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.
Theyâre the correct shape, theyâre coming in at just the right angle, and theyâre covered in an appropriate skinâ¦. Space may be the final frontier, but coming back to Earth after a visit to a planetary neighbor, or even a high orbit, can be perilous. As anyone whoâs seen the movies The Right Stuff and Apollo 13 knows, a spacecraft must reenter Earthâs atmosphere at a precise angle to avoid burning up or skipping back out into space. Well before the space program, astronomers were aware that meteorites burned up when they fell into our atmosphere. The reason, notes Allie Anderson, a graduate student in Aeronautics and Astronautics, is friction with air molecules (remember, thereâs no air in outer space).