Space has some weird effects on the body, as our bodies are meant to live in a world where gravity exists. But perhaps none are stranger than one recently discovered by scientists, as a new study suggests that the brain floats to the top of the skull when it spends a lot of time without the downward pull of Earth’s gravity.

This study, which was published in the New England Journal of Medicine and represents the largest group of astronuats examined yet with 34 participants, found that many of the brains of these astronauts had become repositioned in the skulls. They tended to float higher than in the past, causing certain brain regions to shrink. And it appears the longer they were in space, the more pronounced the effects are.

Of the 34 astronauts, 18 had long trips to space with much of the time on the International Space Station. A total of 17 returned to Earth with smaller regions between the front and parietal lobes, and that area shrunk for three of the 16 astronauts who had shorter trips.

“It’s been 55 years since NASA astronaut John Glenn successfully launched into space to complete three orbits aboard the Friendship 7 Mercury spacecraft, becoming the first American to orbit the Earth,” reads the statement from the Medical University of South Carolina. “The evolution of spaceflight, advancements in science and technologies and the progress of public-private commercial partnerships with companies such as Space X and Blue Horizons have strengthened NASA’s goals and the public’s confidence to move forward in discovery and human exploration.

“More people today are poised to explore space than ever before; those who do will experience the effects of microgravity on the human body. Recognizing the need for data related to those effects, MUSC neuroradiologist Donna Roberts, M.D., conducted a study titled “Effects of Spaceflight on Astronaut Brain Structure as Indicated on MRI,” the results of which will be featured in the Nov. 2 issue of the New England Journal of Medicine.”