I bet you learned in school that momentum is mass times velocity - I sure did!

However, for objects moving close to the speed of light, like the particles in the Large

Hadron Collider or light itself, this equation is no longer accurate.

Instead, we use these equations that I talked about in more detail in the video "E=mc^2

is incomplete".

If you take them as your starting points and solve for momentum, you'll find that objects

with mass have momentum equal to their mass times velocity, DIVIDED by the square root

of one minus velocity squared over the speed of light squared.

That square root part doesn't make much difference if your velocity is small compared to the

speed of light, because then v over c is really small and 1 minus something small is basically

just 1, so momentum (p) is pretty much just mv divided by 1, which is mv, which is why

you learned in school that momentum is mass times velocity.

That's also what physicists thought before 1905, but now they know that's not quite true…

and so do you!