Is there empirical evidence for dark matter and dark energy?

Is there empirical evidence for dark matter and dark energy?This thread is intended to determine with precision what if any is the empirical evidence ascertaining the existence of dark matter and dark energy.For the background of this thread see [click line in bold] Thinking outside the box of empirical evidence, where Percy says that there is empirical evidence for the existence of dark matter and dark energy, and I am asking him there to show the empirical evidence establishing the existence of dark matter and dark energy.My own position is that prescinding from the existence of socalled dark matter and dark energy -- and I for one am certain that dark matter and dark energy do exist, the way people propounding their existence is not because they have empirical evidence.And I want to know on what basis if not on empirical evidence these people say that there are dark matter and dark energy.For myself, how do I know that dark matter and dark energy exist?I know that they exist from intelligent thinking.But I am sincerely very interested with an absolutely open mind -- which is open to receive substantial new ideas and also open to let go of false ideas -- to hear from people who have empirical evidence for the existence of dark matter and dark energy.Yrreg

Hi Yrreg,I'll give you the same definition of empirical evidence that I gave Dawn Bertot: For this discussion the definition of evidence is anything that is apparent to our senses. If we can see, touch, hear, feel or taste it, it's evidence. Evidence that is indirect is still valid evidence. For instance, the reading on a thermometer is valid evidence of the temperature, even though we're not feeling the temperature directly. Much forensic evidence is indirect evidence, such as blood stains and fingerprints.If you agree with this definition then I can promote this thread.

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--	Percy
	EvC Forum Director

Thread copied here from the Is there empirical evidence for dark matter and dark energy? thread in the Proposed New Topics forum.

"Dark matter" and "dark energy" are essentially placeholders. We empirically observe (with telescopes, etc) for instance the amount of mass in a given galaxy, and the strength of gravity. It turns out that the amount of mass that we are able to observe is insufficient to hold the galaxy together - therefore we predict the existence of some other form of mass that we cannot directly observe. For simplicity's sake, we call it "dark matter." We have not empirically observed dark matter directly (if we had, we'd give it a better, more descriptive name and quantify exactly what it is), but we have indirectly observed its effects.Much like the discovery of the outer planets of the solar system - we empirically observe that there is a gravitational anomaly in the orbit of one planet, and predict that there must be an additional planetary mass causing the disruption, even before we observe the new planet directly. Another analogy would be thermometer - you don't directly measure the temperature. You directly observe the thermometer, and predict the temperature based on how high the mercury rises. The temperature measurement is empirical, but indirect.The existence of dark matter et al is a prediction based upon empirical evidence. "Intelligent thinking" is not an answer. You have not described your thought process or made a coherent statement. You may as well say "I know they exist because of phlogiston" - you would be giving the same level of explanation. Could you please elaborate?

Yes. The question of whether they exist is different from the question of whether there is evidence.For dark matter: Scientists observe rotational motion in galaxies. From the rotation, and our science of gravitation, they can compute how much mass there must be in galaxy to account for that rotation. It turns out that there needs to be a lot more mass than is observed. So the unobserved mass, detected by the gravitational evidence, is called "dark matter."There is, of course, a possibility that there is something wrong with our understanding of gravitation. In that case, perhaps there isn't any dark matter, but instead there is another mystery. So the existence of dark matter isn't at the point where it can be considered a certainty, but it is thus far the best explanation of the evidence. And, of course, it is a research area to find out more about what is happening.For dark energy, the issue is the observations related to the expansion of the cosmos. "Dark energy" refers to the energy that would be required to cause that expansion. Again, there is a possibility that there is a problem elsewhere in our understanding, so it isn't a certainty that dark energy exists. And, again, it is a research area to identify the dark energy or to identify what else is going on.It is a certainty that there is evidence. It is not quite so certain what the evidence means, so further research is going on.

To answer your question in a nutshell, No. there is no evidence for dark matter or dark energy. As of right now they are nothing more than speculative theories to explain the problems with galaxy motion and behaviour etc as others have explained.There is also basically little to say about the theories and workings of dark matter/energy since it's currently 1 big mystery. All we say is that it might be some kind of sub atomic particles and there are currently experiments going on deep in the earths crust to try and detect them.it's the biggest mystery in cosmology since it thought to account for 97% of the universe's matter, based on this, it is more than likely that our current view of the universe is quite wrong.

You maybe meant to say that we don't know what is responsible for the evidence and that these are just the labels we use?--Percy

While dark matter is detected purely through it's gravitational effects, it is wrong to say that there is no evidence for it. Beyond the basic "missing mass" observation there are the observations of mass distribution in the Bullet Cluster which show the dark matter separating from the visible matter (the latter slowed by electromagnetic interactions).

no yrreg there is no evidence scientists wanted to have an imaginary plaything too like theists do so out of the blue they came up whit dark matter and dark energy with no evidence pointing to the exsistance of both

Perhaps what you want to say is that we have as much evidence for dark matter as we have for fairies pushing balls of invisible cotton candy through the voids in space. Both are as equally likely since we have the same amount of evidence for both. We are missing 97% of the matter in the universe, so this is the world we are making up to fill that void.Another word for this type of "evidence" is called pure speculation. Its quite similar to the evidence for Darwinian evolution.

I was only correcting Chessmaster. You should respond to Rahvin in Message 11 and Nwr in Message 12. Those messages are where the evidence is described.--Percy

Evidence is simply any fact which make a proposition more likely than would be the case if the fact were not present. Even facts which increase the likelihood by a small amount are still evidence supporting the proposition.Evidence should be distinguished from proof which be an utterly convincing collection of evidence.Sometimes the same facts will support multiple plausible, but contradictory propositions. In that case perhaps the evidence is not sufficient for our needs without still more evidence.Using the above definition, I think it is clear that there is empirical evidence for dark matter. But the same facts are also empirical evidence that our understanding of gravitation is flawed.

thank you Percy. I suppose my "no evidence" could be a little misleading.Unless our view of cosmic gravity leaves alot to be desired, it is almost a certaintity that dark matter/energy exist.my point was that these "labels" right now stand at saying pretty much nothng but "the universe is expanding and galaxies are spinning alot more than their visible matter justifies. Therefore there must be something that we can't see here going on." We call it dark matter/energy and have ideas and speculations about what it might be, but as of 2010 we have no underlying evidence for it, no clue how it works, what it is or anything.

I wouldn't go that far myself. The evidence that is consistent with dark matter is also consistent with MOND (Modified Newtonian Dynamics), and there are also alternatives to dark energy for explaining the accelerating expansion of the universe. Well put.--Percy

The title of this thread as given by me is:

And the way I understand the title is conveyed in the following sentence also in my own words:

Wherefore in other words:

So, let us just keep to factual existence of empirical evidence proving the factual existence of dark matter and dark energy.I gave the example of empirical evidence for the existence of the nose in our face from the fact that I touch the nose in your face and you touch the nose in my face.And please, no need to bring in the word proposition, just keep to facts.Yrreg