Austrian daredevil Felix Baumgartner’s jump from a space-bound platform on October 14 set several human records despite challenging atmospheric conditions. Baumgartner achieved the highest human freefall to Earth ever: 38.6 km, from his pedestal to the New Mexican desert. In addition, he broke the sound barrier—another human-freefall feat—reaching speeds of 1,342 km/h, or Mach 1.24. The daredevil’s descent may have been all the more impressive in light of the varied atmospheric circumstances that he encountered. To that end, Baumgartner passed through two zones of Earth’s atmosphere and experienced potential perils throughout his transit.
Earth’s atmosphere consists of approximately four vertically layered zones with varied sizes and properties. The troposphere extends 0 – 20 km vertically from sea level, and is the region where Earth’s weather patterns form—where air convection and circulation shape distinct climates over time. The stratosphere, Baumgartner’s launch point, extends ~20 km – 50 km above Earth. The upper stratosphere hosts Earth’s ozone layer, which absorbs ultraviolet sunlight. Above the stratosphere, the mesosphere (~50 – 85 km) and thermosphere (~85 – 690 km) can experience phenomena as diverse as meteor activity and aurora formation from ionized atoms, respectively. While Baumgartner did not quite make it to meteor country, therefore, he had quite a ride through the stratosphere and troposphere.
By beginning his ascent high in the stratosphere, Baumgartner faced several dangerous factors that could have harmed him considerably. Aside from potential equipment malfunctions and skydiving’s inherent physical instability, he encountered numerous atmospheric hazards. For starters, pressure above ~19 km is sufficiently low to boil an exposed human’s blood and bodily fluids (again, the jump began 38.6 km above sea level). In addition, temperatures lower than -50°F characterize some stratospheric areas that Baumgartner crossed. UV radiation—100,000 times stronger at 36 km than at Earth’s surface—also could have been problematic for him; however, Baumgartner’s quick descent probably reduced radiation’s relevance. Once in the troposphere, nonetheless, he also would have faced Earth’s unpredictable weather systems: wind and precipitation, namely, could have injured him or sent him off course. A plethora of physical conditions—not to mention the dangers of breaking the sound barrier—thus greeted Baumgartner during his descent from the heavens.
While Felix Baumgartner broke a number of astonishing human records, therefore, the environment in which he broke those records added gravity (knee slapper) to his achievements. The stratosphere is no place for humans, but Baumgartner found his way through it, and through the troposphere, without major complications or setbacks.
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