A natural limestone monolith located at the village of Katskhi in the western Georgian region of Imereti.

What creates the colors in Jupiter's clouds? No one is sure. The thick atmosphere of Jupiter is mostly hydrogen and helium, elements which are colorless at the low temperatures of the Jovian cloud tops. Which trace elements provide the colors remains a topic of research, although small amounts of ammonium hydrosulfide are one leading candidate. What is clear from the featured color-enhanced image -- and many similar images -- is that lighter clouds are typically higher up than darker ones. Pictured, light clouds swirl around reddish regions toward the lower right, while they appear to cover over some darker domains on the upper right.

Building anything or getting anywhere isn’t always going to be easy. Keep moving. Stay positive.

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) winter sky events fan out toward the left, while late winter 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 Geminids meteor shower will peak in mid-December.

This is a gibbous Moon. More Earthlings are familiar with a full moon, when the entire face of Luna is lit by the Sun, and a crescent moon, when only a sliver of the Moon's face is lit. When more than half of the Moon is illuminated, though, but still short of full illumination, the phase is called gibbous. Rarely seen in television and movies, gibbous moons are quite common in the actual night sky.

A near-perfect cast of a right bronchial tree coughed up by a patient experiencing internal bleeding related to anticoagulants administered during treatment of heart failure.

Geologist-Astronaut Harrison Schmitt, Apollo 17 Lunar Module pilot, is photographed next to the American Flag during extravehicular activity (EVA) of NASA's final lunar landing mission in the Apollo series. The photo was taken at the Taurus-Littrow landing site. The highest part of the flag appears to point toward our planet earth in the distant background.

...because you never know whose coming!

So I’m at Timmies, and I look across the counter to the drive-through window…I wonder what the horse was ordering?

I arrived early in the morning to the walkway by Smuggler's Notch to find the whole area engulfed by a void of fog. I was exploring around and shooting some reflections of the trees in a nearby pond when I suddenly noticed the fog was slowly receding, revealing the amazingly colorful foliage on the hills. It was a pretty magical start to my week-long photography stay-cation in Vermont.

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.

Not a Falcon 9 rocket launch after sunset, the Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its haunting symmetries are seen in the very central region of this composited picture, processed to reveal an enormous but extremely faint halo of gaseous material, over three light-years across. Made with data from ground- and space-based telescopes it shows the extended emission which surrounds the brighter, familiar planetary nebula. Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star. But only more recently have some planetaries been found to have halos like this one.

"Ever stared down the gaping eye of a category 4 hurricane? It's chilling, even from space," says European Space Agency astronaut Alexander Gerst, who is currently living and working aboard the International Space Station as a member of the Expedition 56 crew.

Jupiter looks a bit different in ultraviolet light. To better interpret Jupiter's cloud motions and to help NASA's robotic Juno spacecraft understand the planetary context of the small fields that it sees, the Hubble Space Telescope is being directed to regularly image the entire Jovian giant. The colors of Jupiter being monitored go beyond the normal human visual range to include both ultraviolet and infrared light.

What's happened to our Sun? Nothing very unusual -- it just threw a filament. Toward the middle of 2012, a long standing solar filament suddenly erupted into space producing an energetic Coronal Mass Ejection (CME). The filament had been held up for days by the Sun's ever changing magnetic field and the timing of the eruption was unexpected. Watched closely by the Sun-orbiting Solar Dynamics Observatory, the resulting explosion shot electrons and ions into the Solar System, some of which arrived at Earth three days later and impacted Earth's magnetosphere.