You have to ask? 1. My post directly followed your post. 2. Your post, to which I was responding, opened with the words "I was hoping...". My response, opened with the words "I was hoping...." This is a common rhetorical device. Individuals with normal reading comprehension recognise cues like this quite readily. 3. You seem to be the only one in this thread asserting that UFOs are alien craft. My post is clearly directed towards someone who believes UFOs are alien craft. 3. The post was directed to "fools such as yourself" . You are the only fool on this thread. Any one of these pointers should have let you know the post was directed towards you. The fact that you had to ask calls into question - yet again - whether you have the intellectual resources to conduct a serious argument. Finally - and on topic - as other members have pointed out, the propulsion system is independent of the generation of a sonic boom. Therefore your calculation is irrelevant. Continuing to promote this flawed argument helps persuades casual readers, who currently sit on the fence, that those who espouse the "UFOs are aliens" hypothesis are uneducated idiots. It dissuades the audience you need to convince and thereby confirms the view that your ideas are as well structured as a snark's flatulence.