# Unsolved Problems In Physics - Wikipedia

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### #1 rhertz

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Posted 17 May 2019 - 08:50 PM

https://en.wikipedia...lems_in_physics

there is a wiki-consented (whatever it means) about problems still withouth solution in today's physics.

Edited by rhertz, 18 June 2019 - 08:19 PM.

### #2 Dubbelosix

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Posted 18 May 2019 - 06:03 AM

Your list may be considered non-problems because we have reasonably satisfactory answers for them. The list you took from wiki, are considered real problems because there is no clear cut definition or answer to many of things stated. Though, this doesn't mean there are no satisfactory answers to find. I studied Sonoluminscence for a while, it turned out the equation was able to be described mathematically like a Friedmann equation for an expanding or contracting bubble. The bubble has analogy to the observable horizon. Another one on the list was, how big is the universe?

We tend to think these days, the universe is much larger than we had thought (according to Susskind). The observable universe could really just be a portion of the holistic picture since we require to measure the size by the time it takes for light to reach a detector, which over extremely vast area's, takes a very long time. Questions like ''what is length,'' seems like a strange question, when length depends on the measuring stick. Questions like what is time, could be seen as a valid question, but it is really called ''the problem of time,'' which in physics translates roughly from the Wheeler de Witt equation, a very ill-applied equation in physics but clearly at the core of many investigations, including those taken by Hawking who has used the equation a few times to explain different models.

What is gravity? Well, we know what gravity is in relativity and it is not a real force, it is a pseudo force, so these kinds of questions seem like they have valid answers. Just to pick a few.

Edited by Dubbelosix, 18 May 2019 - 06:27 AM.

### #3 Flummoxed

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Posted 18 May 2019 - 08:21 AM

What is gravity? Well, we know what gravity is in relativity and it is not a real force, it is a pseudo force, so these kinds of questions seem like they have valid answers. Just to pick a few.

We know what gravity does. It is not 100% clear what the mechanism is behind what it does. For instance if gravity does not work in the way described by Einstein then Dark matter may not exist. However Dark thingys can be used to describe any observed thing in the universe we do not have a valid explanation for.

### #4 Dubbelosix

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Posted 18 May 2019 - 09:55 AM

I wouldn't say gravity doesn't work as Einstein said, but I would say there are additional factors to gravity we are yet to fully understand which may lead to a better understanding of why these ''dark matter effects'' exist.

### #5 VictorMedvil

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Posted 20 May 2019 - 06:32 AM

Amusingly

Dark energy/matter can be ascribed to anything not PROPERLY understood. Perhaps the expansion of the universe and gravity should both be ascribed to dark energy, and whilst we are at it, ascribe particle creation to dark energy as well.

Further Amusement

Hawking reckons particle creation can happen around a blackhole due to virtual particle separation. Zero point energy at neat absolute zero has similarities with Black Body radiation, and particles can randomly appear from a vacuum. Theoretical Hawking radiation produces particles that would likely decay to photons if the particles were not stable.  These would have very little energy, but over the space of a few billion years the radiation produced could raise the temperature of the universe, and would appear like the CBR. The radiation of the CBR could drive the expansion of the universe, due to increasing radiation pressure.

The mechanism behind gravity could be as simple as Cahills Quantum foam inflow, or more complicated Verlindes Entropic Gravity based on entanglement. Particle creation at near absolute zero would possibly form a stable condensate, which could form particles, in the early universe. Once the radiation temperature becomes too high, particle creation from condensates would be mostly stopped. Once particles are created they would form gas nebulae and stars and produce the heavier elements.

Just how dodgy is the BB theory, it seems claims ref CBR might have been over stretched. Giving the universe a cold beginning could result in the same CBR, and not violate any laws of physics. The heavier elements would quite happily appear from super novae.

Does any one know of any current theories that look at a cold start to the universe not involving any kind of Big Bang theory Hot or Cold.

Sterile Neutrinos or WIMPS are Dark Matter, Personally, I put my bet on Sterile Neutrinos, Dark Energy is expansion of space, I dunno what is so confusing about that with you.

Edited by VictorMedvil, 20 May 2019 - 06:33 AM.

### #6 Dubbelosix

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Posted 20 May 2019 - 06:35 PM

We know what gravity does. It is not 100% clear what the mechanism is behind what it does. For instance if gravity does not work in the way described by Einstein then Dark matter may not exist. However Dark thingys can be used to describe any observed thing in the universe we do not have a valid explanation for.

No ... gravity does act as Einstein stated, if gravity is a pseudo force, which it is, from the first principles of relativity, then the modern approach to quantize it is a serious mistake for the standard model, since pseudo forces are not quantized in nature. This is the main point.

### #7 Flummoxed

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Posted 21 May 2019 - 12:30 PM

No ... gravity does act as Einstein stated, if gravity is a pseudo force, which it is, from the first principles of relativity, then the modern approach to quantize it is a serious mistake for the standard model, since pseudo forces are not quantized in nature. This is the main point.

Gravity may be a pseudo force. General Relativity predicts dark matter which may not exist. MOND gives mostly the same results as Entropic tropic gravity which is based on entanglement a pseudo force arising from quantum theory.