## Prime News!…

Readers will know that this space follows the hunt for new prime numbers, and more particularly, for new “Mersenne primes.”

Now, as ArsTechnica reports:

A new largest prime number has been discovered, mersenne.org reported Tuesday. 2

^{57,885,161}-1, which is also the 48^{th}Mersenne prime, was discovered on the computer of Dr. Curtis Cooper, a professor at the University of Central Missouri.A Mersenne prime is a prime number that can be written in the form M

_{p}= 2^{n}-1, and they’re extremely rare finds. Of all the numbers between 0 and 25,964,951 there are 1,622,441 that are prime, but only 42 are Mersenne primes.The 48

^{th}Mersenne prime was discovered as part of the Great Internet Mersenne Prime Search (GIMPS), a project that has used volunteer computers to calculate and search for primes for 17 years. Dr. Cooper’s computer took 39 days of continuous calculation to verify the prime status of the number, which has over 17 million digits…

Read the full story here; the report from Mersenne.org here; and visit the Mersenne/GIMPS homepage here.

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**As we regret the limited number of fingers and toes with which we were born,** we might recall that it was on this date in 1946 that the first ancestor of Dr. Cooper’s computer– the ENIAC (Electronic Numerical Integrator And Computer)– was first demonstrated in operation. (It was announced to the public te following day.) The first general-purpose computer (Turing-complete, digital, and capable of being programmed and re-programmed to solve different problems), ENIAC was begun in 1943, as part of the U.S’s war effort (as a classified military project known as “Project PX”); it was conceived and designed by John Mauchly and Presper Eckert of the University of Pennsylvania, where it was built. The finished machine, composed of 17,468 electronic vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered joints, weighed more than 27 tons and occupied a 30 x 50 foot room– in its time the largest single electronic apparatus in the world. ENIAC’s basic clock speed was 100,000 cycles per second. Today’s home computers have clock speeds of 1,000,000,000 cycles per second; Dr, Gordon’s, much faster still.