Astronomy Picture of the Day—20180730

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2018July 30

Journeyto the Center of the Galaxy

VideoCredit: ESO/MPE/Nick Risinger (skysurvey.org)/VISTA/J. Emerson/Digitized SkySurvey 2

Explanation:What wonders lie at the center of our Galaxy? In Jules Verne's science fictionclassic A Journey to the Center of the Earth, Professor Liedenbrock and hisfellow explorers encounter many strange and exciting wonders. Astronomers already know of some of the bizarre objects that exist at our Galactic center,including like vast cosmic dust clouds, bright star clusters, swirling rings ofgas, and even a supermassive black hole. Much of the Galactic Center isshielded from our view in visible light by the intervening dust and gas, but itcan be explored using other forms of electromagnetic radiation. The featuredvideo is actually a digital zoom into the Milky Way's center which starts byutilizing visible light images from the Digitized Sky Survey. As the movieproceeds, the light shown shifts to dust-penetrating infrared and highlights gas clouds that were recently discovered in 2013 to be falling toward centralblack hole. In 2018 May, observations of a star passing near the Milky Way'scentral black hole showed, for the first time, a gravitational redshift of thestar's light -- as expected from Einstein's general relativity.