Because you get this mutual curling even in the absence of matter, it doesn't rely on a medium to exist and can be perfectly happy in vacuum.
Because you get this mutual curling even in the absence of matter, it doesn't rely on a medium to exist and can be perfectly happy in vacuum.
就算没有任何物质的存在，也能产生这种效应，它并不依赖于任何一种介质，能够在真空中产生。