[petuniasevan]

Something is out there. Dark matter makes up a percentage of the physical universe (what it is or how much there is is not known). A stream of galactic clusters at least 200 million light-years in length (including our own Milky Way) is being pulled in the direction of the "Great Attractor" (about 250 million light-years away in the constellation Centaurus) at a speed of 400 miles per second.

This "Great Attractor" is thought to be a mass concentration on the order of 10¹⁶ solar masses. We can find less than 10% of the matter required to account for the attraction. Thus the search for dark matter (and its nature) continues...

This is the galactic cluster ACO 3627, also known as the Norma Cluster. It is near the center of the Great Attractor.

[petuniasevan]

[BossyRoofer]

The work your doing is so great. My daughter is asking questions that I can't answer, so we explore the answers togather. Good job APOD!

[mikrofon]

Another fascinating pic -- thanks for the "sonogram" of the universe ;^)

[RightWhale]

The Great Attractor. This might not be good. We better get our space program geared up to investigate, and right now we are short of capability by a few orders of magnitude. Complacency seems to be the order of the day.