So, to my knowledge, things burn up when entering the atmosphere due to the friction caused by all of the air molecules hitting them on the way down which would make sense when an object gets faster, it hits more air molecules, and heats up, however, when an object reaches terminal velocity it no longer goes any faster, and objects that aren’t aerodynamic have a relatively low terminal velocity, meaning it may go just as fast being dropped from a tall building, and obviously, things don’t burn up (or even get hot) when being dropped from a tall building. So my question is why exactly being something falling into the atmosphere will burn up, but not if it’s dropped at a much lower height that would still reach it’s terminal velocity.
In: Physics
Terminal velocity is based on the maximum velocity you reach due to gravity alone. You can go faster than terminal velocity if there are other forces acting on the object. This would include the momentum of an object already in motion.
Think water.
When you push down on water, it becomes compressed, right? Something similar happens with air. The compression from the pressure heats it up.
Meteorites are not, in any way, aerodynamic. If you dropped, say, a knife going point down, it wouldn’t burn up on entry (probably, haven’t tested it) because its so aerodynamic that it doesn’t ‘press’ down on air. But something larger that would, would heat up the air around it at such immense pressure that bam, you have friction.
Because the atmosphere is thinner the higher up you go, objects falling back to Earth are able to gain a lot of speed before normal terminal velocity is achieved.
It’s like jumping off a bridge in to water. The air you travel through is thin but then you hit the much thicker water and it hurts. Reentry is like but with a gradual shift from thin to thick.
Because the atmosphere is so thin, things like parachutes wouldn’t work to effectively slow down, but if you were to release a parachute during the burn up phase it would be too much force and would destroy the parachute. You need to just take it with brute force until terminal velocity is reached.
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