Galaxy was expected to contain 400 times more dark matter than observations show
Grand, majestic spiral galaxies like our Milky Way are hard to miss. Astronomers can spot these vast complexes because of their large, glowing centers and their signature winding arms of gas and dust, where thousands of glowing stars reside.
But some galaxies aren't so distinctive. They are big, but they have so few stars for their size that they appear very faint and diffuse. In fact, they are so diffuse that they look like giant cotton balls.
Observations by NASA's Hubble Space Telescope of... Read more