What divides the north from the south? It all has to do with the spin of the Earth. On Earth’s surface, the equator is the dividing line, but on Earth’s sky, the dividing line is the Celestial Equator — the equator’s projection onto the sky. You likely can’t see the Earth’s equator around you, but anyone with a clear night sky can find the Celestial Equator by watching stars move. Just locate the dividing line between stars that arc north and stars that arc south. Were you on Earth’s equator, the Celestial Equator would go straight up and down. In general, the angle between the Celestial Equator and the vertical is your latitude. The featured image combines 325 photos taken every 30 seconds over 162 minutes. Taken soon after sunset earlier this month, moonlight illuminates a snowy and desolate scene in northwest Iran. The bright streak behind the lone tree is the planet Venus setting. Almost Hyperspace: Random APOD Generator
How does weather on the Sun affect humanity? To help find out, the European Space Agency (ESA) and NASA have just launched the Solar Orbiter. This Sun-circling robotic spaceship will monitor the Sun’s changing light, solar wind, and magnetic field not only from the usual perspective of Earth but also from above and below the Sun. Pictured, a long duration exposure of the launch of the Solar Orbiter shows the graceful arc of the bright engines of United Launch Alliance’s Atlas V rocket as they lifted the satellite off the Earth. Over the next few years, the Solar Orbiter will use the gravity of Earth and Venus to veer out of the plane of the planets and closer to the Sun than Mercury. Violent weather on the Sun, including solar flares and coronal mass ejections, has shown the ability to interfere with power grids on the Earth and communications satellites in Earth orbit. The Solar Orbiter is expected to coordinate observations with the also Sun-orbiting Parker Solar Probe launched in 2018. Solar Orbiter to Space: Watch the Launch
What’s happening behind that camel? A partial eclipse of the Sun. About six and a half weeks ago, the Moon passed completely in front of the Sun as seen from a narrow band on the Earth. Despite (surely) many camels being located in this narrow band, only one found itself stationed between this camera, the distant Moon, and the even more distant Sun. To create this impressive superposition, though, took a well-planned trip to the United Arab Emirates, careful alignments, and accurate timings on the day of the eclipse. Although the resulting featured image shows a partially eclipsed Sun rising, the Moon went on to appear completely engulfed by the Sun in an annular eclipse known as a ring of fire. Forward scattering of sunlight, dominated by quantum mechanical diffraction, gives the camel hair and rope fray an unusual glow. The next solar eclipse is also an annular eclipse and will occur this coming June.