When mountaineers climb Mount Everest, they routinely carry oxygen cylinders, devices that allow them to breathe freely at high altitudes. This is necessary because the closer you get to the edge of Earth's atmosphere, the less oxygen there is available compared with the plentiful amounts found at sea level.
This is just one example of how variable Earth's atmosphere is and showcases the elemental makeup of its layers, from the troposphere, near sea level, to the exosphere, in its outermost regions. Where each layer ends and begins is defined by four key traits, according to the National Weather Service: temperature change, chemical composition, density and the movement of the gases within it.
So, with this in mind, where does Earth's atmosphere actually end? And where does space begin?
Each of the atmosphere's layers plays a role in ensuring our planet can host all manner of life, doing everything from blocking cancer-causing cosmic radiation to creating the pressure required to produce water, according to NASA.
"As you get farther from Earth, the atmosphere becomes less dense," Katrina Bossert, a space physicist at Arizona State University, told Live Science in an email. "The composition also changes, and lighter atoms and molecules begin to dominate, while heavy molecules remain closer to the Earth's surface."
As you move up in the atmosphere, the pressure, or the weight of the atmosphere above you, weakens rapidly. Even though commercial planes have pressurized cabins, rapid changes in altitude can affect the slim eustachian tubes connecting the ear with the nose and throat. "This is why your ears may pop during takeoff in an airplane," said Matthew Igel, an adjunct professor of atmospheric science at the University of California, Davis. READ MORE...
