Missing Matter Found Between Galaxies

Hubble Survey Finds Missing Matter, Probes Intergalactic Web. Scientists were not finding expected levels of normal matter and now they've found some. This isn't the missing matter that lead to dark matter and energy theories, but other missing matter.

"Now, in an extensive search of the local universe, astronomers say they have definitively found about half of the missing normal matter, called baryons, in the spaces between the galaxies...'We think we are seeing the strands of a web-like structure that forms the backbone of the universe,' Mike Shull of the University of Colorado explained. 'What we are confirming in detail is that intergalactic space, which intuitively might seem to be empty, is in fact the reservoir for most of the normal, baryonic matter in the universe.'"

I also really liked the diagram explaining how they found this matter:

"This illustration shows how the Hubble Space Telescope searches for missing ordinary matter, called baryons, by looking at the light from quasars several billion light-years away. Imprinted on that light are the spectral fingerprints of the missing ordinary matter that absorbs the light at specific frequencies (shown in the colorful spectra at right). The missing baryonic matter helps trace out the structure of intergalactic space, called the "cosmic web." "