Marin Mersenne was a mathematician, a natural philosopher, a theologian, a writer, and a teacher. It was said that he was an amateur mathematician. He studied prime numbers and tried to find a formula that would represent all primes. He was unable to do this but his work influenced others to continue what he had started. There was an interest in prime numbers before Marin Mersenne came on the scene. One formula for prime numbers was 2^{n}  1 for all prime numbers n. Several mathematicians (Regius in 1536, Cataldi in 1603, Fermat in 1640) tested this formula and proved it true in some cases and not true in others. Mersenne stated in his book Cognita PhysicaMathematica that the numbers 2^{n}  1 were prime for the primes 2, 3, 5, 7, 13, 17, 19, 31, 67, 127, and 257. It was this conjecture that connected his name to these primes. Mersenne’s peers expressed their doubts that he had actually tested his conjecture and Mersenne, at a later date, admitted he had not. It took until 1947 to completely check Mersenne’s list. It was determined during the 400 year period that Mersenne’s list was not entirely accurate and that the correct list was for n = 2, 3, 5, 7, 13, 17, 19, 31, 61, 89, 107, and 127. The numbers he excluded were 61, 89, and 107. He included incorrectly 67 and 257. The search is still on. In 1947 there were twelve known Mersenne primes; however, currently there are 38 known Mersenne Primesand the search continues. The 38th prime M(6972593) was discovered on June 1, 1999. An organization called the Great Internet Mersenne Primes Search (GIMPS) began in 1996. Currently GIMPS is checking and double checking to verify (prove) that M(6972593) is indeed the 38th Mersenne Prime. It appears Mersenne was not a threat to those in control based on his vocation and educational preparation. He was able to travel extensively through Europe. Herein seems to lie his greatest contribution. He was one who some of the greatest people of mathematics of the time communicated with. Descarte, Desargues, Fermat, Pascal, Galileo, and Huygens were among those who met with Mersenne on a regular basis. Mersenne was able to communicate mathematical knowledge throughout Europe while continuing his own studies. Mersenne worked diligently to expose what he and others considered the unfounded and unexplained sciences (alchemy and astrology). Since there were no scientific journals at the time, he spread the word through his travels and meetings with others. Mersenne did some of his own publishing, often drawing on what others had started or on his version of what others had done. He published a book in 1633 and another in 1634. He also translated some of Galileo’s work into French. He also published books related to mathematical physics in 1636 and 1644. He studied music and acoustics and published a related book in 1627. In conclusion, it seems as though Marin Mersenne assumed many roles during his lifetime. Not only was he a mathematician, a priest, a philosopher, and a published author, it could be said that his most important contribution was in the dissemination of mathematical knowledge.

Contributed by Rodney S. Karjala

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