Dark Matter, Dark Energy, Galaxies, Mathematics and Observations

"Mystery Behind Galaxy Shapes Solved"
Space.com (January 11, 2010)

"Galaxies come in many shapes and sizes, but until recently astronomers have been at a loss to explain why.

"Now scientists have used dark matter theory to predict the menagerie of galaxies found in the universe. Their new model reproduces 13 billion years' worth of cosmic evolution, resulting in a surprisingly accurate tally of the different kinds of galaxies we see.

" 'We were completely astonished that our model predicted both the abundance and diversity of galaxy types so precisely,' said researcher Nick Devereux of Embry-Riddle University in Arizona...."

The article does a pretty good job of explaining the basics of how galaxies are sorted out by shape: and what the latest mathematical model is.

The bottom line:

"...Researchers created a new supercomputer model, based on observational data and the "Lambda Cold Dark Matter" theory of the universe. This theory suggests that about 72 percent of the cosmos is made of up a mysterious force called dark energy, while another 23 percent is composed of an invisible type of matter called dark matter. That leaves only 4 percent of the universe made of normal, visible matter, including all the stars and planets that we see...."

And, despite that "solved" in the headline, the scientists are still firmly connected to the space-time continuum:

"...'These new findings set a clear direction for future research,' Devereux said. 'Our goal now is to compare the model predictions with observations of more distant galaxies seen in images obtained with the Hubble [Space Telescope] and those of the soon-to-be-launched James Webb Space Telescope.'..."

Right now, it looks like dark matter, and dark energy, work very well as explanations for why the universe looks the way it does now. Not all that long ago, a substance called phlogiston was a pretty good explanation to explain why fire works the way it does. Then, in 1772, tests demonstrated that something called oxygen was involved. As it turns out, phlogiston doesn't exist.

But it worked for quite a while as an adequate model to explain combustion.

Dark Matter, Dark Energy, Galaxies, Mathematics and Observations

It's looking more and more like dark matter and dark energy really exist. Or, if they don't, that something that acts a whole lot like them does.

But: "Solved"? What we've got now is a better explanation - and one that can be tested.

Related posts:

• "Lemming Tracks: Dark Matter, Dark Stars, and Keeping Up"
  (December 21, 2009)
• "Like, Far Out! Offbeat Galaxies"
  (August 6, 2009)

Vaguely-related piece:

• "Once it Was Believed / Now We Know"
  Brian's Attic (2003)

Background:

• "Dark Energy, Dark Matter"
  Astrophysics, Science, NASA