term "frame-jumping" I've come across internet discussions where the term "frame-jumping" is used. As far as I can tell from googling, it seems to come up a lot in discussions involving anti-relativity kooks. I looked in the indexes of some relativity books I own, and couldn't find it. Googling doesn't seem to show it being used by professional relativists. My impression, then, is that the term itself has an ill-defined, kook flavor to it, and is used by kooks (whether to criticize other kooks or to criticize standard relativity). On the other hand, it is possible that it is a meaningful term that helps to demonstrate a certain error made in kook theories. Can anyone shed any light on this for me?