APOD: 2022 April 17 - Shuttle Over 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. 2022 April 17 Shuttle Over Earth Image Credit: NASA, Expedition 22 Crew Explanation: What's that approaching?Astronauts on board theInternational Space Station in 2010 first saw it far in the distance. Soon it enlarged to become adark silhouette.As it came even closer, thesilhouette appeared to be a spaceship.Finally, the object revealed itself to be theSpace Shuttle Endeavour, and it soon docked as expected with theEarth-orbiting space station. Pictured here, Endeavour was imaged near Earth's horizon as it approached, where several layers of theEarth's atmosphere were visible.Directly behind the shuttle is themesosphere, which appears blue. The atmospheric layer that appears white is thestratosphere,while the orange layer is Earth'sTroposphere.Together, these thin layers of air -- collectively spanning less than 2 percent of Earth's radius -- sustain us all in many ways, including providing oxygen to breath and a barrier to dangerous radiations from space. Coming up Friday: Earth Day 2022 Tomorrow's picture: steppe sky <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU)...

APOD: 2022 April 16 - Orion Pines 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 16 Orion Pines Image Credit &Copyright: Juan Carlos Casado(Starry Earth,TWAN) Explanation: Taken with a camera fixed to a tripod, many short exposureswere aligned with the stars to unveil this beautiful, dark night sky.Captured nearthe rural village of Albany`aat the northeastern corner of Spain, the threestars of Orion's belt stretch across top center in the starry frame.Alnitak, the easternmost (left) of thebelt stars is seen next to the more diffuse glow of theFlame Nebulaand the dark notch of the famous Horsehead.Easily visible to the naked-eyeThe Great Nebula of Orionis below the belt stars.A mere 1,500 light-years distant, it is the closest largestellar nursery to our fair planet.Best seen in photographs, the broad and faint arc ofBarnard's Loop seems toembrace Orion's brighterstars and nebulae though.In the northern spring the familiarnorthern winter constellationis setting.Near the western horizon toward lower right Orion'sapparently brightblue supergiant Rigel just touches the branches of a pine tree. Tomorrow's picture: Endeavour in Orbit <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors...

APOD: 2022 April 15 - The Gator-Back Rocks of 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 April 15 The Gator-Back Rocks of Mars Image Credit: NASA,JPL-Caltech,MSSS Explanation: Wind-sharpened rocksknown as ventifactscover this broad sloping plain in the foot hillsof Mount Sharp, Gale crater, Mars.Dubbed gator-back rocks their rugged, scaly appearance iscaptured in these digitally stitched Mastcam framesfrom the Curiosity rover on mission sol 3,415 (March 15, 2022).Driving over gator-back rocks before hasresulted in damage tothe rover's wheels, so Curiosity team members decided toturn around andtake another pathto continue the rover's climb.Curiosity has been on an ascent of Gale crater's central 5.5 kilometerhigh mountain since 2014.As it climbs, the durable rover has been able to explore layers shaped bywater on Mars billions of years ago. Tomorrow's picture: the pines of Orion <| 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 14 - Messier 96 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 14 Messier 96 Image Credit &Copyright:Mark HansonandMike Selby Explanation: Spiral arms seem to swirl around the core ofMessier 96 inthiscolorful, detailed portraitof a beautiful island universe.Of course M96 is a spiral galaxy,and counting the faint arms extendingbeyond the brighter central region it spans 100 thousandlight-years or so.That's about the size of our own Milky Way.M96 is known to be 38 million light-years distant, a dominantmember of theLeo I galaxy group.Background galaxies and smaller Leo I group memberscan be found by examining the picture.The most intriguing one is itself a spiral galaxy seennearly edge onbehind the outer spiral arm near the 1 o'clock position fromcenter.Its bright central bulge cut by its own dark dust clouds,the edge-on background spiral appears to be about 1/5 the size of M96.If that background galaxy is similar in actual size to M96, then itwould be about 5 timesfartheraway. Tomorrow's picture: the red planet rocks <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell...

APOD: 2022 April 13 - Milky Way over Devils Tower 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 13 Milky Way over Devils Tower Image Credit & Copyright: MaryBeth Kiczenski Explanation: What created Devils Tower?The origin of this extraordinary rock monolith in Wyoming, USA is still debated, with a leading hypothesis holding that it is a hardened lava plume that never reached the surface to become a volcano. In this theory, the lighter rock that once surrounded the dense volcanic neck has now eroded away, leaving the dramatic tower.Known by Native Americans by names including Bear's Lodge and Great Gray Horn, the dense rock includes the longest hexagonal columns known, some over 180-meters tall.High above, the central band of the Milky Way galaxy arches across the sky. Many notable sky objects are visible, including dark strands of the Pipe Nebula and the reddish Lagoon Nebula to the tower's right. Green grass and trees line the foreground, while clouds appear near the horizon to the tower's left. Unlike many other international landmarks, mountaineers are permitted to climb Devils Tower. Birthday Surprise: What picture did...

APOD: 2022 April 12 - N11: Star Clouds of the LMC 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 12 N11: Star Clouds of the LMC Image Credit: NASA, ESA; Processing: Josh Lake Explanation: Massive stars, abrasive winds, mountains of dust, and energetic light sculpt one of the largest and most picturesque regions of star formation in the Local Group of Galaxies. Known as N11, the region is visible on the upper right of many images of its home galaxy, the Milky Way neighbor known as the Large Magellanic Cloud (LMC). The featured image was taken for scientific purposes by the Hubble Space Telescope and reprocessed for artistry. Although the section imaged above is known as NGC 1763, the entire N11 emission nebula is second in LMC size only to the Tarantula Nebula. Compact globules of dark dust housing emerging young stars are also visible around the image. A recent study of variable stars in the LMC with Hubble has helped to recalibrate the distance scale of the observable universe, but resulted in a slightly different scale than found using the pervasive cosmic...

APOD: 2022 April 11 - A Space Station Crosses a Busy 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 11 A Space Station Crosses a Busy Sun Image Credit & Copyright: Wang Letian (Eyes at Night) Explanation: Typically, the International Space Station is visible only at night. Slowly drifting across the night sky as it orbits the Earth, the International Space Station (ISS) can be seen as a bright spot several times a year from many locations. The ISS is then visible only just after sunset or just before sunrise because it shines by reflected sunlight -- once the ISS enters the Earth's shadow, it will drop out of sight.The only occasion when the ISS is visible during the day is when it passes right in front of the Sun.Then, it passes so quickly that only cameras taking short exposures can visually freeze the ISS's silhouette onto the background Sun.The featured picture did exactly that -- it is actually a series of images taken earlier this month from Beijing, China with perfect timing. This image series was later combined with separate images...

APOD: 2022 April 10 - Shadows at the Moons South Pole 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 10 Shadows at the Moon's South Pole Image Credit: NASA, Arizona State U., Lunar Reconnaissance Orbiter Explanation: Was this image of the Moon's surface taken with a microscope?No -- it's a multi-temporal illumination map made with a wide-angle camera. To create it, the Lunar Reconnaissance Orbiter spacecraft collected 1,700 images over a period of 6 lunar days (6 Earth months), repeatedly covering an area centered on the Moon's south pole from different angles. The resulting images were stacked to produce the featured map -- representing the percentage of time each spot on the surface was illuminated by the Sun. Remaining convincingly in shadow, the floor of the 19-kilometer diameter Shackletoncrater is seen near the map's center. The lunar south pole itself is at about 9 o'clock on the crater's rim. Crater floors near the lunar south and north poles can remain in permanent shadow, while mountain tops can remain in nearly continuous sunlight. Useful for future outposts, the shadowed crater floors could offer reservoirs...

APOD: 2022 April 9 - Mars-Saturn Conjunction 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 9 Mars-Saturn Conjunction Image Credit &Copyright:Damian Peach Explanation: Fainter stars in the zodiacal constellation Capricornus arescattered near the plane ofthe eclipticin this field of view.The two brightest ones at center aren't stars at all though, butthe planets Mars and Saturn.Taken on the morning of April 4, thetelescopic snapshotcaptured their tantalizingclose conjunctionin a predawn sky, the pair of planets separatedby only about 1/3 of a degree.That's easily less than the apparent width of a Full Moon.Can you tell which planet is which?If you guessed Mars is the redder one , you'd be right.Above Mars, slightly fainter Saturn still shines with apaler yellowish tinge inreflected sunlight. Even at the low magnification, Saturn's largest and brightestmoon Titan can be spotted hugging the planet very closely on the left. Tomorrow's picture: in the shadows <| 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 8 - Hale-Bopp: The Great Comet of 1997 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 8 Hale-Bopp: The Great Comet of 1997 Image Credit &Copyright:Stefan Seip(TWAN) Explanation: Only twenty-five years ago,Comet Hale-Bopprounded the Sun and offered a dazzling spectacle inplanet Earth's night skies.Digitized fromthe original astrophoto on 35mm color slide film,this classic image of the Great Comet of 1997was recorded a few days after its perihelion passage onApril 1, 1997.Made with a camera and telephoto lens piggy-backed on a small telescope,the 10 minute long,hand-guided exposure features the memorabletails ofHale-Bopp, a whitish dust tail and blue ion tail.Here, the ion tail extends well over ten degrees acrossthe northern sky.In all, Hale-Bopp was reported as visibleto the naked eye from late May 1996 through September 1997.Also known as C/1995 O1, Hale-Bopp is recognized asone of the most compositionallypristine cometsto pass through the inner Solar System.A visitor from the distantOort cloud,the comet's next perihelion passageshould be around the year 4380 AD.Do youremember Hale-Bopp? Tomorrow's picture: planetary pairing <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors &...

APOD: 2022 April 7 - Messier 24: Sagittarius Star Cloud 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 7 Messier 24: Sagittarius Star Cloud Image Credit &Copyright:Gabriel Rodrigues Santos Explanation: Unlike most entriesin Charles Messier's famous catalog of deep sky objects,M24is not a bright galaxy, star cluster, or nebula.It's a gap in nearby, obscuring interstellar dust clouds that allowsa view of the distant stars in the Sagittarius spiral armof our Milky Way galaxy.When you gaze at the star cloudwith binoculars or small telescope you arelooking through a window over 300 light-years wide at stars some10,000 light-years or more from Earth.Sometimes called the Small Sagittarius Star Cloud, M24's luminousstars fillthis gorgeous starscape.Covering over 3 degrees or the width of 6 full moons in theconstellation Sagittarius,the telescopic field of view includesdark markingsB92 and B93 just above center, along with otherclouds of dust and glowing nebulae toward the center of the Milky Way. 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...

APOD: 2022 April 6 - Earendel: A Star in the Early 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 6 Earendel: A Star in the Early Universe Image Credit: NASA, ESA, B. Welch (JHU), D. Coe (STScI); Processing: A. Pagan (STScI) Explanation: Is Earendel the farthest star yet discovered?This scientific possibility started when the Hubble Space Telescope observed a huge cluster of galaxies.The gravitational lens effect of this cluster was seen to magnify and distort a galaxy far in the background.This distorted background galaxy -- so far away it has a redshift of 6.2 -- appears in the featured image as a long red string, while beads on that string are likely to be star clusters.  The galaxy cluster lens creates a line of maximum magnification line where superposed background objects may appear magnified many thousands of times.On the intersection between the galaxy line and the maximum magnification line is one "bead" which shows evidence of originating from a single bright star in the early universe -- now named Earendel.Future investigations may include more imaging by Hubble to see how Earendel's brightness varies, and, quite...

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 &...