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.
No, it doesn't need any atmosphere to work. The expanding gasses in the exhaust nozzle of a rocket push in all directions at once. Pushing to the sides doesn't do anything, since they push equally on the left and right side, the up and down side. But they also push in the forward and backward directions, too. The gasses that push out the back are gone.