APOD: 2022 March 29 - Venus and Mars: Passing in the Night 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 29 Venus and Mars: Passing in the Night Image Credit & Copyright: Carlos Kiko Fairbairn Explanation: When two planets pass on the night sky, they can usually be seen near each other for a week or more.In the case of this planetary conjunction, Venus and Mars passed within 4 degrees of each other earlier this month.The featured image was taken a few days prior, when Venus was slowing rising in the pre-dawn sky, night by night, while Mars was slowly setting.The image, a four-part mosaic, was captured in Brazil from the small town Teresópolis.Besides Venus and Mars, the morning sky now also includes the more distant planet Saturn. Of course, these conjunctions are only angular -- Venus, Mars, and Saturn continue to orbit the Sun in very different parts of our Solar System. Next week, the angle between Saturn and Mars will drop to below a quarter of a degree. Tomorrow's picture: rings unknown <| Archive| Submissions | Index| Search| Calendar| RSS| Education|...

APOD: 2022 March 28 - Gems of a Maldivean Night 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 28 Gems of a Maldivean Night Image Credit & Copyright: Petr Horálek(ESO Photo Ambassador,Inst. of Physics in Opava) Explanation: The southernmost part of the Milky Way contains not only the stars of the Southern Cross, but the closest star system to our Sun -- Alpha Centauri. The Southern Cross itself is topped by the bright, yellowish star Gamma Crucis. A line from Gamma Crucis through the blue star at the bottom of the cross, Acrux, points toward the south celestial pole, located just above the small island in the featured picture -- taken in early March. That island is Madivaru of the Maldives in the Indian Ocean.Against faint Milky Way starlight, the dark Coal Sack Nebula lies just left of the cross, while farther left along the Milky Way are the bright stars Alpha Centauri (left) and Beta Centauri (Hadar). Alpha Centauri A, a Sun-like star anchoring a three-star system with exoplanets, is a mere 4.3 light-years distant. Seen from Alpha Centauri, our own Sun...

APOD: 2022 March 27 - Titan Seas Reflect Sunlight 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 27 Titan Seas Reflect Sunlight Image Credit: NASA,JPL-Caltech, U. Arizona, U. Idaho Explanation: Why would the surface of Titan light up with a blinding flash?The reason: a sunglint from liquid seas. Saturn's moon Titan has numerous smooth lakes of methane that, when the angle is right, reflect sunlight as if they were mirrors. Pictured here in false-color, the robotic Cassini spacecraft that orbited Saturn from 2004 to 2017 imaged the cloud-covered Titan in 2014 in different bands of cloud-piercing infrared light. This specular reflection was so bright it saturated one of Cassini's infrared cameras.Although the sunglint was annoying -- it was also useful. The reflecting regions confirm that northern Titan houses a wide and complex array of seas with a geometry that indicates periods of significant evaporation. During its numerous passes of our Solar System's most mysterious moon, Cassini has revealed Titan to be a world with active weather -- including times when it rains a liquefied version of natural gas. Tomorrow's picture: stars of the...

APOD: 2022 March 26 - Pluto at Night 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 26 Pluto at Night Image Credit: NASA,Johns Hopkins Univ./APL,Southwest Research Institute Explanation: The night side of Pluto spansthis shadowy scene.In the stunning spacebased perspective the Sun is 4.9 billion kilometers(almost 4.5 light-hours) behind the dim and distant world.It was captured by far flungNew Horizons in July of 2015when the spacecraft was at a range of some 21,000 kilometers from Pluto,about 19 minutes after its closest approach.A denizenof the Kuiper Beltin dramatic silhouette, the image also reveals Pluto's tenuous, surprisinglycomplex layers ofhazy atmosphere.Near the top of the framethe crescent twilight landscape includes southern areas of nitrogen ice plains now formally known asSputnikPlanitiaand rugged mountainsof water-ice in the Norgay Montes. Tomorrow's picture: titanic flash <| 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 25 - The Medusa 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 25 The Medusa Nebula Image Credit &Copyright:Damien Cannane Explanation: Braided and serpentine filaments of glowing gassuggest this nebula's popular name, The Medusa Nebula.Also known as Abell 21, this Medusa is an oldplanetary nebulasome 1,500 light-years away in the constellation Gemini.Like its mythologicalnamesake, the nebula is associated with a dramatic transformation.The planetary nebulaphase represents a final stage inthe evolutionof low mass stars like the sun as they transform themselves fromred giantsto hot white dwarfstars and in the process shrug off their outer layers.Ultravioletradiationfrom the hot star powers the nebular glow.The Medusa's transforming star is the faint one near the centerof the overall bright crescent shape.In this deep telescopic view,fainter filaments clearly extendabove and left of the bright crescent region.The Medusa Nebula is estimated to be over4 light-years across. Tomorrow's picture: behind 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 NoticesA service of:ASD atNASA /GSFC& Michigan...

APOD: 2022 March 24 - Arp 78: Peculiar Galaxy in Aries 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 24 Arp 78: Peculiar Galaxy in Aries Image Credit &License:International Gemini Observatory /NOIRLab /NSF /AURA Processing: T.A. Rector (Univ. Alaska Anchorage),J. Miller (Gemini Observatory/NOIRLab),M. Zamani & D. de Martin Explanation: Peculiarspiral galaxy Arp 78 is found within the boundaries of the head strongconstellation Aries.Some 100 million light-yearsbeyond thestars and nebulae of our Milky Way galaxy,the island universe is over 100,000 light-years across.Also known as NGC 772, it sports a prominent, outer spiral arm inthis detailed cosmic portraitfrom the largeGemini North telescope near thesummit of Maunakea, Hawaii, planet Earth.Tracking along sweeping dust lanes andlined with young blue starclusters, Arp 78's spiral arm is likely pumped-up by galactic-scalegravitational tidal interactionsThe close companion galaxy responsible is NGC 770, located off theupper right of this frame.But more distant background galaxies are clearly visible in thecosmicfield of view. Tomorrow's picture: serpentine protectress <| 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: 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.