Wow. Glad I never tried that.

Sexual physics:

Q: My boyfriend, Terence, is an adventurous physics student always looking
for new ways to improve our sex life. Recently he has been talking about Einstein and relativity, suggesting that we should try having sex at the speed of light or faster. But I am worried. If we were to engage in consensual sex at faster than the speed of light, would I go back in time, so that he would end up having sex with a 5 year old girl? And what are the potential legal implications of this?

Ashweena

A: (...) there might be even more severe complications with this scenario. If we extend the general trend of length contraction (from your point of reference), then your boyfriend’s penis will gradually appear to get shorter and shorter as he speeds up, until at the speed of light it will appear to have no length at all (size does matter). But beyond the speed of light, things get even stranger, and your boyfriend’s penis will actually attain imaginary length (that is, it will have a length equal to the square root of a negative number). And from the relativistic prediction of mass increase with speed, this imaginary oscillating penis will attain beyond infinite mass, essentially becoming a black hole. This penis/black hole complex will generate an intense explosion, attracting anything and everything towards it through the curvature generated in space-time. Ultimately, you and your boyfriend will be inescapably pulled into the centre of this penis/black hole, ripped apart into your constituent atoms, and regurgitated out of the penis in the form of electromagnetic radiation. It would be interesting to see how sex could be performed under such circumstances, but my guess is that it couldn’t be. In response to your original question, you would not go back in time, and he would not end up having sex with a 5 year old girl; but you have good reason to be worried! Don’t let
your boyfriend pressure you into doing anything you don’t want to do.