on quarks.

sm_interactions2.png

to...

ifhiggswerezero2.png


It might explain why the heavier top quarks has the tendency to go forward rather than backward, and top anti-quarks to go backward rather than forward..
 
Last edited:
  • #40
Thats part of the SO(10) MSM model correct? If I recall the seesaw mechanism is thought to be involved in the TeV range for lepto and baryongenesis.

http://www.google.ca/url?sa=t&source=web&cd=2&ved=0CCIQFjAB&url=http://arxiv.org/pdf/hep-ph/0612132&rct=j&q=SO(10) pdf&ei=t3aOVKmBKdGBygS2koG4Ag&usg=AFQjCNEI7K7kIhQ8XdmMCNDvIkA5EKLvzg&sig2=NJSLO6SmZIvBNxLnhJ2hSA&bvm=bv.81828268,d.aWw
Apologies on the link type 40 km from North pole using a phone. This paper is the SO(10) MSSM minimal super symmetric standard model. However I have seen similar research In the minimal standard model SO(10).
 
Last edited:

Similar threads

  • · Replies 38 ·
2
Replies
38
Views
7K
  • · Replies 18 ·
Replies
18
Views
5K
  • · Replies 25 ·
Replies
25
Views
3K
  • · Replies 12 ·
Replies
12
Views
5K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 4 ·
Replies
4
Views
5K
  • · Replies 24 ·
Replies
24
Views
9K