Earphone definition, a sound receiver that fits in or over the ear, as of a radio or telephone. See more.
Answer Wiki. If a rocket went straight up, it would either continue in that direction and leave Earth, or it would fall back down, depending on its velocity. Most rockets intend to enter orbit, which is an elliptical trajectory, and it's much more efficient to arc into this trajectory than to go straight up and then accelerate laterally.
How do rockets move in space? If space is basically a vacuum and void of atmosphere, how do rockets alter the direction and speed of space craft? In other words, how do they push off against nothing? This is a very good question. Isaac Newton worked out the solution and published it in 1687 in his Principia Mathematica.