The uncertainty of science: Astronomers using the Chandra X-Ray Observatory have found that the Milky Way is surrounded by a halo of hot gas.
This is the key quote:
The estimated mass of the halo is comparable to the mass of all the stars in the galaxy. If the size and mass of this gas halo is confirmed, it also could be an explanation for what is known as the “missing baryon” problem for the galaxy.
“Missing baryon” is another way to say “dark matter.” In other words, this discovery might prove that it isn’t necessary to invent exotic unknown particles of physics, such as the Weakly Interacting Massive Particles (WIMPs) to explain the missing matter. The missing matter might simply be this hot gas, previously undetected.