Dark Energy – the most mysterious matter in the Universe

[swansont]

 

You misunderstood.

50+ mL is above in dephlegmator (and not visible on the photo).

So to what is visible on photo (compare difference between levels) there is needed to be added more.

The next time I will do it, I will try to measure how much it's increasing volume more precisely.

But what is on photo (including what is in dephlegmator) looks like 2000 mL -> 2150 mL

I have seen more extreme increases, but have not made photos.

 

Looks like 1/4 of the distance between the 1600 and 2000 mL line, and given the decrease in area of the flask near the neck, that means less than 100 mL. But even 200 mL is 10%, which is still significantly less than 20%.

 

Which is beside the point. All that tells us is there is something in the water which is also expanding. Indirect evidence of something in the water. Which was the point of the example — something is there that cannot be accounted for with the known interactions. Even though we don't know what it is, we know it's there, because of the observed behavior.

[David Levy]

Exactly. You've got it. "Dark energy" is a technical way of saying "dunno"

Thanks

So, with regards to the "dunno" and mutual understanding.

Shall we agree that dark energy is a theory?

Shall we agree that there might be some other explanation for what we see?

[Strange]

Shall we agree that dark energy is a theory?

Shall we agree that there might be some other explanation for what we see?

 

Dark energy is not a theory (because we don't know what it is yet). The various possible explanations for [the effect described as] dark energy are all hypotheses. They will be eliminated or confirmed by further observation. That may, or may not, lead to new theory.

 

As we have no explanation, I don't know what "some other explanation" means. An explanation other than the one we don't have?

 

Or do you mean another hypothesis? There is always room for another hypothesis - as long as it makes predictions that allow it to be tested (and eliminated or confirmed) by observations.

[David Levy]

Dark energy is not a theory (because we don't know what it is yet). The various possible explanations for [the effect described as] dark energy are all hypotheses. They will be eliminated or confirmed by further observation. That may, or may not, lead to new theory.

Agree.

So, Dark energy is under hypotheses category.

 

As we have no explanation, I don't know what "some other explanation" means. An explanation other than the one we don't have?

Or do you mean another hypothesis? There is always room for another hypothesis - as long as it makes predictions that allow it to be tested (and eliminated or confirmed) by observations.

It might be another explanation or different point of view of what we see. This explanation should lead us to new hypothesis.

However, I fully agree that under any condition – it must be tested and fully proved by real evidences.

[Sensei]

However, I fully agree that under any condition – it must be tested and fully proved by real evidences.

 

Evidence is clear: redshift of the farthest galaxies.

 

Do you have alternative explanation of this evidence?

 

Then show us your math equations leading to such redshift..

 

Testing it in lab experiment is not possible. You won't make galaxy in laboratory. Nor will make it recede.

So we're pretty much stuck in analyzing satellite data. Whether it's Hubble or other satellite, doesn't matter (as long as each of them match other satellite data).

Edited March 9, 2015 by Sensei

[David Levy]

 

Evidence is clear: redshift of the farthest galaxies.

 

Do you have alternative explanation of this evidence?

 

Then show us your math equations leading to such redshift..

 

Testing it in lab experiment is not possible. You won't make galaxy in laboratory. Nor will make it recede.

So we're pretty much stuck in analyzing satellite data. Whether it's Hubble or other satellite, doesn't matter (as long as each of them match other satellite data).

Sorry, a new theory is not relevant to the current theory.

There is no need to offer any alternative to the current theory.

Each theory must be verified by itself.

Let me give you an example:

In the past it was believed that the moon is made out of cheese.

At that time, if someone didn't agree with this mainstream, he had to offer better alternative and prove it.

So, assuming that you are living at that time;

What kind of alternative can you offer and how can you prove your new theory?

Please remember:

There was no telescope at that time. If you couldn't prove your new theory, they are going to trash your idea with your life.

However, in our days, we are so lucky.

If you can't prove your theory, they will only trash your idea.

Therefore, no one at our time needs to offer better alternative in order to disqualify the current mean stream concept. And actually, why shall we disqualify any current theory?

We just need to categorize correctly each theory.

Hence, the Dark energy and Dark matter are categorized under Hypothesis. That doesn't mean that those theories are incorrect. It just means that currently, those are available theories, but we have no real evidence to prove them.

What's wrong with that?

Evidence is clear: redshift of the farthest galaxies.

With regards to your approval, please advice if I understand you correctly:

The theory of dark energy had been emerged due to the redshift verification of the farthest galaxies.

And, we prove the dark energy by ---- redshift of the farthest galaxies.

So, if someone has a headache, we can claim that he has a dark disease.

In the same token, we can prove this disease by its headache.

Agree?

I assume that some of us might have a real headache now…

Edited March 10, 2015 by David Levy

[Mordred]

I always prefer the term cosmological constant or Lambda to the term dark energy. Reason being dark energy may only be one contributor to Lambda.

 

As mentioned we still don't understand what causes Lambda, but the indirect evidence of its existence, is partly redshift and distance measurements. Those measurements include galaxies of just about every observable time period.

 

This is how we know that Lambda is constant, at least since the CMB forward.

The other piece of evidence is the thermodynamic laws, in terms of rate of temperature drop in the universe.

 

The full details on how this is done is lengthy, but essentially pv=nRT

 

pressure, volume and temperature of an ideal gas have relations with each other.

 

as the volume increases the energy-density and pressure decreases so does the temperature.

 

We can calculate the temperature and pressure influence of every contributor such as photons, neutrinos, baryons, fermions and leptons by knowing the number of degrees of freedom (interactions) of each particle, the mass of each,the entropy density and energy density per volume.

 

The two key formulas is the Bose-Einstein statistics, and the Fermi-Dirac statistics. Bosons is the previous, Fermions the latter.

 

So as far as the standard model particles, we can account for their influence. This by the way includes the Higgs field @126 GeV.

 

Dark matter or non relativistic baryonic matter has negligible pressure/temperature influence w=0

It's simply too slow moving to exert pressure.

 

Radiation, both relativistic and non, has a greater temperature to pressure influence. However all these exert positive pressure influences. That's all the standard model particles. Hrrrm we have a problem.

 

Lambda has a negative pressure influence. None of the known particles account for this. Then to make matters work, the only way it can remain homogeneous and isotropic, as well as constant, it must be a uniform and equal everywhere (at a point in time distribution). To stay constant work is being done( where is this energy coming from?)

 

Virtual particles via the Heisenberg uncertainty principle was once considered. However it creates too much energy by 120 orders of magnitude.

There is currently hope in a property of the Higgs field, this is currently being tested. (Might also answer dark matter, as relic, sterile neutrinos.) Time will only tell.

 

here is the related Higgs papers.

 

DARK MATTER AS STERILE NEUTRINOS

 

http://arxiv.org/abs/1402.4119

http://arxiv.org/abs/1402.2301

http://arxiv.org/abs/1306.4954

 

Higg's inflation possible dark energy

 

http://arxiv.org/abs/1402.3738

http://arxiv.org/abs/0710.3755

http://arxiv.org/abs/1006.2801

 

 

Now as far as thermodynamic relations in Cosmology as I said that's lengthy.

 

Training (textbook Style Articles)

 

http://arxiv.org/pdf/hep-ph/0004188v1.pdf:"ASTROPHYSICS AND COSMOLOGY"- A compilation of cosmology by Juan Garcıa-Bellido

http://arxiv.org/abs/astro-ph/0409426An overview of Cosmology Julien Lesgourgues

http://arxiv.org/pdf/hep-th/0503203.pdf"Particle Physics and Inflationary Cosmology" by Andrei Linde

 

http://www.wiese.itp.unibe.ch/lectures/universe.pdf

Particle Physics of the Early universe" by Uwe-Jens Wiese Thermodynamics, Big bang Nucleosynthesis

 

Chapter 3 and 4 of the last article.

Indirectly measurements and observational evidence, say DE is present. There is little doubt about that after WMAP, and Planck primarily, though not exclusively, those are just two of the key datasets out of hundreds over the last 20 years. We just can't properly define it. We can define its influence, not the source or cause

Oh forgot to add this paper by Lawrence R Krauss.

 

A Higgs--Saw Mechanism as a Source for Dark Energy

http://arxiv.org/abs/1306.3239

Edited March 10, 2015 by Mordred

[Sensei]

David, before continuing read whole article about redshift.

http://en.wikipedia.org/wiki/Redshift

Especially highest redshifts.

[Strange]

With regards to your approval, please advice if I understand you correctly:

The theory of dark energy had been emerged due to the redshift verification of the farthest galaxies.

And, we prove the dark energy by ---- redshift of the farthest galaxies

 

You have already said that there could be no doubt about the observations which means there is a need for something called "dark energy". In fact, you are more certain about this evidence than I am:

 

No, this issue had been confirmed.

The rate of expansion is accelerating. There is no need for further evidence to confirm this issue.

 

But now you seem to be claiming this is invalid, somehow. Please make your mind up.

[David Levy]

 

You have already said that there could be no doubt about the observations which means there is a need for something called "dark energy". In fact, you are more certain about this evidence than I am:

 

But now you seem to be claiming this is invalid, somehow. Please make your mind up.

Yes, the observation is clear.

Dark energy is currently considered as a feasible solution for this observation.

However, without a real evidence, the dark energy will remain under hypothesis solution.

[Strange]

 

Yes, the observation is clear.

Dark energy is currently considered as a feasible solution for this observation.

However, without a real evidence, the dark energy will remain under hypothesis solution.

 

Dark energy is not a solution: it is a label for any/all hypotheses.

 

Some of those solutions/hypothesis are literally some form of energy.

 

Other solutions/hypothesis are NOT energy. But they are still included under the label "dark energy".

[imatfaal]

Have you never heard the term indirect evidence? Direct evidence is something you can actually see and measure. Like a rock, take that rock drop it in a cup of water. The level of the water rises. From the change in water level we can indirectly measure the mass of the rock.

 

Dark energy is similar. Through the changes in distance measurements and the ideal gas laws, including thermodynamic laws we can measure dark energy. Indirectly.

Volume of the rock - unless it is floating

[Mordred]

Yeah that was already caught earlier P:

[imatfaal]

Yeah that was already caught earlier P:

 

So I was just rubbing it in - sorry. Replied as soon as I saw post. Being a shipping man I tend to react to buoyancy things instantly

[Mordred]

Lol ex sailor so can relate

[Strange]

 

So I was just rubbing it in - sorry. Replied as soon as I saw post. Being a shipping man I tend to react to buoyancy things instantly

 

You picked up the "floating rock" possibility that I missed (Icebergs ahoy!)

[imatfaal]

 

You picked up the "floating rock" possibility that I missed (Icebergs ahoy!)

 

When my ships stop floating I know I will be in trouble! And I had just stopped thinking about mass / volume conversions from the Metric/Imperial thread.

 

Threads like this really make me wish we had never come up with the term "dark energy" but merely stated that some of the past assumptions about the dynamics of the universe on the largest scale were inaccurate.

[Strange]

Threads like this really make me wish we had never come up with the term "dark energy" but merely stated that some of the past assumptions about the dynamics of the universe on the largest scale were inaccurate.

 

But you can sort of understand why people prefer "dark energy to "some of the past assumptions about the dynamics of the universe on the largest scale appear to be inaccurate". Especially headline writers ....

[swansont]

 

When my ships stop floating I know I will be in trouble!

 

I served primarily with submariners, and they had an adage about not wanting to be aboard a vessel that continually operated at its test depth.