Edwin Hubble found that galaxies are constantly moving away from us. According to his observations with the Hubble Space Telescope, galaxies are moving at different speeds. This shows that the universe is expanding.
The farther away a galaxy is, the faster it is moving away.
Based on the redshift that was calculated, Hubble noticed that the galaxies further away were moving faster. When light moves further away, it shifts towards the end of the spectrum (which happens to be red), thus it is called redshift.
Binomial nomenclature is the naming system developed by Carolus Linnaeus. In this system, latin language was used because it is a dead language which cannot be spoken by people in the world. In binomial nomenclature, two names are used. One for genus and the second for specie. For example, Rana tigrina is the scientific name of frog. In this name rana is genus and tigrina is specie.
