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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

#91

Post by bentona »

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…

Seems like a very detailed yet approachable explanation, wondering about your thoughts?

https://www.youtube.com/watch?v=7UNLgPIiWAg

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

#92

Post by ltbarcly3 »

ncmncm wrote: post #85
ltbarcly3 wrote: post #61

I guess people are going to act like I'm a lunatic, but of course it's wrong. Dark Energy violates basic conservation of energy, and the evidence for it has never been strong or convincing. Lots of us have been saying this since forever.

Conservation of energy has only ever been observed in local conditions. The universe is not obliged to respect our local expectations, and has always turned out to violate them in uncomfortable ways. The ground looks flat near you (at least in Nebraska). The Sun seems to go around Earth.

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 follows the same basic laws that the part we can study follows.

That the universe is isotropic and homogeneous is a necessary basic assumption to even begin to measure the distance to objects that are very far away. If you can't assume that the basic laws of physics operate the same everywhere, then you have no basis to make any claims about anything that isn't local.

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

#93

Post by cjonas »

dieppe wrote: post #90
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 This part I don't get (I am in no way versed in astrophysics). If I am in a box, and that the box grows 10%, but that at the same time I grow 10%, what has changed? I mean, if every point in the universe expands at the same rate at the same time, what does it change? Relatively speaking, everything is the same size before and after…

My (limited) understanding is that only space is expanding. Iow there is more space but the space that matter takes up stays constant.

Maybe I'm also confused though

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

#94

Post by AnimalMuppet »

civilian wrote: post #30
zipotm wrote: post #10

Read more about the Primer Fields.

seems like quackery https://www.quora.com/Has-anyone-considered-the-primer-field...

After a bit of looking at it, I agree: It looks very much like a quack.

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

#95

Post by peanutz454 »

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

As a causal science enthusiast I am lost, how does one change our relativistic reference frame?

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

#96

Post by simcop2387 »

cjonas wrote: post #93
dieppe wrote: post #90

Earlier quoted context omitted.

> The Universe is expanding at > every known point at the same > time at the same rate This part I don't get (I am in no way versed in astrophysics). If I am in a box, and that the box grows 10%, but that at the same time I grow 10%, what has changed? I mean, if every point in the universe expands at the same rate at the same time, what does it change? Relatively speaking, everything is the same size before and after…

My (limited) understanding is that only space is expanding. Iow there is more space but the space that matter takes up stays constant. Maybe I'm also confused though

That's basically my lay-person's understanding also. It's because the expansion isn't significant at small scales, so gravity and electromagnetism overpower it. This causes existing objects and clouds to effectively remain the same size [I have to assume that there's an effect, stealing potential energy at very small scales].

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

#97

Post by Hendrikto »

dieppe wrote: post #90
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 This part I don't get (I am in no way versed in astrophysics). If I am in a box, and that the box grows 10%, but that at the same time I grow 10%, what has changed? I mean, if every point in the universe expands at the same rate at the same time, what does it change? Relatively speaking, everything is the same size before and after…

Your interpretation of the expansion is incorrect. Basically, it looks like all points are moving away from each other over large distances.

It is easier to understand in 2D: Imagine a deflated balloon with two dots drawn on it. When you inflate the balloon, its 2D surface increases, which results in the two points "moving away" from each other, without either of them actually moving. It‘s just that the surface on which they lie grows. This is also the reason why distant galaxies are getting more distant faster than the speed of light: They are not actually moving, but the space in between us and them grows.

Notice that the farther two points on the surface of the balloon are apart, the faster they will appear to be moving away from each other, which is why the effect is unnoticeable over small (in astronomical terms) distances. Gravity pulls things together much faster than space expansion pulls them apart.

Bringing this back to your example: Imagine "blowing up" the box. Things inside it are growing a little bit (but gravity pulls them back together), but everything seems to be moving away from everything else.

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

#98

Post by lokedhs »

ltbarcly3 wrote: post #61

I guess people are going to act like I'm a lunatic, but of course it's wrong. Dark Energy violates basic conservation of energy, and the evidence for it has never been strong or convincing. Lots of us have been saying this since forever.

Conservation of energy only applies to closed systems though. And an expanding universe (with or without dark energy) is not a closed system.

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

#99

Post by platz »

ncmncm wrote: post #83
platz wrote: post #66

Sabine Hossenfelder comments on this paper: Dark Energy might not exist after all https://youtu.be/oqgKXQM8FpU

Amusingly, this video is about entirely different work that also calls into question the basis for claims about dark energy. Nobody seems to be saying how the two results interact. Taking away dark energy twice could give us negative dark energy, which would be fun. I don't know whether unexpected negative dark energy would be more embarrassing than unexpected zero dark energy.

Ah, that is funny - I just assumed i didn't understand the different descriptions because I'm not an expert. That they are different explains my puzzlement.

* indeed this is the same result as https://www.quantamagazine.org/no-dark-energy-no-chance-cosm... which is different from the OP paper

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

#100

Post by [deleted] »

wallace_f wrote: post #46
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…

Thanks for the explanation, but I'm stuck on the last sentence of this part: >evidence of accelerating expansion is that based on the redshift of nearby objects, we would expect distant objects to have a higher redshift than they actually do. I think what you mean is "than we'd expect them to."

[deleted]
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