APOD: 2021 August 27 - Elephant s Trunk and Caravan 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 August 27 Elephant's Trunk and Caravan Image Credit &Copyright:Robert Eder Explanation: Like an illustration in a galacticJust So Story, theElephant's Trunk Nebulawinds through the emission nebula and young star clustercomplex IC 1396, in the high and far offconstellationof Cepheus.Also known as vdB 142,seen on the left the cosmic elephant's trunk is over 20 light-years long.Removed by digital processing, novisible stars are in thisdetailed telescopic close-up view highlighting the bright swept-back ridgesthat outline pockets of coolinterstellardust and gas.But the dark,tendril-shaped clouds contain theraw material for star formation and hideprotostars within.Nearly 3,000light-yearsdistant, the relatively faint IC 1396 complexcovers a large region on the sky, spanning over 5 degrees.This starless renditionspans a 1 degree wide field of view though,about the angular size of 2 full moons.Of coursethe dark shapes below and right, marching toward the winding Elephant'sTrunk, are known to some as The Caravan. Tomorrow's picture: looking for a good rock<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry...
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APOD: 2021 August 26 - A Blue Hour Full 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 August 26 A Blue Hour Full Moon Image Credit &Copyright:Giorgia Hofer Explanation: Nature photographers and other fans of planet Earthalways look forward tothe bluehour.That's the transitionin twilight,just before sunrise or after sunset, whenthe Sun is below the horizon but land and sky are still suffused witha beautiful blue light.After sunset on August 21,this blue hour snapshot captured the nearly full Moon as itrose opposite the Sun, above the rugged Italian Alps fromCortina d'Ampezzo, Italy.Sharing bluish hues with the sky, the rocky pyramid of Monte Antelao,also known as the King of the Dolomites,is the region's prominent alpine peak.The moonlightis yellow, but even so this full Moon was known to someas a seasonal Blue Moon.That's because by one definitionthe third full Moon of a season with four full moonsin it is called a Blue Moon.Recognizing a season as the time between a solstice and an equinox,this season's fourthfull Moon will be risingin the blue hour of September 20, just before September's equinox. Tomorrow's picture: pixels in space<| Archive|...
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APOD: 2021 August 25 - Solar System Ball Drop 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. Solar System Ball Drop Video Credit & Copyright: James O'Donoghue (JAXA) & Rami Mandow (Space Australia);Text: James O'Donoghue Explanation: Does a ball drop faster on Earth, Jupiter, or Uranus? The featured animation shows a ball dropping from one kilometer high toward the surfaces of famous solar system bodies, assuming no air resistance. The force of gravity depends on the mass of the attracting object, with higher masses pulling down with greater forces.But gravitational force also depends on distance from the center of gravity, with shorter distances causing the ball to drop faster. Combining both mass and distance, it might be surprising to see that Uranus pulls the ball down slightly slower than Earth, despite containing over 14 times more mass.This happens because Uranus has a much lower density, which puts its cloud tops further away from its center of mass. Although the falling ball always speeds up, if you were on the ball you would not feel this acceleration because you would be in free-fall.Of the three planets...
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APOD: 2021 August 24 - PDS 70: Disk, Planets, 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. 2021 August 24 PDS 70: Disk, Planets, and Moons Image Credit: ALMA (ESO/NAOJ/NRAO); M. Benisty et al. Explanation: It's not the big disk that's attracting the most attention.Although the big planet-forming disk around the star PDS 70 is clearly imaged and itself quite interesting.It's also not the planet on the right, just inside the big disk, that’s being talked about the most. Although the planet PDS 70c is a newly formed and, interestingly, similar in size and mass to Jupiter.It's the fuzzy patch around the planet PDS 70c that's causing the commotion.That fuzzy patch is thought to be itself a dusty disk that is now forming into moons -- and that has never been seen before.The featured image was taken by the Atacama Large Millimeter Array (ALMA) of 66 radio telescopes in the high Atacama Desert of northern Chile. Based on ALMA data, astronomers infer that the moon-forming exoplanetary disk has a radius similar to our Earth's orbit, and may one day form three or so...
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APOD: 2021 August 23 - Abell 3827: Cannibal Cluster Gravitational Lens 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 August 23 Abell 3827: Cannibal Cluster Gravitational Lens Image Credit: ESA/Hubble & NASA, R. Massey Explanation: Is that one galaxy or three?Toward the right of the featured Hubble image of the massive galaxy cluster Abell 3827 is what appears to be a most unusual galaxy -- curved and with three centers. A detailed analysis, however, finds that these are three images of the same background galaxy -- and that there are at least four more images. Light we see from the single background blue galaxy takes multiple paths through the complex gravity of the cluster, just like a single distant light can take multiple paths through the stem of a wine glass.Studying how clusters like Abell 3827 and their component galaxies deflect distant light gives information about how mass and dark matter are distributed.Abell 3827 is so distant, having a redshift of 0.1, that the light we see from it left about 1.3 billion years ago -- before dinosaurs roamed the Earth.Therefore, the cluster's central...
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APOD: 2021 August 22 - Explosions from White Dwarf Star RS Oph 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 August 22 Explosions from White Dwarf Star RS Oph Illustration Credit & Copyright: David A. Hardy & PPARC Explanation: Spectacular explosions keep occurring in the binary star system named RS Ophiuchi. Every 20 years or so, the red giant star dumps enough hydrogen gas onto its companion white dwarf star to set off a brilliant thermonuclear explosion on the white dwarf's surface. At about 5,000 light years distant, the resulting nova explosions cause the RS Oph system to brighten up by a huge factor and become visible to the unaided eye. The red giant star is depicted on the right of the above drawing, while the white dwarf is at the center of the bright accretion disk on the left. As the stars orbit each other, a stream of gas moves from the giant star to the white dwarf. Astronomers speculate that at some time in the next 100,000 years, enough matter will have accumulated on the white dwarf to push it over the...
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APOD: 2021 August 21 - Triple Transit and Mutual Events 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 August 21 Triple Transit and Mutual Events Image Credit &Copyright:Christopher Go Explanation: These three panels feature the Solar System's rulinggas giant Jupiteron August 15 as seen from Cebu City, Phillipines, planet Earth.On that date thewell-timed telescopic viewsdetail some remarkable performances,transits and mutual events, by Jupiter's Galilean moons.In the top panel,Iois just disappearing into Jupiter's shadow atthe far right, but the three other large Jovian moons appear against theplanet's banded disk.BrighterEuropaand darkerGanymedeare at the far left, also castingtheir two shadows on the gas giant's cloud tops.Callistois below and right near the planet's edge, the three moons ina triple transit across the face of Jupiter.Moving to the middle panel, shadowsof Europa and Ganymede are still visible near centerbut Ganymede has occulted or passed in front of Europa.The bottom panel captures a rare view of Jovian moons in eclipsewhile transiting Jupiter, Ganymede's shadow falling on Europa itself.From planet Earth's perspective, similar mutual events,when Galilean moons occult and eclipse each other,can be seen every six years or so whenJupiter is...
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APOD: 2021 August 20 - Three Perseid Nights 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 August 20 Three Perseid Nights Image Credit &Copyright:Balint Lengyel Explanation: Frames from a camerathat spent three moonless nights under the starscreate this composite night skyscape.They were recorded during August 11-13while planet Earth was sweepingthrough the dusty trailof comet Swift-Tuttle.One long exposure, untracked for the foreground, and the manystar tracking captures of Perseid shower meteorswere taken from the village of Magyaregres, Hungary.Each aligned against the background stars,the meteor trailsall point back to the annual shower's radiant in the constellation Perseusheroically standing above this rural horizon.Of course the comet dust particles are traveling along trajectoriesparallel to each other.The radiant effect is due only to perspective, as the parallel tracksappear toconvergein the distance against the starry sky. Notable APOD Image Submissions: Perseid Meteor Shower 2021 Tomorrow's picture: mutual events<| 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 August 19 - Bright Meteor, Starry Sky 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 August 19 Bright Meteor, Starry Sky Image Credit &Copyright:Miguel Claro(TWAN,Dark Sky Alqueva) Explanation: Plowing throughEarth's atmosphere at 60 kilometers per second,this bright perseid meteor streaks along a starry Milky Way.Captured in dark Portugal skies on August 12, it movesright to left through the frame.Its colorful trail starts near Deneb (alpha Cygni)and ends near Altair (alpha Aquilae),stars of the northernsummer triangle.In fact this perseid meteorvery briefly outshines both,two of the brightest stars in planet Earth's night.The trail's initial greenish glow is typical of the brightperseid shower meteors.The grains of cosmic sand,swept updust from periodic comet Swift-Tuttle,are moving fast enough to excitethe characteristic green emission of atomic oxygenat altitudes of 100 kilometersor so before vaporizing in an incandescent flash. Notable APOD Image Submissions: Perseid Meteor Shower 2021 Tomorrow's picture: Three Dark Nights<| 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 August 18 - Rings Around the Ring Nebula 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 August 18 Rings Around the Ring Nebula Image Credit: Hubble, Large Binocular Telescope,Subaru Telescope; Composition & Copyright: Robert Gendler Explanation: The Ring Nebula (M57), is more complicated than it appears through a small telescope. The easily visible central ring is about one light-year across,but this remarkably deep exposure -a collaborative effort combining data from three different large telescopes -exploresthe looping filaments of glowing gas extending much farther from the nebula's central star.This composite image includes red light emitted by hydrogen as well asvisible and infrared light.The Ring Nebula is an elongated planetary nebula, a type of nebula created when a Sun-like star evolves to throw off its outer atmosphere to become a white dwarf star. The Ring Nebula is about 2,500 light-years away toward the musicalconstellationLyra. Amateur Astronomers: Please take the Night Sky Network's Survey Tomorrow's picture: pixels in space dust <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific rights...
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APOD: 2021 August 17 - M57: The Ring Nebula from Hubble 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 August 17 M57: The Ring Nebula from Hubble Image Credit: NASA, ESA, Hubble Legacy Archive; Processing: Judy Schmidt Explanation: Except for the ringsof Saturn, the RingNebula (M57) is probably the most famous celestial circle.Its classic appearance isunderstood to be due to our own perspective, though.The recent mapping of theexpanding nebula's3-D structure, based in part onthis clear Hubble image,indicates thatthe nebula is a relatively dense, donut-like ring wrappedaround the middle of a (American) football-shaped cloud of glowing gas.The view from planet Earth looks down the long axis of the football,face-on to the ring.Of course, in this well-studied example of aplanetary nebula, the glowing materialdoes not come from planets.Instead, the gaseous shroud represents outer layers expelledfrom the dying,oncesun-like star, now a tiny pinprick of lightseen at the nebula's center.Intense ultraviolet light from the hot central starionizes atoms in the gas.The Ring Nebula is about one light-yearacross and 2,500 light-years away. Share the Sky: NASA Open API for APOD Tomorrow's picture: rings upon Ring <| Archive| Submissions |...
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APOD: 2021 August 16 - Perseid Meteor, Red Sprites, and Nova RS Oph 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 August 16 Perseid Meteor, Red Sprites, and Nova RS Ophiuchus Image Credit & Copyright: Daniel Korona Explanation: This was an unusual sky.It wasn't unusual because of the central band the Milky Way Galaxy, visible along the image left. Most dark skies show part of the Milky Way.It wasn't unusual because of the bright meteor visible on the upper right.Many images taken during last week's Perseid Meteor Shower show meteors, although this Perseid was particularly bright.This sky wasn't unusual because of the red sprites, visible on the lower right.Although this type of lightning has only been noted in the past few decades, images of sprites are becoming more common.This sky wasn't unusual because of the nova, visible just above the image center.Novas bright enough to be seen with the unaided eye occur every few years, with pictured Nova RS Ophiuchus discovered about a week ago. What was most unusual, though, was to capture all these things together, in a single night, on a single...
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APOD: 2021 August 15 - Perseid Rain 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 August 15 Perseid Rain Image Credit & Copyright: Luo Hongyang Explanation: Comet dust rained down on planet Earth last week, streakingthrough dark skies in the annual Perseid meteor shower.The featured picture is a composite of many images taken from the same locationover the peak night of the Perseids.The umbrella was not needed as a shield from meteors, since they almost entirely evaporate high in the Earth's atmosphere.Many of the component images featured individual Perseids, while one image featured the foreground nearJiuquan City, Gansu Province, China.The stellar background includes the central band of our Milky Way Galaxy, appearing nearly vertical, as well as the planets Jupiter and Saturn on the left.Although the comet dust particles are traveling parallel to each other, the resulting shower meteors clearly seem to radiate from a single point on the sky -- the radiant in the eponymous constellation Perseus.The image captured so long an angular field that the curvature of the sky is visible in the trajectory of the Perseids. Notable APOD Image Submissions: Perseid...
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APOD: 2021 August 14 - Island Universe, Cosmic Sand 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 August 14 Island Universe, Cosmic Sand Image Credit &Copyright: Marzena Rogozinska Explanation: Stars in our own Milky Way Galaxy are scattered through thiseye-catching field of view.From the early hours after midnight on August 13,the 30 second exposure of the night sky over Busko-Zdroj, Polandrecords thecolorful and bright trail of aPerseid meteor.Seen near the peak of theannual Perseid meteor shower itflashes from lower left to upper right.The hurtling grain of cosmic sand, a piece of dust fromperiodic comet Swift-Tuttle,vaporized as it passed through planet Earth's atmosphereat almost 60 kilometers per second.Just above and right of center, well beyond the stars ofthe Milky Way, lies the island universeknown as M31 or the Andromeda Galaxy.The Andromeda Galaxyis the most distant object easily visible to the naked-eye,about 2.5 million light-years away.The visible meteor trail begins only about100 kilometersabove Earth's surface, though.It points back to the meteor shower radiantin the constellation Perseus off the lower left edge of the frame.Follow this bright perseid meteor trail below and left tothe stars of NGC...
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APOD: 2021 August 13 - A Perfect Spiral 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 August 13 A Perfect Spiral Image Credit: NASA, ESA, Hubble, HLA; Processing: Mehmet Hakan Ozsarac Explanation: If not perfect then thisspiralgalaxy is at least one of the most photogenic.An island universe of about 100 billion stars,32 million light-years away toward the constellation Pisces,M74 presentsa gorgeous face-on view.Classified asan Sc galaxy,the grand design of M74's graceful spiralarms are traced by bright bluestar clusters and dark cosmic dustlanes.This sharp compositewas constructed from image data recorded by the Hubble Space Telescope'sAdvanced Camera for Surveys.Spanning about 30,000 light-years across theface of M74, it includes exposures recording emission fromhydrogen atoms, highlighting the reddish glow of thegalaxy's large star-forming regions.With a lower surface brightness than most galaxies in theMessier catalog,M74 is sometimes known as thePhantom Galaxy. Notable APOD Image Submissions: Perseid Meteor Shower 2021 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.