NASA's Astronomy Pictures of the Day encourages all of us to discover the cosmos through a series of stunning images released daily. Learn a little something, or just sit back and feel small in the grand scheme of things.
Ridges of glowing interstellar gas and dark dust clouds inhabit the turbulent, cosmic depths of the Lagoon Nebula. Also known as M8, the bright star forming region is about 5,000 light-years distant. But it still makes for a popular stop on telescopic tours of the constellation Sagittarius, toward the center of our Milky Way Galaxy. Dominated by the telltale red emission of ionized hydrogen atoms recombining with stripped electrons, this stunning, deep view of the Lagoon is nearly 100 light-years across. Right of center, the bright, compact, hourglass shape is gas ionized and sculpted by energetic radiation and extreme stellar winds from a massive young star. In fact, the many bright stars of open cluster NGC 6530 drift within the nebula, just formed in the Lagoon several million years ago.
Photography: Michael Miller, Jimmy Walker
Near sunset on Thursday, clear skies saw the launch of the OSIRIS-REx spacecraft. Sporting a single solid rocket booster, its Atlas V vehicle blasts off from Cape Canaveral's Complex 41 in this low, wide-angle view toward launch pad and setting Sun. OSIRIS-REx is bound for Bennu, scheduled to encounter the mountain-sized asteroid in 2018. First the spacecraft will swing back by home world planet Earth though, for a gravity assist maneuver to boost it on its way. After a detailed survey of Bennu OSIRIS-REx will collect a sample from the asteroid's surface in 2020 and bring it home, returning to Earth in 2023. If all goes well it will be the largest sample returned by a space mission since the Apollo era.
Photography: United Launch Alliance
What is this meteor doing? Dynamically, the unusually short and asymmetric train may indicate that the sand-sized grain at the center of the glow is momentarily spinning as it ablates, causing its path to be slightly spiral. Geographically, the meteor appears to be going through the Heart Nebula, although really it is in Earth's atmosphere and so is about one quadrillion times closer. Taken last month on the night of the peak, this meteor is likely from the Perseid meteor shower. The Perseids radiant, in the constellation of Perseus, is off the frame to the upper right, toward the direction that the meteor streak is pointing. The Heart Nebula was imaged in 18 one-minute exposures, of which the unusual meteor streak appeared on just one. The meteor train is multicolored as its glow emanates from different elements in the heated gas.
Photography: Roger N. Clark
Wandering through this stunning field of view, Mars really is in front of these colorful cosmic clouds. The mosaic contructed from telescopic images is about 5 degrees (10 full moons) across. It captures the planet's position on August 26, over 7 light-minutes from Earth and very near the line-of-sight to bright star Antares and the Rho Ophiuchi cloud complex. In the exposure yellow-hued Mars, above and left, is almost matched by Antares, also known as Alpha Scorpii, below center. Globular star cluster M4 shines just right of Antares, but M4 lies some 7,000 light-years away compared to Antares' 500 light-year distance. Slightly closer than Antares, Rho Ophiuchi's bluish starlight is reflected by the dusty molecular clouds near the top of the frame.
Photography: Sebastian Voltmer
Follow the handle of the Big Dipper away from the dipper's bowl, until you get to the handle's last bright star. Then, just slide your telescope a little south and west and you might find this stunning pair of interacting galaxies, the 51st entry in Charles Messier's famous catalog. Perhaps the original spiral nebula, the large galaxy with well defined spiral structure is also cataloged as NGC 5194. Its spiral arms and dust lanes clearly sweep in front of its companion galaxy (left), NGC 5195. The pair are about 31 million light-years distant and officially lie within the angular boundaries of the small constellation Canes Venatici. Though M51 looks faint and fuzzy to the human eye, the above long-exposure, deep-field image taken earlier this year shows much of the faint complexity that actually surrounds the smaller galaxy. Thousands of the faint dots in background of the featured image are actually galaxies far across the universe.
Photography: Álvaro Ibáñez Pérez