Solis Lacus: The Eye of Mars

As telescopes around planet Earth watch, Mars is growing brighter in night skies, approaching its 2020 opposition on October 13. Mars looks like its watching too in this view of the Red Planet from September 22. Mars’ disk is already near its maximum apparent size for earthbound telescopes, less than 1/80th the apparent diameter of a Full Moon. The seasonally shrinking south polar cap is at the bottom and hazy northern clouds are at the top. A circular, dark albedo feature, Solis Lacus (Lake of the Sun), is just below and left of disk center. Surrounded by a light area south of Valles Marineris, Solis Lacus looks like a planet-sized pupil, famously known as The Eye of Mars . Near the turn of the 20th century, astronomer and avid Mars watcher Percival Lowell associated the Eye of Mars with a conjunction of canals he charted in his drawings of the Red Planet. Broad, visible changes in the size and shape of the Eye of Mars are now understood from high resolution surface images to be due to dust transported by winds in the thin Martian atmosphere. via NASA https://ift.tt/33jtLUp

Sonified: Eagle Nebula Pillars

Yes, but have you ever experienced the Eagle Nebula with your ears ? The famous nebula, M16, is best known for the feast it gives your eyes, highlighting bright young stars forming deep inside dark towering structures. These light-years long columns of cold gas and dust are some 6,500 light-years distant toward the constellation of the Serpent (Serpens). Sculpted and eroded by the energetic ultraviolet light and powerful winds from M16’s cluster of massive stars, the cosmic pillars themselves are destined for destruction. But the turbulent environment of star formation within M16, whose spectacular details are captured in this combined Hubble (visible) and Chandra (X-ray) image, is likely similar to the environment that formed our own Sun. In the featured video, listen for stars and dust sounding off as the line of sonification moves left to right, with vertical position determining pitch. via NASA https://ift.tt/2EOq2Vw

GW Orionis: A Star System with Titled Rings

Triple star system GW Orionis appears to demonstrate that planets can form and orbit in multiple planes. In contrast, all the planets and moons in our Solar System orbit in nearly the same plane. The picturesque system has three prominent stars, a warped disk, and inner tilted rings of gas and grit. The featured animation characterizes the GW Ori system from observations with the European Southern Observatory’s VLT and ALMA telescopes in Chile. The first part of the illustrative video shows a grand vista of the entire system from a distant orbit, while the second sequence takes you inside the tilted rings to resolve the three central co-orbiting stars. Computer simulations indicate that multiple stars in systems like GW Ori could warp and break-up disks into unaligned, exoplanet-forming rings. via NASA https://ift.tt/3n8oCqj

Filaments of the Cygnus Loop

What lies at the edge of an expanding supernova? Subtle and delicate in appearance, these ribbons of shocked interstellar gas are part of a blast wave at the expanding edge of a violent stellar explosion that would have been easily visible to humans during the late stone age, about 20,000 years ago. The featured image was recorded by the Hubble Space Telescope and is a closeup of the outer edge of a supernova remnant known as the Cygnus Loop or Veil Nebula. The filamentary shock front is moving toward the top of the frame at about 170 kilometers per second, while glowing in light emitted by atoms of excited hydrogen gas. The distances to stars thought to be interacting with the Cygnus Loop have recently been found by the Gaia mission to be about 2400 light years distant. The whole Cygnus Loop spans six full Moons across the sky, corresponding to about 130 light years, and parts can be seen with a small telescope toward the constellation of the Swan (Cygnus). via NASA https://ift.tt/2S73H8F

Lightning over Colorado

Have you ever watched a lightning storm in awe? Join the crowd. Oddly, details about how lightning is produced remains a topic of research. What is known is that updrafts carry light ice crystals into collisions with larger and softer ice balls, causing the smaller crystals to become positively charged. After enough charge becomes separated, the rapid electrical discharge that is lightning occurs. Lightning usually takes a jagged course, rapidly heating a thin column of air to about three times the surface temperature of the Sun. The resulting shock wave starts supersonically and decays into the loud sound known as thunder. Lightning bolts are common in clouds during rainstorms, and on average 44 lightning bolts occur on the Earth every second. Pictured, over 60 images were stacked to capture the flow of lightning-producing storm clouds in July over Colorado Springs, Colorado, USA. via NASA https://ift.tt/36bxzJ2

Moon Pairs and the Synodic Month

Observe the Moon each night and its visible sunlit portion will gradually change. In phases progressing from New Moon to Full Moon to New Moon again, a lunar cycle or synodic month is completed in about 29.5 days. They look full, but top left to bottom right these panels do show the range of lunar phases for a complete synodic month during August 2019 from Ragusa, Sicily, Italy, planet Earth. For this lunar cycle project the panels organize images of the lunar phases in pairs. Each individual image is paired with another image separated by about 15 days, or approximately half a synodic month. As a result the opposite sunlit portions complete the lunar disk and the shadow line at the boundary of lunar night and day, the terminator, steadily marches across the Moon’s familiar nearside. For extra credit, what lunar phase would you pair with the Moon tonight? via NASA https://ift.tt/2EEYzFK

Moon over Andromeda

The Great Spiral Galaxy in Andromeda (also known as M31), a mere 2.5 million light-years distant, is the closest large spiral to our own Milky Way. Andromeda is visible to the unaided eye as a small, faint, fuzzy patch, but because its surface brightness is so low, casual skygazers can’t appreciate the galaxy’s impressive extent in planet Earth’s sky. This entertaining composite image compares the angular size of the nearby galaxy to a brighter, more familiar celestial sight. In it, a deep exposure of Andromeda, tracing beautiful blue star clusters in spiral arms far beyond the bright yellow core, is combined with a typical view of a nearly full Moon. Shown at the same angular scale, the Moon covers about 1/2 degree on the sky, while the galaxy is clearly several times that size. The deep Andromeda exposure also includes two bright satellite galaxies, M32 and M110 (below and right). via NASA https://ift.tt/365QNQw

Enceladus in Infrared

One of our Solar System’s most tantalizing worlds, icy Saturnian moon Enceladus appears in these detailed hemisphere views from the Cassini spacecraft. In false color, the five panels present 13 years of infrared image data from Cassini’s Visual and Infrared Mapping Spectrometer and Imaging Science Subsystem. Fresh ice is colored red, and the most dramatic features look like long gashes in the 500 kilometer diameter moon’s south polar region. They correspond to the location of tiger stripes, surface fractures that likely connect to an ocean beneath the Enceladus ice shell. The fractures are the source of the moon’s icy plumes that continuously spew into space. The plumes were discovered by by Cassini in 2005. Now, reddish hues in the northern half of the leading hemisphere view also indicate a recent resurfacing of other regions of the geologically active moon, a world that may hold conditions suitable for life. via NASA https://ift.tt/32TPYZ0

ISS Transits Mars

Yes, but have you ever seen the space station do this? If you know when and where to look, watching the bright International Space Station (ISS) drift across your night sky is a fascinating sight — but not very unusual. Images of the ISS crossing in front of the half-degree Moon or Sun do exist, but are somewhat rare as they take planning, timing, and patience to acquire. Catching the ISS crossing in front of minuscule Mars, though, is on another level. Using online software, the featured photographer learned that the unusual transit would be visible only momentarily along a very narrow stretch of nearby land spanning just 90 meters. Within this stretch, the equivalent ground velocity of the passing ISS image would be a quick 7.4 kilometers per second. However, with a standard camera, a small telescope, an exact location to set up his equipment, an exact direction to point the telescope, and sub-millisecond timing — he created a video from which the featured 0.00035 second exposure was extracted. In the resulting image capture, details on both Mars and the ISS are visible simultaneously. The featured image was acquired last Monday at 05:15:47 local time from just northeast of San Diego, California, USA. Although typically much smaller, angularly, than the ISS, Mars is approaching its maximum angular size in the next few weeks, because the blue planet (Earth) is set to pass its closest to the red planet (Mars) in their respective orbits around the Sun. via NASA https://ift.tt/33S59RF

Equinox in the Sky

Does the Sun set in the same direction every day? No, the direction of sunset depends on the time of the year. Although the Sun always sets approximately toward the west, on an equinox like today the Sun sets directly toward the west. After today’s September equinox, the Sun will set increasingly toward the southwest, reaching its maximum displacement at the December solstice. Before today’s September equinox, the Sun had set toward the northwest, reaching its maximum displacement at the June solstice. The featured time-lapse image shows seven bands of the Sun setting one day each month from 2019 December through 2020 June. These image sequences were taken from Alberta, Canada — well north of the Earth’s equator — and feature the city of Edmonton in the foreground. The middle band shows the Sun setting during the last equinox — in March. From this location, the Sun will set along this same equinox band again today. via NASA https://ift.tt/33Smb2h