In *nix generally, a space between args to a cmd indicate separate arguments, so the space is (needs to be) 'escaped' using a '\' immediately before it, in order to indicate its a continuation instead.
In some cases, using single or double quotes around the whole thing works as well.
Long story short: although a space char is a syntactically valid part of a filename or cmd name or an argument, in reality it results in a lot of awkwardness; don't do it.
You'll thank me later
See the many threads that end up talking about this.