Twin Primes — The Unproven Infinity

71 and 73 are twin primes — a pair of primes differing by exactly 2. The Twin Prime Conjecture states there are infinitely many such pairs: (3,5), (5,7), (11,13), (17,19), (29,31), and so on. The primes thin out as numbers grow, yet twin primes appear to persist — numerically verified into the trillions. In 2013, Yitang Zhang stunned the mathematical world by proving there are infinitely many prime pairs differing by less than 70 million. The Polymath project reduced this bound to 246. The gap of 2 remains unproven.