NASA's A.P.O.D.

NASA's Astronomy Picture Of The Day taken from apod.nasa.gov/apod

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Comet Churyumov Gerasimenko in Crescent Image Credit: ESA, Rosetta, NAVCAM; processing by Giuseppe Conzo Explanation: What's happening to Comet 67P/Churyumov–Gerasimenko? As the 3-km wide comet moves closer to the Sun, heat causes the nucleus to expel gas and dust. The Rosetta spacecraft arrived at the comet's craggily double nucleus last July and now is co-orbiting the Sun with the giant dark iceberg. Recent analysis of data beamed back to Earth from the robotic Rosetta spacecraft has shown that water being expelled by 67P has a significant difference with water on Earth, indicating that Earth's water could not have originated from ancient collisions with comets like 67P. Additionally, neither Rosetta nor its Philae lander detected a magnetic field around the comet nucleus, indicating that magnetism might have been unimportant in the evolution of the early Solar System. Comet 67P, shown in a crescent phase in false color, should increase its evaporation rate as it nears its closest approach to the Sun in 2015 August, when it reaches a Sun distance just a bit further out than the Earth.

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Massive Nearby Spiral Galaxy NGC 2841

Image Credit: Hubble, Subaru; Composition & Copyright: Roberto Colombari

Explanation: It is one of the more massive galaxies known. A mere 46 million light-years distant, spiral galaxy NGC 2841 can be found in the northern constellation of Ursa Major. This sharp view of the gorgeous island universe shows off a striking yellow nucleus and galactic disk. Dust lanes, small, pink star-forming regions, and young blue star clusters are embedded in the patchy, tightly wound spiral arms. In contrast, many other spirals exhibit grand, sweeping arms with large star-forming regions. NGC 2841 has a diameter of over 150,000 light-years, even larger than our own Milky Way and captured by this composite image merging exposures from the orbiting 2.4-meter Hubble Space Telescope and the ground-based 8.2-meter Subaru Telescope. X-ray images suggest that resulting winds and stellar explosions create plumes of hot gas extending into a halo around NGC 2841.

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Space Station over Lunar Terminator Image Credit & Copyright: Dani Caxete Explanation: What's that in front of the Moon? It's the International Space Station. Using precise timing, the Earth-orbiting space platform was photographed in front of a partially lit Moon last year. The featured image was taken from Madrid, Spain with an exposure time of only 1/1000 of a second. In contrast, the duration of the transit of the ISS across the entire Moon was about half a second. The sun-glinting station can be seen just to the dark side of the day / night line known as the terminator. Numerous circular craters are visible on the distant Moon, as well as comparatively rough, light colored terrain known as highlands, and relatively smooth, dark colored areas known as maria. On-line tools can tell you when the International Space Station will be visible from your area.

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Planetary Nebula Mz3: The Ant Nebula Image Credit: R. Sahai (JPL) et al., Hubble Heritage Team, ESA, NASA Explanation: Why isn't this ant a big sphere? Planetary nebula Mz3 is being cast off by a star similar to our Sun that is, surely, round. Why then would the gas that is streaming away create an ant-shaped nebula that is distinctly not round? Clues might include the high 1000-kilometer per second speed of the expelled gas, the light-year long length of the structure, and the magnetism of the star visible above at the nebula's center. One possible answer is that Mz3 is hiding a second, dimmer star that orbits close in to the bright star. A competing hypothesis holds that the central star's own spin and magnetic field are channeling the gas. Since the central star appears to be so similar to our own Sun, astronomers hope that increased understanding of the history of this giant space ant can provide useful insight into the likely future of our own Sun and Earth.

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Cluster and Starforming Region Westerlund 2 Image Credit & Copyright: NASA, ESA, the Hubble Heritage Team (STScI / AURA), A. Nota (ESA/STScI), and the Westerlund 2 Science Team Explanation: Located 20,000 light-years away in the constellation Carina, the young cluster and starforming region Westerlund 2 fills this cosmic scene. Captured with Hubble's cameras in near-infrared and visible light, the stunning image is a celebration of the 25th anniversary of the launch of the Hubble Space Telescope on April 24, 1990. The cluster's dense concentration of luminous, massive stars is about 10 light-years across. Strong winds and radiation from those massive young stars have sculpted and shaped the region's gas and dust, into starforming pillars that point back to the central cluster. Red dots surrounding the bright stars are the cluster's faint newborn stars, still within their natal gas and dust cocoons. But brighter blue stars scattered around are likely not in the Westerlund 2 cluster and instead lie in the foreground of the Hubble anniversary field of view.

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Blue Tears and the Milky Way Image Credit & Copyright: Rogelio Bernal Andreo (Deep Sky Colors) Explanation: Lapping at rocks along the shore of the Island of Nangan, Taiwan, planet Earth, waves are infused with a subtle blue light in this sea and night skyscape. Composed of a series of long exposures made on April 16 the image captures the faint glow from Noctiluca scintillans. Also known as sea sparkles or blue tears, the marine plankton's bioluminescence is stimulated by wave motion. City lights along the coast of mainland China shine beneath low clouds in the west but stars and the faint Milky Way still fill the night above. Over the horizon the galaxy's central bulge and dark rifts seem to echo the rocks and luminous waves.

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Meteor in the Milky Way Image Credit & Copyright: Marko Korosec Explanation: Earth's April showers include the Lyrid Meteor Shower, observed for more than 2,000 years when the planet makes its annual passage through the dust stream of long-period Comet Thatcher. A grain of that comet's dust, moving 48 kilometers per second at an altitude of 100 kilometers or so, is swept up in this night sky view from the early hours of April 21. Flashing toward the southeastern horizon, the meteor's brilliant streak crosses the central region of the rising Milky Way. Its trail points back toward the shower's radiant in the constellation Lyra, high in the northern springtime sky and off the top of the frame. The yellowish hue of giant star Antares shines to the right of the Milky Way's bulge. Higher still is bright planet Saturn, near the right edge. Seen from Istra, Croatia, the Lyrid meteor's greenish glow reflects in the waters of the Adriatic Sea.

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Colorful Star Clouds in Cygnus Image Credit & Copyright: André van der Hoeven Explanation: Stars can form in colorful surroundings. Featured here is a star forming region rich in glowing gas and dark dust toward the constellation of the Swan (Cygnus), near the bright star Sadr. This region, which spans about 50 light years, is part of the Gamma Cygni nebula which lies about 1,800 light years distant. Toward the right of the image is Barnard 344, a dark and twisted dust cloud rich in cool molecular gas. A dramatic wall of dust and red-glowing hydrogen gas forms a line down the picture center. While the glowing red gas is indicative of small emission nebulas, the blue tinted areas are reflection nebulas -- starlight reflecting from usually dark dust grains. The Gamma Cygni nebula will likely not last the next billion years, as most of the bright young stars will explode, most of the dust will be destroyed, and most of the gas will drift away.

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[click through to use the interactive map!] Vesta Trek: A Digital Model of Asteroid Vesta Image Credit: NASA, JPL, LMMP, SSERVI, USGS, DLR Explanation: You can explore asteroid Vesta. Recently, NASA's robotic spaceship Dawn visited Vesta, the second largest object in our Solar System's main asteroid belt, which lies between Mars and Jupiter. During a year-long stopover, Dawn's cameras photographed Vesta's entire surface, documenting all of the minor planet's major mountains and craters. These images have now been combined into a digital model that allows anyone with a full-featured browser to fly all around Vesta, virtually, and even zoom in on interesting surface features, by just dragging and clicking. If desired, the initially flat 2D map can be wrapped into a nearly spherical object by clicking on the 3D icon at the bottom. Dawn departed Vesta in 2012 and is now just beginning to photograph and explore the mysteries of the largest object in the asteroid belt: dwarf-planet Ceres.

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Total Solar Eclipse over Svalbard Image Credit & Copyright: Thanakrit Santikunaporn Explanation: Going, going, gone. That was the feeling in Svalbard, Norway last month during a total eclipse of the Sun by the Moon. In the featured image, the eclipse was captured every three minutes and then digitally merged with a foreground frame taken from the same location. Visible in the foreground are numerous gawking eclipse seekers, some deploying pretty sophisticated cameras. As the Moon and Sun moved together across the sky -- nearly horizontally from this far north -- an increasing fraction of the Sun appears covered by the Moon. In the central frame, the Moon's complete blockage of the disk of the Sun makes the immediate surroundings appear like night during the day. The exception is the Moon itself, which now appears surrounded by the expansive corona of the Sun. Of course, about 2.5 minutes later, the surface of the Sun began to reappear. The next total eclipse of the Sun will occur in 2016 March and be visible from Southeast Asia.

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Ring Galaxy AM 0644-741 from Hubble Image Credit: Hubble Heritage Team (AURA / STScI), J. Higdon (Cornell) ESA, NASA Explanation: How could a galaxy become shaped like a ring? The rim of the blue galaxy pictured on the right is an immense ring-like structure 150,000 light years in diameter composed of newly formed, extremely bright, massive stars. That galaxy, 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 -- their individual stars rarely come into contact. The ring-like shape is the result of the gravitational disruption caused by an entire small intruder galaxy passing through a large one. When this happens, interstellar gas and dust become condensed, causing a wave of star formation to move out from the impact point like a ripple across the surface of a pond. The intruder galaxy is just outside of the frame taken by the Hubble Space Telescope. This featured image was taken to commemorate the anniversary of Hubble's launch in 1990. Ring galaxy AM 0644-741 lies about 300 million light years away.

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Back from deep space

Hey everyone! Sorry for the lack of posts for the last few years- I'm not actually NASA, just a space fan who started this blog in college cause I thought the Astronomy Picture Of the Day would be great in blog format. I was literally just copy pasting from the site every morning, but life caught up with me and I fell out of the practice. Then I checked up on this and saw that 11,000 (!!!) of you are into it too so I will start posting again. If you're interested in the actual site (and their archives going back years!) check out apod.nasa.gov/apod

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IC 1848: The Soul Nebula  Image Credit & Copyright: Bob Andersson

Explanation: Stars are forming in the Soul of the Queen of Aethopia. More specifically, a large star forming region called the Soul Nebula can be found in the direction of the constellation Cassiopeia, who Greek mythology credits as the vain wife of a King who long ago ruled lands surrounding the upper Nile river. The Soul Nebula houses several open clusters of stars, a large radio source known as W5, and huge evacuated bubbles formed by the winds of young massive stars. Located about 6,500 light years away, the Soul Nebula spans about 100 light years and is usually imaged next to its celestial neighbor the Heart Nebula (IC 1805). The above image appears mostly red due to the emission of a specific color of light emitted by excited hydrogen gas.

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Crescent Neptune and Triton  Image Credit: Voyager 2, NASA

Explanation: Gliding silently through the outer Solar System, the Voyager 2 spacecraft camera captured Neptune and Triton together in crescent phase in 1989. The elegant picture of the gas giant planet and its cloudy moon was taken from behind just after closest approach. 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 thesetting Sun. Neptune is smaller but more massive than Uranus, has several dark rings, and emits more light than it receives from the Sun.

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Sun with Solar Flare  Image Credit: NASA Solar Dynamics Observatory

Explanation: This week the Sun gave up its strongest solar flare so far in 2013, accompanied by a coronal mass ejection (CME) headed toward planet Earth. A false-color composite image in extreme ultraviolet light from the Solar Dynamics Observatory captures the moment, recorded on April 11 at 0711 UTC. The flash, a moderate, M6.5 class flare erupting from active region AR 11719, is near the center of the solar disk. Other active regions, areas of intense magnetic fields seen as sunspot groups in visible light, mottle the surface as the solar maximum approaches. Loops and arcs of glowing plasma trace the active regions' magnetic field lines. A massive cloud of energetic, charged particles, the CME will impact the Earth's magnetosphere by this weekend and skywatchers should be on the alert for auroral displays.

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Yuri's Planet  Image Credit: ISS Expedition 30, NASA

Explanation: On another April 12th, in 1961, Soviet cosmonaut Yuri Alexseyevich Gagarin became the first human to see planet Earth from space. Commenting on his view from orbit he reported, "The sky is very dark; the Earth is bluish. Everything is seen very clearly". On yet another April 12th, in 1981 NASA launched the first space shuttle. To celebrate in 2013, consider this image from the orbiting International Space Station, a stunning view of the planet at night from low Earth orbit. Constellations of lights connecting the densely populated cities along the Atlantic east coast of the United States are framed by two Russian spacecraft docked at the space station. Easy to recognize cities include New York City and Long Island at the right. From there, track toward the left for Philadelphia, Baltimore, and then Washington DC near picture center.