The Search for Mersenne Primes

For centuries, mathematicians have tried to find larger and larger prime numbers. In recent times, a Mersenne prime has always held the record of largest prime ever discovered.

A project called GIMPS [Great Internet Mersenne Prime Search], started in 1996, has enabled computer users around the world to participate in the search for ever-larger Mersenne primes. By downloading software from the internet, they can combine their machines' computing power, forming a "virtual computer" far more powerful than any single machine that could be dedicated to this task.

GIMPS made headlines in August, 2008, by finding a record-breaking Mersenne prime more than 12 million digits long! The following month, it found the second-longest known Mersenne prime, containing more than 11 million digits. (The August discovery won GIMPS a $100,000 prize which the Electronic Frontier Foundation had offered to whomever first found a prime number with at least 10 million digits.)

With the help of GIMPS, a Norwegian mathematician found a new second-largest Mersenne prime (again, more than 12 million digits) in the spring of 2009.

How large can Mersenne primes be? Some mathematicians think there is no limit, while others aren't sure. As computers get faster, and as more people join efforts like GIMPS, expect to see the record shattered again and again!