The speed of light is a constant we use in principles throughout physics. We know the exact speed that light travels. So, why haven’t we ever truly measured it? It turns out that the answer is more complicated than you might think.
Stop robocalls for good with Kim’s new eBook
Robocalls interrupt us constantly and scam Americans out of millions of dollars every year. Learn Kim's best tricks for stopping annoying robocalls in this handy guide.