Stunning imagery capturing the Earth's rotation around its axis, Orion's figure eight and the violent creation of stars are just a few of today's picks from NASA's Astronomy Picture of the Day.apod.nasa.gov
It does look like a flying saucer, but this technologically advanced structure is not here to deliver the wise extraterrestrial from the scifi classic movie The Day the Earth Stood Still. It is here to advance our knowledge of the Universe though. Shown sitting near the top of a mountain in Hawaii, the dome of the Gemini Observatory North houses one of two identical 8.1-meter diameter telescopes. Used with its southern hemisphere twin observatory in Chile, the two can access the entire sky from planet Earth. Constructed from 85 exposures lasting 30 seconds each with camera fixed to a tripod, the image also clearly demonstrates that the Earth did not stand still. Adjusted to be brighter at the ends of their arcs, the concentric star trails centered on the North Celestial Pole are a reflection of Earth's rotation around its axis. Close to the horizon at Hawaiian latitdues, Polaris, the North Star, makes the shortest star trail. The fainter denser forest of star trails toward the right is part of the rising Milky Way.
Photography: Joy Pollard (Gemini Observatory)
This dramatic image peers within M42, the Orion Nebula, the closest large star-forming region. Using data at infrared wavelengths from the Herschel Space Observatory, the false-color composite explores the natal cosmic cloud a mere 1,500 light-years distant. Cold, dense filaments of dust that would otherwise be dark at visible wavelengths are shown in reddish hues. Light-years long, the filaments weave together bright spots that correspond to regions of collapsing protostars. The brightest bluish area near the top of the frame is warmer dust heated by the hot Trapezium cluster stars that also power the nebula's visible glow. Herschel data has recently indicated ultraviolet starlight from the hot newborn stars likely contributes to the creation of carbon-hydrogen molecules, basic building blocks of life. This Herschel image spans about 3 degrees on the sky. That's about 80 light-years at the distance of the Orion Nebula.
The central bulge of our Milky Way Galaxy rises over the northern Chilean Atacama altiplano in this postcard from planet Earth. At an altitude of 4500 meters, the strange beauty of the desolate landscape could almost belong to another world though. Brownish red and yellow tinted sulfuric patches lie along the whitish salt flat beaches of the Salar de Aguas Calientes region. In the distance along the Argentina border is the stratovolcano Lastarria, its peak at 5700 meters (19,000 feet). In the clear, dark sky above, stars, nebulae, and cosmic dust clouds in the Milky Way echo the colors of the altiplano at night. Extending the view across extragalactic space, the Large and Small Magellanic Clouds, satellite galaxies of the Milky Way, shine near the horizon through a faint greenish airglow.
Photography: Stéphane Guisard (Los Cielos de America, TWAN)
Sometimes, stars form in walls -- bright walls of interstellar gas. In this vivid skyscape, stars are forming in the W-shaped ridge of emission known as the Cygnus Wall. Part of a larger emission nebula with a distinctive outline popularly called The North America Nebula, the cosmic ridge spans about 20 light-years. Constructed using narrowband data to highlight the telltale reddish glow from ionized hydrogen atoms recombining with electrons, the image mosaic follows an ionization front with fine details of dark, dusty forms in silhouette. Sculpted by energetic radiation from the region's young, hot, massive stars, the dark shapes inhabiting the view are clouds of cool gas and dust with stars likely forming within. The North America Nebula itself, NGC 7000, is about 1,500 light-years away.
Photography: Sara Wager
Sharing dawn's twilight with the Moon on September 29, Mercury was about as far from the Sun as it can wander, the innermost planet close to its maximum elongation in planet Earth's skies. In this colorful scene fleeting Mercury is joined by a waning sunlit lunar crescent and earthlit lunar nightside, the New Moon in the Old Moon's arms. Below is the Italian Medicina Radio Astronomical Station near Bologna with a low row of antennae that is part of Italy's first radio telescope array dubbed the "Northern Cross", and a 32-meter-diameter parabolic dish. Of course, moonwatchers won't have to rise in early morning hours on October 8. After sunset the Moon will be high and bright in evening skies, at its first quarter phase for International Observe the Moon Night.
Photography: Pierluigi Giacobazzi