Now is the best time to get a glimpse of Comet C/2021 A1, better known as Comet Leonard. It's named for its discoverer, Gregory Leonard, a senior research specialist at the University of Arizona Lunar and Planetary Laboratory.

Every night with clear skies, astronomers with LPL's Catalina Sky Survey scan the sky for near-Earth asteroids—space rocks with the potential of venturing close to Earth at some point.

During one such routine observation run on Jan. 3, Leonard spotted a fuzzy patch of light tracking across the starfield background in a sequence of four images taken with the 1.5-meter telescope at the summit of Mount Lemmon.

The moon may be a mostly uniform expanse of gray, but if you look closely, you can still find a few nooks and crannies in its surface, from deep trenches to pits and maybe even caves.

Now, researchers at CU Boulder have set out to explore what the environment might be like inside some of these shadowy features—many of which are too dark to see clearly from orbit.

The team's preliminary results suggest that pits and caves on the moon showcase remarkably stable conditions. They don't seem to experience the wild swings in temperature that are common at the moon's surface, said Andrew Wilcoski, a graduate student in the Department of Astrophysical and Planetary Sciences at CU Boulder. He will present the group's initial findings Friday at the American Geophysical Union fall meeting in New Orleans.

"If we're hoping to send people into these caves in the decades ahead, we want to know what they should expect down there," said Wilcoski, a co-author of the new research.

A Japanese space tourist on Monday rejected criticism from those who questioned his decision to pay a fortune for a trip to the International Space Station, saying the "amazing" experience was worth it.