A different astronomy and space science related image is featured each day, along with a brief explanation.
http://antwrp.gsfc.nasa.gov/apod/astropix.html - Nov 26, 2014 5:46:07 AM - Nov 28, 2004 12:29:17 PM
Io and Callisto Mutual Event Image Credit & Copyright: Marco Guidi
A 24 minute sequence from top to bottom, this intriguing series of telescopic frames tracks the occultation of Io by Callisto, two of Jupiter's Galilean moons, from San Pietro Polesine, Italy, planet Earth. A challenging observational project using a small telescope, the two contrasting Jovian worlds are both slightly larger than Earth's Moon. In fact, bright, volcanic Io and dark, cratered Callisto are about 3,640 and 4,820 kilometers in diameter respectively. With Earth itself now crossing near the orbital plane of Jupiter's moons, astronomers are enjoying a season of Galilean moon mutual events ranging from eclipses to occultations. The series of orbital plane crossings produce a mutual event season every 5 to 6 years.
The Creature from the Red Lagoon Image Credit & Copyright: Derek DemeterEmil Buehler Planetarium
What creature lurks near the red Lagoon nebula? Mars. This gorgeous color deep-sky photograph has captured the red planet passing below two notable nebulae -- cataloged by the 18th century cosmic registrar Charles Messier as M8 and M20. M20 (upper right of center), the Trifid Nebula, presents a striking contrast in red/blue colors and dark dust lanes. Just below and to the left is the expansive, alluring red glow of M8, the Lagoon Nebula. Both nebulae are a few thousand light-years distant. By comparison, temporarily situated below them both, is the dominant "local" celestial beacon Mars. Taken late last month while near its closest approach to the Earth, the red planet was only a few light-minutes away.
Now Available: APOD 2015 Wall CalendarsIo-Callisto
2014 November 24
Video Credit: Cassini Radar MapperJPL, USGS, ESA,
What would it look like to fly over Titan? Radar images from NASA's robotic Cassini satellite in orbit around Saturn have been digitally compiled to simulate such a flight. Cassini has swooped past Saturn's cloudiest moon several times since it arrived at the ringed planet in 2004. The virtual flight featured hereshows numerous lakes colored black and mountainous terrain colored tan. Surface regions without detailed vertical information appear more flat, while sufficiently mapped regions have their heights digitally stretched. Among the basins visualized is KrakenMare, Titan's largest lake which spans over 1,000 kilometers long. Titan's lakes are different from Earth's lakes in that they are composed of hydrocarbons with similarities to liquid natural gas. How Titan's lakes were created and why they survive continues to be a topic of research.
Tornado and Rainbow Over Kansas Image Credit & Copyright: Eric NguyenOklahoma U.), www.mesoscale.ws
The scene might have been considered serene if it weren't for the tornado. During 2004 in Kansas, storm chaser Eric Nguyen photographed this budding twister in a different light -- the light of a rainbow. Featured here, a white tornado cloud descends from a dark storm cloud. The Sun, peeking through a clear patch of sky to the left, illuminates some buildings in the foreground. Sunlight reflects off raindrops to form a rainbow. By coincidence, the tornado appears to end right over the rainbow. Streaks in the image are hail being swept about by the high swirling winds. Over 1,000 tornadoes, the most violent type of storm known, occur on Earth every year, many in tornado alley. If you see a tornado while driving, do not try to outrun it -- park your car safely, go to a storm cellar, or crouch under steps in a basement.
Follow APOD on: FacebookGoogle Plus, or TwitterSoaring over Titan
Solar Flare from a Sharper Sun Image Credit:Solar Dynamics Observatory/AIA, Processing:NAFE by Miloslav DruckmullerBrno University of Technology
Solar active region AR2192 was the largest recorded sunspot group of the last 24 years. Before rotating off the Earth-facing side of the Sun at the end of October, it produced a whopping six energetic X-class flares. Its most intense flare was captured on October 24 in this stunning view from the orbiting Solar Dynamics Observatory. The scene is a color combination of images made at three different wavelengths of extreme ultraviolet light; 193 angstroms shown in blue, 171 angstroms in white, and 304 angstroms in red. The emission, from highly ionized Iron and Helium atoms, traces magnetic field lines looping through the hot plasma of the Sun's outer chromosphere and corona. Beneath, the cooler solar photosphere appears dark at extreme ultraviolet wavelengths. The exceptionally sharp composite image has been processed with a new mathematical algorithm (NAFE) that adapts to noise and brightness in extreme ultraviolet image data to reliably enhance small details.
on a cloudy day
M1: The Crab Nebula Martin Pugh
The Crab Nebula is cataloged as M1, the first object on Charles Messier's famous 18th century list of things which are not comets. In fact, the Crab is now known to be a supernova remnant, debris from the death explosion of a massive star, witnessed by astronomers in the year 1054. This sharp, ground-based telescopic view uses narrowband data to track emission from ionized oxygen and hydrogen atoms (in blue and red) and explore the tangled filaments within the still expanding cloud. One of the most exotic objects known to modern astronomers, the Crab Pulsar, a neutron star spinning 30 times a second, is visible as a bright spot near the nebula's center. Like a cosmic dynamo, this collapsed remnant of the stellar core powers the Crab's emission across the electromagnetic spectrum. Spanning about 12 light-years, the Crab Nebula is a mere 6,500 light-years away in the constellation Taurus
a sharper view
LDN 988: Dark Nebula in Cygnus Image Credit & Copyright: Bob Franke
Obscuring the rich starfields of northern Cygnus, dark nebula LDN 988 lies near the center of this cosmic skyscape. Composed with telescope and camera, the scene is some 2 degrees across. That corresponds to 70 light-years at the estimated 2,000 light-year distance of LDN 988. Stars are forming within LDN 988, part of a larger complex of dusty molecular clouds along the plane of our Milky Way galaxy sometimes called the Northern Coalsack. In fact, nebulosities associated with young stars abound in the region, including variable star V1331 Cygni shown in the inset. At the tip of a long dusty filament and partly surrounded by a curved reflection nebula, V1331 is thought to be a T-Tauri star, a sun-like star still in the early stages of formation.
pixels in space
dark nebula in Cygnus