Earths atmosphere is large, extending out to around 10,000 km from the surface of the planet. Its so large, in fact, that scientists break it into five separate sections, and theres one particular section that hasnt got a whole lot of attention due to the difficulty in keeping any craft afloat there. Planes and balloons can visit the troposphere and stratosphere, the two sections closest to the ground, while satellites can sit in orbit in the thermosphere and exosphere, allowing for a platform for consistent observations. But the mesosphere, the section in the middle, is too close to have a stable orbit, but too sparse in air for traditional airplanes or balloons to work. As a result, we dont have a lot of data on it, but it impacts climate and weather forecasting, so scientists have simply had to make a lot of assumptions about what it's like up there. But a new study from researchers at Harvard and the University of Chicago might have found a way to put stable sensing platforms into the mesosphere, using a novel flight mechanism known as photophoresis.