I did not know that yesterday!

If I drove my car at the speed of light and turned on the lights, what
would happen?

Alas, hapless traveler, a car cannot travel at the speed of light. Only bodies without mass can move at the required 186,000 miles per second, so the simple answer is, nothing.

But that's no fun. The beauty of this brainteaser is that it helps to shed light (so to speak) on some of the more interesting properties of Albert Einstein's theories of relativity. That must be why the question is often posed in online science forums. In fact, headscratchers like this originally inspired Einstein to explore his
theories -- and judging by the scientist's frazzled hairstyle, they may have caused him to literally scratch his head more than once.

Theoretically, the family minivan could come close to the speed of light. Given that distant possibility, some sources claim its headlights would work as advertised. How? Light travels at a constant speed. Assuming your car could never reach the speed of light, you'd still be able to see your way through the cosmos because the
headlights are out in front.

As fun as it sounds, we don't recommend you take the trip. The amount of petrol needed to fuel such a fantastic voyage would be prohibitively expensive. Plus there's a good chance you'd suffer a horrible death in the attempt. So, for safety's sake, keep your headlights focused on the motorway.