Again..what is a "vaccum" made of? Dear All, I am new to this forum and hasten to add I'm not a Physicist. I'm a medic. I have read some of the previous threads regarding the above question (many thanks to all the contributors), but all threads seem to lead elsewhere, so I thought I would try again for more information. So here is the question again... If all particles and waves were removed from a chunk of space, what would the remaning space be made of? I am assuming that since the space would still exist, it must be made of something. Have I got this completely wrong? I would be most grateful for information and apologies if everyone is bored with this topic.