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 work in the vacuum of space? My understanding of space is that it is a vacuum, i.e., devoid of pretty much all matter, just empty space. Also from my amazingly limited knowledge of physics I understand that in order for a force to create movement it must act upon something.