Abyssal plains were not recognized as distinct physiographic features of the sea floor until the late 1940s and, until very recently, none had been studied on a systematic basis. They are poorly preserved in the sedimentary record, because they tend to be consumed by the subduction process.
The first man to discover that the earth moves around the sun was an Italian scientist named Galileo Galilei.
The theory used to determine these very great distances in the universe is based on the discovery by Edwin Hubble that the universe is expanding. In 1929, Edwin Hubble announced that almost all galaxies appeared to be moving away from us. In fact, he found that the universe was expanding - with all of the galaxies moving away from each other. This phenomenon was observed as a redshift of a galaxy's spectrum.