APOD: 2022 March 23 - The Bubble 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. 2022 March 23 The Bubble Nebula from Hubble Image Credit: NASA, ESA, Hubble; Processing & Copyright: Mehmet Hakan Özsaraç Explanation: Massive stars can blow bubbles. The featured image shows perhaps the most famous of all star-bubbles, NGC 7635, also known simply asThe Bubble Nebula.Although it looks delicate, the 7-light-year diameter bubble offers evidence of violent processes at work.Above and left of the Bubble's center is a hot,O-type star,several hundred thousand times more luminous and some 45-times more massive than the Sun.A fierce stellar wind and intense radiation from thatstar has blasted out thestructure of glowing gas against denser materialin a surroundingmolecular cloud.The intriguing Bubble Nebula and associated cloud complexlie a mere 7,100 light-years away toward the boastful constellationCassiopeia.This sharp, tantalizing view of the cosmic bubble is a reprocessed composite of previously acquired Hubble Space Telescope image data. Birthday Surprise: What picture did APOD feature on your birthday? (post 1995) Tomorrow's picture: open space <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors...

APOD: 2022 March 22 - A Whale of an Aurora over Swedish Forest 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. 2022 March 22 A Whale of an Aurora over Swedish Forest Image Credit & Copyright: Göran Strand Explanation: What's that in the sky?An aurora.A large coronal mass ejection occurred on our Sun earlier this month, throwing a cloud of fast-moving electrons, protons, and ions toward the Earth.Part of this cloud impacted our Earth's magnetosphere and, bolstered by a sudden gap, resulted in spectacular auroras being seen at some high northern latitudes.Featured here is a particularly photogenic auroral corona captured above a forest in Sweden from a scenic perch overlooking the city of Östersund.To some, this shimmering green glow of recombining atmospheric oxygen might appear like a large whale, but feel free to share what it looks like to you. The unusually quiet Sun of the past few years has now passed.As our Sun now approaches a solar maximum in its 11-year solar magnetic cycle, dramatic auroras like this are sure to continue. Open Science: Browse 2,700+ codes in the Astrophysics Source Code Library Tomorrow's...

APOD: 2022 March 21 - The Sky in 2021 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. 2022 March 21 The Sky in 2021 Image Credit & Copyright: Cees Bassa(Netherlands Institute for Radio Astronomy) Explanation: What if you could see the entire sky -- all at once -- for an entire year?That, very nearly, is what is pictured here. Every 15 minutes during 2021, an all-sky camera took an image of the sky over the Netherlands.Central columns from these images were then aligned and combined to create the featuredkeogram, with January at the top, December at the bottom, and the middle of the night running vertically just left of center.What do we see? Most obviously, the daytime sky is mostly blue, while the nighttime sky is mostly black. The twelve light bands crossing the night sky are caused by the glow of the Moon.The thinnest part of the black hourglass shape occurs during the summer solstice when days are the longest, while the thickest part occurs at the winter solstice.Yesterday was an equinox -- when night and day were equal -- and the northern-spring equinox...

APOD: 2022 March 20 - A Picturesque Equinox Sunset 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. 2022 March 20 A Picturesque Equinox Sunset Image Credit & Copyright: Roland Christen Explanation: What's that at the end of the road?The Sun.Many towns have roads that run east - west, and on two days each year, the Sun rises and sets right down the middle.Today is one of those days: an equinox.Not only is today a day of equal night ("aequus"-"nox") and day time, but also a day when the sun rises precisely to the east and sets due west.Featured here is a picturesque road in northwest Illinois, USA that runs approximately east -west.The image was taken during the March Equinox of 2015, and shows the Sun down the road at sunset.In many cultures, this March equinox is taken to be the first day of a season, typically spring in Earth's northern hemisphere, and autumn in the south.Does your favorite street run east - west?Tonight, at sunset, you can find out with a quick glance. Tomorrow's picture: every single day last year <| Archive| Submissions | Index|...

APOD: 2022 March 19 - 2MASS J17554042 6551277 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. 2022 March 19 2MASS J17554042+6551277 Image Credit :NASA,STScI,JWST Explanation: 2MASS J17554042+6551277doesn't exactly roll off the tongue but that'sthe name, a coordinate-based catalog designation, of the star centered inthis sharp field of view.Fans of the distant universeshould get used to its spiky appearancethough.The diffraction pattern is created by the 18 hexagonal mirror segmentsof theJames Webb Space Telescope.After unfolding, the segments have now been adjusted toachieve a diffraction limited alignmentat infrared wavelengths whileoperating in concertas a single 6.5 meter diameter primary mirror.The resulting image taken by Webb's NIRcam demonstrates their precisealignment is the bestphysics will allow.2MASS J17554042+6551277 is about 2,000 light-years awayand well within our own galaxy.But the galaxies scattered across the background ofthe Webb telescope alignment evaluation imageare likely billions of light-years distant, farbeyond the Milky Way. Tomorrow's picture: day = night <| 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: 2022 March 18 - A Filament in Monoceros 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. 2022 March 18 A Filament in Monoceros Image Credit &Copyright:Giorgio Ferrari Explanation: Bluish reflection nebulae seem to fill this dusty expanse.The sharptelescopic framespans over 1 degree on the sky towardthe faint but fanciful constellationMonoceros,the Unicorn.Seen within the Monoceros R1 cloud complex some 2,500 light-years away,bluish IC 447 is on the left, joined by a long dark filament of dust to IC 446 at lower right.Embedded in IC 447 are young, massive blue stars much hotter thanthe Sun, whose light is reflected by the cosmic cloudof star stuff.Observations reveal that IC 446 also contains ayoung stellar object,a massive star still in an early stage of evolution.The dark filamentof dust and molecular gas joiningthe two star-forming regions is over 15 light-years long. Tomorrow's picture: 2MASS J17554042+6551277 <| 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: 2022 March 17 - Centaurus 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. 2022 March 17 Centaurus A Image Credit &Copyright:David Alemazkour Explanation: A mere 11 million light-years away,Centaurus Ais the closestactivegalaxy to planet Earth.Spanning over 60,000 light-years,the peculiar elliptical galaxy also knownas NGC 5128,is featured in this sharp telescopic view.Centaurus A isapparently the result of a collision of two otherwise normal galaxiesresulting in a fantastic jumble of star clusters andimposing dark dust lanes.Near the galaxy's center,leftover cosmic debris is steadilybeing consumed by acentral black hole with a billion timesthe mass of the Sun.As in other active galaxies, that process likely generates theenormous radio, X-ray, andgamma-ray energyradiated byCentaurus A. 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: Phillip NewmanSpecific rights apply.NASA WebPrivacy Policy and Important NoticesA service of:ASD atNASA /GSFC& Michigan Tech. U.

APOD: 2022 March 16 - The Observable Universe 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. 2022 March 16 The Observable Universe Illustration Credit & Licence: Wikipedia, Pablo Carlos Budassi Explanation: How far can you see?Everything you can see, and everything you could possibly see, right now, assuming your eyes could detect all types of radiations around you -- is the observable universe. In light, the farthest we can see comes from the cosmic microwave background, a time 13.8 billion years ago when the universe was opaque like thick fog.Some neutrinos and gravitational waves that surround us come from even farther out, but humanity does not yet have the technology to detect them.The featured image illustrates the observable universe on an increasingly compact scale, with the Earth and Sun at the center surrounded by our Solar System, nearby stars, nearby galaxies, distant galaxies, filaments of early matter, and the cosmic microwave background.Cosmologists typically assume that our observable universe is just the nearby part of a greater entity known as "the universe" where the same physics applies. However, there are several lines of popular but speculative...

APOD: 2022 March 15 - A Road to the Stars 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. 2022 March 15 A Road to the Stars Image Credit: ESO, Petr Horálek(ESO Photo Ambassador,Inst. of Physics in Opava) Explanation: Pictured -- a very scenic road to the stars. The road approaches La Silla Observatory in Chile, with the ESO's 3.6-meter telescope just up ahead.To the left are some futuristic-looking support structures for the planned BlackGEM telescopes, an array of optical telescopes that will help locate optical counterparts to gravitational waves detections by LIGO and other detectors. But there is much more.Red airglow illuminates the night sky on the right, while the central band of our Milky Way Galaxy slants across the image center.Jupiter can be seen just above the band near the image center, while Saturn is visible just above the 3.6-meter telescope dome.The two largest satellite galaxies of our Milky Way Galaxy, the LMC and SMC, are seen on the far right.The featured image panorama was built up from multiple 15-second exposures that were captured on 2019 June 30. Two days later, La Silla experienced...

APOD: 2022 March 14 - Star Formation in the Eagle 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. 2022 March 14 Star Formation in the Eagle Nebula Image Credit: NASA, ESA, Hubble; Processing & Copyright: Ignacio Diaz Bobillo & Diego Gravinese Explanation: Where do stars form? One place, star forming regions known as "EGGs", are being uncovered at the end of this giant pillar of gas and dust in the Eagle Nebula (M16). Short for evaporating gaseous globules, EGGs are dense regions of mostly molecular hydrogen gas that fragment and gravitationally collapse to form stars. Light from the hottest and brightest of these new stars heats the end of the pillar and causes further evaporation of gas and dust -- revealing yet more EGGs and more young stars. This featured picture was created from exposures spanning over 30 hours with the Earth-orbiting Hubble Space Telescope in 2014, and digitally processed with modern software by experienced volunteers in Argentina.Newborn stars will gradually destroy their birth pillars over the next 100,000 years or so -- if a supernova doesn't destroy them first. Tomorrow's picture: road to...

APOD: 2022 March 13 - Colorful Airglow Bands Surround 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. 2022 March 13 Colorful Airglow Bands Surround Milky Way Image Credit & Copyright: Xiaohan Wang Explanation: Why would the sky glow like a giant repeating rainbow? Airglow. Now air glows all of the time, but it is usually hard to see.A disturbance however -- like an approaching storm -- may cause noticeable rippling in the Earth's atmosphere.These gravity waves are oscillations in air analogous to those created when a rock is thrown in calm water. Red airglow likely originates from OH molecules about 87-kilometers high, excited by ultraviolet light from the Sun, while orange and green airglow is likely caused by sodium and oxygen atoms slightly higher up. While driving near Keluke Lake in Qinghai Provence in China a few years ago, the photographer originally noticed mainly the impressive central band of the Milky Way Galaxy. Stopping to photograph it, surprisingly, the resulting sensitive camera image showed airglow bands to be quite prominent and span the entire sky.The featured image has been digitally enhanced to make...

APOD: 2022 March 12 - Point Reyes 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. 2022 March 12 Point Reyes Milky Way Image Credit &Copyright:Dan Zafra Explanation: Northern winterconstellations and a long arc of the Milky Wayare setting in this night skyscape looking toward the Pacific Ocean fromPoint Reyes onplanet Earth'sCalifornia coast.Sirius, alpha star of Canis Major, is prominent below the starry arctoward the left.Orion's yellowishBetelgeuse, Aldebaran in Taurus, and the blue tintedPleiades star clusteralso find themselves betweenMilky Way and northwestern horizon near the center of the scene.The nebulae visible in the series of exposures used to constructthis panoramic view were captured in early March,but are just too faint to be seen with the unaided eye.On that northern night theirexpansive glow includesthe reddish semi-circle of Barnard's Loopin Orion andNGC 1499 above and right of the Pleiades, also known as theCalifornia Nebula. Tomorrow's picture: colorful airglow <| 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: 2022 March 11 - When Rainbows Smile 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. 2022 March 11 When Rainbows Smile Image Credit &Copyright:Marcella Giulia Pace Explanation: Want to see a rainbow smile?Look near the zenith (straight up) when the sun is low in thesky and you might.This example of an ice haloknown as a circumzenithal arc wascaptured above a palm tree top from Ragusa, Sicily on February 24.The vividly colorful arcs are often called smiling rainbowsbecause of their upside down curvature and colors.For circumzenithal arcsthezenith isat the center and red is on the outside, compared to rainbows whose arcsbend toward the horizonafter a downpour.True rainbows are formed by water droplets refractingthe sunlight to produce a spectrum of colors,though.Circumzenithal arcs are the product ofrefraction and reflectionin flat hexagonal ice crystals, like the ice crystals that create sundogs,formed in high thin clouds. Tomorrow's picture: Point Reyes Milky Way <| 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....

Globular star cluster 47 Tucanae is a jewel of the southern sky.

APOD: 2022 March 9 - A Flower Shaped Rock on Mars 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. 2022 March 9 A Flower-Shaped Rock on Mars Image Credit: NASA,JPL-Caltech,MSSS Explanation: It is one of the more unusual rocks yet found on Mars.Smaller than a penny, the rock has several appendages that make it look, to some, like a flower.Although it would be a major discovery if the rock was truly a fossilized ancient Martian flower, there are less spectacular -- and currently preferred -- explanations for its unusual structure. One theory that has emerged is that the rock is a type of concretion created by minerals deposited by water in cracks or divisions in existing rock.These concretions can be compacted together, can be harder and denser than surrounding rock, and can remain even after the surrounding rock erodes away. The flower structure may also be caused by crystal clusters.The small rock, named Blackthorn Salt, has similarities to previously imaged Martian pebbles.The featured image was taken by the Curiosity rover on Mars in late February. Scientists will continue to study data and images taken of...

APOD: 2022 March 8 - Moon in Inverted Colors 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. 2022 March 8 Moon in Inverted Colors Image Credit & Copyright: Dawid Glawdzin Explanation: Which moon is this?It's Earth's moon -- but in inverted colors.Here, the pixel values corresponding to light and dark areas have been translated in reverse, or inverted, producing a false-color representation reminiscent of a black and white photographic negative. However, this is an inverted color image -- where the muted colors of the moon are real but digitally exaggerated before inversion. Normally bright rays from the large crater Tycho dominate the southern (bottom) features as easily followed dark green lines emanating from the 85-kilometer diameter impact site. Normally dark lunar mare appear light and silvery. The image was acquired in Southend-on-Sea, England, UK. Historically, astronomical images recorded on photographic plates were directly examined on inverted-color negatives because it helped the eye pick out faint details. Tomorrow's picture: martian rock flower <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific...

APOD: 2022 March 7 - A Lion in Orion 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. 2022 March 7 A Lion in Orion Image Credit & Copyright: Maroun Mahfoud Explanation: Yes, but can you see the lion?A deep exposure shows the famous dark indentation that looks like ahorse's head, visible just left and below center, and known unsurprisingly as the Horsehead Nebula. The Horsehead Nebula (Barnard 33) is part of a vast complex of dark absorbingdust and brightglowing gas. To bring out details of the Horsehead's pasture, an astrophotographer artistically combined light accumulated for over 20 hours in hydrogen (orange), oxygen (blue), and sulfur (green).The resulting spectacular picturecaptured from Raachine,Lebanon,details an intricate tapestry of gaseous wisps and dust-laden filaments that were created andsculpted over eons by stellar winds andancient supernovas. The featured composition brings up another pareidolic animal icon -- that of a lion's head -- in the expansive orange colored gas above the horse's head. The Flame Nebula is visible just to the left of the Horsehead. The Horsehead Nebula lies 1,500 light years distant towards the constellation of Orion. Tomorrow's picture: oddly...

APOD: 2022 March 6 - Venus and the Triply Ultraviolet 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. 2022 March 6 Venus and the Triply Ultraviolet Sun Image Credit: NASA/SDO & the AIA, EVE, and HMI teams; Digital Composition: Peter L. Dove Explanation: This was a very unusual type of solar eclipse. Typically, it is the Earth's Moon that eclipses the Sun. In 2012, though, the planet Venus took a turn. Like a solar eclipse by the Moon, the phase of Venus became a continually thinner crescent as Venus became increasingly better aligned with the Sun. Eventually the alignment became perfect and the phase of Venus dropped to zero. The dark spot of Venus crossed our parent star. The situation could technically be labeled a Venusian annular eclipse with an extraordinarily large ring of fire. Pictured here during the occultation, the Sun was imaged in three colors of ultraviolet light by the Earth-orbiting Solar Dynamics Observatory, with the dark region toward the right corresponding to a coronal hole.Hours later, as Venus continued in its orbit, a slight crescent phase appeared again. The next Venusian...

APOD: 2022 March 5 - Interstellar Comet 2I Borisov 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. 2022 March 5 Interstellar Comet 2I Borisov NASA, ESA, and D.Jewitt (UCLA) et al. Explanation: From somewhere elsein the Milky Way galaxy,Comet 2I/Borisovwas just visiting the Solar System.Discovered by amateur astronomer Gennady Borisovon August 30, 2019, the first known interstellar cometis seen in these two Hubble Space Telescope imagesfrom November and December 2019.On the left, a distant background galaxy near the line-of-sight toBorisov is blurred asHubbletracked the speeding comet and dust tail about327 million kilometers from Earth.At right, 2I/Borisov appears shortly after perihelion, its closestapproach to Sun.European Southern Observatoryobservations indicatethat this comet may never have passed closeto any star before its 2019 perihelion passage.Borisov's closestapproach to our fair planet, a distance of about 290 millionkilometers, came on December 28, 2019.Even though Hubble's sharp images don't resolve the comet's nucleus,they did lead to estimates of less than 1 kilometer for its diameter. Tomorrow's picture: triple Sun holes <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official:...

APOD: 2022 March 4 - The Multiwavelength Crab 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. 2022 March 4 The Multiwavelength Crab NASA,ESA,G. Dubner(IAFE, CONICET-University of Buenos Aires) et al.;A. Loll et al.;T. Temim et al.;F. Seward et al.;VLA/NRAO/AUI/NSF;Chandra/CXC;Spitzer/JPL-Caltech;XMM-Newton/ESA;Hubble/STScI Explanation: The Crab Nebula is cataloged as M1, the first object onCharlesMessier's famous list of things which are not comets.In fact, theCrabis now known to be asupernovaremnant, expanding debris from massive star's death explosion,witnessed on planet Earth in 1054 AD.Thisbrave new image offers a 21st centuryview of the Crab Nebula by presenting image data from across theelectromagneticspectrum as wavelengths of visible light.From space, Chandra (X-ray)XMM-Newton (ultraviolet),Hubble (visible), andSpitzer (infrared),data are in purple, blue, green, and yellow hues.From the ground,Very Large Arrayradio wavelength data is shown in red.One of the most exotic objects known to modern astronomers,the Crab Pulsar,a neutron star spinning 30 times a second,is the bright spot near picture center.Like a cosmic dynamo,this collapsed remnant of the stellar corepowers the Crab's emission across the electromagnetic spectrum.Spanning about 12 light-years, the Crab Nebula is6,500 light-years away in the constellationTaurus. Tomorrow's picture: from somewhere else <| Archive|...