... Editor's choices for the most educational Astronomy Pictures of the Day about spiral galaxies: . APOD: 2003 March 10 - M101: The Pinwheel Galaxy . Explanation: Why do many galaxies appear as spirals ? ... One result is that M101 , also called the Pinwheel Galaxy , has several extremely bright star-forming regions (called HII regions ) spread across its spiral arms. ... APOD: 2003 April 13 - NGC 1365: A Nearby Barred Spiral Galaxy . ... NGC 1365 is a member of the Fornax Cluster of Galaxies . ...

... The Fornax Cluster of Galaxies . ... Blasted out by energetic massive star formation the bullets, relatively dense, hot gas clouds about ten times the size of Pluto's orbit, are blue in the false color image. ... Drifting near bright star Eta Geminorum, at the foot of a celestial twin, the Jellyfish Nebula is seen dangling tentacles from the bright arcing ridge of emission left of center. ... Open Star Clusters M35 and NGC 2158 . ... Bright blue stars frequently distinguish younger open clusters. ...

... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

... Kalirai and Harvey Richer of the University of British Columbia led the study, which began as an investigation of a globular star cluster in the Milky Way galaxy known as NGC 6397. ... Within the population of stars and galaxies behind NGC 6397, the Hubble image revealed a large elliptical galaxy that contains several hundred globular clusters. ... In fact, a single giant star in NGC 6397 appears 10 million times brighter than one of the distant globular clusters. ...

... Planets . ... Earth Satellites . ... Looking in the direction of the constellation Cygnus the Swan and launched by NASA in 2009 is the Kepler Space Observatory.Many previous missions searching for exoplanets mainly detected large giant planets, like large hot Jupiters (it is easier to detect larger planets).However KeplerтАЩs main objective is to search for much smaller planets located in a habitable zone which is not too close nor too far from their star; planets which may be just like our Earth. ...

... STScI-PRC97-25 HUBBLE ASTRONOMERS USE LENS IN NATURE TO UNCOVER MOST DISTANT GALAXY IN THE UNIVERSE [LEFT] A NASA Hubble Space Telescope image of the galaxy cluster CL1358+62 has uncovered a gravitationally-lensed image of a more distant galaxy located far beyond the cluster. The gravitationally-lensed image appears as a red crescent to the lower right of center. ... The image was taken with Hubble's Wide Field Planetary Camera-2 on January 13, 1996. ...

... We have made observations of the Perseus cluster with the Westerbork Telescope at 610 MHz. ... Several newly detected sources are identified with cluster galaxies. ... No evidence is found for the existence of the previously reported ~ 65'x25' cluster halo, 3C 84B. Key words: radio galaxies - clusters - tailed radio sources buoyancy The Perseus Cluster of galaxies is one of the most fascinating systems accessible to extragalactic astronomers. ...

... Neutral and Ionised Hydrogen in NGC 4214 V. J. McIntyre1,2 1 2 Physics Department, University of Wollongong, Wollongong, NSW 2522, Australia Astrophysics Department, University of Sydney, NSW 2006, Australia vjm@physics.usyd.edu.au Abstract: It is not clear at present how the diffuse ionised gas (DIG) component in galaxies is ionised. ... How porous the ISM must be depends on the (unknown) location of the ionised emission relative to the disk. ... 1996). ... Local H I surface density is 2в1021 cm-3 ...