Explanation: How far are you from a naturally dark night sky? In increasing steps, this world map (medium | large) shows the effect of artificial night sky brightness on the visual appearance of the night sky. The brightness was modeled using high resolution satellite data and fit to thousands of night sky brightness measurements in recent work. Color-coded levels are compared to the natural sky brightness level for your location. For example, artificial sky brightness levels in yellow alter the natural appearance of the night sky. In red they hide the Milky Way in an artificial luminous fog. The results indicate that the historically common appearance of our galaxy at night is now lost for more than one-third of humanity. That includes 60% of Europeans and almost 80% of North Americans, along with inhabitants of other densely populated, light-polluted regions of planet Earth.
Explanation: This beautiful telephoto composition spans light-years in a natural night skyscape from the island of Crete. Looking south, exposures both track the stars and record a fixed foreground in three merged panels that cover a 10×12 degree wide field of view. The May 15 waxing gibbous moonlight illuminates the church and mountainous terrain. A mere 18 thousand light-years away, huge globular star cluster Omega Centauri (NGC 5139) shining above gives a good visual impression of its appearance in binoculars on that starry night. Active galaxy Centaurus A (NGC 5128) is near the top of the frame, some 11 million light-years distant. Also found toward the expansive southern constellation Centaurus and about the size of our own Milky Way is edge on spiral galaxy NGC 4945. About 13 million light-years distant it’s only a little farther along, and just above the horizon at the right.
Explanation: What will NASA’s Juno spacecraft find when it reaches Jupiter next Monday? Very little, if Juno does not survive Jupiter Orbit Insertion, a complex series of operations in an unknown environment just above Jupiter’s cloud tops. If successful, as explained in the featured video, Juno will swoop around Jupiter, passing closer than any previous spacecraft. The goal is to decelerate, enter into a highly elliptical orbit, and begin two years of science operations. Juno’s science mission objectives include mapping Jupiter’s deep structure, determining how much water is in Jupiter’s atmosphere, and exploring Jupiter’s powerful magnetic field and how it creates auroras around Jupiter’s poles. These lessons hold promise to help humanity better understand the history of our Solar System and the dynamics of our Earth. Juno is powered predominantly by three large solar panels, each measuring a side of small truck. Launched in 2011, Juno’s planned mission will take it around the Jovian giant 37 times, after which, to avoid contaminating Europa with microbes, it will be directed to dive into Jupiter‘s thick atmosphere, where it will break apart and melt.