Astronomy Picture of the Day 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. 2024 March 28 Millions of Stars in Omega Centauri Image Credit &Copyright:Massimo Di Fuscoand Mirco Turra Explanation: Globular star clusterOmega Centauri,also known as NGC 5139, is 15,000 light-years away.The cluster is packed with about 10 millionstars much older than the Sun within a volume about 150 light-years indiameter.It's the largest and brightest of 200 or so knownglobular clusters that roam the halo of our Milky Way galaxy.Though most star clusters consist of stars with the same age andcomposition, the enigmatic Omega Cen exhibits the presence ofdifferentstellar populations with a spread of ages and chemical abundances.In fact,Omega Cen may betheremnantcore of a small galaxy merging with the Milky Way.With a yellowish hue,Omega Centauri's red giant stars are easy to pick out in thissharp, color telescopic view. 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: Amber StraughnSpecific rights apply.NASA Web Privacy,Accessibility NoticesA service of:ASD atNASA /GSFC,NASA Science Activation& Michigan Tech. U.

APOD: 2024 March 21 - The Leo Trio 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. 2024 March 21 The Leo Trio Image Credit &Copyright: Steve Cannistra Explanation: This popular group leaps into the early evening sky around the Marchequinox andthe northern hemisphere spring. Famous as theLeo Triplet,the three magnificent galaxies found in the prominentconstellation Leogather here in one astronomical field of view.Crowd pleasers when imaged with even modesttelescopes, they can be introduced individually asNGC 3628 (left), M66 (bottom right), and M65 (top).All three are largespiral galaxies buttend to look dissimilar, because their galactic disks aretilted at different angles to our line of sight.NGC 3628,also known as the Hamburger Galaxy,is temptingly seen edge-on, with obscuring dust lanescutting across its puffy galactic plane.The disksof M66andM65 areboth inclined enough to show off their spiral structure. Gravitational interactions between galaxies in the grouphave left telltale signs, including the tidal tails andwarped, inflated disk of NGC 3628 and the drawn out spiral arms of M66.This gorgeous viewof the region spans over 1 degree (two full moons) on the skyin a frame that covers over half a million light-years at...

Astronomy Picture of the Day 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. 2024 March 22 Phobos: Moon over Mars Image Credit: NASA,ESA,Zolt Levay (STScI)-Acknowledgment:J.Bell (ASU) andM.Wolff (SSI) Explanation: A tiny moon with a scary name,Phobos emerges from behindthe Red Planet in this timelapse sequence from the Earth-orbitingHubble Space Telescope.Over 22 minutes the 13 separate exposures werecaptured near the 2016 closestapproach of Mars to planet Earth.Martians have to look to the westto watch Phobos rise, though.The small moon is closer to itsparent planet than any othermoon in the Solar System, about 3,700 miles (6,000 kilometers)above the Martian surface.It completes one orbit in just 7 hours and 39 minutes.That's faster than a Mars rotation, which corresponds toabout 24 hours and 40 minutes.So on Mars, Phobos can be seen to rise abovethe western horizon 3 times a day.Still, Phobos is doomed. Tomorrow's picture: Ares 3 Landing Site <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Amber StraughnSpecific rights apply.NASA Web Privacy,Accessibility NoticesA service of:ASD atNASA /GSFC,NASA Science Activation& Michigan Tech. U.

Astronomy Picture of the Day 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. 2024 March 21 The Leo Trio Image Credit &Copyright: Steve Cannistra Explanation: This popular group leaps into the early evening sky around the Marchequinox andthe northern hemisphere spring. Famous as theLeo Triplet,the three magnificent galaxies found in the prominentconstellation Leogather here in one astronomical field of view.Crowd pleasers when imaged with even modesttelescopes, they can be introduced individually asNGC 3628 (left), M66 (bottom right), and M65 (top).All three are largespiral galaxies buttend to look dissimilar, because their galactic disks aretilted at different angles to our line of sight.NGC 3628,also known as the Hamburger Galaxy,is temptingly seen edge-on, with obscuring dust lanescutting across its puffy galactic plane.The disksof M66andM65 areboth inclined enough to show off their spiral structure. Gravitational interactions between galaxies in the grouphave left telltale signs, including the tidal tails andwarped, inflated disk of NGC 3628 and the drawn out spiral arms of M66.This gorgeous viewof the region spans over 1 degree (two full moons) on the skyin a frame that covers over half a million light-years at thetrio's estimated distance...

APOD: 2024 March 15 - Portrait of NGC 1055 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. 2024 March 15 Portrait of NGC 1055 Image Credit &Copyright: Dave Doctor Explanation: Big, beautiful spiral galaxy NGC 1055 is a dominant member ofa small galaxy groupa mere 60 million light-years away towardthe aquatically intimidatingconstellation Cetus.Seen edge-on, the island universe spans over 100,000 light-years,a little larger than ourown Milky Way galaxy.The colorful, spiky stars decorating this cosmicportrait of NGC 1055are in the foreground, well within the Milky Way.But the telltale pinkish star formingregions are scattered throughwinding dust lanes along the distant galaxy's thin disk.With a smattering of even more distant background galaxies, thedeep image also reveals a boxy halo that extendsfar above and below the central bulge and disk of NGC 1055.The halo itself is laced with faint, narrow structures,and could represent the mixed and spread outdebris from a satellite galaxydisrupted bythe larger spiral some10 billion years ago. Tomorrow's picture: an extremely large telescope <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Amber StraughnSpecific...

Astronomy Picture of the Day 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. 2024 March 16 ELT and the Milky Way Image Credit &License:European Southern Observatory -Courtesy: Jens Scheidtmann Explanation: The southern winterMilky Way sprawlsacross this night skyscape.Looking due south, thewebcam viewwas recorded near local midnighton March 11 in dry, dark skies over the central Chilean Atacama desert.Seen below the graceful arc of diffuse starlightare satellite galaxies of the mighty Milky Way, also known asthe Large and SmallMagellanic clouds.In the foreground is the site of the European SouthernObservatory's 40-metre-classExtremely Large Telescope(ELT).Under construction at the 3000 metre summit ofCerro Armazones, the ELT ison track to become planet Earth's biggest Eye on the Sky. Tomorrow's picture: when galaxies collide <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Amber StraughnSpecific rights apply.NASA Web Privacy,Accessibility NoticesA service of:ASD atNASA /GSFC,NASA Science Activation& Michigan Tech. U.

APOD: 2024 March 14 - Moon Pi and Mountain Shadow 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. 2024 March 14 Moon Pi and Mountain Shadow Image Credit & Copyright:Daniel Lopez(El Cielo de Canarias) Explanation: What phase of the Moon is 3.14 radians from the Sun?The Full Moon, of course.Even though theMoon might look fullfor several days, the Moon is truly at its full phase when it isPi radians(aka 180 degrees) from the Sun in ecliptic longitude.That's opposite the Sun in planet Earth's sky.Rising as the Sun set on March 9, 2020, only an hour or so after the moment ofits full phase, this orange tinted andslightly flattenedMoon still looked full.It was photographed opposite the setting Sun from Teide National Parkon the Canary Island of Tenerife.Also opposite the setting Sun, seen from near the Teide volcano peakabout 3,500 meters above sea level, is the mountain's risingtriangular shadowextending into Earth's dense atmosphere.Below the distant ridge line on the left are thewhite telescope domes ofTeide Observatory.Again Pi radians from the Sun, on March 25 the Full Moon will dimslightly as it glides through Earth's outer shadow in...

Astronomy Picture of the Day 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. 2024 March 15 Portrait of NGC 1055 Image Credit &Copyright: Dave Doctor Explanation: Big, beautiful spiral galaxy NGC 1055 is a dominant member ofa small galaxy groupa mere 60 million light-years away towardthe aquatically intimidatingconstellation Cetus.Seen edge-on, the island universe spans over 100,000 light-years,a little larger than ourown Milky Way galaxy.The colorful, spiky stars decorating this cosmicportrait of NGC 1055are in the foreground, well within the Milky Way.But the telltale pinkish star formingregions are scattered throughwinding dust lanes along the distant galaxy's thin disk.With a smattering of even more distant background galaxies, thedeep image also reveals a boxy halo that extendsfar above and below the central bulge and disk of NGC 1055.The halo itself is laced with faint, narrow structures,and could represent the mixed and spread outdebris from a satellite galaxydisrupted bythe larger spiral some10 billion years ago. Tomorrow's picture: an extremely large telescope <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Amber StraughnSpecific rights apply.NASA Web Privacy,Accessibility...

Astronomy Picture of the Day 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. 2024 March 14 Moon Pi and Mountain Shadow Image Credit & Copyright:Daniel Lopez(El Cielo de Canarias) Explanation: What phase of the Moon is 3.14 radians from the Sun?The Full Moon, of course.Even though theMoon might look fullfor several days, the Moon is truly at its full phase when it isPi radians(aka 180 degrees) from the Sun in ecliptic longitude.That's opposite the Sun in planet Earth's sky.Rising as the Sun set on March 9, 2020, only an hour or so after the moment ofits full phase, this orange tinted andslightly flattenedMoon still looked full.It was photographed opposite the setting Sun from Teide National Parkon the Canary Island of Tenerife.Also opposite the setting Sun, seen from near the Teide volcano peakabout 3,500 meters above sea level, is the mountain's risingtriangular shadowextending into Earth's dense atmosphere.Below the distant ridge line on the left are thewhite telescope domes ofTeide Observatory.Again Pi radians from the Sun, on March 25 the Full Moon will dimslightly as it glides through Earth's outer shadow in apenumbral lunar eclipse. Tomorrow's picture:...

APOD: 2024 March 8 - The Tarantula Zone 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. 2024 March 8 The Tarantula Zone Image Credit &Copyright: Processing -Robert Gendler,Roberto ColombariData -Hubble Tarantula Treasury,European Southern Observatory,James Webb Space Telescope,AmateurSources Explanation: The Tarantula Nebula,also known as 30 Doradus, is more than a thousand light-years in diameter,a giant star forming region within nearby satellite galaxy theLarge Magellanic Cloud.About 180 thousand light-years away, it's the largest,most violent star forming region known in the whole LocalGroup of galaxies.The cosmic arachnid sprawls acrossthis magnificent view,an assembly of image data from large space- and ground-based telescopes.Within the Tarantula (NGC 2070),intense radiation, stellar winds, and supernova shocksfrom the central young cluster of massive stars cataloged as R136energize the nebular glow and shape the spidery filaments.Around theTarantula are other star forming regions withyoung star clusters, filaments, and blown-outbubble-shaped clouds.In fact, the frame includes the site of the closest supernova inmodern times, SN 1987A,at lower right.The rich field of view spans about 2 degreesor 4 full moons in the southernconstellation Dorado.But were the Tarantula Nebula closer, say 1,500 light-years distant likethe Milky Way's own star forming...

Astronomy Picture of the Day 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. 2024 March 9 Comet Pons-Brooks in Northern Spring Image Credit &Copyright: Petr Horálek /Institute of Physics in Opava Explanation: As spring approaches for northern skygazersComet 12P/Pons-Brooksis growing brighter.Currently visiblewith small telescopes and binocularsthe Halley-type comet could reach naked eye visibility in thecoming weeks.Seen despite a foggy atmosphere,the comet's green coma and long tail hover near the horizon,in this well-composeddeep night skyscapefrom Revuca, Slovakia recorded on March 5.In the sky above the Halley-type comet,the Andromeda (right) and Triangulum galaxiesflank bright star Mirach,beta star of the constellation Andromeda.The two spiral galaxies are members of our local galaxy group andover 2.5 million light-years distant.Comet Pons-Brooks is a periodicvisitor to the inner Solar Systemand less than 14 light-minutes away.Reaching its perihelion on April 21, this comet should be visiblein the skyduring the April 8 total solar eclipse. Tomorrow's picture: at the End of the World <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Amber StraughnSpecific rights apply.NASA WebPrivacy Policy and Important NoticesA...

APOD: 2024 March 7 - The Crew-8 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. 2024 March 7 The Crew-8 Nebula Image Credit &Copyright: Michael Seeley Explanation: Not theJames Webb Space Telescope'slatest view of a distant galactic nebula,this cloud of gas and dust dazzledspacecoast skygazers on March 3.The telephoto snapshot was taken minutes after the launch ofa Falcon 9 rocket onthe SpaceX Crew-8 missionto the International Space Station.It captures plumes and exhaust from the separatedfirst and second stages, a driftingRorschach patternin dark evening skies. The bright spot near bottom center within thestunning terrestrial nebulosity isthe second stage engine firing to carry 4humans to spacein the Crew Dragonspacecraft Endeavour.In sharp silhouette just above it is the Falcon 9 first stage booster orienting itself for returnto a landing zoneat Cape Canaveral, planet Earth.This reuseable first stage booster was making its first flight.But theCrew Dragon Endeavourcapsule has flown humans to low Earth orbit and back again 4 times before.Endeavour,as a name for a spacecraft, has also seen reuse, christening retiredSpace Shuttle Endeavourand theApollo 15 command module. Tomorrow's picture: distant galactic nebula <| Archive| Submissions | Index| Search|...

Astronomy Picture of the Day 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. 2024 March 8 The Tarantula Zone Image Credit &Copyright: Processing -Robert GendlerData -Hubble Tarantula Treasury,European Southern Observatory,James Webb Space Telescope,AmateurSources Explanation: The Tarantula Nebula,also known as 30 Doradus, is more than a thousand light-years in diameter,a giant star forming region within nearby satellite galaxy theLarge Magellanic Cloud.About 180 thousand light-years away, it's the largest,most violent star forming region known in the whole LocalGroup of galaxies.The cosmic arachnid sprawls acrossthis magnificent view,an assembly of image data from large space- and ground-based telescopes.Within the Tarantula (NGC 2070),intense radiation, stellar winds, and supernova shocksfrom the central young cluster of massive stars cataloged as R136energize the nebular glow and shape the spidery filaments.Around theTarantula are other star forming regions withyoung star clusters, filaments, and blown-outbubble-shaped clouds.In fact, the frame includes the site of the closest supernova inmodern times, SN 1987A,at lower right.The rich field of view spans about 2 degreesor 4 full moons in the southernconstellation Dorado.But were the Tarantula Nebula closer, say 1,500 light-years distant likethe Milky Way's own star forming Orion Nebula,it would take...

Astronomy Picture of the Day 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. 2024 March 7 The Crew-8 Nebula Image Credit &Copyright: Michael Seeley Explanation: Not theJames Webb Space Telescope'slatest view of a distant galactic nebula,this cloud of gas and dust dazzledspacecoast skygazers on March 3.The telephoto snapshot was taken minutes after the launch ofa Falcon 9 rocket onthe SpaceX Crew-8 mission,to the International Space Station.It captures plumes and exhaust from the separatedfirst and second stage, a driftingRorschach patternin dark evening skies. The bright spot near bottom center within thestunning terrestrial nebulosity isthe second stage engine firing to carry 4humans to spacein the Crew Dragonspacecraft Endeavour.In sharp silhouette just above it is the Falcon 9 first stage booster orienting itself for returnto a landing zoneat Cape Canaveral, planet Earth.This reuseable first stage booster was making its first flight.But theCrew Dragon Endeavourcapsule has flown humans to low Earth orbit and back again 4 times before.Endeavour,as a name for a spacecraft, has also seen reuse, christening retiredSpace Shuttle Endeavourand theApollo 15 command module. Tomorrow's picture: distant galactic nebula <| Archive| Submissions | Index| Search| Calendar| RSS| Education|...

APOD: 2024 March 1 - Odysseus and The Dish 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. 2024 March 1 Odysseus and The Dish Image Credit &Copyright: John Sarkissian(ATNF Parkes Radio Observatory) Explanation: Murriyang, the CSIRO’s Parkes Radio Telescope,points toward a nearly Full Moon in this imagefrom New South Wales, Australia, planet Earth.Bathed in moonlight, the 64 meter dish isreceiving weak radio signals from Odysseus,following therobotic lander's February 22touch down some300 kilometers north of the Moon's south pole.The landing of Odysseus representsthe first U.S. landing on the Moon since theApollo 17 mission in 1972.Odysseus' tilted orientationon the lunar surface prevents its high-gain antennafrom pointing toward Earth.But the sensitivity of the large, steerable Parkes dishsignificantly improvedthe reception of data from the experiments delivered to thelunar surface by the robotic moon lander.Of course the Parkes Radio Telescope dishbecame famous for its superiorlunar television receptionduring the Apollo 11 mission in 1969,allowing denizens of planet Earth to watchthe first moonwalk. 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: Amber StraughnSpecific rights apply.NASA...

Astronomy Picture of the Day 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. 2024 March 2 Odysseus on the Moon Image Credit: Intuitive Machines Explanation: Methaloxrocket engine firing, Odysseus' landing legs absorbfirst contact with the lunar surface in this wide-angle snapshot froma camera on board the robotic Intuitive MachinesNova-C moon lander.Following thelanding on February 22,broken landing legs,visible in the image,ultimately left the lander at rest but tilted.Odysseus' gentle leaninto a sloping lunar surfacepreserved the phone booth-sized lander'sability to operate, collect solar power, andreturn images and data to Earth.Its exact landing sitein the Moon's far south polar regionwas imaged by NASA's Lunar Reconnaissance Orbiter.Donated by NASA,the American flag seen on the lander's central panel is 1970 Apolloprogram flight hardware. Tomorrow's picture: behind the Moon <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Amber StraughnSpecific rights apply.NASA WebPrivacy Policy and Important NoticesA service of:ASD atNASA /GSFC,NASA Science Activation& Michigan Tech. U.

APOD: 2024 February 29 - Julius Caesar and Leap Days 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. 2024 February 29 Julius Caesar and Leap Days Image Credit &License: Classical Numismatic Group, Inc.,Wikimedia Explanation: In 46 BC Julius Caesar reformed the calendar system.Based on advice by astronomerSosigenes of Alexandria,the Julian calendar included oneleap dayevery four years to account for the fact that an Earthyear is slightly more than 365 days long.In modern terms, the time it takes for the planet to orbit the Sunonce is 365.24219 mean solar days.So if calendar years contained exactly 365 days they would driftfrom the Earth's year by about 1 day every 4 years andeventually July (named forJulius Caesarhimself) would occur during the northern hemisphere winter.By adopting a leap year with an extra day every four years, the Julian calendar year would drift much less.In 1582 Pope Gregory XIII provided the further fine-tuning that leap days should not occur in years ending in 00, unless divisible by 400.This GregorianCalendar system is the one in wide use today.Of course, tidal frictionin the Earth-Moon system slows Earth's rotation and graduallylengthens the day...

Astronomy Picture of the Day 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. 2024 March 1 Odysseus and The Dish Image Credit &Copyright: John Sarkissian(ATNF Parkes Radio Observatory) Explanation: Murriyang, the CSIRO’s Parkes radio telescopepoints toward a nearly Full Moon in this imagefrom New South Wales, Australia, planet Earth.Bathed in moonlight, the 64 meter dish isreceiving weak radio signals from Odysseus,following therobotic lander's February 22touch down some300 kilometers north of the Moon's south pole.The landing of Odysseus representsthe first U.S. landing on the Moon since theApollo 17 mission in 1972.Odysseus' tilted orientationon the lunar surface prevents its high-gain antennafrom pointing toward Earth.But the sensitivity of the large, steerable Parkes dishsignificantly improvedthe reception of data from the experiments delivered to thelunar surface by the robotic moon lander.Of course the Parkes Radio Telescope dishbecame famous for its superiorlunar television receptionduring the Apollo 11 mission in 1969,allowing denizens of planet Earth to watchthe first moonwalk. 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: Amber StraughnSpecific rights apply.NASA WebPrivacy Policy and Important...

Astronomy Picture of the Day 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. 2024 February 29 Julius Caesar and Leap Days Image Credit &License: Classical Numismatic Group, Inc.,Wikimedia Explanation: In 46 BC Julius Caesar reformed the calendar system.Based on advice by astronomerSosigenes of Alexandria,the Julian calendar included oneleap dayevery four years to account for the fact that an Earthyear is slightly more than 365 days long.In modern terms, the time it takes for the planet to orbit the Sunonce is 365.24219 mean solar days.So if calendar years contained exactly 365 days they would driftfrom the Earth's year by about 1 day every 4 years andeventually July (named forJulius Caesarhimself) would occur during the northern hemisphere winter.By adopting a leap year with an extra day every four years, the Julian calendar year would drift much less.In 1582 Pope Gregory XIII provided the further fine-tuning that leap days should not occur in years ending in 00, unless divisible by 400.This GregorianCalendar system is the one in wide use today.Of course, tidal frictionin the Earth-Moon system slows Earth's rotation and graduallylengthens the day by about 1.4 milliseconds per...

APOD: 2024 February 23 - The Pencil Nebula Supernova Shock Wave 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. 2024 February 23 The Pencil Nebula Supernova Shock Wave Image Credit &Copyright: Helge Buesing Explanation: This supernova shock wave plows through interstellar space at over 500,000 kilometers per hour.Centered and moving upward in thesharply detailed color compositeits thin, bright, braided filaments are actually long ripples in a cosmic sheet of glowing gas seen almost edge-on.Discovered in the 1840s bySir John Herschel,the narrow-looking nebulais sometimes known as Herschel's Ray.Cataloged as NGC 2736, its pointed appearance suggests its modern popular name, the Pencil Nebula.The Pencil Nebulais about 800 light-years away.Nearly 5 light-years long it represents only a small part of theVela supernova remnant though.The enormous Vela remnant itselfis around 100 light-years in diameter, the expandingdebris cloud of a starthat was seen to explode about 11,000 years ago.Initially, the section of theshock wave seen as the Pencil nebula was movingat millions of kilometersper hour but has slowed considerably, sweeping upsurrounding interstellar material. Tomorrow's picture: light-weekend <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors...