Moon Walk

Moon walking: Not as easy as it looks!

This is Sandra Tsing Loh with the Loh Down on Science.

For astronauts, the moon’s weaker gravity can be disorienting. How do we know? Astronauts stumble! NASA has the blooper reels to prove it.

That’s because gravity doesn’t just anchor us. It also provides our sense of what’s called “perceptual upright.” That’s knowing which way is up. We need it for lots of things. Like: knowing how an object will move when thrown, or if writing is upside down. We even need it to recognize faces.

Weird, huh?

But how weak must gravity be, before we get confused? No one’s ever determined this.

So researchers from Britain’s York University placed volunteers on a human centrifuge, then spun them! Different speeds simulated gravitational fields of various strengths.

Overhead, a monitor flashed the lower case letters “p” and “d.” Little p is an upside-down little d, and vice-versa.

Volunteers indicated which letter they thought they saw. This measured their perception of “up.”

Result? At about 15 percent of Earth’s gravity level we become disoriented. That’s equivalent to moon gravity.

But does it affect breakdancing? Next experiment!