Explanation: Many bright nebulae and star clusters in planet Earth's sky are associated with the name of astronomer Charles Messier from his famous 18th century catalog. His name is also given to these two large and remarkable craters on the Moon. Standouts in the dark, smooth lunar Sea of Fertility or Mare Fecunditatis, Messier (left) and Messier A have dimensions of 15 by 8 and 16 by 11 kilometers respectively. Their elongated shapes are explained by the extremely shallow-angle trajectory followed by an impactor, moving left to right, that gouged out the craters. The shallow impact also resulted in two bright rays of material extending along the surface to the right, beyond the picture. Intended to be viewed with red/blue glasses (red for the left eye), this striking stereo picture of the crater pair was recently created from high resolution scans of two images (AS11-42-6304, AS11-42-6305) taken during the Apollo 11 mission to the Moon.

Explanation: It's easy to get lost following the intricate looping filaments in this detailed image of supernova remnant Simeis 147. Also cataloged as Sharpless 2-240 it goes by the popular nickname, the Spaghetti Nebula. Seen toward the boundary of the constellations Taurus and Auriga, it covers nearly 3 degrees or 6 full moons on the sky. That's about 150 light-years at the stellar debris cloud's estimated distance of 3,000 light-years. This composite includes image data taken through narrow-band filters where reddish emission from ionized hydrogen atoms and doubly ionized oxygen atoms in faint blue-green hues trace the shocked, glowing gas. The supernova remnant has an estimated age of about 40,000 years, meaning light from the massive stellar explosion first reached Earth 40,000 years ago. But the expanding remnant is not the only aftermath. The cosmic catastrophe also left behind a spinning neutron star or pulsar, all that remains of the original star's core.

Explanation: Don’t miss the coming great conjunction. In just under two weeks, the two largest planets in our Solar System will angularly pass so close together in Earth's sky that the Moon would easily be able to cover them both simultaneously. This pending planetary passage -- on December 21 -- will be the closest since 1623. Jupiter and Saturn will remain noticeably bright and can already be seen together toward the southwest just after sunset. Soon after dusk is the best time to see them -- because they set below the horizon soon after. In mid-November, the Jovian giants were imaged together here about three degrees apart -- and slowly closing. The featured image, including a crescent moon, captured the dynamic duo beyond the Cape Murro di Porco Lighthouse in Syracuse, Sicily, Italy.

Explanation: What's that below those strange clouds? Presidents. If you look closely, you may recognize the heads of four former US Presidents carved into famous Mount Rushmore in South Dakota, USA. More obvious in the featured image are the unusual mammatus clouds that passed briefly overhead. Both were captured together by a surprised tourist with a quick camera in early September. Unlike normal flat-bottomed clouds which form when moist and calm air plateaus rise and cool, bumpy mammatus clouds form as icy and turbulent air pockets sink and heat up. Such turbulent air is frequently accompanied by a thunderstorm. Each mammatus lobe spans about one kilometer. The greater mountain is known to native Lakota Sioux as Six Grandfathers, deities responsible for the directions north, south, east, west, up, and down.

Explanation: These dark pillars may look destructive, but they are creating stars. This pillar-capturing image of the inside of the Eagle Nebula, taken with the Hubble Space Telescope in 1995, shows evaporating gaseous globules (EGGs) emerging from pillars of molecular hydrogen gas and dust. The giant pillars are light years in length and are so dense that interior gas contracts gravitationally to form stars. At each pillars' end, the intense radiation of bright young stars causes low density material to boil away, leaving stellar nurseries of dense EGGs exposed. The Eagle Nebula, associated with the open star cluster M16, lies about 7000 light years away. The pillars of creation have been imaged more recently in infrared light by Hubble, NASA's Spitzer Space Telescope, and ESA's Herschel Space Observatory -- showing new detail.

Explanation: Mons Rumker, a 70 kilometer wide complex of volcanic domes, rises some 1100 meters above the vast, smooth lunar mare known as Oceanus Procellarum, the Ocean of Storms. Daylight came to the area late last month. The lunar terminator, the shadow line between night and day, runs diagonally across the left side in this telescopic close-up of a waxing gibbous Moon from November 27. China's Chang'e-5 mission landing site is also in the frame. The probe's lander-ascender combination touch down on the lunar surface within a region right of center and north of Mons Rumker's domes on December 1. On December 3 the ascender left the Ocean of Storms carrying 2 kilograms of lunar material for return to planet Earth.

Explanation: A bright spiral galaxy of the northern sky, Messier 63 is nearby, about 30 million light-years distant toward the loyal constellation Canes Venatici. Also cataloged as NGC 5055, the majestic island universe is nearly 100,000 light-years across, about the size of our own Milky Way. Its bright core and majestic spiral arms lend the galaxy its popular name, The Sunflower Galaxy, while this exceptionally deep exposure also follows faint, arcing star streams far into the galaxy's halo. Extending nearly 180,000 light-years from the galactic center the star streams are likely remnants of tidally disrupted satellites of M63. Other satellite galaxies of M63 can be spotted in this remarkable wide-field image, made with a small telescope, including five newly identified faint dwarf galaxies, which could contribute to M63's star streams in the next few billion years.

Explanation: Sixty million light-years away toward the southerly constellation Corvus, these two large galaxies are colliding. The cosmic train wreck captured in stunning detail in this Hubble Space Telescope snapshot takes hundreds of millions of years to play out. Cataloged as NGC 4038 and NGC 4039, the galaxies' individual stars don't often collide though. Their large clouds of molecular gas and dust do, triggering furious episodes of star formation near the center of the wreckage. New star clusters and interstellar matter are jumbled and flung far from the scene of the accident by gravitational forces. This Hubble close-up frame is about 50,000 light-years across at the estimated distance of the colliding galaxies. In wider-field views their suggestive visual appearance, with extended structures arcing for hundreds of thousands of light-years, gives the galaxy pair its popular name, The Antennae Galaxies.

Explanation: Who's watching who? The featured image of the Moon through a gap in a wall of rock may appear like a giant eye looking back at you. Although, in late October, it took only a single exposure to capture this visual double, it also took a lot of planning. The photographic goal was achieved by precise timing -- needed for a nearly full moon to appear through the eye-shaped arch, by precise locating -- needed for the angular size of the Moon to fit iconically inside the rock arch, and by good luck -- needed for a clear sky and for the entire scheme to work. The seemingly coincidental juxtaposition was actually engineered with the help of three smartphone apps. The pictured sandstone arch, carved by erosion, is millions of years old and just one of thousands of natural rock arches that have been found in Arches National Park near Moab, Utah, USA. Contrastingly, the pictured Moon can be found up in the sky from just about anywhere on Earth, about half the time.

Explanation: Are stars still forming in the Milky Way's satellite galaxies? Found among the Small Magellanic Cloud's (SMC's) clusters and nebulas, NGC 346 is a star forming region about 200 light-years across, pictured here in the center of a Hubble Space Telescope image. A satellite galaxy of the Milky Way, the Small Magellanic Cloud (SMC) is a wonder of the southern sky, a mere 210,000 light-years distant in the constellation of the Toucan (Tucana). Exploring NGC 346, astronomers have identified a population of embryonic stars strung along the dark, intersecting dust lanes visible here on the right. Still collapsing within their natal clouds, the stellar infants' light is reddened by the intervening dust. Toward the top of the frame is another star cluster with intrinsically older and redder stars. A small, irregular galaxy, the SMC itself represents a type of galaxy more common in the early Universe. These small galaxies, though, are thought to be building blocks for the larger galaxies present today.

Explanation: The sky is filled with faintly glowing gas, though it can take a sensitive camera and telescope to see it. For example, this twelve-degree-wide view of the northern part of the constellation Cygnus reveals a complex array of cosmic clouds of gas along the plane of our Milky Way galaxy. The featured mosaic of telescopic images was recorded through two filters: an H-alpha filter that transmits only visible red light from glowing hydrogen atoms, and a blue filter that transmits primarily light emitted by the slight amount of energized oxygen. Therefore, in this 18-hour exposure image, blue areas are hotter than red. Further digital processing has removed the myriad of point-like Milky Way stars from the scene. Recognizable bright nebulas include NGC 7000 (North America Nebula), and IC 5070 (Pelican Nebula) on the left with IC 1318 (Butterfly Nebula) and NGC 6888 (Crescent Nebula) on the right -- but others can be found throughout the wide field.

Explanation: Could you survive a jump off the tallest cliff in the Solar System? Quite possibly. Verona Rupes on Uranus' moon Miranda is estimated to be 20 kilometers deep -- ten times the depth of the Earth's Grand Canyon. Given Miranda's low gravity, it would take about 12 minutes for a thrill-seeking adventurer to fall from the top, reaching the bottom at the speed of a racecar -- about 200 kilometers per hour. Even so, the fall might be survivable given proper airbag protection. The featured image of Verona Rupes was captured by the passing Voyager 2 robotic spacecraft in 1986. How the giant cliff was created remains unknown, but is possibly related to a large impact or tectonic surface motion.

Explanation: Grand spiral galaxies often seem to get all the glory, flaunting their young, bright, blue star clusters in beautiful, symmetric spiral arms. But small galaxies form stars too, like nearby NGC 6822, also known as Barnard's Galaxy. Beyond the rich starfields in the constellation Sagittarius, NGC 6822 is a mere 1.5 million light-years away, a member of our Local Group of galaxies. A dwarf irregular galaxy similar to the Small Magellanic Cloud, NGC 6822 is about 7,000 light-years across. Brighter foreground stars in our Milky Way have a spiky appearance. Behind them, Barnard's Galaxy is seen to be filled with young blue stars and mottled with the telltale pinkish hydrogen glow of star forming regions in this deep color composite image.

Explanation: This Long March-5 rocket blasted off from the Wenchang launch site in southernmost Hainan province on Tuesday November 24, at 4:30 am Beijing Time, carrying China's Chang'e-5 mission to the Moon. The lunar landing mission is named for the ancient Chinese goddess of the moon. Its goal is to collect about 2 kilograms (4.4 pounds) of lunar material from the surface and return it to planet Earth, the first robotic sample return mission to the Moon since the Soviet Union's Luna 24 mission in 1976. The complex Chang'e-5 mission landing target is in the Oceanus Procellarum (Ocean of Storms). The smooth volcanic plain was also visited by the Apollo 12 mission in 1969. Chang'e-5's lander is solar-powered and scheduled to operate on the lunar surface during its location's lunar daylight, which will last about two Earth weeks, beginning around November 27. A capsule with the lunar sample on board would return to Earth in mid-December.

Explanation: Surprisingly reminiscent of The Great Nebula in Orion, The Great Turkey Nebula spans this creative field of view. Of course if it were the Orion Nebula it would be our closest large stellar nursery, found at the edge of a large molecular cloud a mere 1,500 light-years away. Also known as M42, the Orion Nebula is visible to the eye as the middle "star" in the sword of Orion the Hunter, a constellation now rising in planet Earth's evening skies. Stellar winds from clusters of newborn stars scattered throughout the Orion Nebula sculpt its ridges and cavities seen in familiar in telescopic images. Similar in size to the Orion Nebula, this Great Turkey Nebula was imagined to be about 13 light-years across. Stay safe and well.

Explanation: How far can you see? The Andromeda Galaxy at 2.5 million light years away is the most distant object easily seen with your unaided eye. Most other apparent denizens of the night sky -- stars, clusters, and nebulae -- typically range from a few hundred to a few thousand light-years away and lie well within our own Milky Way Galaxy. Given its distance, light from Andromeda is likely also the oldest light that you can see. Also known as M31, the Andromeda Galaxy dominates the center of the featured zoomed image, taken from the dunes of Bahía Creek, Patagonia, in southern Argentina. The image is a combination of 45 background images with one foreground image -- all taken with the same camera and from the same location within 90 minutes. M110, a satellite galaxy of Andromenda is visible just below and to the left of M31's core. As cool as it may be to see this neighboring galaxy to our Milky Way with your own eyes, long duration camera exposures can pick up many faint and breathtaking details. Recent data indicates that our Milky Way Galaxy will collide and combine with the similarly-sized Andromeda galaxy in a few billion years.

Explanation: Will our Sun look like this one day? The Helix Nebula is one of brightest and closest examples of a planetary nebula, a gas cloud created at the end of the life of a Sun-like star. The outer gasses of the star expelled into space appear from our vantage point as if we are looking down a helix. The remnant central stellar core, destined to become a white dwarf star, glows in light so energetic it causes the previously expelled gas to fluoresce. The Helix Nebula, given a technical designation of NGC 7293, lies about 700 light-years away towards the constellation of the Water Bearer (Aquarius) and spans about 2.5 light-years. The featured picture was taken with the Canada-France-Hawaii Telescope (CFHT) located atop a dormant volcano in Hawaii, USA. A close-up of the inner edge of the Helix Nebula shows complex gas knots of unknown origin.

Explanation: Why do colorful cloud bands encircle Jupiter? Jupiter's top atmospheric layer is divided into light zones and dark belts that go all the way around the giant planet. It is high horizontal winds -- in excess of 300 kilometers per hour -- that cause the zones to spread out planet-wide. What causes these strong winds remains a topic of research. Replenished by upwelling gas, zonal bands are thought to include relatively opaque clouds of ammonia and water that block light from lower and darker atmospheric levels. One light-colored zone is shown in great detail in the featured vista taken by the robotic Juno spacecraft in 2017. Jupiter's atmosphere is mostly clear and colorless hydrogen and helium, gases that are not thought to contribute to the gold and brown colors. What compounds create these colors is another active topic of research -- but is hypothesized to involve small amounts of sunlight-altered sulfur and carbon. Many discoveries have been made from Juno's data, including that water composes an unexpectedly high 0.25 percent of upper-level cloud molecules near Jupiter's equator, a finding important not only for understanding Jovian currents but for the history of water in the entire Solar System.

Explanation: Where did all the stars go? What used to be considered a hole in the sky is now known to astronomers as a dark molecular cloud. Here, a high concentration of dust and molecular gas absorb practically all the visible light emitted from background stars. The eerily dark surroundings help make the interiors of molecular clouds some of the coldest and most isolated places in the universe. One of the most notable of these dark absorption nebulae is a cloud toward the constellation Ophiuchus known as Barnard 68, pictured here. That no stars are visible in the center indicates that Barnard 68 is relatively nearby, with measurements placing it about 500 light-years away and half a light-year across. It is not known exactly how molecular clouds like Barnard 68 form, but it is known that these clouds are themselves likely places for new stars to form. In fact, Barnard 68 itself has been found likely to collapse and form a new star system. It is possible to look right through the cloud in infrared light.

Explanation: A brilliant yellowish celestial beacon, Mars still dazzles in the night. Peering between clouds the wandering planet was briefly joined by the flash of a meteor in this moonless dark sky on November 18. The single exposure was taken as the Earth swept up dust from periodic comet Tempel-Tuttle during the annual Leonid Meteor Shower. The view of a rugged western horizon looks along the Yulong mountain range in Yunnan province, southwestern China. Yulong (Jade Dragon) Snow Mountain lies below the clouds and beyond the end of the meteor streak.

Explanation: This may be the best global Mars map made with a telescope based on planet Earth. The image data were captured by a team of observers over six long nights at the Pic du Midi mountaintop observatory between October 8 and November 1, when the fourth rock from the Sun had not wandered far from its 2020 opposition and its biggest and brightest appearance in Earth's night sky. The large telescope used, 1 meter in diameter with a 17 meter focal length, was also used in support of NASA's Apollo lunar landing missions. After about 30 hours of processing, the data were combined to produced this remarkably sharp projected view of the martian surface extending to about 45 degrees northern latitude. The image data have also been mapped onto a rotating sphere and rotating stereo, views. Fans of Mars can easily pick out their favorite markings on the Red Planet by eyeing a labeled version of this global map of Mars.

Explanation: Leaving planet Earth for a moment, a SpaceX Falcon 9 rocket arced into the early evening sky last Sunday at 7:27 pm EST. This 3 minute 20 second exposure traces the launch streak over Kennedy Space Center's Launch Complex 39A. The rocket carried four astronauts en route to the International Space Station on the first flight of a NASA-certified commercial human spacecraft system. Dubbed Resilience, the astronauts' Crew Dragon spacecraft successfully docked with the orbital outpost one day later, on Monday, November 16. At the conclusion of their six-month stay on the ISS, the Crew-1 astronauts will use their spacecraft return to Earth. Of course about 9 minutes after launch the Falcon 9 rocket's first stage returned to Earth, landing in the Atlantic Ocean on autonomous spaceport drone ship Just Read The Instructions.

Explanation: Most star clusters are singularly impressive. Open clusters NGC 869 and NGC 884, however, could be considered doubly impressive. Also known as "h and chi Persei", this unusual double cluster, shown above, is bright enough to be seen from a dark location without even binoculars. Although their discovery surely predates recorded history, the Greek astronomer Hipparchus notably cataloged the double cluster. The clusters are over 7,000 light years distant toward the constellation of Perseus, but are separated by only hundreds of light years. In addition to being physically close together, the clusters' ages based on their individual stars are similar - evidence that both clusters were likely a product of the same star-forming region.

Explanation: What's creating these long glowing streaks in the sky? No one is sure. Known as Strong Thermal Emission Velocity Enhancements (STEVEs), these luminous light-purple sky ribbons may resemble regular auroras, but recent research reveals significant differences. A STEVE's great length and unusual colors, when measured precisely, indicate that it may be related to a subauroral ion drift (SAID), a supersonic river of hot atmospheric ions thought previously to be invisible. Some STEVEs are now also thought to be accompanied by green picket fence structures, a series of sky slats that can appear outside of the main auroral oval that does not involve much glowing nitrogen. The featured wide-angle composite image shows a STEVE in a dark sky above Childs Lake, Manitoba, Canada in 2017, crossing in front of the central band of our Milky Way Galaxy.

Explanation: The month was July, the place was the Greek island of Crete, and the sky was spectacular. Of course there were the usual stars like Polaris, Vega, and Antares -- and that common asterism everyone knows: the Big Dipper. But this sky was just getting started. The band of the Milky Way Galaxy stunned as it arched across the night like a bridge made of stars and dust but dotted with red nebula like candy. The planets Saturn and Jupiter were so bright you wanted to stop people on the beach and point them out. The air glowed like a rainbow -- but what really grabbed the glory was a comet. Just above the northern horizon, Comet NEOWISE spread its tails like nothing you had ever seen before or might ever see again. Staring in amazement, there was only one thing to do: take a picture

Explanation: Why is this galaxy so thin? Many disk galaxies are just as thin as NGC 5866, pictured here, but are not seen edge-on from our vantage point. One galaxy that is situated edge-on is our own Milky Way Galaxy. Classified as a lenticular galaxy, NGC 5866 has numerous and complex dust lanes appearing dark and red, while many of the bright stars in the disk give it a more blue underlying hue. The blue disk of young stars can be seen extending past the dust in the extremely thin galactic plane, while the bulge in the disk center appears tinged more orange from the older and redder stars that likely exist there. Although similar in mass to our Milky Way Galaxy, light takes about 60,000 years to cross NGC 5866, about 30 percent less than light takes to cross our own Galaxy. In general, many disk galaxies are very thin because the gas that formed them collided with itself as it rotated about the gravitational center. Galaxy NGC 5866 lies about 44 million light years distant toward the constellation of the Dragon (Draco).

Explanation: Yesterday, early morning risers around planet Earth were treated to a waning Moon low in the east as the sky grew bright before dawn. From the Island of Ortigia, Syracuse, Sicily, Italy this simple snapshot found the slender sunlit crescent just before sunrise. Never wandering far from the Sun in Earth's sky, inner planets Venus and Mercury shared the calm seaside view. Also in the frame, right of the line-up of Luna and planets, is bright star Spica, alpha star of the constellation Virgo and one of the 20 brightest stars in Earth's night. Tomorrow the Moon will be New. The dark lunar disk means mostly dark nights for planet Earth in the coming week and a good chance to watch the annual Leonid Meteor Shower.

Explanation: The Tarantula Nebula, also known as 30 Doradus, is more than a thousand light-years in diameter, a giant star forming region within nearby satellite galaxy the Large Magellanic Cloud. About 180 thousand light-years away, it's the largest, most violent star forming region known in the whole Local Group of galaxies. The cosmic arachnid sprawls across the top of this spectacular view, composed with narrowband filter data centered on emission from ionized hydrogen and oxygen atoms. Within the Tarantula (NGC 2070), intense radiation, stellar winds and supernova shocks from the central young cluster of massive stars, cataloged as R136, energize the nebular glow and shape the spidery filaments. Around the Tarantula are other star forming regions with young star clusters, filaments, and blown-out bubble-shaped clouds. In fact, the frame includes the site of the closest supernova in modern times, SN 1987A, right of center. The rich field of view spans about 2 degrees or 4 full moons, in the southern constellation Dorado. But were the Tarantula Nebula closer, say 1,500 light-years distant like the local star forming Orion Nebula, it would take up half the sky.

Explanation: What color is the Moon? It depends on the night. Outside of the Earth's atmosphere, the dark Moon, which shines by reflected sunlight, appears a magnificently brown-tinged gray. Viewed from inside the Earth's atmosphere, though, the moon can appear quite different. The featured image highlights a collection of apparent colors of the full moon documented by one astrophotographer over 10 years from different locations across Italy. A red or yellow colored moon usually indicates a moon seen near the horizon. There, some of the blue light has been scattered away by a long path through the Earth's atmosphere, sometimes laden with fine dust. A blue-colored moon is more rare and can indicate a moon seen through an atmosphere carrying larger dust particles. What created the purple moon is unclear -- it may be a combination of several effects. The last image captures the total lunar eclipse of 2018 July -- where the moon, in Earth's shadow, appeared a faint red -- due to light refracted through air around the Earth. The next full moon will occur at the end of this month (moon-th) and is known in some cultures as the Beaver Moon.

Explanation: This cosmic close-up looks deep inside the Soul Nebula. The dark and brooding dust clouds near the top, outlined by bright ridges of glowing gas, are cataloged as IC 1871. About 25 light-years across, the telescopic field of view spans only a small part of the much larger Heart and Soul nebulae. At an estimated distance of 6,500 light-years the star-forming complex lies within the Perseus spiral arm of our Milky Way Galaxy, seen in planet Earth's skies toward the constellation Cassiopeia. An example of triggered star formation, the dense star-forming clouds in the Soul Nebula are themselves sculpted by the intense winds and radiation of the region's massive young stars. In the featured image, stars have been digitally removed to highlight the commotion in the gas and dust.