Subj : Daily APOD Report To : All From : Ben Ritchey Date : Wed Feb 13 2019 08:58:45 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. 2019 February 13 [2] The Helix Nebula in Hydrogen and Oxygen Image Credit & Copyright: Andrew Campbell [3] Explanation: Is the Helix Nebula looking at you? No, not in any biological sense, but it does look quite like an eye. The Helix Nebula [4] is so named because it also appears that you are looking down the axis of a helix [5] . In actuality, it is now understood to have a surprisingly complex geometry [6] , including radial filaments and extended outer loops [7] . The Helix Nebula ( aka [8] NGC 7293) is one of brightest and closest examples of a planetary nebula [9] , a gas cloud created [10] at the end of the life of a Sun-like star. The remnant central stellar core, destined to become a white dwarf star [11] , glows in light so energetic [12] it causes the previously expelled gas to fluoresce [13] . The featured picture [14] , taken in the light emitted by oxygen [15] (shown in blue) and hydrogen [16] (shown in red), was created from 74 hours of exposure over three months from a small telescope in a backyard of suburban Melbourne [17] , Australia [18] . A close-up [19] of the inner edge [20] of the Helix Nebula shows complex gas knots of unknown origin [21] . Tomorrow's picture: open space ------------------------------------------------------------------------------- < [22] | Archive [23] | Submissions [24] | Index [25] | Search [26] | Calendar [27] | RSS [28] | Education [29] | About APOD [30] | Discuss [31] | > [32] ------------------------------------------------------------------------------- Authors & editors: Robert Nemiroff [33] (MTU [34] ) & Jerry Bonnell [35] (UMCP [36] ) NASA Official: Phillip Newman Specific rights apply [37] . NASA Web Privacy Policy and Important Notices [38] A service of: ASD [39] at NASA [40] / GSFC [41] & Michigan Tech. U. [42] ---------- Site notes: [1] archivepix.html [2] image/1902/Helix_Campbell_1585.jpg [3] https://www.facebook.com/AndysAstropix/ [4] https://en.wikipedia.org/wiki/Helix_Nebula [5] http://mathworld.wolfram.com/Helix.html [6] http://hubblesite.org/image/1605/news_release/2004-32 [7] ap180103.html [8] https://grammarist.com/acronym/a-k-a-or-aka/ [9] https://en.wikipedia.org/wiki/Planetary_nebula [10] http://www.youtube.com/watch?v=KXNSYo8ZdoU [11] https://imagine.gsfc.nasa.gov/science/objects/dwarfs2.html [12] https://science.nasa.gov/ems/10_ultravioletwaves [13] https://www.youtube.com/watch?v=YvN8zFhWn04 [14] https://www.astrobin.com/378608/C/ [15] https://periodic.lanl.gov/8.shtml [16] http://www.astronomyknowhow.com/hydrogen-alpha.htm [17] https://www.youtube.com/watch?v=fxRa7czldw0 [18] https://en.wikipedia.org/wiki/Australia [19] http://www.youtube.com/watch?v=UwAKNMC2PeM [20] ap080413.html [21] http://adsabs.harvard.edu/abs/2002ApJ...573L..55H [22] ap190212.html [23] archivepix.html [24] lib/apsubmit2015.html [25] lib/aptree.html [26] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search [27] calendar/allyears.html [28] /apod.rss [29] lib/edlinks.html [30] lib/about_apod.html [31] http://asterisk.apod.com/discuss_apod.php?date=190213 [32] ap190214.html [33] http://www.phy.mtu.edu/faculty/Nemiroff.html [34] http://www.phy.mtu.edu/ [35] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html [36] http://www.astro.umd.edu/ [37] lib/about_apod.html#srapply [38] https://www.nasa.gov/about/highlights/HP_Privacy.html [39] https://astrophysics.gsfc.nasa.gov/ [40] https://www.nasa.gov/ [41] https://www.nasa.gov/centers/goddard/ [42] http://www.mtu.edu/ --- Mystic BBS v1.12 A43 (Windows/32) * Origin: FIDONet - The Positronium Repository (1:393/68) .