Then there is the moon’s wrinkled surface — a topography that might be more threatening than rugged terrain on Earth.

“A lot of people think the moon is like a desert, but it’s actually more like an ocean,” Dr. Richard Scheuring, a flight surgeon at NASA, said. “It has a very undulating surface, like sea swells.”

Throw in the intense contrast between light and dark — unlike anything we see here on Earth — and those changes in the terrain can play tricks on your eyes.

When Pete Conrad and Alan Bean landed on the moon during the Apollo 12 mission, one of their tasks was to enter the 650-foot-wide Surveyor Crater. But as they skirted its rim, searching for the best path down, they informed Houston that the crater was far too steep.

Topographic maps, however, revealed an easy, 21-degree slope. The sharp shadows had fooled the astronauts.

That means the act of simply walking around on the moon might be perilous.

The moon might also be rippling. A recent study suggests that our lunar neighbor is tectonically active, with moonquakes as large as 5.5-magnitude earthquakes. That is bad news for future lunar bases, which might be vulnerable to the shaking.

Sleepy moon men

Sleep may not come easy on the moon. Our body clocks are wound by light exposure, as day sweeps to night once every 24 hours. But on the moon, that same shift occurs once every 28 days.