APOD: 2021 September 26 - The Red Square 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 September 26 The Red Square Nebula Image Credit & Copyright: Peter Tuthill(Sydney U.)& James Lloyd (Cornell U.) Explanation: How did a round star create this square nebula?No one is quite sure.The round star, known as MWC 922 and possibly part of a multiple star system, appears at the center of the Red Square Nebula. The featured image combinesinfrared exposures from theHale Telescope onMt. Palomar inCalifornia, and theKeck-2 Telescope onMauna Kea inHawaii. A leading progenitor hypothesis for thesquare nebula is that the central star or stars somehow expelled cones of gas during a latedevelopmental stage.For MWC 922,these cones happen to incorporate nearlyright anglesand be visible from the sides. Supporting evidence for theconehypothesis includes radial spokes in the image that might run along thecone walls.Researchers speculate that the cones viewed fromanother angle would appear similar to the gigantic rings ofsupernova 1987A,possibly indicating that a star in MWC 922 might one day itself explode in a similarsupernova. Tomorrow's picture: Armstrong moon <| Archive| Submissions | Index| Search| Calendar| RSS| Education|...
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APOD: 2021 September 25 - The Bubble and the Star Cluster 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 September 25 The Bubble and the Star Cluster Image Credit &Copyright:Lorand Fenyes Explanation: To the eye,this cosmic compositionnicely balances theBubble Nebula at the right with open star cluster M52.The pair would be lopsided on other scales, though.Embedded in a complex ofinterstellar dustand gas and blown by the winds from a single, massiveO-type star,the Bubble Nebula, also known as NGC 7635, is amere 10 light-years wide. On the other hand,M52 is a rich opencluster of around a thousand stars.The cluster is about 25 light-years across.Seen toward the northern boundaryof Cassiopeia, distance estimatesfor the Bubble Nebula and associated cloud complex are around11,000 light-years, whilestar cluster M52lies nearly 5,000 light-years away.The wide telescopic field of view spans about 1.5 degrees on the skyor three times the apparent size of a full Moon. Tomorrow's picture: The Red Square Nebula<| 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...
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Perseid Outburst at Westmeath Lookout
APOD: 2021 September 23 - Harvest Moon Trail 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 September 23 Harvest Moon Trail Image Credit &Copyright:Mike Cohea Explanation: Famed in festival, story, and song the best knownfull moon is the Harvest Moon.For northern hemisphere dwellers that's a traditional name of thefull moon nearest the September equinox.Seen from Saunderstown,Rhode Island, planet Earth, thisHarvest Moon left a broad streak of warm hues as it rose through a twilightsky over the Newport Bridge.On September 20 its trail was captured in a single 22 minute exposureusing a dense filter and a digital camera.Only two days later the September equinoxmarked a change of season and the beginning of autumn in the north.In fact, recognizing a season as the timebetween solstice and equinox,this Harvest Moon was thefourth full moon of the season,coming just before the astronomical end of northern summer. Tomorrow's picture: Perseid meteor outburst<| 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 September 22 - Equinox on a Spinning Earth 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. Equinox on a Spinning Earth Image Credit: Meteosat 9, NASA, earthobservatory, Robert Simmon Explanation: When does the line between night and day become vertical?Today.Today is an equinox on planet Earth, a time of year when day and night are most nearly equal.At an equinox, the Earth's terminator -- the dividing line between day and night -- becomes vertical and connects the north and south poles.The featured time-lapse video demonstrates this by displaying an entire year on planet Earth in twelve seconds.From geosynchronous orbit, the Meteosat 9 satellite recorded these infrared images of the Earth every day at the same local time. The video started at the September 2010 equinox with the terminator line being vertical.As the Earth revolved around the Sun, the terminator was seen to tilt in a way that provides less daily sunlight to the northern hemisphere, causing winter in the north.As the year progressed, the March 2011 equinox arrived halfway through the video, followed by the terminator tilting the other way, causing winter in...
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APOD: 2021 September 21 - Sun Spot Hill 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 September 21 Sun Spot Hill Image Credit & Copyright: Jordi Coy Explanation: Is this giant orange ball about to roll down that tree-lined hill?No, because the giant orange ball is actually the Sun.Our Solar System's central star was captured rising beyond a hill on Earth twelve days ago complete with a delightfully detailed foreground. The Sun's disk showed five sunspots, quite a lot considering that during the solar minimum in solar activity of the past few years, most days showed no spots.A close look at the hill -- Sierra del Cid in Perter, Spain -- reveals not only silhouetted pine trees, but silhouetted people -- by coincidence three brothers of the photographer. The trees and brothers were about 3.5-kilometers away during the morning of the well-planned, single-exposure image.A dark filter muted the usually brilliant Sun and brought up great detail on the lower sunspots. Within a few minutes, the Sun rose far above the hill, while within a week, the sunspots rotated around the Sun, out of view.The...
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APOD: 2021 September 20 - Lynds Dark 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 September 20 Lynds Dark Nebula 1251 Image Credit &Copyright:Cristiano Gualco Explanation: Stars are forming in Lynds Dark Nebula(LDN)1251.About 1,000 light-years away and drifting above the plane of ourMilky Way galaxy, the dusty molecular cloudis part of a complex of dark nebulae mapped toward theCepheus flare region.Across the spectrum,astronomical explorations of the obscuringinterstellar clouds reveal energetic shocks and outflowsassociated with newborn stars,including the telltale reddish glow from scatteredHerbig-Haroobjects hiding in the image.Distant background galaxies also lurk on the scene,almost buried behind the dusty expanse.This alluring viewspans over two full moons on the sky, or 17 light-years at theestimated distance of LDN 1251. Tomorrow's picture: sun spot hill<| 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 September 19 - Rings and Seasons of Saturn 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 September 19 Rings and Seasons of Saturn Image Credit &Copyright: Damian Peach/SEN Explanation: On Saturn, the rings tell you the season.On Earth, Wednesday marks an equinox, the time when the Earth's equator tilts directly toward the Sun.Since Saturn's grand rings orbit along the planet's equator, these rings appear most prominent -- from the direction of the Sun -- when the spin axis of Saturn points toward the Sun.Conversely, when Saturn's spin axis points to the side, an equinox occurs and the edge-on rings are hard to see from not only the Sun -- but Earth.In the featured montage, images of Saturn between the years of 2004 and 2015 have been superposed to show the giant planet passing from southern summer toward northern summer.Saturn was as close as it can get to planet Earth last month, and this month the ringed giant is still bright and visible throughout much of the night Tomorrow's picture: dark nebula 1251 <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About...
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APOD: 2021 September 18 - Rubin's Galaxy 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 September 18 Rubin's Galaxy Image Credit: NASA,ESA,B. Holwerda (University of Louisville) Explanation: In this Hubble Space Telescope imagethe bright, spiky starslie in the foreground toward the heroic northern constellationPerseus and well within our own Milky Way galaxy.In sharp focus beyond isUGC 2885,a giant spiral galaxy about 232 million light-years distant.Some 800,000 light-years across compared to the Milky Way'sdiameter of 100,000 light-years or so, it has around 1 trillion stars.That's about 10 times as many stars as the Milky Way.Part of an investigationto understand how galaxies can grow to such enormous sizes,UGC 2885 was also part ofAn Interesting Voyageand astronomer Vera Rubin'spioneering study of the rotation of spiral galaxies.Her work was the first to convincingly demonstratethe dominating presence ofdark matter in our universe. Tomorrow's picture: equinox on Saturn<| 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 September 17 - Video: Flash on Jupiter 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. Video: Flash on Jupiter Video Credit & Copyright: T. Humbert, S. Barré, A. Desmougin & D. Walliang (Société Lorraine d'Astronomie),Astroqueyras Explanation: There has been a flash on Jupiter.A few days ago, several groups monitoring our Solar System's largest planet noticed a two-second long burst of light.Such flashes have been seen before, with the most famous being a series of impactor strikes in 1994.Then, fragments of Comet Shoemaker-Levy 9 struck Jupiter leaving dark patches that lasted for months.Since then, at least seven impacts have been recorded on Jupiter -- usually discovered by amateur astronomers.In the featured video, variations in the Earth's atmosphere cause Jupiter's image to shimmer when, suddenly, a bright flash appears just left of center. Io and its shadow are visible on the right.What hit Jupiter will likely never be known, but considering what we do know of the nearby Solar System, it was likely a piece of rock and ice -- perhaps the size of a bus -- that broke off long-ago from a passing comet...
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APOD: 2021 September 16 - North America and the Pelican 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 September 16 North America and the Pelican Image Credit &Copyright:Andrew Klinger Explanation: Fans of our fair planetmight recognize the outlines of thesecosmic clouds.On the left, bright emission outlined by dark, obscuring dust lanesseems to trace a continental shape, lending the popular nameNorth America Nebulato the emission region cataloged as NGC 7000.To the right, just off the North America Nebula's east coast,is IC 5070, whose avianprofile suggeststhePelican Nebula. The two bright nebulae are about 1,500 light-years away,part of the samelarge and complexstar forming region, almost as nearby as thebetter-known Orion Nebula.At that distance, the 3 degree wide field of view would span80 light-years.This careful cosmic portraitusesnarrow bandimages combined to highlight the brightionization frontsand the characteristic glow from atomic hydrogen, sulfur, and oxygen gas.These nebulae can be seen with binoculars from a dark location. Look northeast of bright starDeneb in the constellation Cygnus the Swan. Tomorrow's picture: Flash on Jupiter<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry...
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APOD: 2021 September 15 - Cyclone Paths on Planet Earth 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 September 15 Cyclone Paths on Planet Earth Image Credit: National Hurricane Center, NOAA, NASA; Processing: Nilfanion (via Wikipedia) Explanation: Where on Earth do cyclones go?Known as hurricanes when in the Atlantic Ocean and typhoons when in the Pacific, the featured map shows the path of all major storms from 1985 through 2005. The map shows graphically that cyclones usually occur over water, which makes sense since evaporating warm water gives them energy.The map also shows that cyclones never cross -- and rarely approach -- the Earth's equator, since the Coriolis effect goes to zero there, and cyclones need the Coriolis force to circulate.The Coriolis force also causes cyclone paths to arc away from the equator.Although long-term trends remain a topic of research, evidence indicates that hurricanes have become, on the average, more powerful in the North Atlantic over the past 30 years, and their power is projected to keep increasing. Follow APOD on Instagram in: English,Farsi,Indonesian,Persian, or Portuguese Tomorrow's picture: off the coast <| Archive| Submissions...
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APOD: 2021 September 14 - Mars Panorama 360 from Curiosity 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 September 14 Mars Panorama 360 from Curiosity Image Credit: NASA,JPL-Caltech,MSSS; Processing & License: Elisabetta Bonora & Marco Faccin (aliveuniverse.today) Explanation: Which way up Mount Sharp?In early September, the robotic rover Curiosity continued its ascent up the central peak of Gale Crater, searching for more clues about ancient water and further evidence that Mars could once have been capable of supporting life. On this recent Martian morning, before exploratory drilling, the rolling rover took this 360-degree panorama, in part to help Curiosity's human team back on Earth access the landscape and chart possible future routes. In the horizontally-compressed featured image, an amazing vista across Mars was captured, complete with layered hills, red rocky ground, gray drifting sand, and a dusty atmosphere.The hill just left of center has been dubbed Maria Gordon Notch in honor of a famous Scottish geologist. The current plan is to direct Curiosity to approach, study, and pass just to the right of Gordon Notch on its exploratory trek. Tomorrow's picture: cyclone earth <|...
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APOD: 2021 September 13 - Night Sky Reflected 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 September 13 Night Sky Reflected Image Credit & Copyright: Egon Filter Explanation: What's that in the mirror?In the featured image of the dark southern sky, the three brightest galaxies of the night are all relatively easy to identify.Starting from the left, these are the Small Magellanic Cloud (SMC), the Large Magellanic Cloud (LMC), and part of the central band of our Milky Way Galaxy.All three are also seen reflected in a shallow pool of water.But what is seen in the mirror being positioned by the playful astrophotographer?Dust clouds near the center of our Milky Way -- and the planet Jupiter. The composite was carefully planned and composed from images captured from the same camera in the same location and during the same night in mid-2019 in Mostardas, south Brazil. The picture won first place in the Connecting to the Dark division of the International Dark-Sky Association's Capture the Dark contest for 2021. Quiz: What is pictured in the double-reflection below the main mirror? Tomorrow's picture: mars 360 panorama...
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What's happened to the sky?