Tag Archives: NASA

Pandora Close up at Saturn

What do the craters of Saturn’s small moon Pandora look like up close? To help find out, NASA sent the robotic Cassini spacecraft, now orbiting Saturn, past the unusual moon two weeks ago. The highest resolution image of Pandora ever taken was then captured from about 40,000 kilometers out and is featured here. Structures as small as 300 meters can be discerned on 80-kilometer wide Pandora. Craters on Pandora appear to be covered over by some sort of material, providing a more smooth appearance than sponge-like Hyperion, another small moon of Saturn. Curious grooves and ridges also appear to cross the surface of the small moon. Pandora is partly interesting because, along with its companion moon Prometheus, it helps shepherd the particles of Saturn’s F ring into a distinct ring. via NASA

Shell Game in the LMC

An alluring sight in southern skies, the Large Magellanic Cloud (LMC) is seen here through narrowband filters. The filters are designed to transmit only light emitted by ionized sulfur, hydrogen, and oxygen atoms. Ionized by energetic starlight, the atoms emit their characteristic light as electrons are recaptured and the atom transitions to a lower energy state. As a result, this false color image of the LMC seems covered with shell-shaped clouds of ionized gas surrounding massive, young stars. Sculpted by the strong stellar winds and ultraviolet radiation, the glowing clouds, dominated by emission from hydrogen, are known as H II (ionized hydrogen) regions. Itself composed of many overlapping shells, the Tarantula Nebula is the large star forming region at top center. A satellite of our Milky Way Galaxy, the LMC is about 15,000 light-years across and lies a mere 180,000 light-years away in the constellation Dorado. via NASA

Curiosity Surveys Lower Mount Sharp on Mars

If you could stand on Mars — what might you see? If you were the Curiosity rover, then just last month you would have contemplated the featured image — a breathtaking panorama of the lower portion of Mount Sharp. The colors have been adjusted to mimic lighting familiar to Earthlings. Surveyed here was a rocky plain before increasingly high rolling hills. The rounded hills in the middle distance, called the Sulfate Unit, are Curiosity’s highest currently planned destination. One reason these hills are interesting is because sulfates are an energy source for some micro-organisms. The immediate path forward, though, was toward the southeast on the left part of the image. via NASA

Fox Fur, a Unicorn, and a Christmas Tree

Clouds of glowing hydrogen gas fill this colorful skyscape in the faint but fanciful constellation Monoceros, the Unicorn. A star forming region cataloged as NGC 2264, the complex jumble of cosmic gas and dust is about 2,700 light-years distant and mixes reddish emission nebulae excited by energetic light from newborn stars with dark interstellar dust clouds. Where the otherwise obscuring dust clouds lie close to the hot, young stars they also reflect starlight, forming blue reflection nebulae. The tall, telescopic mosaic image stands up about 3/4 degree or nearly 1.5 full moons, covering 40 light-years at the distance of NGC 2264. Its cast of cosmic characters includes the the Fox Fur Nebula, whose dusty, convoluted pelt lies just left of center, bright variable star S Monocerotis immersed in the blue-tinted haze right of the Fox Fur, and the Cone Nebula pointing down from the top of the frame. Of course, the stars of NGC 2264 are also known as the Christmas Tree star cluster. The triangular tree shape traced by the stars has its apex at the Cone Nebula. The tree’s broader base is centered near S Monocerotis. via NASA

Once Upon a Solstice Eve

Once upon a solstice eve a little prince gazed across a frozen little planet at the edge of a large galaxy. The little planet was planet Earth of course, seen in this horizon to horizon, nadir to zenith projection, a digitally stitched mosaic from the shores of the Sec reservoir in the Czech Republic. So the large galaxy must be the Milky Way, and the brightest beacon on the planet’s horizon Venus, visible around the globe as this season’s brilliant evening star. Celestial treasures in surrounding dark skies include the Pleiades star cluster, and the North America nebula found along a dusty galactic rift. Embracing Venus, Zodiacal light traces a faint band across the night, but the more colorful pillars of light shine above streets a little closer to home. via NASA

Sharpless 308: Star Bubble

Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 2-308 it lies some 5,200 light-years away toward the constellation of the Big Dog (Canis Major) and covers slightly more of the sky than a full moon. That corresponds to a diameter of 60 light-years at its estimated distance. The massive star that created the bubble, a Wolf-Rayet star, is the bright one near the center of the nebula. Wolf-Rayet stars have over 20 times the mass of the Sun and are thought to be in a brief, pre-supernova phase of massive star evolution. Fast winds from this Wolf-Rayet star create the bubble-shaped nebula as they sweep up slower moving material from an earlier phase of evolution. The windblown nebula has an age of about 70,000 years. Relatively faint emission captured in the expansive image is dominated by the glow of ionized oxygen atoms mapped to a blue hue. via NASA

Southern Jupiter from Perijove 3

Southern Jupiter looms some 37,000 kilometers away in this JunoCam image from December 11. The image data was captured near Juno’s third perijove or closest approach to Jupiter, the spacecraft still in its 53 day long looping orbit. With the south polar region on the left, the large whitish oval toward the right is massive, counterclockwise rotating storm system. Smaller than the more famous Great Red Spot, the oval storm is only about half the diameter of planet Earth, one of a string of white ovals currently in the southern hemisphere of the Solar System’s, ruling gas giant. via NASA

Meteors over Four Girl Mountains

On some nights it rains meteors. Peaking over the next two nights, asteroid dust is expected to rain down on Earth during the annual Geminids meteor shower. This year, unfortunately, fainter Geminids will be harder to see because of the brightness of the Long Nights Full Moon, which occurs Wednesday. Pictured, an image from this year’s Perseids meteor shower in August captured multiple streaks over Four Girls Mountain in central China. The bright Pleaides open star cluster appears toward the upper right, while numerous emission nebulas are visible in red, many superposed on the diagonal band of the Milky Way. via NASA

Over Saturns Turbulent North Pole

The Cassini spacecraft’s Grand Finale at Saturn has begun. The Grand Finale will allow Cassini to explore Saturn and some of Saturn’s moons and rings in unprecedented detail. The first phase started two weeks ago when a close flyby of Titan changed Cassini’s orbit into one that passes near Saturn’s poles and just outside of Saturn’s outermost F-ring. Featured here is an image taken during the first of Cassini’s 20 week-long F-ring orbits around Saturn. Visible are the central polar vortex on the upper left, a hexagonal cloud boundary through the image center, and numerous light-colored turbulent storm systems. In 2017 April, Cassini will again use the gravity of Titan to begin a new series of 22 Proximal orbits — trajectories that will take Cassini inside of Saturn’s rings for the first time. Cassini’s new science adventure is scheduled to end on 2017 September 17, though, when the robotic spacecraft will be directed into a dramatic mission-ending dive into Saturn’s atmosphere. via NASA

The Extraordinary Spiral in LL Pegasi

What created the strange spiral structure on the left? No one is sure, although it is likely related to a star in a binary star system entering the planetary nebula phase, when its outer atmosphere is ejected. The huge spiral spans about a third of a light year across and, winding four or five complete turns, has a regularity that is without precedent. Given the expansion rate of the spiral gas, a new layer must appear about every 800 years, a close match to the time it takes for the two stars to orbit each other. The star system that created it is most commonly known as LL Pegasi, but also AFGL 3068. The unusual structure itself has been cataloged as IRAS 23166+1655. The featured image was taken in near-infrared light by the Hubble Space Telescope. Why the spiral glows is itself a mystery, with a leading hypothesis being illumination by light reflected from nearby stars. via NASA