Unifying physics - key challenges?

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Discussion Overview

The discussion revolves around the challenges of unifying physics, with participants questioning fundamental assumptions in the field. The scope includes theoretical considerations, conceptual clarifications, and speculative reasoning about the nature of the universe, atomic structure, and the forces of nature.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that atomic nuclei are single particles, while others argue that subnuclear particles like quarks exist, challenging this view.
  • There is a debate on whether 'charge' and 'mass' are fundamentally the same, with some suggesting they lead to different types of interactions.
  • Participants discuss the nature of light, with some asserting it is made of particles (photons) while others emphasize its wave-like behavior demonstrated in experiments like the double-slit experiment.
  • The expansion of the universe is contested, with some affirming it based on red-shift observations and cosmic microwave background radiation, while others suggest alternative models, such as cyclic universes.
  • There are differing views on the Big Bang theory, with some participants supporting it based on observational evidence, while others propose that the universe could be eternal and expanding.
  • Some participants express a desire for simpler explanations of physical phenomena, suggesting that accepting certain assumptions could lead to a more unified understanding of forces.
  • Concerns are raised about the speculative nature of the discussion, with reminders to adhere to forum rules regarding overly speculative posts.
  • One participant argues that unification in physics may not be feasible at this stage, suggesting that more foundational questions need to be addressed first.

Areas of Agreement / Disagreement

Participants express multiple competing views on the fundamental assumptions of physics, with no consensus reached on the validity of these assumptions or the implications for unification.

Contextual Notes

Some arguments rely on specific interpretations of experimental evidence, and there are unresolved questions regarding the implications of accepting or rejecting certain assumptions. The discussion reflects a range of perspectives on the nature of physical laws and the universe.

Who May Find This Useful

This discussion may be of interest to those exploring theoretical physics, cosmology, and the philosophical implications of scientific assumptions in the quest for unification in physics.

very_curious
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Hi everyone,

Like a lot of other people, I'm keen to see physics unified. But there hasn't been much progress on this lately and I'm wondering if we need to revisit some very basic assumptions.

I've got some proposals that I would like to be challenged on.

Assumption 1: Atomic nuclei are single particles (there is nothing inside them)

Evidence against:
1a. sub-atomic particles have been observed
1b. atomic collisions have predictable results i.e. if we hit an atom with one thing, we know what will come out the other side

Assumption 2: 'charge' and 'mass' are two aspects of the same, more fundamental, thing

Evidence against:
2a. mass always attracts mass, whereas charges can attract or repel each other
2b. the two forces involved have very different strengths

Assumption 3: Light is made up of particles (not waves)

Evidence against:
3a. result of double-slit experiment
3b. inteference patterns (thought..are these the only two pieces of evidence?)

Assumption 4: The universe is not expanding

Evidence against:
4a. red-shift of light from far-away galaxies
4b. (indirect evidence) Einstein's equations predict a dynamic universe

Assumption 5: The universe has been around forever i.e. the Big Bang did not happen

Evidence against:
5a. there is light/microwave radiation from the early universe coming from all parts of the sky
5b. we should have run out of hydrogen by now - it would have all fused to make heavier elements

The way I see it, the first step towards a new theory is to dissect/re-explain the 'evidence against' all of these five assumptions.

Can you think of any more evidence against these assumptions, or reasons they might not hold? Have I mis-understood anything?

Thanks
 
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I would like everyone in this thread to check the PF Rules about overly speculative posts. If this thread drifts too far in that direction, it will be closed.
 
please don't close it up just yet :)

Some bits of evidence are stronger than others - I'm interested to get views on these to help in working out where the gaps are.
 
very_curious said:
Assumption 1: Atomic nuclei are single particles (there is nothing inside them)

Evidence against:
1a. sub-atomic particles have been observed
1b. atomic collisions have predictable results i.e. if we hit an atom with one thing, we know what will come out the other side
Subatomic particles have nothing to do with subnuclear particles, which are what you are referring to. Quarks, which are subnuclear particles, have been observed in particle collisions.

Assumption 2: 'charge' and 'mass' are two aspects of the same, more fundamental, thing

Evidence against:
2a. mass always attracts mass, whereas charges can attract or repel each other
2b. the two forces involved have very different strengths
Perhaps, but as you say, they source two different types of interactions.

Assumption 3: Light is made up of particles (not waves)

Evidence against:
3a. result of double-slit experiment
3b. inteference patterns (thought..are these the only two pieces of evidence?)
Light is made up of particles (photons). The photoelectric effect captures this property of light. The wavelike nature of light results from the quantum mechanical properties of photons (this is also termed 'wave-particle duality').

Assumption 4: The universe is not expanding

Evidence against:
4a. red-shift of light from far-away galaxies
4b. (indirect evidence) Einstein's equations predict a dynamic universe
4c. Cosmic Microwave background of temperature ~ 2.7 K.
4d. Big Bang Nucleosynthesis supports a hotter and denser early universe.

Assumption 5: The universe has been around forever i.e. the Big Bang did not happen

Evidence against:
5a. there is light/microwave radiation from the early universe coming from all parts of the sky
5b. we should have run out of hydrogen by now - it would have all fused to make heavier elements
Assumption 5 can only be true if Assumption 4 is true (ie Assumption 5 is refuted by the refutation of Assumption 4). The universe could have been around forever *and* expanding today if it is cyclic, in which case what we perceive to have been a big bang was really the start of the present phase of expansion following a previous state of contraction. But the universe does not appear to be eternal and static, for reasons suggested here and elsewhere.

The way I see it, the first step towards a new theory is to dissect/re-explain the 'evidence against' all of these five assumptions.
What are the deficiencies that you see with the current standard cosmology?
 
That was very useful - thanks. Especially for pointing out 4c and 4d.

bapowell said:
What are the deficiencies that you see with the current standard cosmology?

I'm looking for simpler and more robust explanations than the ones we currently have.
For example, if we accept Assumptions 1 and 2 then there is only one fundamental physical force (rather than four), and this should make the unification of the forces much easier.

In the same way, if we accept Assumptions 4 and 5 (yes, 5 does depend on 4) then the features of the observable universe become much easier to explain. I think so, anyway.

Any more thoughts?
 
Assume for a moment that dog, jellyfish and blackbird are the same species (identical, so to speak). This would make biology much simpler - but unfortunately it's wrong. So you have to go back and explain unification in biology via evolution, DNA etc.
 
The universe is expanding. The big bang did happen
 
accepting 1,2 or 4,5 doesn't give us better explanations or help in uni-faction each on of those 4 forces are there because we observed a group of phenomena which we were able to unify each set in single force which have differing natures, to assume only one of them u would need a lot more assumptions and theories to explain all phenomena
 
I partly see your point - if we try to simplify one part of physics we might complicate another. But that's conjecture until we actually try it :)

The question is: where can we find new insight?

Here are the assumptions again, slightly re-written:
Assumption 1: Atomic nuclei are single, charged particles
Assumption 2: 'charge' and 'mass' are two ways of trying to explain one single, more fundamental property of matter
Assumption 3: Light is made up of particles.
Assumption 3a: Single particles never behave like waves.
Assumption 4: The universe is not expanding
Assumption 5: The universe has been around forever

To get into detail - what's the evidence against assumption 3a?
 
  • #10
because when they pass through a double slit they produce an interference pattern by making one point per particle, and u also violate the uncertainty principle.
the wave behavior is because even when u have a point particle u can't know where it is and so it's physics is "spread" over space.
 
  • #11
Hello all, but one.
Unification in my opinion is not something that can be applied yet. The problem isn’t finding the link between these interactions, its applying better keys to map and itemize the experiments conducted today. Galileo gala lay wasn’t limited by his telescope it was the mainstream understanding. Although he challenged and changed the understanding of our universe at the time, he still was no ware near Einstein’s General relativity. The point I’m making is, could Galileo gala lay discover Einstein’s General relativity with only research Galileo had at the time? For me to think of unification now when so many questions and variables are yet to be figured out, would be time better spent mapping unknown areas of our universe.
TM
 

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