Autor: Rafael Bustamante

That’s not a young crescent Moon poised above the hills along the western horizon at sunset. It’s Venus in a crescent phase. About 54 million kilometers away and less than 20 percent illuminated, it was captured by telescope and camera on September 30 near Bacau, Romania. The bright celestial beacon is now languishing in the evening twilight, its days as the Evening Star in 2018 coming to a close. But it also grows larger in apparent size and becomes an ever thinner crescent in telescopic views. Heading toward an inferior conjunction (non-judgmental), the inner planet will be positioned between Earth and Sun on October 26 and lost from view in the solar glare. At month’s end a crescent Venus will reappear in the east though, rising just before the Sun as the brilliant Morning Star. [via NASA] https://ift.tt/2O8yFxo

Yes, but can your rainbow do this? After the remnants of Hurricane Florence passed over Jersey Shore, New Jersey, USA last month, the Sun came out in one direction but something quite unusual appeared in the opposite direction: a hall of rainbows. Over the course of a next half hour, to the delight of the photographer and his daughter, vibrant supernumerary rainbows faded in and out, with at least five captured in this featured single shot. Supernumerary rainbows only form when falling water droplets are all nearly the same size and typically less than a millimeter across. Then, sunlight will not only reflect from inside the raindrops, but interfere, a wave phenomenon similar to ripples on a pond when a stone is thrown in. In fact, supernumerary rainbows can only be explained with waves, and their noted existence in the early 1800s was considered early evidence of light’s wave nature. [via NASA] https://ift.tt/2NYPbzY

Why is this neutron star off-center? Recently a lone neutron star has been found within the debris left over from an old supernova explosion. The «lonely neutron star» in question is the blue dot at the center of the red nebula near the bottom left of E0102-72.3. In the featured image composite, blue represents X-ray light captured by NASA’s Chandra Observatory, while red and green represent optical light captured by ESO’s Very Large Telescope in Chile and NASA’s Hubble Space Telescope in orbit. The displaced position of this neutron star is unexpected since the dense star is thought to be the core of the star that exploded in the supernova and created the outer nebula. It could be that the neutron star in E0102 was pushed away from the nebula’s center by the supernova itself, but then it seems odd that the smaller red ring remains centered on the neutron star. Alternatively, the outer nebula could have been expelled during a different scenario — perhaps even involving another star. Future observations of the nebulas and neutron star appear likely to resolve the situation. [via NASA] https://ift.tt/2DDSt7b

For 55 consecutive nights Mediterranean skies were at least partly clear this summer, from the 1st of July to the 24th of August 2018. An exposure from each night was incorporated in this composited telephoto and telescopic image to follow bright planet Saturn as it wandered through the generous evening skies. Through August, the outer planet’s seasonal apparent retrograde motion slowed and drifted to the right, framed by a starry background. That brought it near the line-of-sight to the central Milky Way, and the beautiful Lagoon (M8) and Trifid (20) nebulae. Of course Saturn’s largest moon Titan was also along for the ride. Swinging around the gas giant in a 16 day long orbit, Titan’s resulting wave-like motion is easier to spot when the almost-too-bright Saturn is digitally edited from the scene. [via NASA] https://ift.tt/2P1qe3H

This colorful skyscape spans about two full moons across nebula rich starfields along the plane of our Milky Way Galaxy in the royal northern constellation Cepheus. Near the edge of the region’s massive molecular cloud some 2,400 light-years away, bright reddish emission region Sharpless (Sh) 155 is below and right of center, also known as the Cave Nebula. About 10 light-years across the cosmic cave’s bright walls of gas are ionized by ultraviolet light from the hot young stars around it. Dusty blue reflection nebulae, like vdB 155 at upper left, and dense obscuring clouds of dust also abound on the interstellar canvas. Astronomical explorations have revealed other dramatic signs of star formation, including the bright red fleck of Herbig-Haro (HH) 168. Near top center in the frame, the Herbig-Haro object emission is generated by energetic jets from a newborn star. [via NASA] https://ift.tt/2Opmax7

It is still not known why the Sun’s light is missing some colors. Here are all the visible colors of the Sun, produced by passing the Sun’s light through a prism-like device. The spectrum was created at the McMath-Pierce Solar Observatory and shows, first off, that although our white-appearing Sun emits light of nearly every color, it does indeed appear brightest in yellow-green light. The dark patches in the above spectrum arise from gas at or above the Sun’s surface absorbing sunlight emitted below. Since different types of gas absorb different colors of light, it is possible to determine what gasses compose the Sun. Helium, for example, was first discovered in 1870 on a solar spectrum and only later found here on Earth. Today, the majority of spectral absorption lines have been identified – but not all. [via NASA] https://ift.tt/2OQxUWg

What can you see in the night sky this season? The featured graphic gives a few highlights for Earth’s northern hemisphere. Viewed as a clock face centered at the bottom, early (northern) autumn sky events fan out toward the left, while late autumn events are projected toward the right. Objects relatively close to Earth are illustrated, in general, as nearer to the cartoon figure with the telescope at the bottom center — although almost everything pictured can be seen without a telescope. As happens during any season, constellations appear the same year to year, and, as usual, the Leonids meteor shower will peak in mid-November. Also as usual, the International Space Station (ISS) can be seen, at times, as a bright spot drifting across the sky after sunset. Planets visible after sunset this autumn include Jupiter and Mars, and during late autumn, Saturn. [via NASA] https://ift.tt/2QUpFK9

Two small robots have begun hopping around the surface of asteroid Ryugu. The rovers, each the size of a small frying pan, move around the low gravity of kilometer-sized 162173 Ryugu by hopping, staying aloft for about 15 minutes and typically landing again several meters away. On Saturday, Rover 1A returned an early picture of its new home world, on the left, during one of its first hops. On Friday, lander MINERVA-II-1 detached from its mothership Hayabusa2, dropped Rovers 1A and 1B, and then landed on Ryugu. Studying Ryugu could tell humanity not only about Ryugu’s surface and interior, but about what materials were available in the early Solar System for the development of life. Two more hopping rovers are planned for release, and Hayabusa2 itself is scheduled to collect a surface sample from Ryugu and return it to Earth for detailed analysis before 2021. [via NASA] https://ift.tt/2NybBIq