As physicists, we often say “nothing can travel faster than the speed of light.” You may have heard the words "cosmic speed limit" before and perhaps even know the value—approx. 300,000 km/s. So when I say your shadow can travel faster than light, I don't blame you if your skeptic senses are tingling. But humour me, because shadows are one thing that can travel faster than light.
Read MoreNeedless to say, the world didn’t end on November 19th, 2017. Nor did it on October 15th, 2017 or between September 20 and 23, 2017: the two previous doomsday predictions made by Christian numerologist and planet Nibiru conspiracy theorist David Meade.
So what gives? Is the date that Nibiru will actually impact or tidally disrupt the Earth sometime in 2018? Or is it actually never?
It’s never. Never is the answer.
Let’s start with the most obvious reason.
Read MoreJust how far is an astronomical unit (AU)? Such an enormous distance is not easy to comprehend. I could say, well, it’s the average distance from the Earth to the Sun. But nobody can actually travel from the Earth to the Sun to get a feel for that distance (and even a future space explorer would never travel it in a straight line). But maybe we can put this distance in terms of human experiences by asking: has anybody traveled an AU in their lifetime?
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