In space, there is no up or down. Without the gravitational pull that we experience on Earth, astronauts and everything else aboard a spacecraft float freely.
Earthlings can experience the sensation of zero gravity without blasting into space. How? A zero-gravity flight. When an airplane flies in a series of arcs called parabolas, a temporary zero-gravity environment is created. Everything in the plane floats, even passengers.
“There is truly no other feeling like it on Earth,” Michelle Peters told TIME for Kids. She is director of research and education for Zero-G. The company organizes zero-gravity flights for scientists and teachers. It also takes passengers as young as 8 on flights that are just for fun.
Gravity has an impact on everything from the human body and mind to the behavior of plants and the way machines run. Space travel is expensive and risky. But zero-gravity flights let scientists conduct experiments in an environment that mimics the conditions of space.
On its research trips, Zero-G flies about 30 parabolas. Each of these arcs creates a period of weightlessness that lasts about 30 seconds. Nikolaus Kuhn of the University of Basel, in Switzerland, flew with Zero-G. He was conducting an experiment about soil and the flow of water on Mars. The Red Planet has about one-third of the gravity that Earth has. This means water flows more slowly on Mars. By making the parabolas less steep, Zero-G pilots can create the feeling of Martian gravity.
For decades, NASA used zero-gravity flights to prepare and train astronauts. “I have not been to space,” Peters of Zero-G says. “But I have been told by astronauts that [zero-gravity] feels exactly the same.”
As humans continue to explore the universe beyond Planet Earth, zero-gravity flights will remain an important—and fun—tool. “It never gets old,” Peters says. “I would do it every weekend for the rest of my life if I could.”