In classical electromagnetism , the vacuum of free space , or sometimes just free space or perfect vacuum , is a standard reference medium for electromagnetic effects.   Some authors refer to this reference medium as classical vacuum ,  a terminology intended to separate this concept from QED vacuum or QCD vacuum , where vacuum fluctuations can produce transient virtual particle densities and a relative permittivity and relative permeability that are not identically unity.   
You can easily trim unnecessary whitespace from the start and the end of a string or the lines in a text file by doing a regex search-and-replace. Search for ^ [ \t ] + and replace with nothing to delete leading whitespace (spaces and tabs). Search for [ \t ] + $ to trim trailing whitespace. Do both by combining the regular expressions into ^ [ \t ] + | [ \t ] + $ . Instead of [ \t ] which matches a space or a tab, you can expand the character class into [ \t \r \n ] if you also want to strip line breaks. Or you can use the shorthand \s instead.
If you are an avid space enthusiast, it is critical that you learn all that you can about not only the planets, solar systems and galaxies themselves, you also need to understand the science behind studying them so that you can make the most out of it. With this in mind, one of the best and most useful facets that you can keep in mind is the Edwin Hubble classification system. The article below will teach you all about this system, so that you can further your knowledge of galaxies and space, so that you can use that info to the best of your ability. More