Evidence that the key assumption made in discovery of dark energy is in error • Hacker News Board

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

#181

Post by BoiledCabbage » Tue, Jan 07, 2020, 12:00 PM UTC

guygurari wrote: post #125

It is hard to overstate how important the resolution of this question is to physics, and in particular to theoretical physics. The “cosmological constant problem”, that is the problem explaining the cosmological acceleration (if it exists), is arguably the most important and hardest question in high energy theoretical physics. Many theoreticians have spent significant effort studying this question, working under the…

What's more mind-boggling to me is all these thousands of scientists running around looking at the extreme oddity of multi-dimensional string theory, and nobody bothered to check if the cosmological constant is actually real.

It seems like physics is really being held back by perverse incentives.

And of course my pocket view that string theory will turn out to be the single largest waste of brilliant human minds in history.

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

#182

Post by nighthawk648 » Tue, Jan 07, 2020, 12:12 PM UTC

scotty79 wrote: post #144

qyv wrote: post #135

Earlier quoted context omitted.

> 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.

But that doesn’t make sense. Here space expands n. Go a distance d away and now you have nd! So if we were to integrate the summation of nd!+V (velocity vector) Spaces, wouldn’t the relationship not be linear? You have an infinite amount of points between A and B. Each point expands at v. Each time point pk+1 is created you are introducing a new expansion that will then add as many expansions as are vector / dimensions at play.

I know my maths is not very accurate and maybe you can help correct my understanding. It just seems adding up each point that creates even more expanding points would never be a linear function.

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

#183

Post by shpeak » Tue, Jan 07, 2020, 12:14 PM UTC

Certhas wrote: post #169

galaxyLogic wrote: post #164

Earlier quoted context omitted.

Well so in other words "space" is NOT expanding. It's particles of matter that are moving away from each other. Right? So fine, but then why would we say that space is expanding, that would seem to imply we know there is some edge of space which is moving away from us, but what evidence do we have that space has such an edge? Saying that "space is expanding" seems to hold the assumption that space has a (limited) wid…

No space really is expanding. Think of it this way: You have a rubber band and you pull it apart, if you place two beads on the rubber band the distance between the beads will increase (even though they don't move relative to the rubber). But if you connect the two beads by a strong spring, then their distance will stay the same, despite space expanding. The force of the spring makes them move (relative to the rubber…

Such counteract action will make lot of side effects, which can be measured. For example, trajectories of separating or oscillating bodies will be slightly curved. Do you have any experimental support for this theory?

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

#184

Post by shpeak » Tue, Jan 07, 2020, 12:19 PM UTC

wolfram74 wrote: post #180

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…

Think about drawing two circles on a balloon, one with radius 1cm, and the other with radius 2cm. the distance between the two perimeters is 1cm, but if we inflate the balloon so that the surfaces double, now the inner circle has a radius of 2, and the outer circle a radius of 4, the distance between the perimeters has grown along side the rest of all the lengths. That's my best understanding of the situation, I most…

Who pumping the balloon? Where is source of this energy? Can we use this source of energy for our own needs?

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

#185

Post by DavidSJ » Tue, Jan 07, 2020, 12:24 PM UTC

shpeak wrote: post #183

Certhas wrote: post #169

Earlier quoted context omitted.

No space really is expanding. Think of it this way: You have a rubber band and you pull it apart, if you place two beads on the rubber band the distance between the beads will increase (even though they don't move relative to the rubber). But if you connect the two beads by a strong spring, then their distance will stay the same, despite space expanding. The force of the spring makes them move (relative to the rubber…

Such counteract action will make lot of side effects, which can be measured. For example, trajectories of separating or oscillating bodies will be slightly curved. Do you have any experimental support for this theory?

This isn’t Certhas’s personal theory. It’s part of standard cosmology, called the metric expansion of space. That term should get you pointed in the right direction if you want to learn more about the evidence for it.

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

#186

Post by Koshkin » Tue, Jan 07, 2020, 12:26 PM UTC

Certhas wrote: post #169

galaxyLogic wrote: post #164

Earlier quoted context omitted.

Well so in other words "space" is NOT expanding. It's particles of matter that are moving away from each other. Right? So fine, but then why would we say that space is expanding, that would seem to imply we know there is some edge of space which is moving away from us, but what evidence do we have that space has such an edge? Saying that "space is expanding" seems to hold the assumption that space has a (limited) wid…

No space really is expanding. Think of it this way: You have a rubber band and you pull it apart, if you place two beads on the rubber band the distance between the beads will increase (even though they don't move relative to the rubber). But if you connect the two beads by a strong spring, then their distance will stay the same, despite space expanding. The force of the spring makes them move (relative to the rubber…

> relative to the rubber

This makes me uneasy about your analogy. It’s like saying “relative to space” which is nonsense. Also, why would space limit itself to only expanding outside a physical body?

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

#187

Post by Koshkin » Tue, Jan 07, 2020, 12:35 PM UTC

adrianN wrote: post #113

cjonas wrote: post #93

Earlier quoted context omitted.

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

As I understand it, the forces that keep matter together are strong enough to counteract any expansion.

Unlikely, because expansion of space is equivalent to the slowing of light, as other commenters have mentioned.

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

#188

Post by cygx » Tue, Jan 07, 2020, 12:45 PM UTC

Koshkin wrote: post #187

adrianN wrote: post #113

Earlier quoted context omitted.

As I understand it, the forces that keep matter together are strong enough to counteract any expansion.

Unlikely, because expansion of space is equivalent to the slowing of light, as other commenters have mentioned.

Such heuristic explanations are distractions: Locally, gravitational effects (including spatial expansion) manifest as pseudo-forces and hence can be counteracted.

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

#189

Post by shpeak » Tue, Jan 07, 2020, 12:56 PM UTC

DavidSJ wrote: post #185

shpeak wrote: post #183

Earlier quoted context omitted.

Such counteract action will make lot of side effects, which can be measured. For example, trajectories of separating or oscillating bodies will be slightly curved. Do you have any experimental support for this theory?

This isn’t Certhas’s personal theory. It’s part of standard cosmology, called the metric expansion of space . That term should get you pointed in the right direction if you want to learn more about the evidence for it.

It's too complex to explain, I will not understand it. Right?

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

#190

Post by beowulfey » Tue, Jan 07, 2020, 12:57 PM UTC

phkahler wrote: post #50

empath75 wrote: post #22

Earlier quoted context omitted.

Scientist have no idea what dark matter or dark energy is so it’s not like our world would be overturned. If it turns out to be wrong assumptions, that’s fine. Although it would be embarrassing.

The problem is that these topics get enough press that the general public has heard of them. It's nice that there are no obvious consequences if dark matter or dark energy turn out to be fiction. But the public will hear that "scientists" were wrong about these things they've been talking about for 50 years. Then the public will get another report on a topic like climate change which is also proven by "scientists" al…

The answer is to properly educate the public on how science works. Science is a series of hypotheses, tested extensively and built upon given the evidence.

It is the fault of our education system and pop culture that people are so terrified of scientists being wrong. People should be thrilled when scientists are shown to be wrong, as it means they are one step closer to understanding what is right.