In This Image Taken By NASA / ESA Hubble Space Telescope, The Spectacular Spiral Galaxy M99 Fills The Whole Picture M99 - Located In The Constellation Retrohair, About 42 Million Light-years Away From Earth - Is A "big Design" Spiral Galaxy. The So-called Big Design Is Because The Clearly Defined And Prominent Spiral Arms Can Be Seen In This Picture.
M99 Was Taken By Hubble's Third Generation Wide Area Camera On Two Different Occasions. It Can Be Used To Help Astronomers Study Two Completely Different Astronomical Phenomena.
Among Them, The First Set Of Observations Aims To Explore The Gap Between Two Different Types Of Cosmic Explosions: Nova And Supernova. New Stars Are Caused By The Interaction Between White Dwarfs And Larger Stars In Binary Systems. Their Brightness Is Much Lower Than That Of Supernovae, Which Marks The Catastrophic Violent Death Of Massive Stars. However, Current Astronomical Theories Predict That Sudden And Fleeting Events May Shine At A Brightness Between Nova And Supernova. Although Described By Astronomers As Shrouded In Mystery And Controversy, Such An Event Was Observed In M99. In Response, Astronomers Turned To Hubble's Keen Vision And Accurately Located The Disappearing Light Source.
The Second Set Of Observations Is Part Of The Hubble Project, Which Aims To Map The Relationship Between Young Stars And The Cold Gas Clouds That Form Them. Hubble Examined 38 Nearby Galaxies, Which Identified Hot, Young Star Clusters. These Galaxies Were Also Observed By The Atacama Large Millimeter / Submillimeter Array (ALMA), A Huge Radio Telescope Composed Of 66 Independent Discs Located High In The Andes Mountains Of Chile. Hubble's Observation Of Young Stars Combined With Alma's Insight Into Cold Gas Clouds Will Enable Astronomers To Study The Details Of Star Formation And Pave The Way For Future Scientific Research Using NASA / ESA / CSA's James Webb Space Telescope.