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.
Of course, we only see the stars move around part of their circular path, because when the Sun comes up, the bright blue scattered Sunlight--the blue sky--drowns out the starlight. If there were no atmosphere, we would see the stars all the time, and see the complete circles for those that stayed above the horizon.