Home » News & Blogs » Globular Clusters and Dark Satellite Galaxies
Bookmark and Share
Beyond Earthly Skies

Globular Clusters and Dark Satellite Galaxies

24 Jul 2014, 22:00 UTC
Globular Clusters and Dark Satellite Galaxies ESA/Hubble & NASA.
(200 words excerpt, click title or image to see full post)

Globular clusters are dense spherical collections of stars. Every large galaxy, such as the Milky Way, contains a system of globular clusters. Observations of globular clusters show that they do not contain gravitationally bound dark matter. Most of the matter in the universe is in the form of dark matter. Dark matter neither emits nor absorbs light, and its presence can only be inferred from its gravitational effects on normal matter and radiation. Nevertheless, the existence of dark matter is important because it provides the gravitational framework for normal matter to come together to form galaxies and clusters of galaxies. As a result, it remains a challenge to explain how normal matter could gravitate so tightly together to form globular clusters.The globular cluster NGC 1806 located within the Large Magellanic Cloud as observed by the Hubble Space Telescope. Image credit: ESA/Hubble & NASA.A study by Noaz & Narayan (2014) suggests that globular clusters can form naturally whenever there is some relative velocity between normal matter and dark matter. In this scenario, the formation of a globular cluster begins with a collapsing clump of normal matter in a dark matter halo which is itself also collapsing. The gravity that is driving ...

Latest Vodcast

Latest Podcast

Advertise PTTU

NASA Picture of the Day

Astronomy Picture of the Day