I think I need someone far cleverer than me to explain this to me. Dark Matter [wiki]…
In astronomy and cosmology, dark matter is matter that is inferred to exist from gravitational effects on visible matter and background radiation, but is undetectable byemitted or scattered electromagnetic radiation. Its existence was hypothesized to account for discrepancies between measurements of the mass of galaxies, clusters of galaxies and the entire universe made through dynamical and general relativistic means, and measurements based on the mass of the visible “luminous” matter these objects contain: stars and the gas and dust of the interstellar and intergalactic medium.
According to observations of structures larger than galaxies, as well as Big Bang cosmology interpreted under the Friedmann equations and the FLRW metric, dark matter accounts for 23% of the mass-energy density of the observable universe. In comparison, ordinary matter accounts for only 4.6% of the mass-energy density of the observable universe, with the remainder being attributable to dark energy. From these figures, dark matter constitutes 80% of the matter in the universe, while ordinary matter makes up only 20%.
Dark matter was postulated by Fritz Zwicky in 1934 to account for evidence of “missing mass” in the orbital velocities of galaxies in clusters. Subsequently, other observations have indicated the presence of dark matter in the universe; these observations include the rotational speeds of galaxies, gravitational lensing of background objects by galaxy clusters such as the Bullet Cluster, and the temperature distribution of hot gas in galaxies and clusters of galaxies.
Dark matter plays a central role in state-of-the-art modeling of structure formation and galaxy evolution, and has measurable effects on the anisotropies observed in thecosmic microwave background. All these lines of evidence suggest that galaxies, clusters of galaxies, and the universe as a whole contain far more matter than that which interacts with electromagnetic radiation. The largest part of dark matter, which does not interact with electromagnetic radiation, is not only “dark” but also, by definition, utterly transparent.
As important as dark matter is believed to be in the cosmos, direct evidence of its existence and a concrete understanding of its nature have remained elusive. Though the theory of dark matter remains the most widely accepted theory to explain the anomalies in observed galactic rotation, some alternative theoretical approaches have been developed which broadly fall into the categories of modified gravitational laws, and quantum gravitational laws.
Look, I jut don't get it. I mean I do get it in that I understand the basic concept – when we look at the universe and see all the stuff that we can see we end up with a real problem, that all the observable material around us only accounts for 20% of the matter that should be there if our current understandings of gravity etc are correct.
Is it me, or does that not make you want to argue that either we're very bad at just looking for stuff or maybe our current theories just aren't up to scratch at all? The wiki article goes on to present that latter choice as one possible alternative:
One group of alternative theories to dark matter assume that the observed inconsistencies are due to an incomplete understanding of gravitation rather than invisible matter. These theories propose to modify the laws of gravity instead.
But again, is this just me or doesn't this just all boil down to the fact that really, for all our claims to cleverness and despite all the incredible discoveries we've made about the Universe, we just still don't have a clue?
I have an alternate explanation for why we're still nowhere near close to having anything like a Theory of Everything. Some of you aren't going to like it,
Hebrews 1:3 The Son is the radiance of God's glory and the exact representation of his being, sustaining all things by his powerful word.
Now that is really going to mess up any theory built on materialism.
Now, can someone let me know if I'm just getting this hopelessly messed up or is all of this dark matter stuff really an exercise in trying to explain away our ignorance?
(image from ScienceBlogs.com)