Out-of-This-World Facts for International Observe the Moon Night

This Saturday marks International Observe the Moon Night—an evening where people around world are invited to revel in the glow of our nearest celestial neighbor.

Sponsored by the NASA’s Lunar Reconnaissance Orbiter, NASA’s Solar System Exploration Research Virtual Institute (SSERVI), and the Lunar and Planetary Institute, the evening is intended to encourage "observation, appreciation, and understanding" about the moon, according to the event website. There are moon-gazing events around the world—and of course, you can always just watch on your own.

To get you excited for the event, here are five out-of-this-world facts about our celestial buddy:

Cataclysmic Beginnings

Our moon was formed 4.5 billion years ago by a giant planetary collision, Jesse Emspak wrote for Smithsonian.com in 2015, when a Mars-sized proto-planet named Theia collided with proto-Earth. The crash would have “largely melted the Earth,” writes Charles Quoi at Space.com. And debris from the collision made up a large part of the moon.

Could We Live on Our Lunar Neighbor

A newly discovered cave raises hopes for a moon base, Justin McCurry reports for The Guardian. Earlier this month, the Japanese Space Agency (JAXA) confirmed the detection of a massive cave, some 31 miles across, near volcanic domes known as Marius Hills. The cave is likely part of an ancient fractured lava tube, which was formed when molten rock flowed across the celestial surface. The hollow could provide stable temperature conditions and protection from micrometeorites and cosmic ray radiation, Junichi Haruyama, a senior JAXA researcher, tells McCurry.

The Moon Has a Buddy

Another orb is locked in a dance with the Earth and moon, researchers at NASA’s Jet Propulsion Laboratory recently discovered. Dubbed 2016 HO3, the small asteroid that orbits along on a similar path as our moon, never drifting more than 100 times the moon’s orbit. Researchers believe it's hung on for around a century—essentially “caught in a little dance with Earth,” NASA’s Paul Chodas says in a press release. Others have called the tag-along satellite a “baby moon,” but Snopes clarifies that the asteroid can not truly be classed as a moon because its orbit is too wobbly and likely temporary. Luna’s reign continues, unchallenged.

The Moon Once Had an Atmosphere

Although today’s moon doesn’t have much of an atmosphere—NASA calls it “infinitesimal” in comparison to Earth’s—a study published earlier this month suggests that what it does have was created from ancient explosive volcanism. Researchers even believe that the lunar body once had a relatively robust atmosphere, writes Hanneke Weitering at Scientific American. By calculating the amount of gases released from flowing lava, scientists determined the the atmosphere grew large enough that it was accumulating faster than it was lost to space.

Explore the Moon Online

If clouds obscure your vision tomorrow night, never fear. Google Maps has recently expanded their maps to outer space, giving users a closeup view of the moon's surface. Along with the moon, viewers can explore the surface of 15 other bodies from our solar system. Each was created in collaboration with astronomical artist Björn Jónsson, and incorporate beautiful maps of the celestial body, reports Frederic Lardinois for Tech Crunch.