APOD: 2022 April 5 - Seven Sisters versus California 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 April 5 Seven Sisters versus California Image Credit & Copyright: Neven Krcmarek Explanation: On the upper right, dressed in blue, is thePleiades. Also known as theSeven Sisters andM45,the Pleiadesis one of the brightest andmost easily visibleopen clusterson the sky.The Pleiadescontains over 3,000 stars, is about 400 light years away, and only 13 lightyears across.Surrounding the stars is a spectacular bluereflection nebula made of finedust. Acommon legend is that one of the brighter starsfaded since the cluster was named.On the lower left, shining in red, is theCalifornia Nebula. Named for its shape, theCaliforniaNebula is much dimmer and hence harder to seethan the Pleiades. Also known as NGC 1499, this mass of red glowinghydrogen gas is about 1,500 light years away.Although about 25 full moons could fitbetween them, the featured wide angle, deep field image composite has capturedthem both. A careful inspection of the deep image will also reveal the star forming region IC 348 and the molecular cloud LBN 777 (the Baby Eagle Nebula). Tomorrow's picture: far star...

APOD: 2022 April 4 - A Vortex Aurora 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. 2022 April 4 A Vortex Aurora over Iceland Image Credit & Copyright: Christophe Suarez Explanation: No, the car was not in danger of being vacuumed into space by the big sky vortex.For one reason, the vortex was really an aurora, and since auroras are created by particles striking the Earth from space, they do not create a vacuum.This rapidly developing auroral display was caused by a Coronal Mass Ejection from the Sun that passed by the Earth closely enough to cause a ripple in Earth's magnetosphere. The upper red parts of the aurora occur over 250 kilometers high with its red glow created by atmospheric atomic oxygen directly energized by incoming particles.The lower green parts of the aurora occur over 100 kilometers high with its green glow created by atmospheric atomic oxygen energized indirectly by collisions with first-energized molecular nitrogen. Below 100 kilometers, there is little atomic oxygen, which is why auroras end abruptly.The concentric cylinders depict a dramatic auroral corona as seen from the side.The featured...

APOD: 2022 April 3 - CMB Dipole: Speeding Through the 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 April 3 CMB Dipole: Speeding Through the Universe Image Credit: DMR,COBE,NASA, Four-Year Sky Map Explanation: Our Earth is not at rest. The Earth moves around the Sun. The Sun orbits the center of theMilky Way Galaxy. The Milky Way Galaxy orbits in theLocal Group of Galaxies. The Local Group falls toward theVirgo Cluster of Galaxies. But these speeds are less than the speed thatall of these objects togethermove relative to thecosmic microwave background radiation (CMBR). In thefeatured all-sky map from theCOBE satellite in 1993,microwave light in the Earth's direction of motion appearsblueshifted and hence hotter, whilemicrowave light on the opposite side of the sky isredshifted and colder. The map indicates that theLocal Group moves at about 600 kilometers per second relative to thisprimordial radiation. This high speed was initially unexpected and its magnitude is still unexplained. Why are we moving so fast? What is out there? Tomorrow's picture: auroral vortex <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors &...

APOD: 2022 April 2 - Nova Scotia Northern Lights 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 April 2 Nova Scotia Northern Lights Image Credit &Copyright: Jason Dain Explanation: This almost otherworldlydisplay of northern lights was captured inclear skies during the early hours of March 31 from44 degrees north latitude, planet Earth.In a five second exposure the scene looks north fromMartinique Beach Provincial Park in Nova Scotia, Canada.Stars of the W-shaped constellation Cassiopeiashine well above the horizon,through the red tintof thehigher altitude auroral glow.Auroral activity was anticipated by skywatchersalerted to the possibility ofstormy space weatherby Sun-staring spacecraft.The predicted geomagnetic storm was sparked as acoronal mass ejection, launched fromprolificsolar active region 2975, impacted ourfair planet's magnetosphere. Tomorrow's picture: Why are we moving so fast? <| 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 April 1 - Leaning Tower, Active 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 April 1 Leaning Tower, Active Sun Image Credit &Copyright: Antonio Tartarini Explanation: The natural filter of a hazy atmosphere offered thisrecognizable architecture and sunset telephoto view on March 27.Dark against the solar disk,large sunspots in solar active regions 2975 and 2976 are wedged betweenthe Duomo of Pisa and itsfamous Leaning Tower.Only one day later,Sun-staring spacecraftwatched active region 2975 unleash afrenzy of solar flaresalong with two coronal mass ejections.The largest impacted the magnetosphere on March 31triggering a geomagnetic storm andaurorae in high-latitudenight skies.On March 30,active region 2975 erupted again with a powerfulX-class solar flarethat caused a temporary radio blackout on planet Earth. Tomorrow's picture: a colour out of 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 31 - Exploring the Antennae 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 31 Exploring the Antennae Image Credit &Copyright: Dietmar Hager,Eric Benson Explanation: Some 60 million light-years away in the southerlyconstellationCorvus, two large galaxies are colliding.Stars in the two galaxies, cataloged asNGC 4038 and NGC 4039,very rarely collide in the course of theponderous cataclysm that lasts for hundreds of millions of years.But the galaxies' largeclouds of molecular gas and dustoften do, triggeringfurious episodes of star formationnear the center of thecosmic wreckage.Spanning over 500 thousand light-years, thisstunning view also reveals new star clusters andmatter flung far from the scene of the accident bygravitational tidalforces.Theremarkably sharp ground-based image,an accumulation of 88 hours of exposure captured during 2012-2021,follows the faint tidal tails and distant background galaxies in thefield of view.The suggestive overall visual appearance of the extended arcingstructures gives the galaxy pair, also known as Arp 244,its popular name - The Antennae. Tomorrow's picture: leaning tower, active sun <| 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 30 - Animation: Odd Radio Circles 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. Animation: Odd Radio Circles Credits: Illustration: Sam Moorfield;Data: CSIRO, HST (HUDF), ESA, NASA; Image: J. English (U. Manitoba),EMU, MeerKAT,DES (CTIO); Text: Jayanne English Explanation: What do you call a cosmic puzzle that no one expected to see? In this case, Odd Radio Circles, aka ORCs. ORC-1 typifies the enigmatic five objects, only visible at radio frequencies, that were serendipitously discovered in 2019 using the new Australian SKA Pathfinder radio array. The final image in the featured video uses 2021 data from the South African MeerKAT array to reveal more detail. The radio data, assigned turquoise colors, are combined with a Dark Energy Survey optical/IR map. The animated artist’s illustration explores just one idea about the ORCs’ origins. If two supermassive black holes merge in the center of a galaxy, the associated shockwaves could generate rings of radio radiation. These grow to fill the video frame. The video zooms out so the expansion the ORC can be tracked until it is about a million light-years across. Fortunately, the up-coming...

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...