APOD: 2021 December 18 - Stephan s Quintet Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 18 Stephan's Quintet Image Credit: NASA, ESA, Hubble Legacy Archive; Processing & Copyright: Bernard Miller Explanation: The first identified compact galaxy group,Stephan's Quintetis featured inthis eye-catching imageconstructed with data drawn fromthe extensive Hubble Legacy Archive.About 300 million light-years away, only four of these five galaxiesare actually locked in a cosmic danceof repeated close encounters.The odd man out is easy to spot, though.The interacting galaxies,NGC 7319, 7318A, 7318B, and 7317have an overall yellowish cast.They also tend to have distortedloops and tails, grown under theinfluence of disruptive gravitational tides.But the predominantly bluish galaxy, NGC 7320,is closer, just 40 million light-years distant,and isn't part of the interacting group.Stephan's Quintet lies within the boundaries of the high flyingconstellation Pegasus.At the estimated distance of the quartet of interacting galaxies,this field of view spans about 500,000 light-years.But moving just beyond this field, up and to the right,astronomers can identify another galaxy,NGC 7320C, that is also 300 millionlight-years distant.Including it would bring theinteracting quartet back up to quintet status. Tomorrow's picture: five in a...

APOD: 2021 December 17 - Gemind of the North Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 17 Geminid of the North Image Credit &Copyright:Alvin Wu Explanation: An arid expanse of theTengger Desertin north-central China, planet Earthfills the foreground of this starry scene.A widefield panoramic view, it was recordedshortly after moonset in the local predawn hours of December 14.Pictured in the still dark sky, stars of thenorthern winter hexagonsurround a luminous Milky Way.Seen near the peak of theannual meteor shower,the startling flash of a bright Geminid fireball meteor was alsocaptured on that night.Above the western horizon and just below bright star Capella,its dagger-like trail points back to the meteor shower'sradiant in Gemini.Of course, the constellation Gemini is easy to spot.Its twin bright stars, bluishCastor and yellowish Polluxare near top center in the frame. Tomorrow's picture: light-weekend<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific rights apply.NASA WebPrivacy Policy and Important NoticesA service of:ASD atNASA /GSFC& Michigan Tech. U.

APOD: 2021 December 16 - Geminds of the South Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 16 Geminids of the South Image Credit &Copyright:Fefo Bouvier Explanation: Fireflies flash along a moonlit countryside in this scenetaken on the night of December 13/14from southern Uruguay, planet Earth.On that night meteors fell in the partly cloudy skies above during theannual Geminid meteor shower.Frames recorded over a period of 1.5 hours are alignedin the composite image made with the camera facing south.That direction was opposite the shower's radianttoward the north and so theGeminid meteor streaksappear to converge at an antiradiant below the southern horizon.The shower's apparent radiant (andantiradiant) is just due toperspective though.As Earth sweeps through the dust trail ofmysterious asteroid 3200 Phaethon,the dust grains that create the Geminid shower meteorsare really moving along parallel tracks.They enter Earth's atmosphere traveling at about 22 kilometers persecond. Tomorrow's picture: Geminids of the North<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific rights apply.NASA WebPrivacy Policy and Important NoticesA service of:ASD atNASA /GSFC& Michigan...

APOD: 2021 December 15 - Comet Leonard from Space Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 15 Comet Leonard from Space Image Credit & Copyright: Zhuoxiao Wang, Yangwang-1 Space Telescope, Origin.Space Explanation: What does Comet Leonard look like from space? Today's featured image from Origin.Space's Yangwang-1 space telescope shows not only the currently bright comet -- but several other space delights as well.Taken in optical and ultraviolet light, C/2021 A1 (Leonard) is visible with an extended tail near the image center as it appeared five days ago. The Earth is visible on the lower right, while layers of the Earth's atmosphere glow diagonally from the lower left to the upper right.The trails of two satellites can be seen in front of a myriad of distant stars that dot the background on the upper left.The faint bands of light running diagonally from the lower right to the upper left are auroras.Finally, the image also caught a meteor streaking just below the airglow.To see Comet Leonard yourself from the Earth's surface during the next few days, look toward the western horizon just after sunset...

APOD: 2021 December 14 - HH 666: Carina Dust Pillar with Jet Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 14 HH 666: Carina Dust Pillar with Jet Image Credit: NASA, ESA, Hubble; Processing & Copyright: Mehmet Hakan Özsaraç Explanation: To some, it may look like a beehive.In reality, the featured image from the Hubble Space Telescope captures a cosmic pillar of dust, over two-light years long, inside of which is Herbig-Haro 666 -- a young star emitting powerful jets.The structure lies within one of our galaxy's largest star forming regions, the Carina Nebula, shining in southern skies at a distance of about 7,500 light-years. The pillar's layered outline are shaped by the winds and radiation of Carina's young, hot, massive stars, some of which are still forming inside the nebula. A dust-penetrating view in infrared light better shows the two, narrow, energetic jets blasting outward from a still hidden infant star. Open Science: Browse 2,600+ codes in the Astrophysics Source Code Library Tomorrow's picture: comet from orbit <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors &...

APOD: 2021 December 13 - Meteors and Auroras over Iceland Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 13 Meteors and Auroras over Iceland Image Credit & Copyright: James Boardman-Woodend; Annotation: Judy Schmidt Explanation: What's going on behind that mountain?Quite a bit. First of all, the mountain itself, named Kirkjufell, is quite old and located in western Iceland near the town of Grundarfjörður. In front of the steeply-sloped structure lies a fjord that had just begun to freeze when the above image was taken -- in mid-December of 2012.Although quite faint to the unaided eye, the beautiful colors of background aurorae became quite apparent on the 25-second exposure.What makes this image of particular note, though, is that it also captures streaks from the Geminids meteor shower -- meteors that might not have been evident were the aurora much brighter.Far in the distance, on the left, is the band of our Milky Way Galaxy, while stars from our local part of the Milky Way appear spread across the background. Tonight the Geminids meteor shower peaks again and may well provide sky enthusiasts with their...

APOD: 2021 December 12 - Comet Leonard Before Star Cluster M3 Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 12 Comet Leonard Before Star Cluster M3 Image Credit & Copyright: Dan Bartlett Explanation: Comet Leonard is now visible to the unaided eye -- but just barely. Passing nearest to the Earth today, the comet is best seen this week soon after sunset, toward the west, low on the horizon. Currently best visible in the north, by late December the comet will best be seen from south of Earth's equator.The featured image of Comet C/2021 A1 (Leonard) was taken a week ago from California, USA.The deep exposure shows in great detail the comet's green gas coma and developing dust tail.The comet -- across our inner Solar System and only light-minutes away -- was captured passing nearly in front of globular star cluster M3.In contrast, M3 is about 35,000 light-years away. In a week, Comet Leonard will pass unusually close to Venus, but will continue on and be at its closest to the Sun in early January. Tomorrow's picture: meteor mountain <| Archive| Submissions |...

APOD: 2021 December 11 - Postcard from the South Pole Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 11 Postcard from the South Pole Image Credit &Copyright:Aman Chokshi Explanation: From this vantage point about three quarters of a mile fromplanet Earth's geographic South Pole, theDecember 4 eclipse of the Sunwas seen as a partial eclipse.At maximum the New Moon blocked 90 percent of the solar disk.Of course, crews at theSouth Pole Telescope(left) andBICEP telescope(right) climbed to the roof ofAmundsen-Scott station'sDark Sector Laboratory to watch.Centered near the local eclipse maximum,the composite timelapse view features animage of the Sun traversing cold antarctic skies taken every four minutes.Left to right along the roof line it also features the raised arms ofBrandon Amat,Aman Chokshi,Cheng Zhang,James BevingtonandAllen Forster. Tomorrow's picture: in darker skies<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific rights apply.NASA WebPrivacy Policy and Important NoticesA service of:ASD atNASA /GSFC& Michigan Tech. U.

APOD: 2021 December 10 - Eclipse on a Polar Day Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 10 Eclipse on a Polar Day Image Credit &Copyright:Stephanie Ziyi Ye Explanation: During polar day,in Arctic and Antarctic summer, the Sun stays abovethe horizon for periods of 24 hours or more.Recorded on December 4, thisfisheye timelapse imagetracks the Sun in multiple frames as it completes a circle in the summer skyabove Union Glacier, Antarctica.Of course on that date,Union Glacier's sky did grow dark even though the Sun was above the horizon.Captured during the brief period of totality,an eclipsed Sunis at bottom center of the composite view.Near the edge of the total eclipse path across planet Earth,the Moon's shadowdarkens the sky above. Tomorrow's picture: light-weekend<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific rights apply.NASA WebPrivacy Policy and Important NoticesA service of:ASD atNASA /GSFC& Michigan Tech. U.

APOD: 2021 December 9 - A Total Eclipse of the Sun Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 9 A Total Eclipse of the Sun Image Credit &Copyright:Theo Boris, Christian A. Lockwood, David Zimmermann(JM Pasachoff Antarctic Expedition)Compositing: Zev Hoover and Ron Dantowitz (MARS Scientific) Explanation: Few were able to stand in theMoon's shadowand watch theDecember 4 total eclipseof the Sun.Determined bycelestial mechanics and not geographical boundaries, thenarrow path of totality trackedacross planet Earth's relatively inaccessible southernmost continent.Still, some enthusiastic and well-insulated eclipse chasers wererewarded with the dazzlingspectacle in Antarctica's cold but clear skies.Taken just before the brief totality began, this image from a ground-basedtelescope inside the edge of the shadow pathat Union Glaciercatches a glimmer of sunlight near the top of the silhouetted lunar disk.Look closely for the pinkish solar prominences arcing above the Sun'slimb.During totality, themagnificent solar corona,the Sun's outer atmosphere,made its much anticipated appearance, seen in the compositeview streaming far from the Sun's edge. Tomorrow's picture: pixels in space<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official:...

APOD: 2021 December 8 - Comet Hale Bopp Over Val Parola Pass Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 8 Comet Hale-Bopp Over Val Parola Pass Image Credit & Copyright: A. Dimai, (Col Druscie Obs.),AAC Explanation: Comet Hale-Bopp,the Great Comet of 1997, became much brighter than any surrounding stars.It was seen even over bright city lights.Away from city lights, however, it put on quite aspectacular show.Here Comet Hale-Bopp was photographed above Val Parola Pass in the Dolomitemountains surroundingCortinad'Ampezzo,Italy.Comet Hale-Bopp'sblue ion tail, consisting ofions from thecomet's nucleus,is pushed out by the solar wind.The whitedust tail is composed of larger particles ofdust from the nucleus driven bythe pressure of sunlight, that orbit behind thecomet.Comet Hale-Bopp (C/1995 O1) remained visible to the unaided eye for 18 months -- longer than any other comet in recorded history.The large comet is next expected to return around the year 4385. This month, Comet Leonard is brightening and may soon become visible to the unaided eye. Tomorrow's picture: open space <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry...

APOD: 2021 December 7 - Ninety Gravitational Wave Spectrograms and Counting Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 7 Ninety Gravitational Wave Spectrograms and Counting Image Credit: NSF, LIGO, VIRGO, KAGRA, Georgia Tech, Vanderbilt U.; Graphic : Sudarshan Ghonge & Karan Jani Explanation: Every time two massive black holes collide, a loud chirping sound is broadcast out into the universe in gravitational waves.Humanity has only had the technology to hear these unusual chirps for the past seven years, but since then we have heard about 90 -- during the first three observing runs.Featured above are the spectrograms -- plots of gravitational-wave frequency versus time -- of these 90 as detected by the giant detectors of LIGO (in the USA), VIRGO (in Europe), and KAGRA (in Japan).The more energy received on Earth from a collision, the brighter it appears on the graphic.Among many science firsts, these gravitational-radiation chirps are giving humanity an unprecedented inventory of black holes and neutron stars, and a new way to measure the expansion rate of our universe.A fourth gravitational wave observing run with increased sensitivity is currently planned...

APOD: 2021 December 6 - Space Station Silhouette on the Moon Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 6 Space Station Silhouette on the Moon Image Credit & Copyright: Andrew McCarthy Explanation: What's that unusual spot on the Moon?It's the International Space Station.Using precise timing, the Earth-orbiting space platform was photographed in front of a partially lit gibbous Moon last month.The featured composite, taken from Payson, Arizona, USA last month,was intricately composed by combining, in part, many 1/2000-second images from a video of the ISS crossing the Moon.A close inspection of this unusually crisp ISS silhouette will reveal the outlines of numerous solar panels and trusses. The bright crater Tycho is visible on the upper left, as well as comparatively rough, light colored terrain known as highlands, and relatively smooth, dark colored areas known as maria. On-line tools can tell you when the International Space Station will be visible from your area. Tomorrow's picture: 90 black holes merging <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific...

Yesterday there was a total solar eclipse visible only at the end of the Earth.

Iridescent by Moonlight

APOD: 2021 December 3 - Comet Leonard and the Whale Galaxy Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 3 Comet Leonard and the Whale Galaxy Image Credit &Copyright:Gregg Ruppel Explanation: Sweeping throughnorthern predawn skies, on November 24Comet Leonard (C/2021 A1)was caught betweentwo galaxies in thiscomposite telescopic image.Sporting a greenish coma the comet's dusty tail seems to harpoon theheartof NGC 4631 (top) also known as the Whale Galaxy.Of courseNGC 4631 and NGC 4656(bottom, aka the Hockey Stick)are background galaxies some 25 million light-years away.On that date the comet was about 6 light-minutes from our fair planet.Its closest approach to Earth (and even closer approachto Venus)still to come,Comet Leonard willgrow brighter in December.Already a good objectfor binoculars and small telescopes,this comet will likely not return to the inner Solar System.Its perihelion, or closest approach to the Sun, will be on January 3, 2022. Tomorrow's picture: light-weekend<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific rights apply.NASA WebPrivacy Policy and Important NoticesA service of:ASD atNASA /GSFC& Michigan Tech. U.

APOD: 2021 December 2 - NGC 6822: Barnard's Galaxy Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 2 NGC 6822: Barnard's Galaxy Image Credit &Copyright:Dietmar Hager,Eric Benson Explanation: Grand spiral galaxiesoften seem to get all the glory, flaunting theiryoung, bright, blue star clusters in beautiful, symmetric spiral arms.But small galaxies form stars too, like nearby NGC 6822, also known asBarnard'sGalaxy.Beyond the rich starfields in the constellation Sagittarius,NGC 6822 is a mere 1.5 million light-years away, a member of ourLocal Groupof galaxies.A dwarf irregular galaxy similar to theSmall Magellanic Cloud,NGC 6822 is about 7,000 light-years across.Brighter foreground stars in our Milky Way have a spiky appearance.Behind them,Barnard's Galaxy is seen to be filled with young blue stars and mottledwith the telltale pinkish hydrogen glowof star forming regions in this deepcolor composite image. Tomorrow's picture: Queequeg's comet<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific rights apply.NASA WebPrivacy Policy and Important NoticesA service of:ASD atNASA /GSFC& Michigan Tech. U.

APOD: 2021 December 1 - A Blue Banded Blood Moon Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 December 1 A Blue-Banded Blood Moon Image Credit: Angel Yu Explanation: What causes a blue band to cross the Moon during a lunar eclipse?The blue band is real but usually quite hard to see.The featured HDR image of last week's lunar eclipse, however -- taken from Yancheng, China -- has been digitally processed to equalize the Moon's brightness and exaggerate the colors. The gray color of the bottom right is the Moon's natural color, directly illuminated by sunlight.The upper left part of the Moon is not directly lit by the Sun since it is being eclipsed -- it in the Earth's shadow.It is faintly lit, though, by sunlight that has passed deep through Earth's atmosphere.This part of the Moon is red -- and called a blood Moon -- for the same reason that Earth's sunsets are red: because air scatters away more blue light than red.The unusual blue band is different -- its color is created by sunlight that has passed high through Earth's atmosphere, where...

APOD: 2021 November 30 - In Motion: Uranus and Moons Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. In Motion: Uranus and Moons Video Credit: David Campbell (U. Hertfordshire), Bayfordbury Observatory Explanation: What's that moving across the sky?A planet just a bit too faint to see with the unaided eye: Uranus.The gas giant out past Saturn was tracked earlier this month near opposition -- when it was closest to Earth and at its brightest.The featured video captured by the Bayfordbury Observatory in Hertfordshire, UK is a four-hour time-lapse showing Uranus with its four largest moons in tow: Titania, Oberon, Umbriel and Ariel.Uranus' apparent motion past background stars is really dominated by Earth's own orbital motion around our Sun. The cross seen centered on Uranus is called a diffraction spike and is caused by light diffracting around the four arms that hold one of the telescope's mirrors in place. The rotation of the diffraction spikes is not caused by the rotation of Uranus but, essentially, by the rotation of the Earth.During the next few months Uranus itself will be visible with binoculars, but, as always, to...

APOD: 2021 November 29 - The Extraordinary Spiral in LL Pegasi Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 November 29 The Extraordinary Spiral in LL Pegasi Image Credit: NASA, ESA, Hubble, HLA;Processing & Copyright: Jonathan Lodge Explanation: What created the strange spiral structure on the upper left? No one is sure, although it is likely related to a star in a binary star system entering the planetary nebula phase, when its outer atmosphere is ejected. The huge spiral spans about a third of a light year across and, winding four or five complete turns, has a regularity that is without precedent. Given the expansion rate of the spiral gas, a new layer must appear about every 800 years, a close match to the time it takes for the two stars to orbit each other.The star system that created it is most commonly known as LL Pegasi, but also AFGL 3068 and IRAS 23166+1655. The featured image was taken in near-infrared light by the Hubble Space Telescope.Why the spiral glows is itself a mystery, with a leading hypothesis being illumination by light reflected from...