Welcome to brain Stuff production of I Heart Radio. Hey brain Stuff, Lauren Bogabam. Here, I'm looking up into the sky, be it a cloudy day or bright clear night with the stars shining down. It may seem like Earth's atmosphere is a single solid mass, but our sky is more like a lasagna or maybe a trifle, with layers that ripple up and down depending on what's beneath them, and merge into each other in different and interesting ways. And today, though,
let's talk about the layer called the stratosphere. But first, we're all creatures of the troposphere. This atmosphere layer is where almost all of the weather related phenomena on planet Earth unfold. Although the troposphere begins at the surface of our planet, its upper boundary is less consistent, and depending on your latitude and the current season, the layer's top might be located anywhere from four to seven miles that's seven to twelve kilometers overhead. Above the troposphere. We have
in order the stratosphere, mesisphere, thermosphere, and exosphere. But let's go back and talk about those first two layers more. The troposphere stratosphere boundary or tropopause separates two areas with inverted temperature trends. Inside the troposphere, the global average temperature decreases as you go higher, and yet it's a different story in the stratosphere, where things get warmer as you go higher. Eventually you'll hit the stratosphere's ceiling some thirty
miles or fifty kilometers up. Beyond that point, the trend starts to reverse itself. Things get pretty chilly in the mesisphere. You've probably visited the stratosphere once or twice at least. The region's hard to avoid for anyone who travels by air frequented by commercial airlines. The stratosphere is also a bastion of ozone gas and rapid winds, where clouds are scarce but life indoors. The scientists have found microorganisms adrift
in the stratosphere. Participants in a study published in August eighteen in the journal Frontiers and Microbiology designed and built an air capturing probe that was installed on a NASA plane. The gadget detected bacteria whizzing around above the local tropopause at altitudes of seven miles or twelve kilometers. UV radiation and extreme temperatures make the stratosphere a rough place for living things to survive up there. Some bacteria depend on
sun blocking pigments and protective outer shells. Fast DNA repair is another life saving trick. Hitching rides on storms and volcanic eruptions. Microbes used the stratosphere as an atmospheric super highway. There, winds carry them across the continents at great speeds, allowing the microbes to disperse. The fact that life can tolerate our stratosphere, even for limited periods, could profoundly impact the
hunt for, for example, Martian organism. But speaking of life, other stuff in the stratosphere makes most life on Earth possible. Ozone gas safeguards this planet from excessive ultraviolet or UV radiation that's sent to us by the Sun. Made up of oxygen atoms, ozone, like many sunscreens, absorbs UV light. Entire ecosystems would fail if not for that critical service. Our atmosphere supply of the gas is mostly limited to the famous ozone layer, and about this layer is contained
within the stratosphere. On a related note, the ozone explains why stratospheric temperatures climb at higher altitudes. Not only does it absorb the Sun's UV rays, but it also soaks up infrared radiation from the troposphere. The result a stratosphere that grows toastier by the mile. Okay, so the troposphere is cloud city, but be they stratos or cumulonimbus. You need water droplets and or ice crystals to make clouds, So the relatively wet troposphere is a great environment for them,
but the stratosphere not so much. By and large, it's just too dry to facilitate cloud formation. Still, that cloud shortage isn't a bad thing. The stratosphere combines largely cloud free skies with limited turbulence, making it attractive to airline pilots. Indeed, most commercial planes hit their cruising altitudes in the lower stratosphere. When stratospheric clouds do form, they're sometimes created by the mixing of ice with volcanic dust. Also the polar regions
see stratosphere level clouds during the wintertime. That's because the stratosphere is also home to the Arctic seasonal polar vortex, a huge swirling cyclone with a pocket of super cold air on the inside caused by the big temperature contrast of air over the pole versus warmer air from lower latitudes. The vortex collapses every spring and reforms every winter, trapping
the coldest air right around the pole. We've been hearing a lot about it the past few years because many scientists think that due to climate change and warmer than usual temperatures, the stratospheric polar vortex is weakening, allowing those ultra cold winds that it normally traps head south. Today's episode is based on the article the Stratosphere where birds and planes fly and bacteria thrives on how stuff works
dot Com, written by Mark Mancini. Brain Stuff is production of I Heart Radio in partnership with how stuff Works dot Com and is produced by Tyler Clang. Four more podcasts my heart Radio, visit the heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows