Astronauts Cannot Burp in Space

A simple burp on Earth becomes a messy affair in orbit. The reason lies in the way our digestive system relies on gravity. Here on the ground, gravity pulls the denser liquids and solids in our stomach downward, allowing the less dense gas to rise to the top, ready for a clean release. In the microgravity of space, however, there is no "up" or "down" inside an astronaut's stomach. The contents—gas, liquid, and food—all float together in a bubbly mixture.

This lack of separation means that if an astronaut were to try and release trapped gas, it wouldn't be just gas that comes up. Instead, they would experience an unpleasant event known as a "wet burp," where a mixture of liquid and gas is regurgitated. To avoid this uncomfortable situation, astronauts have to be mindful of what they consume. This is precisely why carbonated beverages like soda are banned on space missions; the excess gas they introduce would be nearly impossible for the body to manage without the helpful sorting power of gravity.