Although microplastics have been found in human lungs, intestines, livers, blood, testicles and even semen, it has long been thought that the body's protective blood-brain barrier may keep these particles out of the brain. But it turns out that tiny plastic particles are still present in the human brain.

The first time a tourist visited the space station was in 2001, and opportunities for private space travel have increased in recent years. Researchers analyzed samples from several space tourists and found widespread changes in cells and changes in the immune system.