Michael-Bell / astronomy_picture_of_the_day

http://apod.nasa.gov/apod/ap140228.html

2014-02-28

Only two days past full, <a href="http://apod.nasa.gov/apod/ap130228.html">February's moon</a> shines through thin clouds, rising on the left in this fisheye <a href="http://www.lauriehatch.com/ GalleryMain.asp?GalleryID=134736&AKey=6Q457TBG">night skyscape</a>. The moonlight illuminates a weathered, rounded foreground in the <a href="http://www.sierranevadageotourism.org/ content_detail.php?uid=sieC867C1748AAFCC202">Alabama Hills</a>, conveniently located east of <a href="http://apod.nasa.gov/apod/ap090827.html">Mt. Whitney</a> along the Sierra Nevada range in California, USA, planet Earth. Orion the Hunter stands at the right, a familiar northern <a href="http://apod.nasa.gov/apod/ap040304.html">winter constellation</a>. Bright Jupiter, the solar system's <a href="http://apod.nasa.gov/apod/ap120302.html">ruling gas giant</a>, is near center at the top of the frame. Below Jupiter, Sirius, <a href="http://stars.astro.illinois.edu/sow/sirius.html">alpha star</a> of the Big Dog, poses above a bowed and twisted landform known as Möbius Arch, its curve reminiscent of the <a href="http://en.wikipedia.org/wiki/M%C3%B6bius_strip">mathematically famous</a> surface with only one side. <a href="http://www.georgehart.com/bagel/bagel.html">Of course</a>, instead of using rock, wind, and weather, a Möbius strip is easier to make with paper, <a href="http://www.youtube.com/watch?v=BVsIAa2XNKc">scissors</a>, and tape.

http://apod.nasa.gov/apod/image/1402/LH8056_MobiusArchMoonrise_1024x683.jpg

Mobius Arch Moonrise

http://apod.nasa.gov/apod/ap140227.html

2014-02-27

Venus now appears as planet Earth's brilliant <a href="http://www.universetoday.com/22570/ venus-the-morning-star/">morning star</a> standing above the eastern horizon before dawn. <a href="http://spaceweathergallery.com/ index.php?title=venus">For most</a>, the silvery celestial beacon rose in a close pairing with an old crescent Moon on February 26. But <a href="http://www.lunar-occultations.com/iota/planets/ 0226venus.htm">seen from locations</a> in western Africa before sunrise, the lunar crescent actually occulted or passed in front of Venus, also in a crescent phase. Farther to the east, the occultation occurred during daylight hours. In fact, this telescopic snapshot of the <a href="http://apod.nasa.gov/apod/ap090424.html">dueling crescents</a> was captured just before the occultation began under an afternoon's crystal clear skies from <a href="http://apod.nasa.gov/apod/ap140206.html">Yunnan Province</a>, China. The unforgettable scene was easily visible to the naked eye in broad daylight.

http://apod.nasa.gov/apod/image/1402/venus_occultation_20140226x.jpg

Daytime Moon Meets Morning Star

http://apod.nasa.gov/apod/ap140226.html

2014-02-26

Sometimes the more you look at an image, the more you see. Such may be the case for <a href="http://www.flickr.com/photos/rinsed/12633917883/in/photostream/">this beautiful nighttime panorama</a> taken last week in <a href="http://en.wikipedia.org/wiki/New_Zealand">New Zealand</a>. Visible right off, on the far left, are common clouds, slightly altered by the digital fusion of combining 11 separate 20-second exposures. More striking, perhaps, is the broad <a href="http://apod.nasa.gov/apod/ap120725.html">pink aurora</a> that dominates the right part of the image, a less common auroral color that is likely tinted by excited <a href="http://periodic.lanl.gov/8.shtml">oxygen</a> atoms high in Earth's atmosphere. Keep looking and you might notice a bright light just beyond the mountain on the left. That is the <a href="http://apod.nasa.gov/apod/ap130130.html">rising Moon</a> -- and an even closer look will reveal faint <a href="http://www.atoptics.co.uk/atoptics/rayim1.htm">crepuscular rays</a> emanating from it. Musing over the image center may cause you to notice the <a href="http://apod.nasa.gov/apod/ap990224.html">central band</a> of the <a href="http://en.wikipedia.org/wiki/Milky_Way">Milky Way Galaxy</a> which here appears to divide, almost vertically, the left clouds from the right aurora. Inspecting the upper right of the image reveals a fuzzy patch, high in the sky, that is the <a href="http://apod.nasa.gov/apod/ap100903.html">Small Magellanic Cloud</a>. Numerous stars discretely populate the distant background. Back on Earth, the image foreground features two domes of the <a href="http://www.phys.canterbury.ac.nz/research/mt_john/index.shtml">Mt. John University Observatory</a> and a camera tripod looking to <a href="http://www.youtube.com/watch?v=C-68j-OC-NY">capture</a> much of this scene over a serene <a href="http://www.youtube.com/watch?v=T_IIGGR2Zu0">Lake Tekapo</a>.

http://apod.nasa.gov/apod/image/1402/auroraNZ_weir_2048.jpg

Aurora over New Zealand

http://apod.nasa.gov/apod/ap140225.html

2014-02-25

The well known <a href="http://www.ras.ucalgary.ca/~gibson/pleiades/">Pleiades</a> star cluster is slowly destroying part of a passing cloud of <a href="http://www-ssg.sr.unh.edu/ism/what1.html">gas and dust</a>. The <a href="http://en.wikipedia.org/wiki/Pleiades">Pleiades</a> is the brightest <a href="http://apod.nasa.gov/apod/open_clusters.html">open cluster of stars</a> on Earth's sky and <a href="http://apod.nasa.gov/apod/ap130212.html">can be seen</a> from almost any northerly location with the <a href="http://www.youtube.com/watch?v=cFVbLnXWn6A">unaided eye</a>. The passing young dust cloud is thought to be part of <a href="http://kencroswell.com/GouldBelt.html">Gould's belt</a>, an <a href="http://www.newscientist.com/data/images/archive/2735/27350901.jpg">unusual ring</a> of young star formation surrounding the Sun in the <a href="http://www.atlasoftheuniverse.com/5000lys.html">local Milky Way Galaxy</a>. Over the past 100,000 years, part of <a href="http://www.solstation.com/x-objects/goulds-b.htm">Gould's belt</a> is by chance moving right through the older <a href="http://apod.nasa.gov/apod/ap131122.html">Pleiades</a> and is causing a strong reaction between stars and dust. Pressure from the stars' light significantly repels the dust in the surrounding blue <a href="http://apod.nasa.gov/apod/reflection_nebulae.html">reflection nebula</a>, with smaller <a href="http://apod.nasa.gov/apod/ap030706.html">dust</a> particles being repelled more strongly. A short-term result is that parts of the dust cloud have become <a href="http://apod.nasa.gov/apod/ap120215.html">filamentary</a> and stratified, as seen in the <a href="http://re-prop.com/M45_Final_sm.jpg">above deep-exposure image</a>.

http://apod.nasa.gov/apod/image/1402/pleiades_lane_1153.jpg

The Pleiades Deep and Dusty

http://apod.nasa.gov/apod/ap140223.html

2014-02-23

If this is Saturn, where are the rings? When Saturn's "appendages" <a href="http://huygensgcms.gsfc.nasa.gov/Shistory.htm">disappeared</a> in 1612, <a href="http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Galileo.html">Galileo</a> did not understand why. Later that century, it became understood that <a href="http://www.nineplanets.org/saturn.html">Saturn</a>'s unusual protrusions were rings and that when the <a href="http://apod.nasa.gov/apod/ap950801.html">Earth crosses the ring plane</a>, the edge-on rings will <a href="http://www.youtube.com/watch?v=ZaTAYOpUP6o">appear to disappear</a>. This is because Saturn's rings are confined to a <a href="http://coolcosmos.ipac.caltech.edu/cosmic_kids/AskKids/saturnrings.shtml">plane many times thinner</a>, in proportion, than a <a href="http://en.wikipedia.org/wiki/Razor">razor blade</a>. In modern times, the <a href="http://saturn.jpl.nasa.gov/spacecraft/overview/">robot Cassini spacecraft</a> orbiting Saturn now also crosses <a href="http://apod.nasa.gov/apod/ap040117.html">Saturn's ring</a> plane. A series of plane crossing images from 2005 February was dug out of the vast <a href="http://saturn.jpl.nasa.gov/multimedia/images/raw/index.cfm">online Cassini raw image</a> archive by interested Spanish amateur Fernando Garcia Navarro. <a href="http://www.slate.com/blogs/bad_astronomy/2005/05/31/saturn_sans_rings.html">Pictured above</a>, digitally cropped and set in representative colors, is the striking result. <a href="http://apod.nasa.gov/apod/ap080720.html">Saturn's thin ring plane</a> appears in blue, bands and clouds in <a href="http://apod.nasa.gov/apod/ap041102.html">Saturn's upper atmosphere</a> appear in gold. Details of Saturn's rings can be seen in the high <a href="http://apod.nasa.gov/apod/ap090901.html">dark shadows</a> across the top of this image, taken back in 2005. Moons appear as bumps in the rings.

http://apod.nasa.gov/apod/image/1402/saturnplane_cassini_1004.jpg

Cassini Spacecraft Crosses Saturns Ring Plane

http://apod.nasa.gov/apod/ap140222.html

2014-02-22

A mere 600 light-years away, M44 is one of the closest star clusters to our solar system. Also known as the <a href="http://en.wikipedia.org/wiki/Beehive_Cluster">Praesepe or the Beehive cluster</a> its stars are young though, about 600 million years old compared to our Sun's 4.5 <a href="http://www.kokogiak.com/megapenny/nine.asp">billion</a> years. Based on similar ages and motion through space, M44 and the even closer <a href="http://apod.nasa.gov/apod/ap121224.html">Hyades</a> star cluster in Taurus are thought to have been born together in the same large molecular cloud. <a href="http://en.wikipedia.org/wiki/Open_cluster">An open cluster</a> spanning some 15 light-years, M44 holds 1,000 stars or so and covers about 3 full moons (1.5 degrees) on the sky in the constellation Cancer. Visible to the unaided eye, M44 has been recognized since antiquity. Described as a faint cloud or celestial mist long before being included as the 44th entry in Charles Messier's 18th century catalog, the cluster was not resolved into its individual stars until telescopes were available. A popular target for modern, binocular-equiped sky gazers, the cluster's few <a href="http://apod.nasa.gov/apod/ap110211.html">yellowish tinted</a>, cool, <a href="http://apod.nasa.gov/apod/ap110408.html">red giants</a> are scattered through the field of its brighter hot blue main sequence stars in this colorful <a href="http://bf-astro.com/m44/m44.htm">stellar group snapshot</a>.

http://apod.nasa.gov/apod/image/1402/m44franke1600.jpg

M44: The Beehive Cluster

http://apod.nasa.gov/apod/ap140221.html

2014-02-21

<a href="http://arxiv.org/abs/1309.6792">The Lighthouse nebula</a> was formed by the wind of a pulsar, a rapidly rotating, magnetized neutron star, as it speeds through the interstellar medium at over 1,000 kilometers per <i>second</i>. Some 23,000 light-years distant toward the southern constellation Carina, pulsar and wind nebula (cataloged as IGR J1104-6103) are indicated at the lower right in <a href="http://chandra.harvard.edu/photo/2014/igrj11014/">this remarkable image</a> from the Chandra <a href="http://chandra.harvard.edu/xray_astro/medxray.html">X-ray</a> Observatory. Energetic particles <a href="http://apod.nasa.gov/apod/ap081227.html">generated by the pulsar</a> are swept back into the wind's comet-like tail trailing up and to the left, along the direction of the pulsar's motion away from its parent supernova remnant. Both runaway pulsar and expanding remnant debris field are the aftermath of the <a href="http://en.wikipedia.org/wiki/ Type_II_supernova">core-collapse-explosion</a> of a massive star, with the pulsar kicked out by the supernova explosion. Adding to the scene of exotic cosmic extremes is a long, spiraling jet extending for almost 37 light-years, but nearly at a right angle to the pulsar's motion. The high-energy <a href="http://apod.nasa.gov/apod/ap030703.html">particle jet</a> is the longest known for any object in our Milky Way galaxy.

http://apod.nasa.gov/apod/image/1402/igrj11014_xray_label.jpg

The Long Jet of the Lighthouse Nebula

http://apod.nasa.gov/apod/ap140220.html

2014-02-20

Fading now as it returns to the outer solar system <a href="http://apod.nasa.gov/apod/ap140103.html">Comet Lovejoy</a> (C/2013 R1) still graces planet Earth's sky, a delicate apparition in <a href="http://cometchasing.skyhound.com/">binoculars or small telescopes</a>. The comet, a relic <a href="http://solarsystem.nasa.gov/planets/ profile.cfm?Object=Comets&Display=OverviewLong">of the solar system's</a> formative years, is seen here rising in the morning twilight on January 12 among the stars of <a href="http://en.wikipedia.org/wiki/Ophiuchus">Ophiuchus</a>, the Serpent Bearer. Posing near the comet is bright star Alpha Ophiuchi, also <a href="http://stars.astro.illinois.edu/sow/rasalhague.html">known as Rasalhague</a>, from Arabic "the head of the serpent collector". Of course, the serpentine shape below is the ancient <a href="http://apod.nasa.gov/apod/ap080831.html">Great Wall of China</a>, along the <a href="http://www.greatwallforum.com/forum/gubeikou/ 481-gubeikou-panlongshan-great-wall-review.html">Panlongshan</a> section northeast of Beijing. Panlongshan is translated as "a coiled dragon". A moving and fortuitous scene, it was captured with a digital camera and telephoto lens in two consecutive exposures. The exposures were merged to show a natural looking foreground and twilight sky.

http://apod.nasa.gov/apod/image/1402/LovejoyJiajieZhang.jpg

Comet Lovejoy over The Great Wall

http://apod.nasa.gov/apod/ap140219.html

2014-02-19

Yes, but how many dark clouds have a multicolored lining? Pictured, behind this darker cloud, is a <a href="http://www.atoptics.co.uk/fz503.htm">pileus</a> <a href="http://en.wikipedia.org/wiki/Cloud_iridescence">iridescent cloud</a>, a group of water droplets that have a uniformly similar size and <a href="http://www.atoptics.co.uk/droplets/irid1.htm">so together</a> <a href="http://en.wikipedia.org/wiki/Diffraction">diffract</a> different colors of sunlight by different amounts. The <a href="http://estherhavens.com/blog/archives/2516">above image</a> was taken just before sunset when it was noticed by chance by a photographer in <a href="http://mapcarta.com/27181974">Murambi</a> East, near <a href="http://en.wikipedia.org/wiki/Odzi">Odzi</a> Valley and the <a href="http://apod.nasa.gov/apod/ http://www.worldatlaspedia.com/en/mtanda-range/lugares_reconditos30/busquedaLibreDetalle-0-885627">Mtanda Range</a> of <a href="http://en.wikipedia.org/wiki/Zimbabwe">Zimbabwe</a>. Also captured were unusual cloud ripples above the <a href="http://en.wikipedia.org/wiki/Pileus_cloud">pileus cloud</a>. The formation of a rare pileus cloud capping a common <a href="http://apod.nasa.gov/apod/ http://en.wikipedia.org/wiki/Cumulus_cloud">cumulus cloud</a> is an indication that the lower cloud is <a href="http://www.youtube.com/watch?v=KVxWOmcfLR4">expanding upward</a> and might well develop into a <a href="http://apod.nasa.gov/apod/ap130618.html">storm</a>. In this case, however, only a few minutes after the <a href="http://apod.nasa.gov/apod/ap090512.html">colorful cloud</a> was noticed, it <a href="http://wac.450f.edgecastcdn.net/80450F/1079ishot.com/files/2011/04/Camouflagecat1.jpg">disappeared</a>.

http://apod.nasa.gov/apod/image/1402/pileus_lowenstein_4320.jpg

A Rainbow Pileus Cloud over Zimbabwe

http://apod.nasa.gov/apod/ap140218.html

2014-02-18

An important threshold on Mars has now been crossed. Landing in mid-2012, the Curiosity rover is searching for clues of whether <a href="http://www.nasa.gov/mission_pages/msl/news/msl20130312.html">life could</a> ever have existed on the <a href="https://solarsystem.nasa.gov/planets/profile.cfm?Object=Mars">red planet</a>. Recent findings of Curiosity include evidence for an ancient (but now dried) <a href="http://www.universetoday.com/107013/curiosity-discovers-ancient-mars-lake-could-support-life/">freshwater lake</a>, and the <a href="http://online.wsj.com/news/articles/SB10001424127887324807704579085122527662010">non-detection</a> of the <a href="http://en.wikipedia.org/wiki/Biomarker">biomarker</a> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA16461">methane</a> in the Martian atmosphere. To continue its investigation, the car-sized rover is on an <a href="http://www.youtube.com/watch?v=KKhBTrW_W5Y">expedition</a> to roll up <a href="http://apod.nasa.gov/apod/ap130427.html">Mt. Sharp</a>, the central peak of the large crater in which it <a href="http://apod.nasa.gov/apod/ap120731.html">landed</a>. Life might have shown preference for <a href="http://en.wikipedia.org/wiki/Water_on_Mars#Curiosity_rover">water</a> that once ran down the Martian mountain. Two weeks ago, to avoid more dangerous and <a href="http://apod.nasa.gov/apod/ap130625.html">rocky terrain</a>, Curiosity was directed to roll across a one-meter high sand dune that blocked a <a href="http://www.youtube.com/watch?v=eiTgn5f7-CY">useful entrance</a> to Mt. Sharp. Just after the short trip over <a href="http://en.wikipedia.org/wiki/File:MarsCuriosityRover-TraverseMap-Sol0533-20140204.jpg">Dingo Gap</a> was successful, the robotic rover took the <a href="http://www.db-prods.net/blog/2014/02/11/le-franchissement-de-dingo-gap-en-carte-postale-sol-538/">above image</a> showing the now-traversed <a href="http://m3.i.pbase.com/o4/53/171253/1/52601593.475_7575.jpg">sand mound</a> covered with its <a href="http://apod.nasa.gov/apod/ap130603.html">wheel tracks</a>.

http://apod.nasa.gov/apod/image/1402/dingogap_curiositybouric_2288.jpg

Crossing Dingo Gap on Mars