In space, astronauts can cry, but their tears don't flow down their faces. Without gravity, tears form a liquid ball that sticks to the eye, gradually growing larger until it spreads across the nose to the other eye or needs to be wiped away with a towel.
Astronaut Tears Form Liquid Balls That Stick to Eyes
Crying is a universal human experience, but in the microgravity environment of space, even something as simple as shedding tears becomes weird. Astronauts can absolutely cry in space—their tear ducts work just fine—but what happens next is nothing like crying on Earth.
On our planet, tears stream down your face thanks to gravity. But 250 miles above Earth on the International Space Station, there's no gravity to pull those tears down. Instead, they just... sit there. The liquid pools on the surface of your eye, gradually forming a larger and larger ball of water.
Chris Hadfield's Famous Demonstration
In 2013, Canadian astronaut Chris Hadfield posted a video that went viral, demonstrating exactly what happens when you cry in space. Using drinking water as a substitute for tears, he squirted some into his eye and let viewers watch what happened.
The water clung to his eyeball like a wobbling contact lens made of liquid. As Hadfield explained: "If you keep crying you just end up with a bigger and bigger ball of water in your eye, until eventually it crosses across your nose and gets into your other eye, or evaporates, or maybe spreads over your cheek, or you grab a towel and dry it up."
That's right—cry enough in space and your tears will form a bridge from one eye to the other via your nose.
It Actually Stings
Hadfield also mentioned that the experience stings more than crying on Earth. This might seem surprising, but there's a reason: over 30% of ISS astronauts report dry eye symptoms during their missions. The recycled air and microgravity environment are tough on eyes.
When tears finally arrive to moisturize that irritated cornea, the sensation is apparently more uncomfortable than the gentle relief you'd feel on Earth.
The Practical Problem
Beyond the physical discomfort, there's a practical issue. If an astronaut doesn't wipe away their tears, droplets can eventually break free and float away into the cabin. In the confined environment of a spacecraft, you definitely don't want liquid balls drifting around near sensitive equipment and instruments.
So astronauts reaching for tissues aren't just being tidy—they're protecting millions of dollars worth of technology from rogue teardrops.
It's one of countless small ways that life in space is profoundly different from life on Earth. Even in moments of emotion, astronauts are reminded that the rules of physics don't take a break.