Spartan Profiles: Michael Shafer
DISCOVERER OF LARGEST KNOWN PRIME
Imagine a number 6,320,430 digits long that requires some 1,500 pages to print out. This particular number, 2 to the 20,996,011th power minus 1, is the largest known prime number. It was discovered in November by Michael Shafer, ’04, an MSU doctorate student in chemical engineering. “It was just a matter of time,” says Shafer, who grew up in the greater Lansing area. “Somebody else could have found the number. You install the program on a computer and it takes care of itself. I get the credit, along with the people that developed the software. People are going to make posters of it to hang up on the wall.”
The project—GIMPS, for the “Great Internet Mersenne Prime Search” (www.mersenne.org) —involved 60,000 worldwide volunteers using 211,000 computers as a supercomputer capable of 9 trillion calculations per second. “It’s a neat accomplishment, but it really doesn’t have any applicability,” says Mike, shrugging off his achievement. “I don’t think I’m going to be recognized as I go down the street or anything like that.”
Interestingly, fellow Spartan David Slowinski (see p. 9, Fall 1983), ’76, M.A. ’80, had previously discovered seven Mersenne prime numbers—No. 27, 28, and 30 through 34—each the largest known prime number at the time of their discovery. Slowinski used Cray supercomputers, while Mike used a 2 GHz Pentium 4 PC. It took Mike 19 days to make the find, which he shares with George Woltman, who created the software, and Scott Kurowski, who developed the server that coordinated all the GIMPS computers.
Mike intends to continue helping to find even larger primes, an avocation that will have no end, since it has been proven there is no “largest” prime number.
