What Is A Dark Matter In Astronomy?

In astronomy, dark matter refers to the non-luminous objects, that is, the objects in space that are no longer able to emanate or reflect lights. As we look at the sky through telescope (and even through bare eyes), we may see varieties of luminous objects such as stars, planets, nebulae, galaxies, etc, whereas, dark matters are such objects that are potentially invisible to us. Astoundingly, they are more in numbers that we may consider looking at the visible one.

Dark matters cannot be seen. Thus, its presence can only be detected through the analysis of its existence. For example, it exerts gravitational force on other objects around it likewise visible objects. Hence, by measuring velocities of stars it can be estimated through the different between actual velocity and assumed velocity. It has been observed that the presence of massive 'halos' of dark matter out there surrounding the entire galaxies.

Dark matter has played an important role in the research area of astronomical physics. It has been crucially interrelated with the most widely accepted theory of origin and evolution of universe, the famous "Big Bang Theory".