Subj : Daily APOD Report To : All From : Ben Ritchey Date : Mon Oct 29 2018 09:38:50 Astronomy Picture of the Day Astronomy Picture of the Day Discover the cosmos! [1] Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2018 October 29 [2] Shells of Stars in Elliptical Galaxy PGC 42871 Image Credit: Hubble Legacy Archive [3] , NASA [4] , ESA [5] ; Processing & Copyright: Domingo Pestana [6] Explanation: How do galaxies grow? To help find out, the Hubble Space Telescope [7] was deployed to image the unusual elliptical galaxy [8] PGC 42871. How this galaxy came to be surrounded by numerous shells of stars [9] may give clues about how it evolved. Embedded in the diffuse shells [10] are massive globular clusters of stars [11] -- stars which analyses show were born during three different epochs. This and other data indicate [12] that PGC 42871 [13] has been in at least two galactic collisions [14] , at least one of which might have been with a former spiral galaxy [15] . The remaining spiral galaxy on the far left is at the same distance as PGC 42871 [16] and may have been involved in some of the collisions. PGC 42871 spans about 20 thousand light years [17] and lies about 270 million light years away toward [18] the constellation of Centaurus [19] . Open Science: Browse 1,800+ codes in the Astrophysics Source Code Library [20] Tomorrow's picture: orionids from orion ------------------------------------------------------------------------------- < [21] | Archive [22] | Submissions [23] | Index [24] | Search [25] | Calendar [26] | RSS [27] | Education [28] | About APOD [29] | Discuss [30] | > [31] ------------------------------------------------------------------------------- Authors & editors: Robert Nemiroff [32] (MTU [33] ) & Jerry Bonnell [34] (UMCP [35] ) NASA Official: Phillip Newman Specific rights apply [36] . NASA Web Privacy Policy and Important Notices [37] A service of: ASD [38] at NASA [39] / GSFC [40] & Michigan Tech. U. [41] ---------- Site notes: [1] archivepix.html [2] image/1810/PGC42871_HubblePestana_5051.jpg [3] https://hla.stsci.edu/ [4] https://www.nasa.gov/ [5] https://www.esa.int/ [6] https://www.flickr.com/photos/122467237@N08/ [7] https://www.spacetelescope.org/announcements/ann1813/ [8] https://en.wikipedia.org/wiki/Elliptical_galaxy [9] ap180206.html [10] ap140105.html [11] ap160427.html [12] http://adsabs.harvard.edu/abs/2009AJ....137..383M [13] https://www.spacetelescope.org/news/heic1516/ [14] ap130514.html [15] https://www.nasa.gov/multimedia/imagegallery/image_feature_2132.html [16] https://www.spacetelescope.org/images/heic1516a/ [17] https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html [18] https://www.youtube.com/watch?v=0gYTXaLWqyI [19] https://en.wikipedia.org/wiki/Centaurus [20] http://ascl.net/code/all [21] ap181028.html [22] archivepix.html [23] lib/apsubmit2015.html [24] lib/aptree.html [25] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search [26] calendar/allyears.html [27] /apod.rss [28] lib/edlinks.html [29] lib/about_apod.html [30] http://asterisk.apod.com/discuss_apod.php?date=181029 [31] ap181030.html [32] http://www.phy.mtu.edu/faculty/Nemiroff.html [33] http://www.phy.mtu.edu/ [34] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html [35] http://www.astro.umd.edu/ [36] lib/about_apod.html#srapply [37] https://www.nasa.gov/about/highlights/HP_Privacy.html [38] https://astrophysics.gsfc.nasa.gov/ [39] https://www.nasa.gov/ [40] https://www.nasa.gov/centers/goddard/ [41] http://www.mtu.edu/ --- Mystic BBS v1.12 A39 (Windows/32) * Origin: FIDONet - The Positronium Repository (1:393/68) .