Mersenne Primes

A Mersenne Prime is a prime number p which is of the form 2ⁿ-1. 7 is an example (2³-1). I learnt about Mersenne Primes a long time ago. The Great Internet Mersenne Prime Search (GIMPS) was one of the early examples of using spare cycles on peoples computers to find these numbers.

What I learnt today, though, is that nobody knows if there are an infinite number of these objects. So far we have found 47 of these with the largest one being 2^43,112,609 -1.

As we search for the next one, I find it quite weird... like looking for some animal that is becoming extinct. I hope we will someday be able to prove that there are infinitely many of them.

This is the blog where I read today that we have not yet proven that they are infinite.

The McGurk Effect

The McGurk effect is the phenomenom where what we hear is affected by what we see. There is an excellent illustration of it here. Obligatory Wikipedia link.