Astronomy Picture of the Day (Unofficial) apod@hub.polari.us
SPACE!
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Astronomy Picture of the Day for 2021-07-28 12:30:01.608815
2021-07-28T17:30:02Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 28
Ring Galaxy AM 0644-741
Image Credit: NASA, ESA, Hubble, HLA; Processing: Jonathan LodgeExplanation: The rim of the large blue galaxy at the right is an immense ring-like structure 150,000 light years in diameter composed of newly formed, extremely bright, massive stars. AM 0644-741 is known as a ring galaxy and was caused by an immense galaxy collision. When galaxies collide, they pass through each other and their individual stars rarely come into contact. The large galaxy's ring-like shape is the result of the gravitational disruption caused by a small intruder galaxy passing through it. When this happens, interstellar gas and dust become compressed, causing a wave of star formation to move out from the impact point like a ripple across the surface of a pond. Other galaxies in the field of view are background galaxies, not interacting with AM 0644-741. Foreground spiky stars are within our own Milky Way. But the smaller intruder galaxy is caught above and right, near the top of the frame taken by the Hubble Space Telescope. Ring galaxy AM 0644-741 lies about 300 million light years away toward the southern constellation Volans.
Tomorrow's picture: the flower and the black hole
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-27 12:30:01.856361
2021-07-27T17:30:02Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 27
Fleming's Triangular Wisp
Image Credit & Copyright: Anthony SaabExplanation: Chaotic in appearance, these tangled filaments of shocked, glowing gas are spread across planet Earth's sky toward the constellation of Cygnus as part of the Veil Nebula. The Veil Nebula itself is a large supernova remnant, an expanding cloud born of the death explosion of a massive star. Light from the original supernova explosion likely reached Earth over 5,000 years ago. The glowing filaments are really more like long ripples in a sheet seen almost edge on, remarkably well separated into the glow of ionized hydrogen atoms shown in blue and oxygen in red hues. Also known as the Cygnus Loop and cataloged as NGC 6979, the Veil Nebula now spans about 6 times the diameter of the full Moon. The length of the wisp corresponds to about 30 light years, given its estimated distance of 2,400 light years. Often identified as Pickering's Triangle for a director of Harvard College Observatory, it is also named for its discoverer, astronomer Williamina Fleming, as Fleming's Triangular Wisp.
Tomorrow's picture: ring of fire galaxy
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-26 12:30:01.557202
2021-07-26T17:30:02Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 26
CG4: A Ruptured Cometary Globule
Image Credit & Copyright: Nicolas Rolland & Martin PughExplanation: Can a gas cloud grab a galaxy? It's not even close. The "claw" of this odd looking "creature" in the featured photo is a gas cloud known as a cometary globule. This globule, however, has ruptured. Cometary globules are typically characterized by dusty heads and elongated tails. These features cause cometary globules to have visual similarities to comets, but in reality they are very much different. Globules are frequently the birthplaces of stars, and many show very young stars in their heads. The reason for the rupture in the head of this object is not yet known. The galaxy to the left of the globule is huge, very far in the distance, and only placed near CG4 by chance superposition.
Tomorrow's picture: wisp of star death
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-25 12:30:02.316670
2021-07-25T17:30:03Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 25
Crescent Neptune and Triton
Image Credit: NASA, Voyager 2Explanation: Gliding silently through the outer Solar System, the Voyager 2 spacecraft camera captured Neptune and Triton together in crescent phase. The elegant picture of the gas giant planet and its cloudy moon was taken from behind just after closest approach in 1989. It could not have been taken from Earth because Neptune never shows a crescent phase to sunward Earth. The unusual vantage point also robs Neptune of its familiar blue hue, as sunlight seen from here is scattered forward, and so is reddened like the setting Sun. Neptune is smaller but more massive than Uranus, has several dark rings, and emits more light than it receives from the Sun.
Tomorrow's picture: galaxy grabber
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-24 12:30:01.749070
2021-07-24T17:30:02Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 24
The Edge of Space
Image Credit & Copyright: Ralf RohnerExplanation: Where does space begin? For purposes of spaceflight some would say at the Karman line, currently defined as an altitude of 100 kilometers (60 miles). Others might place a line 80 kilometers (50 miles) above Earth's mean sea level. But there is no sharp physical boundary that marks the end of atmosphere and the beginning of space. In fact, the Karman line itself is near the transition between the upper mesophere and lower thermosphere. Night shining or noctilucent clouds are high-latitude summer apparitions formed at altitudes near the top of the mesophere, up to 80 kilometers or so, also known as polar mesopheric clouds. Auroral bands of the northern (and southern) lights caused by energetic particles exciting atoms in the thermosphere can extend above 80 kilometers to over 600 kilometers altitude. Taken from a cockpit while flying at an altitude of 10 kilometers (33,000 feet) in the realm of stratospheric aeronautics, this snapshot captures both noctilucent clouds and aurora borealis under a starry sky, looking toward planet Earth's horizon and the edge of space.
Tomorrow's picture: crescent father and son
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-23 12:30:01.967305
2021-07-23T17:30:02Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 23
Elephant, Bat, and Squid
Image Credit & Copyright: Patrick HsiehExplanation: Sprawling emission nebulae IC 1396 and Sh2-129 mix glowing interstellar gas and dark dust clouds in this 10 degree wide field of view toward the northern constellation Cepheus the King. Energized by its bluish central star IC 1396 (left) is hundreds of light-years across and some 3,000 light-years distant. The nebula's intriguing dark shapes include a winding dark cloud popularly known as the Elephant's Trunk below and right of center. Tens of light-years long, it holds the raw raw material for star formation and is known to hide protostars within. Located a similar distance from planet Earth, the bright knots and swept back ridges of emission of Sh2-129 on the right suggest its popular name, the Flying Bat Nebula. Within the Flying Bat, the most recently recognized addition to this royal cosmic zoo is the faint bluish emission from Ou4, the Giant Squid nebula.
Tomorrow's picture: at the edge of space
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-22 12:30:02.173319
2021-07-22T17:30:03Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 22
NGC 7814: Little Sombrero with Supernova
Image Credit & Copyright: CHART32 TeamExplanation: Point your telescope toward the high flying constellation Pegasus and you can find this expanse of Milky Way stars and distant galaxies. NGC 7814 is centered in the pretty field of view that would almost be covered by a full moon. NGC 7814 is sometimes called the Little Sombrero for its resemblance to the brighter more famous M104, the Sombrero Galaxy. Both Sombrero and Little Sombrero are spiral galaxies seen edge-on, and both have extensive halos and central bulges cut by a thin disk with thinner dust lanes in silhouette. In fact, NGC 7814 is some 40 million light-years away and an estimated 60,000 light-years across. That actually makes the Little Sombrero about the same physical size as its better known namesake, appearing smaller and fainter only because it is farther away. In this telescopic view from July 17, NGC 7814 is hosting a newly discovered supernova, dominant immediately to the left of the galaxy's core. Cataloged as SN 2021rhu, the stellar explosion has been identified as a Type Ia supernova, useful toward calibrating the distance scale of the universe.
Tomorrow's picture: cosmic zoo
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-21 12:30:01.658981
2021-07-21T17:30:02Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 21
Colors: Ring Nebula versus Stars
Image Credit: Robert Vanderbei (Princeton U.)Explanation: What if you could see, separately, all the colors of the Ring? And of the surrounding stars? There's technology for that. The featured image shows the Ring Nebula (M57) and nearby stars through such technology: in this case, a prism-like diffraction grating. The Ring Nebula is seen only a few times because it emits light, primarily, in only a few colors. The two brightest emitted colors are hydrogen (red) and oxygen (blue), appearing as nearly overlapping images to the left of the image center. The image just to the right of center is the color-combined icon normally seen. Stars, on the other hand, emit most of their light in colors all across the visible spectrum. These colors, combined, make a nearly continuous streak -- which is why stars appear accompanied by multicolored bars. Breaking object light up into colors is scientifically useful because it can reveal the elements that compose that object, how fast that object is moving, and how distant that object is.
Tomorrow's picture: open space
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-20 12:30:02.097084
2021-07-20T17:30:03Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 20
Thor's Helmet
Image Credit & Copyright: Bernard MillerExplanation: Thor not only has his own day (Thursday), but a helmet in the heavens. Popularly called Thor's Helmet, NGC 2359 is a hat-shaped cosmic cloud with wing-like appendages. Heroically sized even for a Norse god, Thor's Helmet is about 30 light-years across. In fact, the cosmic head-covering is more like an interstellar bubble, blown with a fast wind from the bright, massive star near the bubble's center. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre-supernova stage of evolution. NGC 2359 is located about 15,000 light-years away toward the constellation of the Great Overdog. This remarkably sharp image is a mixed cocktail of data from broadband and narrowband filters, capturing not only natural looking stars but details of the nebula's filamentary structures. The star in the center of Thor's Helmet is expected to explode in a spectacular supernova sometime within the next few thousand years.
Almost Hyperspace: Random APOD Generator
Tomorrow's picture: colors of ring
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-19 12:30:01.529432
2021-07-19T17:30:02Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 19
Framed by Trees: A Window to the Galaxy
Image Credit & Copyright: Will GodwardExplanation: The photographer had this shot in mind for some time. He knew that objects overhead are the brightest -- since their light is scattered the least by atmospheric air. He also that knew the core of our Milky Way Galaxy was just about straight up near midnight around this time of year in South Australia. Chasing his mental picture, he ventured deep inside the Kuipto Forest where tall radiata pines blocked out much of the sky -- but not in this clearing. There, through a window framed by trees, he captured his envisioned combination of local and distant nature. Sixteen exposures of both trees and the Milky Way Galaxy were recorded. Antares is the bright orange star to left of our Galaxy's central plane, while Alpha Centauri is the bright star just to the right of the image center. The direction toward our Galaxy's center is below Antares. Although in a few hours the Earth's rotation moved the Galactic plane up and to the left -- soon invisible behind the timber, his mental image was secured forever -- and is featured here.
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Tomorrow's picture: two days early
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Whoaaaa, niiiiice 😎
Astronomy Picture of the Day for 2021-07-18 12:30:01.468603
2021-07-18T17:30:02Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 18
The Andromeda Galaxy in Ultraviolet
Image Credit: NASA, JPL-Caltech, GALEXExplanation: What does the Andromeda galaxy look like in ultraviolet light? Young blue stars circling the galactic center dominate. A mere 2.5 million light-years away, the Andromeda Galaxy, also known as M31, really is just next door as large galaxies go. Spanning about 230,000 light-years, it took 11 different image fields from NASA's Galaxy Evolution Explorer (GALEX) satellite telescope to produce this gorgeous portrait of the spiral galaxy in ultraviolet light in 2003. While its spiral arms stand out in visible light images, Andromeda's arms look more like rings in ultraviolet. The rings are sites of intense star formation and have been interpreted as evidence that Andromeda collided with its smaller neighboring elliptical galaxy M32 more than 200 million years ago. The Andromeda galaxy and our own comparable Milky Way galaxy are the most massive members of the Local Group of galaxies and are projected to collide in several billion years -- perhaps around the time that our Sun's atmosphere will expand to engulf the Earth.
Tomorrow's picture: the galaxy above
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-17 12:30:01.723132
2021-07-17T17:30:02Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 17
Alphonsus and Arzachel
Image Credit & Copyright: Noel DonnardExplanation: Point your telescope at tonight's first quarter Moon. Along the terminator, the shadow line between night and day, you might find these two large craters staring back at you with an owlish gaze. Alphonsus (left) and Arzachel are ancient impact craters on the north eastern shores of Mare Nubium, the lunar Sea of Clouds. The larger Alphonsus is over 100 kilometers in diameter. A low sun angle highlights the crater's sharp 1.5 kilometer high central peak in bright sunlight and dark shadow. Scouting for potential Apollo moon landing sites, the Ranger 9 spacecraft returned closeup pictures of Alphonsus before it crashed in the crater just northeast (toward the upperleft) of its central mountain in 1965. Alpetragius, between Alphonsus and Arzachel, is the small crater with the deeply shadowed floor and overly large central beak.
Tomorrow's picture: 2.5 million light-years away
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-16 12:30:02.109015
2021-07-16T17:30:03Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 16
Love and War by Moonlight
Image Credit & Copyright: Shi HuanExplanation: Venus, named for the Roman goddess of love, and Mars, the war god's namesake, come together by moonlight in this serene skyview, recorded on July 11 from Lualaba province, Democratic Republic of Congo, planet Earth. Taken in the western twilight sky shortly after sunset the exposure also records earthshine illuminating the otherwise dark surface of the young crescent Moon. Of course the Moon has moved on. Venus still shines in the west though as the evening star, third brightest object in Earth's sky, after the Sun and the Moon itself. Seen here above a brilliant Venus, Mars moved even closer to the brighter planet and by July 13 could be seen only about a Moon's width away. Mars has since slowly wandered away from much brighter Venus in the twilight, but both are sliding toward bright star Regulus. Alpha star of the constellation Leo, Regulus lies off the top of this frame and anticipates a visit from Venus and then Mars in twilight skies of the coming days.
Tomorrow's picture: when the moon watches you
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-15 12:30:01.482053
2021-07-15T17:30:02Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 15
The Dark Tower in Scorpius
Image Credit & Copyright: Data - Martin Pugh Processing - Rocco SungExplanation: In silhouette against a crowded star field along the tail of the arachnalogical constellation Scorpius, this dusty cosmic cloud evokes for some the image of an ominous dark tower. In fact, clumps of dust and molecular gas collapsing to form stars may well lurk within the dark nebula, a structure that spans almost 40 light-years across this gorgeous telescopic portrait. Known as a cometary globule, the swept-back cloud, is shaped by intense ultraviolet radiation from the OB association of very hot stars in NGC 6231, off the upper edge of the scene. That energetic ultraviolet light also powers the globule's bordering reddish glow of hydrogen gas. Hot stars embedded in the dust can be seen as bluish reflection nebulae. This dark tower, NGC 6231, and associated nebulae are about 5,000 light-years away.
Tomorrow's picture: love and war by moonlight
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-14 12:30:02.124670
2021-07-14T17:30:03Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 14
GW200115: Simulation of a Black Hole Merging with a Neutron Star
Video Credit: Simulation: S.V. Chaurasia (Stockholm U.), T. Dietrich (Potsdam U. & MPIGP);
Visualization: T. Dietrich (Potsdam U. & MPIGP), N. Fischer, S. Ossokine, H. Pfeiffer (MPIGP)Explanation: What happens when a black hole destroys a neutron star? Analyses indicate that just such an event created gravitational wave event GW200115, detected in 2020 January by LIGO and Virgo observatories. To better understand the unusual event, the featured visualization was created from a computer simulation. The visualization video starts with the black hole (about 6 times the Sun's mass) and neutron star (about 1.5 times the Sun's mass) circling each other, together emitting an increasing amount of gravitational radiation. The picturesque pattern of gravitational wave emission is shown in blue. The duo spiral together increasingly fast until the neutron star becomes completely absorbed by the black hole. Since the neutron star did not break apart during the collision, little light escaped -- which matches the lack of an observed optical counterpart. The remaining black hole rings briefly, and as that dies down so do the emitted gravitational waves. The 30-second time-lapse video may seem short, but it actually lasts about 1000 times longer than the real merger event.
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Tomorrow's picture: open space
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-13 12:30:02.423897
2021-07-13T17:30:03Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 13
Saturn's Iapetus: Painted Moon in 3D
Image Credit: NASA, ESA, JPL, SSI, Cassini Imaging Team; 3D Rendering: NASA's VTADExplanation: What has happened to Saturn's moon Iapetus? Vast sections of this strange world are dark brown, while others are as bright white. The composition of the dark material is unknown, but infrared spectra indicate that it possibly contains some dark form of carbon. Iapetus also has an unusual equatorial ridge that makes it appear like a walnut. To help better understand this seemingly painted moon, NASA directed the robotic Cassini spacecraft orbiting Saturn to swoop within 2,000 kilometers in 2007. Iapetus is pictured here in 3D. A huge impact crater seen in the south spans a tremendous 450 kilometers and appears superposed on an older crater of similar size. The dark material is seen increasingly coating the easternmost part of Iapetus, darkening craters and highlands alike. Close inspection indicates that the dark coating typically faces the moon's equator and is less than a meter thick. A leading hypothesis is that the dark material is mostly dirt leftover when relatively warm but dirty ice sublimates. An initial coating of dark material may have been effectively painted on by the accretion of meteor-liberated debris from other moons.
Tomorrow's picture: black hole eats
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-12 12:30:01.784108
2021-07-12T17:30:02Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 12
M27: The Dumbbell Nebula
Image Credit & Copyright: Bray Falls & Keith QuattrocchiExplanation: What will become of our Sun? The first hint of our Sun's future was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets. The 27th object on Messier's list, now known as M27 or the Dumbbell Nebula, is a planetary nebula, one of the brightest planetary nebulae on the sky -- and visible toward the constellation of the Fox (Vulpecula) with binoculars. It takes light about 1000 years to reach us from M27, featured here in colors emitted by hydrogen and oxygen. We now know that in about 6 billion years, our Sun will shed its outer gases into a planetary nebula like M27, while its remaining center will become an X-ray hot white dwarf star. Understanding the physics and significance of M27 was well beyond 18th century science, though. Even today, many things remain mysterious about planetary nebulas, including how their intricate shapes are created.
Tomorrow's picture: Iapetus 3D
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-11 12:30:01.816929
2021-07-11T17:30:03Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 11
Find the Moon
Image Credit & Copyright: Jimmy Westlake (Colorado Mountain College)Explanation: Where's the Moon? Somewhere in this image, the Earth's Moon is hiding. The entire Moon is visible, in its completely full phase, in plain sight. Even the photographer's keen eye couldn't find it even though he knew exactly where to look -- only the long exposure of his camera picked it up -- barely. Although by now you might be congratulating yourself on finding it, why was it so difficult to see? For one reason, this photograph was taken during a total lunar eclipse, when the Earth's shadow made the Moon much dimmer than a normal full Moon. For another, the image, taken in Colorado, USA, was captured just before sunrise. With the Moon on the exact opposite side of the sky from the Sun, this meant that the Sun was just below the horizon, but still slightly illuminating the sky. Last, as the Moon was only about two degrees above the horizon, the large volume of air between the camera and the horizon scattered a lot of light away from the background Moon. Twelve minutes after this image was acquired in 2012, the Sun peeked over the horizon and the Moon set.
Tomorrow's picture: comet, planet, or star?
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-10 12:30:01.793807
2021-07-10T17:30:03Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 10
Mercury and the Da Vinci Glow
Image Credit & Copyright: Gabriel FunesExplanation: On July 8th early morning risers saw Mercury near an old Moon low on the eastern horizon. On that date bright planet, faint glow of lunar night side, and sunlit crescent were captured in this predawn skyscape from Tenerife's Teide National Park in the Canary Islands. Never far from the Sun in planet Earth's sky, the fleeting inner planet shines near its brightest in the morning twilight scene. Mercury lies just below the zeta star of the constellation Taurus, Zeta Tauri, near the tip of the celestial bull's horn. Of course the Moon's ashen glow is earthshine, earthlight reflected from the Moon's night side. A description of earthshine, in terms of sunlight reflected by Earth's oceans illuminating the Moon's dark surface, was written over 500 years ago by Leonardo da Vinci. Waiting for the coming dawn in the foreground are the Teide Observatory's sentinels of the Sun, also known as (large domes left to right) the THEMIS, VTT, and GREGOR solar telescopes.
Tomorrow's picture: try to see the Moon
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Astronomy Picture of the Day for 2021-07-09 12:30:02.253159
2021-07-09T17:30:03Z via PyPump To: Public
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2021 July 9
M82: Starburst Galaxy with a Superwind
Image Credit & Copyright: Team ARO, Alentejo Remote ObservatoryExplanation: M82 is a starburst galaxy with a superwind. In fact, through ensuing supernova explosions and powerful winds from massive stars, the burst of star formation in M82 is driving a prodigious outflow. Evidence for the superwind from the galaxy's central regions is clear in sharp telescopic snapshot. The composite image highlights emission from long outflow filaments of atomic hydrogen gas in reddish hues. Some of the gas in the superwind, enriched in heavy elements forged in the massive stars, will eventually escape into intergalactic space. Triggered by a close encounter with nearby large galaxy M81, the furious burst of star formation in M82 should last about 100 million years or so. Also known as the Cigar Galaxy for its elongated visual appearance, M82 is about 30,000 light-years across. It lies 12 million light-years away near the northern boundary of Ursa Major.
Tomorrow's picture: Mercury and the Da Vinci Glow
< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
NASA Web Privacy Policy and Important Notices
A service of: ASD at NASA / GSFC
& Michigan Tech. U.
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