Video Description: NOVA scienceNOW | Twin Prime Conjecture | PBS. New insight into a 2,300-year-old mystery surrounding prime numbers inspires a song.

Twin Prime Conjecture is is a famous unsolved problem in number theory. It says that it is possible to find two twin primes that are as big as wanted.

Twin primes are prime numbers that differ by two. For example 3 and 5, 5 and 7, 11 and 13, 17 and 19, and so on are twin primes. 23 is prime, but it is not a twin prime. The primes nearest to 23 are 19 and 29. Twin primes were discovered by Euclid in 300 B.C.

Prime number is a natural number which has exactly two distinct natural number divisors: 1 and itself. The first twenty-five prime numbers are:
 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97