## Wednesday, December 21, 2005 ... //

### 43rd known Mersenne prime: M30402457

One of the GIMPS computers that try to find the largest prime integers of the form

• 2^p - 1
i.e. the Mersenne primes has announced a new prime which will be the 43rd known Mersenne prime. The discovery submitted on 12/16 comes 10 months after the previous Mersenne prime. It seems that the lucky winner is a member of one of the large teams. Most likely, the number still has less than 10 million digits - assuming that 9,152,052 is less than 10 million - and the winner therefore won't win one half of the $100,000 award. The Reference Frame is the only blog in the world that also informs you that the winner is Curtis Cooper and his new greatest exponent is p = 30,402,457. (Steven Boone became a co-discoverer; note added on Saturday.) You can try to search for this number on the whole internet and you won't find anything; nevertheless, on Saturday, it will be announced as the official new greatest prime integer after the verification process is finished around 1 am Eastern time. If you believe in your humble correspondent's miraculous intuition, you may want to make bets against your friends. ;-) Actually I am so incredibly sure that you should bet thousands of dollars if someone is ready (and has the courage) to argue that I am mistaken and the exponent won't be 30,402,457. Trust me. Note that we predicted the previous Mersenne prime correctly, too. The new greatest prime looks like follows (more than 9 million digits are omitted): • 315416475 … 652943871 The exponent may count the number of curves of a given genus in a particular elliptically fibered Calabi-Yau manifold. Or something else. #### snail feedback (2) : reader Quantoken said... I have long since outgrown my initial curiosity about GIMPS, which I now think is childish. If you are willing to devote money and computing resource to such childish games, you can always find the next bigger Mersenne prime. But what for? It's so boring it's not even fun. An average computer consumes 200 watts of power. The collective array of computers in the GIMPS network which dedicate 99% of their idle time on GIMPS may exceeds one million of them. Running for 6 months each, it consumes 876 kwh of electricity for each user. At$0.125 per kwh it costed each user $110 in electricity bill for a chance to win the GIMPS prize. And that's not factoring the wear and tear of the computer. Would you like to buy a$110 lottery ticket, for a one-in-a-million chance to win a prize of just \$50000? No one in a sane mind would do that.

Collectively, these folks who run the GIMPS have collectively wasted 876x10^6 kwh of electricity, an amount of electricity that costs almost half a million tons of coal to generate. Half a million ton fossil fuel burned just for the curiosity of discovering the 43th Mersenne prime? What for?

You might argue that these user's machines are running idle and wasting electricity anyway had they not been running GIMPS. But keep in mind:

One: a computer which is doing intensive computation do consume more energy than one which is simply idling.

Two: The users doesn't need to leave the machine idling. If they have nothing useful to do, simply turn off the computer and save some energy.

Three: Even if there is idle time to be wasted. You would prefer let the idle CPU time do something more useful, like do the kind of computation that helps design cancer curing drugs, or things like that nature. It does not make sense to use the idle time for the search of prime numbers.

Quantoken