the.com/escape velocity
the speed at which gravity finally takes the hint and lets you leave.
means The minimum speed an object needs to break free from a massive body's gravitational pull without further propulsion — about 11.2 km/s to leave Earth.
from A compound of plain English parts pressed into service by physics. 'Escape' descends, through Old French 'eschaper,' from Late Latin 'excappare' — literally 'to slip out of one's cape,' the image of wriggling free of a cloak someone has grabbed. 'Velocity' comes from Latin 'velocitas,' from 'velox,' meaning swift. The phrase itself is a 19th-century product of celestial mechanics, born once Newton's gravitation let astronomers actually calculate how fast you'd have to flee a planet to never fall back.
- earth's number
- about 25,000 mph to break free
- mass matters
- doesn't depend on the object's weight
- black holes
- theirs exceeds light, so nothing escapes
- slow exit
- with constant thrust, you never need it
- jupiter's grip
- requires roughly 133,000 mph to flee
apollo 10 mission — reached 39,897 km/h (11.08 km/s), fastest crewed spacecraft, may 1969
parker solar probe — first human object to exceed solar escape velocity at ~191 km/s, 2021