NGC 5584: Expanding the Universe

Credit: NASA, ESA, A. Riess (STScI/JHU), L. Macri (Texas A & M Univ.) et al., Hubble Heritage (STScI/AURA)

"Big, beautiful NGC 5548 is more that 50,000 light-years across and lies 72 million light-years away toward the constellation Virgo. The winding spiral arms of this gorgeous island universe are loaded with luminous young star clusters and dark dust lanes. In this sharp Hubble image of NGC 5548, many of the small reddish smudges are distant background galaxies."

The study of this spiral galaxy "lends weight to the theory that dark energy really is responsible for accelerating the expansion of the Universe, restricting models that try to explain the observed acceleration without the mysterious dark energy."

This "dark energy" theory is an example of a crazy idea that seems to be gaining in popularity.

Taken from the site Astronomy Picture of the Day at http://apod.nasa.gov/apod/ on 30 March 2011.