question: Why do people like Felix Baumgartner are able to jump from the stratosphere without burning
comment: As u/Concise_Pirate says, it's not the height that cause things to heat up on re-entry, it's the speed. The thing is, it's not the friction from the air that causes the heat, it's the *compression* of the air in front of the thing hitting the atmosphere. Because it's coming in at (much) more than the speed of sound, the air can't get out of the way fast enough. So it gets squeezed together, and compressing a gas makes it hotter (see Boyle's law). It's the heat from that compression that burns objects up on reentry. Baumgartner started out in the atmosphere (albeit really, really thin atmosphere), and started from a standstill (relative to the atmosphere). As a result, he never broke the speed of sound (because the wind resistance prevented him), so the air was always able to get out of his way fast enough to not compress very much. So he didn't heat up very much.
passages: BULLET::::- On 14 October 2012, after seven years of planning, the Red Bull Stratos mission came into dramatic climax. At 9.28 a.m. local time (3:28 p.m. GMT), Felix Baumgartner (Austria) lifted off from Roswell, New Mexico, USA. Destination: the edge of space. Within 3 hours, Felix would be back on earth after achieving the highest jump altitude, the highest freefall and the highest speed in freefall. He also became the first skydiver to break the sound barrier.
   Baumgartner is also renowned for the particularly dangerous nature of the stunts he has performed during his career. Baumgartner spent time in the Austrian military where he practiced parachute jumping, including training to land on small target zones.
  
  Section::::Biography.
   Section::::Biography.:Red Bull Stratos.:Training for the jump.
  
  Baumgartner initially struggled with claustrophobia after spending time in the pressurized suit required for the jump, but overcame it with help from a sports psychologist and other specialists.
  
  Section::::Biography.:Audi Motorsport.
  
  In 2014, Baumgartner decided to join Audi Motorsport to drive an Audi R8 LMS for the 2014 24 Hours of Nurburgring after racing Volkswagen Polos in 2013. He underwent another intense physical and driver training session to prepare him for the race. He helped the team to a ninth place overall finish.
  
  Section::::Personal life.
   The square root of the product of thermal conductivity, density, and specific heat capacity is called thermal effusivity, and tells how much heat energy the body absorbs or releases in a certain amount of time per unit area when its surface is at a certain temperature. Since the heat taken in by the cooler body must be the same as the heat given by the hotter one, the surface temperature must lie closer to the temperature of the body with the greater thermal effusivity. The bodies in question here are human feet (which mainly consist of water) and burning coals.
   BULLET::::- When the embers cool down, their temperature sinks below the flash point, so they stop burning, and no new heat is generated.
  
  BULLET::::- Firewalkers do not spend very much time on the embers, and they keep moving.
  
  Section::::Explanation.:Risks when firewalking.
  
  BULLET::::- People have burned their feet when they remained in the fire for too long, enabling the thermal conductivity of the embers to catch up.
  
  BULLET::::- One is more likely to be burned when running through the embers since running pushes one's feet deeper into the embers, resulting in the top of the feet being burnt.
   One can think of this as going from a scenario were before the majority of people caught in the open, who just stood there staring at the fireball out to a radius of 11 km would probably die from lethal [[Burn|3rd-degree burns]] on their unclothed skin, to a scenario now were instead the vast majority of people who 'duck and cover' from 7 km out to 11 km would remain alive, with generally non life-threatening [[Burn|1st-degree burns]] and [[Burn|2nd-degree burns]] over their exposed skin, with the burn severity naturally depending on their range from the explosion.
   On 25 July 2012, Baumgartner completed the second of two planned test jumps from . It took Baumgartner about 90 minutes to reach the target altitude and his free fall was estimated to have lasted three minutes and 48 seconds before his parachutes were deployed.
  
  Section::::Biography.:Red Bull Stratos.:Main jump.
   Section::::Biography.:Red Bull Stratos.:Test jumps.
  
  On 15 March 2012, Baumgartner completed the first of 2 test jumps from . During the jump, he spent approximately 3 minutes and 43 seconds in free fall, reaching speeds of more than , before opening his parachute. In total, the jump lasted approximately eight minutes and eight seconds and Baumgartner became the third person to safely parachute from a height of over .
   During the opening ceremony of the 2012 Summer Paralympics, Joe Townsend (a Royal Marine and double amputee) delivered the Paralympic flame into Olympic Stadium via a zipline that was attached to the top of "Orbit".
   Red Bull Stratos
  
  Red Bull Stratos was a high altitude diving project involving Austrian skydiver Felix Baumgartner. On 14 October 2012, Baumgartner flew approximately into the stratosphere over New Mexico, United States, in a helium balloon before free falling in a pressure suit and then parachuting to Earth. The total jump, from leaving the capsule to landing on the ground, lasted approximately ten minutes. While the free fall was initially expected to last between five and six minutes, Baumgartner deployed his parachute after 4 minutes and 19 seconds.
   In 2009, Seppe Smits won the rookie Big Air competition at the Air & Style festival in Innsbruck.
   During the offseason, Encarnación suffered first and second-degree burns to the forehead and the right side of his face when a rocket firecracker hit him in the jaw and exploded near his mouth. After initially being treated near his Dominican Republic home, Encarnacion was transferred to a Miami hospital. He was discharged less than two days after the incident.
   Kittinger served as a fighter pilot during the Vietnam War, and he achieved an aerial kill of a North Vietnamese MiG-21 jet fighter and was later shot down himself, spending 11 months as a prisoner of war in a North Vietnamese prison. He participated in the Red Bull Stratos project as capsule communicator in 2012 at age 84, directing Felix Baumgartner on his record-breaking freefall from Earth's stratosphere.
  
  Section::::Early life and military career.
   On 25 July 2012, Baumgartner completed the second of two planned test jumps, from . It took Baumgartner about 90 minutes to reach the target altitude and his free fall was estimated to have lasted three minutes and 48 seconds before his parachutes were deployed. Baumgartner landed safely near Roswell, New Mexico, USA. His top speed was an estimated according to Brian Utley, an official observer on site. The jump represented a personal best for Baumgartner. Joseph Kittinger, who parachuted from 31,300 m (102,800 feet) in 1960, became involved with the mission to advise Baumgartner and to help gather scientific data on next-generation full pressure suits.
   Flame uses just a little more energy than a human of the same weight. It turned out Flame walked most efficiently if the 'rear heel' is lifted the moment the 'front heel' hits the ground. Humans do the same.
   Section::::Preparation.
  
  On 15 March 2012, Baumgartner completed the first of two test jumps, from . During the jump, he spent approximately three minutes and 43 seconds in free fall, claiming to have reached speeds of more than , before opening his parachute. In total, the jump lasted approximately eight minutes and eight seconds and Baumgartner became only the third person to parachute safely from a height of over .
   While stationed at Quantico, George was a passenger in an aircraft flown by one of AES-12's officers The weather was clear and sunny that day when both of the engines failed at approximately above the Carolinas. Both pilots worked to get the engines restarted, dipping to an altitude of about before they succeeded. Another time, an aircraft caught fire; he had to bail out, in the first parachute jump of his life.
   The launch was originally scheduled for 9 October 2012 but was aborted due to adverse weather conditions. Launch was rescheduled and the mission instead took place on 14 October 2012 when Baumgartner landed in eastern New Mexico after jumping from a then world-record and falling a record distance of ; the altitude record was broken by Alan Eustace in 2014. Baumgartner also set the record for fastest speed of free fall at , making him the first human to break the sound barrier outside a vehicle. Baumgartner was in free fall for 4 minutes and 19 seconds, 17 seconds short of mentor Joseph Kittinger's 1960 jump.
   “I've been thinking about what Chris would have wanted me to say today. The advice he'd give me, which'd be something like, 'Know what, babe? Fuck it. These guys know all about me. Tell them about someone different.' So I thought I'd tell you about a hero of Chris's: a man called Captain Joe Kittinger. In 1960, climbing into a foil balloon, Captain Joe ascended 32 kilometers into the stratosphere. And then, armed only with a parachute, he jumped out. He fell for four minutes and thirty-six seconds, reaching seven hundred and forty miles per hour before opening his parachute five kilometers above the Earth. It had never been done before, and it's never been done since. He did it just because he could. And that's why Chris loved him - because the thing about Chris was, he said yes. He said yes to everything. He loved everyone. And he was the bravest boy - man - I knew. And that was - he flung himself out of a foil balloon every day. Because he could. Because he was. And that's why - and that's why...we, we loved him.”
   Kuettner flight-tested the world's largest airplane, the Gigant, during World War II, narrowly escaping death as the plane broke apart in flight and his parachute opened just 200 meters (660 feet) above ground. After the war, "I wanted to go to a mountaintop and be alone," Kuettner recalled. He spent three years studying many atmospheric phenomena, including thunderstorm electricity, at the observatory atop the Zugspitze, the highest point in Germany.
  
  Section::::Move to U.S..
   Henceforth, one's chance of survival at 11 km goes from the previous 50% chance of death if they just stood there, gazing at the 1-megaton fireball as it emits all its energy over tens of seconds, to now a mere sunburn, or a [[Burn|1st-degree burn]] injury on exposed skin. With the 50% lethal thermal range being thus downrated to being equivalent to a 550 kt explosion, the 50% lethal thermal radius goes from the previous 11 km without ducking and covering to ~7 km with prompt duck and covering within 2 seconds. 
   In January 2010, it was reported that Baumgartner was working with a team of scientists and sponsor Red Bull to attempt the highest sky-dive on record. By wearing the Equivital LifeMonitor, researchers were able to monitor Felix Baumgartner’s physiological response within an extreme environment. Baumgartner was going to make the jump from a capsule suspended from a balloon filled with helium, intending to become the first parachutist to break the sound barrier.
   Jump injuries are infrequent, and smokejumper personnel take deliberate precautions before deciding whether to jump a particular fire. Multiple factors are analyzed, and then a decision is made as to whether jumping the fire is safe. Bases tend to look for highly motivated individuals who are in superior shape and have the ability to think independently and react to changing environments rapidly. Many smokejumpers have previous experience as hotshots, who provide a strong foundation of woodland fire experience and physical conditioning.
  
  Section::::Smokejumper Crews.
   Christian Stadler from Germany invented the "VegaV3 wingsuit system" that uses an electronic adjustable hydrogen peroxide rocket. The rocket provides 1000 Newtons (100 kgf) of thrust and produces no flames or poisonous fumes. His first successful powered wingsuit jump was in 2007, when he reached horizontal speeds of over 255 km/h (160 mph).
  
  Section::::Training.
   BULLET::::- Foreign objects in the embers may result in burns. Metal is especially dangerous since it has a high thermal conductivity.
  
  BULLET::::- Embers which have not burned long enough can burn feet more quickly. Embers contain water, which increases their heat capacity as well as their thermal conductivity. The water must be evaporated already when the firewalk starts.
  
  BULLET::::- Wet feet can cause embers to cling to them, increasing the exposure time.
  
presuppositions: Friction from air causes heat, so jumping from the stratosphere would cause burns. 
corrections: Heat from the compression of air is what burns on reentry when an object is traveling at high enough speeds. 
raw_presuppositions: Friction from air causes heat, so jumping from the stratosphere would cause burns.  Felix Baumgartner jumping from the stratosphere should burn.
raw_corrections: Heat from the compression of air is what burns on reentry when an object is traveling at high enough speeds.  When Felix Baumgartner jumped from the thin atmosphere he did not break the speed of sound (because the wind resistance prevented him), so the air was always able to get out of his way quickly enough to not compress much, thus he didn't heat up much.