Mars in the Loop

This composite of images spaced some 5 to 9 days apart, from late April (bottom right) through November 5 (top left), traces the retrograde motion of ruddy-colored Mars through planet Earth’s night sky. To connect the dots and dates in this 2018 Mars retrograde loop, just slide your cursor over the picture (and check out this animation). But Mars didn’t actually reverse the direction of its orbit. Instead, the apparent backwards motion with respect to the background stars is a reflection of the motion of the Earth itself. Retrograde motion can be seen each time Earth overtakes and laps planets orbiting farther from the Sun, the Earth moving more rapidly through its own relatively close-in orbit. On July 27, Mars was near its favorable 2018 parihelic opposition, when Mars was closest to the Sun in its orbit while also opposite the Sun in Earth’s sky. For that date, the frame used in this composite was taken during the total lunar eclipse. [via NASA]

NGC 6188: The Dragons of Ara

Dark shapes with bright edges winging their way through dusty NGC 6188 are tens of light-years long. The emission nebula is found near the edge of an otherwise dark large molecular cloud in the southern constellation Ara, about 4,000 light-years away. Born in that region only a few million years ago, the massive young stars of the embedded Ara OB1 association sculpt the fantastic shapes and power the nebular glow with stellar winds and intense ultraviolet radiation. The recent star formation itself was likely triggered by winds and supernova explosions, from previous generations of massive stars, that swept up and compressed the molecular gas. With image data from the Chilescope Observatory, a false-color Hubble palette was used to create this gorgeous wide-field image and shows emission from sulfur, hydrogen, and oxygen atoms in red, green, and blue hues. The field of view spans about four full Moons, corresponding to about 150 light years at the estimated distance of NGC 6188. [via NASA]

NGC 1499: The California Nebula

There’s even a California in space. Drifting through the Orion Arm of the spiral Milky Way Galaxy, this cosmic cloud by chance echoes the outline of California on the west coast of the United States. Our own Sun also lies within the Milky Way’s Orion Arm, only about 1,500 light-years from the California Nebula. Also known as NGC 1499, the classic emission nebula is around 100 light-years long. On the featured image, the most prominent glow of the California Nebula is the red light characteristic of hydrogen atoms recombining with long lost electrons, stripped away (ionized) by energetic starlight. The star most likely providing the energetic starlight that ionizes much of the nebular gas is the bright, hot, bluish Xi Persei just to the right of the nebula. A regular target for astrophotographers, the California Nebula can be spotted with a wide-field telescope under a dark sky toward the constellation of Perseus, not far from the Pleiades. [via NASA]

IC 4592: The Blue Horsehead Reflection Nebula

Do you see the horse’s head? What you are seeing is not the famous Horsehead nebula toward Orion but rather a fainter nebula that only takes on a familiar form with deeper imaging. The main part of the here imaged molecular cloud complex is a reflection nebula cataloged as IC 4592. Reflection nebulas are actually made up of very fine dust that normally appears dark but can look quite blue when reflecting the light of energetic nearby stars. In this case, the source of much of the reflected light is a star at the eye of the horse. That star is part of Nu Scorpii, one of the brighter star systems toward the constellation of the Scorpion (Scorpius). A second reflection nebula dubbed IC 4601 is visible surrounding two stars to the right of the image center. [via NASA]

Flying Saucer Crash Lands in Utah Desert

A flying saucer from outer space crash-landed in the Utah desert after being tracked by radar and chased by helicopters. The year was 2004, and no space aliens were involved. The saucer, pictured here, was the Genesis sample return capsule, part of a human-made robot Genesis spaceship launched in 2001 by NASA itself to study the Sun. The unexpectedly hard landing at over 300 kilometers per hour occurred because the parachutes did not open as planned. The Genesis mission had been orbiting the Sun collecting solar wind particles that are usually deflected away by Earth’s magnetic field. Despite the crash landing, many return samples remained in good enough condition to analyze. So far, Genesis-related discoveries include new details about the composition of the Sun and how the abundance of some types of elements differ across the Solar System. These results have provided intriguing clues into details of how the Sun and planets formed billions of years ago. [via NASA]

Lunar LOVE

A more creative search by a group of amateur astronomers in the Ehime Prefecture of Shikoku Island, Japan has found lunar L-O-V-E. Their secret was an examination of this sharp image of the First Quarter Moon. To discover it for yourself you’ll need to look closely at details of the shadow and light along the terminator, the line between lunar night and day Created by the contrast of shadowed crater floors with sunlit walls and ridges, the letter V is not too hard to find near the center of the image. Letters L and E are a bit more challenging though, but can be teased out of shadow and light along the terminator at the bottom. Of course, on the cratered surface of the Moon the O is easy … . Moonwatchers on planet Earth should understand that like the famous lunar X, also seen here, these lunar letters are transient and only appear along the terminator in the hours around the Moon’s first quarter phase. So your next chance for lunar L-O-V-E is the first quarter Moon on November 15. [via NASA]

Shells of Stars in Elliptical Galaxy PGC 42871

How do galaxies grow? To help find out, the Hubble Space Telescope was deployed to image the unusual elliptical galaxy PGC 42871. How this galaxy came to be surrounded by numerous shells of stars may give clues about how it evolved. Embedded in the diffuse shells are massive globular clusters of stars — stars which analyses show were born during three different epochs. This and other data indicate that PGC 42871 has been in at least two galactic collisions, at least one of which might have been with a former spiral galaxy. The remaining spiral galaxy on the far left is at the same distance as PGC 42871 and may have been involved in some of the collisions. PGC 42871 spans about 20 thousand light years and lies about 270 million light years away toward the constellation of Centaurus. [via NASA]