# Slowing down the time

The first thing Simon said this morning was: “Mom, do you know that if you keep moving, you get one quadrillionth of a second per second younger than if you just sit still?” Simon had heard this fact on VSauce the night before (and I think we watched another VSauce video earlier and also read in our Eine kleine Nachtphysik book about how in spacetime, we barely move through space and only move through time, and the faster one moves through space, the slower one moves through time – that’s why time stops for anyone moving through space at the speed of light.

This morning, Simon wanted to calculate how much less older one gets within a lifetime of 100 years if one keeps moving all the time. He first calculated how many seconds there are in a 100 years. He said he knew that there were 10! seconds in 6 weeks and went on from there:

And then, multiplied that value by one quadrillionth (see below). He ended up with approximately one three hundred thousandth of a second per 100 years – getting that much less older than if you sit still for a century. The value is very approximate, as Simon is not exactly sure whether the initial value of one quadrillionth per second is correct – it could be even less!