A Very Large Array of Radio Telescopes

Explanation: Pictured above is one of the world's premiere radio astronomical observatories: The Very Large Array (VLA). Each antenna dish is as big as a house (25 meters across) and mounted on railroad tracks. The VLA consists of 27 dishes - together capable of spanning the size of a city (35 kilometers). The VLA is the most sensitive radio telescope ever, and, through interferometry , can resolve a golf ball-sized radio source 150 kilometers away (0.04 arcsec). The VLA is continually making new discoveries, including determining the composition of galaxies , passing comets , quasars , HII regions , and clusters of galaxies . The VLA is also used to receive the weak radio signals broadcast from interplanetary spacecraft . The VLA is located in New Mexico , USA. A significant upgrade of VLA's capabilities is planned.