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Evidence that the key assumption made in discovery of dark energy is in error

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Re: Evidence that the key assumption made in discovery of dark energy is in error

#141

Post by has2k1 »

mikorym wrote: post #133

As a mathematician, I will inherently be biased against dark matter and dark energy (if you're calculations don't fit, then your mathematics is not suitable, so change the math before you change the physical description). What is the relationship between dark matter and dark energy, and does this have any effect on the r^2 law assumptions and the introduction of dark matter? For example, does this mean that when we t…

> if you're calculations don't fit, then your mathematics is not suitable, so change the math before you change the physical description

Physics is littered with mathematical formulations predicting new phenomenon (forces and particles).

> What is the relationship between dark matter and dark energy

There is no known relationship between dark matter and dark energy. They could have been called unknown matter and unknown energy! The absence of a good account for each does not infer a relationship between the two.

Re: Evidence that the key assumption made in discovery of dark energy is in error

#143

Post by vectorEQ »

if you look at the magnetic soup we call matter, or maybe electromagnetism is a better term, is dark matter / dark energy / anti-matter (&anti energy??) just the same thing of a higher frequency

say if matter / observables go from 0hz - 30+ Zhz.. is dark energy from 30+Zhz to ???Zhz and perhaps anti matter / energy from ???Zhz to ???????Zhz? (more question marks being higher ? :D )

or is this completely invalid and a dumb thought?

Re: Evidence that the key assumption made in discovery of dark energy is in error

#144

Post by scotty79 »

qyv wrote: post #135
bananabreakfast wrote: post #77

Earlier quoted context omitted.

Speaking from the pov as a former astrophysicist, that definition of redshift is not quite accurate. While we have observed the universe expanding since Edwin Hubble published his findings 90 years ago, it was in fact the Friedmann equations produced 10 years earlier that established how it would work within the context of general relativity. The Universe is expanding at every known point at the same time at the same…

> However, as you go further and further out from our galaxy the metric expansion of spacetime begins to dominate the relative motion of all bodies, leading to observing progressively redder and redder light curves. A galaxy billions of light years away is perceived to be moving away from our reference frame at a significant percentage of the speed of light! Is this not because there is simply more space between thin…

I think that's exactly the idea. But if space expanded at the same rate everywhere and forever then the relationship would be linear. But it seems that further objects seem to be moving away slower than linear relationship would suggest which might mean that earlier space expanded slower.

Re: Evidence that the key assumption made in discovery of dark energy is in error

#145

Post by ltbarcly3 »

cthalupa wrote: post #131
ltbarcly3 wrote: post #92

Earlier quoted context omitted.

Which is more likely, that you can have infinite free energy or that the very careful measurements of the distances to supernova that happened billions of years ago on the other side of the universe, and for which we have virtually no standard yardstick to compare against are not accurate? You are just making an appeal to ignorance. All of physics and astronomy is based on the assumption that the rest of the universe…

This is a false dichotomy. We have known energy is not (always) conserved since long before we began discussing dark energy. This is such a misunderstood topic vis a vis dark energy that Discovery specifically has an article on it: https://www.discovermagazine.com/the-sciences/energy-is-not-...

Nope. We have no actual evidence of a violation of the conservation of energy. What has happened here is that astrophysicists got way out on a branch. They were quite excited and came up with a theory that seemed to explain why there appeared to be increasing redshift with distance, and later that theory was shown to violate conservation of energy. Doubling down, they waved their hands and said that conservation of energy must not hold at 'cosmological scales', without any evidence to make such a claim.

Re: Evidence that the key assumption made in discovery of dark energy is in error

#146

Post by scotty79 »

Are galaxies in old universe more densely packed than in our neighbourhood?

Can expansion be seen not in redshift but in angular distances of galaxies? I'm asking in general not in relationship to the article. It wouldn't help for the problem raised by this article.

Re: Evidence that the key assumption made in discovery of dark energy is in error

#147

Post by ltbarcly3 »

ncmncm wrote: post #112
ltbarcly3 wrote: post #92

Earlier quoted context omitted.

Which is more likely, that you can have infinite free energy or that the very careful measurements of the distances to supernova that happened billions of years ago on the other side of the universe, and for which we have virtually no standard yardstick to compare against are not accurate? You are just making an appeal to ignorance. All of physics and astronomy is based on the assumption that the rest of the universe…

That is the condition of cosmology. Not everyone envies it.

It's an assumption, and while you might make a reasonable argument to try to justify it, it's still an assumption. The real problem is when we cross from 'assuming these things, which we don't really have a strong reason to assume' to 'this is the way the universe is'. Without the qualifications it's extremely misleading and loses any basis it started with.

Re: Evidence that the key assumption made in discovery of dark energy is in error

#148

Post by cygx »

raattgift wrote: post #127
bananabreakfast wrote: post #77

Earlier quoted context omitted.

Speaking from the pov as a former astrophysicist, that definition of redshift is not quite accurate. While we have observed the universe expanding since Edwin Hubble published his findings 90 years ago, it was in fact the Friedmann equations produced 10 years earlier that established how it would work within the context of general relativity. The Universe is expanding at every known point at the same time at the same…

> The Universe is expanding at every known point at the same time at the same rate No, it's not. The (local) metrics sourced by the Earth, Earth-Moon, Sun, solar system, Milky Way, and the Local Group are not at all like FLRW with or without a cosmological constant, while all those metrics are very much like Kerr or LTB, wherein ordinary matter like gas and dust gradually condenses into a point. Conversely, the metri…

Kinematical interpretations fall apart really spectacularly

I disagree: Relativistic frequency shifts (doppler shift, gravitational shift, cosmological shift,...) can all be understood kinematically:

The invariant quantity you have to consider is photon 4-momentum, with energies at time of emission and absorption given by the projections onto the 4-velocities of the respective observers, so it's all about the relative orientation of some vectors, ie kinematics.

If spacetime is flat, photon momentum is constant, so all that matters is the relationship between emitter and observer frame. However, in curved spacetimes, there's no distance parallelism, and photon momentum at time of emission and absorption will be related by parallel transport along the photon geodesic.

In principle, you could even view the process of parallel transport as a series of infinitesimal Doppler shifts, though I would argue that puts emphasis on the wrong thing (the arbitrary frames chosen along the geodesic).

Re: Evidence that the key assumption made in discovery of dark energy is in error

#149

Post by cygx »

bananabreakfast wrote: post #77
flashman wrote: post #34

To know if the universe is expanding, we need to know the following: how far away things are, and whether they're moving away from us. In an accelerating universe, there's evidence that things were moving away from us slower in the past. The evidence that things are moving away from us is that as the universe expands, the wavelength of any light travelling through it also expands, shifting it towards the red end of t…

Speaking from the pov as a former astrophysicist, that definition of redshift is not quite accurate. While we have observed the universe expanding since Edwin Hubble published his findings 90 years ago, it was in fact the Friedmann equations produced 10 years earlier that established how it would work within the context of general relativity. The Universe is expanding at every known point at the same time at the same…

However, if you were to change our relativistic reference frame to match a distance galaxy's [...]

In general, you can't do that: There's no distance parallelism in curved spacetimes...

Re: Evidence that the key assumption made in discovery of dark energy is in error

#150

Post by mr_mitm »

ncmncm wrote: post #48
coliveira wrote: post #12

Earlier quoted context omitted.

> If these are both overturned it will be a huge blow to "scientists" credibility This is nonsense. Scientists have been wrong in several occasions, it is just part of the profession. For example, in the years leading to the discovery of relativity, many physicists believed there was something called "ether" that worked to fix the speed of light that they had evidence to be the same in all directions.

When chemists were asked, at the end of the 19th century, whether the the atoms in their molecular diagrams were real, they always said, "No, that's just a model we use." It wasn't until Brownian motion needed actual atoms that they began to say atoms had objective reality. Cosmologists could learn a lot from 19th-century chemists.

You know what they say. Or at least what Lev Landau supposedly said: "Cosmologists are often in error, but never in doubt."
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