FWIW, it's a common misconception that the heat from re-entry is due to friction. While it does contribute in a small way, the vast majority of the heating experienced by meteors or spacecraft is due to compression. They're moving so quickly that air literally cannot get out of their way fast enough, and so they end up "squishing" the air in front of them. Reducing the volume of a parcel of air heats it up (same principle that helps drive pistons in internal combustion engines), so as more and more compressed air piles up in front of the object, it gets hotter and hotter. This heat is harder to dissipate, because it's the air itself that's warming, not just the object.
Yep. This phenomenon is also what determines the sound barrier. At subsonic speeds, air is simply being displaced, but as you transition past mach one, the air cannot be displaced fast enough so it begins to be compressed instead.
FWIW, it's a common misconception that the heat from re-entry is due to friction. While it does contribute in a small way, the vast majority of the heating experienced by meteors or spacecraft is due to compression. They're moving so quickly that air literally cannot get out of their way fast enough, and so they end up "squishing" the air in front of them. Reducing the volume of a parcel of air heats it up (same principle that helps drive pistons in internal combustion engines), so as more and more compressed air piles up in front of the object, it gets hotter and hotter. This heat is harder to dissipate, because it's the air itself that's warming, not just the object.
Oh really? TIL, also makes sense
Yep. This phenomenon is also what determines the sound barrier. At subsonic speeds, air is simply being displaced, but as you transition past mach one, the air cannot be displaced fast enough so it begins to be compressed instead.