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. via NASA https://ift.tt/3nKcQ4P

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. via NASA https://ift.tt/35SD531

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. via NASA https://ift.tt/2IYi9yg

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. via NASA https://ift.tt/3fgKmwj

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. via NASA https://ift.tt/3nFLtZo

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. via NASA https://ift.tt/3pxv5vU

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. via NASA https://ift.tt/3nw1fGu

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. via NASA https://ift.tt/2UuR9Jh

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). via NASA https://ift.tt/3eYXvdv

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. via NASA https://ift.tt/3lvjLyb