Why is hydrogen considered the most efficient fuel? I mean I know it is very light and can be accelerated very fast, but can’t you use a denser fuel but throw it at a slower speed bunch, and it’ll still achieve the same force as it’s heavier?
Also, why do people say that a rocket engine with hydrogen fuel also generally has lower thrust compared to other denser fuels? Can’t that hydrogen engine just throw hydrogen out faster, since it’s lighter and easier to throw, to achieve the same thrust from an engine that uses a denser fuel?
And if you can answer this relating to the concept of ISP (specific impulse), which still confuses me, it’ll be even better!