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...

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.

APOD: 2021 August 12 - A Beautiful Trifid 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 12 A Beautiful Trifid Image Credit &Copyright: Mike Selby Explanation: The beautiful Trifid Nebulais a cosmicstudy in contrasts.Also known as M20, it lies about5,000light-years away toward the nebula richconstellation Sagittarius.A star forming region in the plane of our galaxy,the Trifid does illustrate three different types ofastronomical nebulae;red emission nebulae dominated bylight from hydrogen atoms,blue reflection nebulae producedby dust reflecting starlight, anddark nebulae wheredense dust clouds appear in silhouette.But the red emission region roughly separated into threeparts by obscuring dust lanes is what lends the Trifid itspopular name.Pillars and jets sculpted by newborn stars, below and left ofthe emission nebula's center, appear in famous Hubble Space Telescopeclose-upimages of the region.The Trifid Nebula is about 40 light-years across.Just too faint to be seen by the unaided eye, it almost covers thearea of a full moon in planet Earth's sky. Tomorrow's picture: a perfect spiral<| 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...

APOD: 2021 August 11 - Mammatus Clouds over Saskatchewan 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 11 Mammatus Clouds over Saskatchewan Image Credit & Copyright: Michael F Johnston Explanation: When do cloud bottoms appear like bubbles?Normally, cloud bottoms are flat.This is because moist warm airthat rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. As waterdroplets grow, an opaque cloud forms. Under some conditions, however, cloud pockets can develop that contain large droplets of water or ice that fall into clear air as they evaporate. Such pockets may occur in turbulent air near a thunderstorm. Resulting mammatus clouds can appear especially dramatic if sunlit from the side. The mammatus clouds pictured here, lasting only a few minutes, were photographed over Regina,Saskatchewan, Canada,just after a storm in 2012. Meteor Shower Tonight: Peak of the Perseids Tomorrow's picture: a beautiful trifid <| 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...

APOD: 2021 August 10 - Fire in 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 August 10 Fire in Space Image Credit: NASA Explanation: What does fire look like in space?In the gravity on Earth, heated air rises and expands, causing flames to be teardrop shaped.In the microgravity of the air-filled International Space Station (ISS), however, flames are spheres.Fire is the rapid acquisition of oxygen, and space flames meet new oxygen molecules when they float by randomly from all directions -- creating the enveloping sphere. In the featured image taken in the ISS's Combustion Integration Rack, a spherical flame envelopes clusters of hot glowing soot. Without oxygen, say in the vacuum of empty space, a fire would go out immediately. The many chemical reactions involved with fire are complex, and testing them in microgravity is helping humanity not only to better understand fire -- but how to put out fire, too. Tomorrow's picture: bubble cloud row <| 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...

APOD: 2021 August 9 - Perseus and the Lost Meteors 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 9 Perseus and the Lost Meteors Image Credit & Copyright: Tomas Slovinsky (Slovakia) & Petr Horalek (Czech Republic;Institute of Physics in Opava) Explanation: What's the best way to watch a meteor shower? This question might come up later this week when the annual Perseid Meteor Shower peaks.One thing that is helpful is a dark sky, as demonstrated in the featured composite image of last year's Perseids. Many more faint meteors are visible on the left image, taken through a very dark sky in Slovakia, than on the right image, taken through a moderately dark sky in the Czech Republic. The band of the Milky Way Galaxy bridges the two coordinated images, while the meteor shower radiant in the constellation of Perseus is clearly visible on the left.In sum, many faint meteors are lost through a bright sky.Light pollution is shrinking areas across our Earth with dark skies, although inexpensive ways to combat this might be implemented. Notable Perseids Submissions to APOD: 2018, 2019, 2020 Tomorrow's...

APOD: 2021 August 8 - A Perseid Below 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 8 A Perseid Below Image Credit: NASAISS Expedition 28 Crew,Ron Garan Explanation: Earthlings typically watch meteor showers by looking up.But thisremarkable view, captured on August 13, 2011 by astronaut Ron Garan, caught a Perseid meteor by looking down.From Garan'sperspective onboard theInternational Space Stationorbiting at an altitude of about 380 kilometers,the Perseid meteors streak below,swept up dustleft from comet Swift-Tuttle heated to incandescence.The glowing comet dustgrains are traveling atabout 60 kilometers per second throughthe denser atmosphere around 100 kilometers above Earth's surface.In this case, the foreshortened meteor flash is right of frame center,below the curving limb of the Earth and a layer of greenishairglow, just below bright starArcturus.Want to look up at a meteor shower? You're in luck, as the 2021 Perseids meteor shower peaks this week.This year, even relatively faint meteors should be visible through clear skies from a dark location as the bright Moon will mostly absent. Notable Perseids Submissions to APOD: 2018, 2019, 2020 Tomorrow's picture: perseids from perseus <| Archive| Submissions | Index| Search|...

APOD: 2021 August 7 - Jezero Crater: Raised Ridges in 3D 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 7 Jezero Crater: Raised Ridges in 3D Image Credit:NASA,JPL-Caltech,Ingenuity Explanation: Get out your red-blue glasses andhover over the surface of Mars.Taken on July 24, the 3D color view is from the MarsIngenuity Helicopter's 10thflight above the Red Planet.Two images from Ingenuity's color camera,both captured at an altitude of 12 meters (40 feet), but a few meters apartto provide a stereo perspective, were used to construct the color anaglyph.Ingenuity's stereo images were made at the request of the MarsPerseverancerover science team.The team is considering a visitto these raised ridges on the floor of Jezero Crater during Perseverance'sfirst science campaign. Tomorrow's picture: meteor below<| 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 6 - Stars and Dust Across Corona Australis 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 6 Stars and Dust Across Corona Australis Image Credit &Copyright:Vikas Chander Explanation: Cosmic dust clouds cross a rich field of stars inthis telescopic vista near the northern boundary ofCorona Australis, the Southern Crown.Less than 500 light-years away the dust cloudseffectively block light frommore distant background stars in theMilky Way.Top to bottom the frame spans about 2 degrees or over 15 light-years atthe clouds' estimated distance.At top right is a groupof lovely reflection nebulae cataloged asNGC 6726, 6727, 6729,and IC 4812.A characteristic blue color is produced as lightfrom hot stars is reflected bythe cosmic dust.The dust also obscures from view starsin the regionstill in the process of formation.Just above the bluish reflection nebulae a smaller NGC 6729 surroundsyoung variable starR Coronae Australis.To its right are telltale reddish arcs and loops identified asHerbig Haro objectsassociated with energetic newborn stars.Magnificent globular star cluster NGC 6723is at bottom left in the frame.Though NGC 6723 appearsto be partof the group,its ancient stars actually lie nearly 30,000 light-years away,far beyond...

APOD: 2021 August 5 - Tycho and Clavius 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 5 Tycho and Clavius Image Credit &Copyright:Eduardo Schaberger Poupeau Explanation: South is upin this detailed telescopic view across the Moon's ruggedsouthern highlands.Captured on July 20, the lunar landscape features the Moon's young and old,the large craters Tycho and Clavius.About 100 million years young,Tycho isthe sharp-walled 85 kilometerdiameter crater near center, its 2 kilometer tall central peakin bright sunlight anddark shadow.Debris ejected during the impact that created Tycho still make it thestandout lunar crater when theMoon is near full, producinga highly visible radiating system of light streaks,bright rays that extend across much of the lunar near side.In fact, some of the material collected at the Apollo 17 landing site,about 2,000 kilometers away, likely originatedfrom the Tycho impact. One of the oldest and largest craters on the Moon's near side,225 kilometer diameterClavius is due south(above) of Tycho.Clavius crater'sown ray system resulting from its original impact eventwould have faded long ago.The old crater's worn walls and smooth floor are now overlayed bysmaller craters from impacts that occurred after Clavius wasformed.Observations...

APOD: 2021 August 4 - EHT Resolves Central Jet from Black Hole in Cen A 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 4 EHT Resolves Central Jet from Black Hole in Cen A Image Credit: Radboud University; CSIRO/ATNF/I.Feain et al., R.Morganti et al., N.Junkes et al.; ESO/WFI; MPIfR/ESO/APEX/A. Weiss et al.; NASA/CXC/CfA/R. Kraft et al.; TANAMI/C. Mueller et al.; EHT/M. Janssen et al. Explanation: How do supermassive black holes create powerful jets?To help find out, the Event Horizon Telescope (EHT) imaged the center of the nearby active galaxy Centaurus A. The cascade of featured inset images shows Cen A from it largest, taking up more sky than many moons, to its now finest, taking up only as much sky as an golf ball on the moon.The new image shows what may look like two jets -- but is actually two sides of a single jet. This newly discovered jet-edge brightening does not solve the jet-creation mystery, but does imply that the particle outflow is confined by a strong pressure -- possibly involving a magnetic field. The EHT is a coordination of radio...

APOD: 2021 August 3 - A Perseid Meteor and the Milky Way 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 3 A Perseid Fireball and the Milky Way Image Credit & Copyright: Dandan Huang Explanation: It was bright and green and flashed as it moved quickly along the Milky Way.It left a trail that took 30 minutes to dissipate. Given the day, August 12, and the direction, away from Perseus, it was likely a small bit from the nucleus of Comet Swift-Tuttle plowing through the Earth's atmosphere -- and therefore part of the annual Perseids meteor shower. The astrophotographer captured the fireball as it shot across the sky in 2018 above a valley in Yichang, Hubei, China.The meteor's streak, also caught on video, ended near the direction of Mars on the lower left.Next week, the 2021 Perseids meteor shower will peak again. This year the Moon will set shortly after the Sun, leaving a night sky ideal for seeing lots of Perseids from dark and clear locations across planet Earth. Follow APOD in English on: Facebook, Instagram, or Twitter Tomorrow's picture: Event Horizon...

APOD: 2021 August 2 - The Hubble Ultra Deep Field in Light and Sound 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 2 The Hubble Ultra Deep Field in Light and Sound Image Credit: NASA, ESA, Hubble; Sonification: G. Salvesen (UCSB); Data: M. Rafelski et al. Explanation: Have you heard about the Hubble Ultra-Deep Field? Either way, you've likely not heard about it like this -- please run your cursor over the featured image and listen! The Hubble Ultra-Deep Field (HUDF) was created in 2003-2004 with the Hubble Space Telescope staring for a long time toward near-empty space so that distant, faint galaxies would become visible. One of the most famous images in astronomy, the HUDF is featured here in a vibrant way -- with sonified distances.Pointing to a galaxy will play a note that indicates its approximate redshift.Because redshifts shift light toward the red end of the spectrum of light, they are depicted here by a shift of tone toward the low end of the spectrum of sound. The further the galaxy, the greater its cosmological redshift (even if it appears blue),...

APOD: 2021 August 1 - Pluto in Enhanced Color 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 1 Pluto in Enhanced Color Image Credit: NASA,Johns Hopkins Univ./APL,Southwest Research Inst. Explanation: Pluto is more colorful than we can see.Color data and high-resolution images of our Solar System's most famous dwarf planet, taken by the robotic New Horizons spacecraft during its flyby in 2015 July, have been digitally combined to give an enhanced-color view of this ancient world sporting an unexpectedly young surface.The featured enhanced color image is not only esthetically pretty but scientifically useful, making surface regions of differing chemical composition visually distinct.For example, the light-colored heart-shaped Tombaugh Regio on the lower right is clearly shown here to be divisible into two regions that are geologically different, with the leftmost lobe Sputnik Planitia also appearing unusually smooth.After Pluto, New Horizons continued on, shooting past asteroid Arrokoth in 2019 and has enough speed to escape our Solar System completely. Pluto-Related Images with Brief Explanations: APOD Pluto Search Tomorrow's picture: deep galaxy sounds <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| >...

APOD: 2021 July 31 - Remembering NEOWISE 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 July 31 Remembering NEOWISE Image Credit &Copyright:Petr Horalek /Institute of Physics in Opava Explanation: It was just last July.If you could see the stars ofthe Big Dipper, you could findComet NEOWISE in your evening sky.After sunsetdenizens of the north could look for the naked-eye cometbelow the bowl of that famous celestial kitchen utensiland above the northwestern horizon.The comet looked like a fuzzy 'star' with a tail, though probably not so long a tail as in thismemorable skyviewrecorded from the Czech Republic on July 23th, 2020, near the comet'sclosest approach to planet Earth.Photographs ofC/2020 F3(NEOWISE) often did show the comet's broad dust tail and fainter butseparate bluish ion tail extendingfarther than the eye could follow.Skygazers around the world weredelightedto witness Comet NEOWISE,surprise visitor from the outer Solar System. Notable Comet NEOWISE Images 2020: July 3130, 29,28,27,26,25,24 Tomorrow's picture: better than Pluto<| 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...