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The Jovian moon Io as seen by the New Horizons spacecraft. The mission's camera caught a view of one of this moon's volcanos erupting. (NASA Goddard Space Flight Center Scientific Visualization Studio) The Large Binocular Telescope (LBT), located on Mount Graham in Arizona and run by the University of Arizona, is part of the next generation of extremely large telescopes (ELTs). With two primary mirrors measuring 8.4 m (~27.5 ft), it has a collecting area slightly greater than that of a 30-meter (98.4 ft) telescope. With their resolution, adaptive optics, and sophisticated instruments, these telescopes are expected to probe deeper...

The 4th through 7th centuries are often considered periods of decay and decline for the Roman Empire. I view them, however, as times of crisis and regeneration, as the previously pagan Empire was transformed into an amazingly resilient Christian Empire which persisted for another millennium despite attacks on all sides and myriad convulsions from within. Who were the most effective rulers during this period? Opinions vary, but here are my choices. Portraits of all, taken from antiquity, may be found in the above image: Constantine the Great (AD 306-337). Constantine may be considered the founder of the Christian Roman...

Radio, IR and optical observations show evolution of plumes and their impact on belts and zones Storm clouds rooted deep in Jupiter's atmosphere are affecting the planet's white zones and colorful belts, creating disturbances in their flow and even changing their color. Thanks to coordinated observations of the planet in January 2017 by six ground-based optical and radio telescopes and NASA's Hubble Space Telescope, a University of California, Berkeley, astronomer and her colleagues have been able to track the effects of these storms -- visible as bright plumes above the planet's ammonia ice clouds -- on the belts in which...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2003 March 19 Jupiter's Great Dark Spot Credit: Cassini Imaging Team, Cassini Project, NASA Explanation: Seventeenth century astronomer Giovanni Domenico Cassini was an astute observer of Jupiter's Great Red Spot. So it seems only fitting that his namesake, the Cassini spacecraft, has enabled detailed observations of another planet-sized blemish -- Jupiter's Great Dark Spot. Unlike the Red Spot, the Great Dark Spot lies near Jupiter's north pole and...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 December 7 Jupiter, Io and Shadow Credit: Cassini Imaging Team, Cassini Project, NASA Explanation: Pictured above is the innermost of Jupiter's Galilean satellites, Io, superposed in front of the gas giant planet. To the left of Io is a dark spot that is Io's own shadow. A solar eclipse would be seen from within the shadow spot on Jupiter. Viewed from planet Earth, similar shadows of Jupiter's...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 June 22 Io: The Prometheus Plume Credit: Galileo Project, JPL, NASA Explanation: Two sulfurous eruptions are visible on Jupiter's volcanic moon Io in this color composite Galileo image. On the left, over Io's limb, a new bluish plume rises about 86 miles above the surface of a volcanic caldera known as Pillan Patera. In the middle of the image, near the night/day shadow line, the ring shaped...