mersenneforum.org 2^64 is not a big number!
 User Name Remember Me? Password
 Register FAQ Search Today's Posts Mark Forums Read

 2021-05-30, 18:17 #1 Bobby Jacobs     May 2018 3408 Posts 2^64 is not a big number! We have searched all primes up to 264=18446744073709551616, but that is not a big number. If something had 264 atoms in it, then it would be like a small grain of sand. 264 is a small number when it comes to atoms.
2021-05-30, 19:32   #2
xilman
Bamboozled!

"πΊππ·π·π­"
May 2003
Down not across

2·5,387 Posts

Quote:
 Originally Posted by Bobby Jacobs We have searched all primes up to 264=18446744073709551616, but that is not a big number. If something had 264 atoms in it, then it would be like a small grain of sand. 264 is a small number when it comes to atoms.
About a milligram of sand if I calculate correctly.

Easily visible but not especially large --- about 1mm across.

 2021-05-30, 19:52 #3 rudy235     Jun 2015 Vallejo, CA/. 5·199 Posts Bobby: There is very little correlation between small numbers in the Physical world and "small numbers" when it comes to searching for primes. PRIMO has the capability of proving primes in the range of 1040000 to 1050000 Lucas-Lehmer can prove Mersenne primes in the order of 2100,000,000 to probably 21000,000,000 (with current technolog). In the physical world Atoms in the planet Earth. (approx) 1052 Atoms in the Solar System (if it is conceived as a solid sphere of 50 Light Year Radius is of the order of 1069 Even if you go the atoms in all know Undiverse which is estimated to have Radius of 4.65*1010 light-years, the number of atoms in that volume would "only be" 2*10106 So, in conclusion even a number as "small" as 10120 would have no equivalent in the physical world. You can try creating sort of fancy artificial numbers: for instance the number of distinct molecules theoretically possible by combining up to 1000 atoms of Carbon, Oxygen, Nitrogen, Hydrogen, Chlorine, Magnesium, Iron, Flour, Calcium and Sodium atoms but even that won't get you any closer the the smallest composite number that has not been factored which is RSA-260 (Of course they are millions of smaller numbers that have not been factored, but that is because no serious effort has been applied to them.) Last fiddled with by rudy235 on 2021-05-30 at 20:04
2021-05-30, 20:08   #4
charybdis

Apr 2020

2·5·37 Posts

Quote:
 Originally Posted by Bobby Jacobs We have searched all primes up to 264=18446744073709551616, but that is not a big number.
Depends who you're talking to...

Quote:
 Originally Posted by Daniel Schroeder, An Introduction to Thermal Physics Small numbers are small numbers, like 6, 23, and 42. You already know how to manipulate small numbers. Large numbers are much larger than small numbers, and are frequently made by exponentiating small numbers... The most important property of large numbers is that you can add a small number to a large number without changing it. For example, $$10^{23}+23 = 10^{23}$$ ... Very large numbers are even larger than large numbers, and can be made by exponentiating large numbers. An example would be $$10^{10^{23}}$$. Very large numbers have the amazing property that you can multiply them by large numbers without changing them. For instance, $$10^{10^{23}} \times 10^{23} = 10^{10^{23}+23} = 10^{10^{23}}$$

2021-05-30, 23:08   #5
sweety439

"99(4^34019)99 palind"
Nov 2016
(P^81993)SZ base 36

290510 Posts

Quote:
 Originally Posted by Bobby Jacobs We have searched all primes up to 264=18446744073709551616, but that is not a big number. If something had 264 atoms in it, then it would be like a small grain of sand. 264 is a small number when it comes to atoms.
People have found (but not stored) all the primes up to 2^64, this is because small primes are too easy to find. They can be found far faster than they can be read from a hard disk, however, this is a zipped list for all the primes up to 358*2^25

 2021-05-31, 00:25 #6 retina Undefined     "The unspeakable one" Jun 2006 My evil lair 184D16 Posts I've seen estimates of the total number of configurations (permutations or orderings?) of all particles in the observable universe is ~10^360. What about TREE(3)? Or TREE(G)? Or TREE(G)^^...^^TREE(G)? What do you compare it to? Compared to infinity, all numbers you can think of will be insignificant and lost in the rounding error.
2021-05-31, 02:23   #7
sweety439

"99(4^34019)99 palind"
Nov 2016
(P^81993)SZ base 36

5·7·83 Posts

Quote:
 Originally Posted by retina Or TREE(G)^^...^^TREE(G)? What do you compare it to? Compared to infinity, all numbers you can think of will be insignificant and lost in the rounding error.
This number is less than TREE(TREE(TREE(...TREE(TREE(TREE(G)))...))) with G TREE's

 2021-05-31, 04:02 #8 a1call     "Rashid Naimi" Oct 2015 Remote to Here/There 29·71 Posts If you started drawing 10 short lines/notches every second 24/7, it would take you well over 7 billion years to finish drawing 2^64 lines. Light travels 0.3 Micrometers (1/1000 of a millimeter) in 1 femtosecond. Light will travel more than 18446 Light-Years in 2^64 femtoseconds. This is more than 4000 times the distance to the closest stars to our sun. ETA OTOH, If you could fold a piece of paper (in half) a mere 64 times it would have 2^64 layers. The Samurai-Swords (as well as the Chinese-Noodles) are folded about 50 times and stretched/flattened each time. This gives the sword an edge which is about one molecule thick. Last fiddled with by a1call on 2021-05-31 at 04:17
2021-06-01, 04:18   #9
gd_barnes

May 2007
Kansas; USA

7·1,487 Posts

Quote:
 Originally Posted by a1call If you started drawing 10 short lines/notches every second 24/7, it would take you well over 7 billion years to finish drawing 2^64 lines.
Yes it's definitely over 7 billion years but...it's much worse than that:

2^64 = 18,446,744,073,709,551,616 (~1.8447 * 10^19)

2^64 / 3600 seconds per hour / 24 hour per day / ~365.25 days per year / = ~584,542,046,090.6 years.

At 10 lines / second it would be 1/10th that length but would still be ~58,454,204,609.06 or ~58.454 billion years!

Since 10 lines per second seems a little faster than the average person can write...I would go with 1 line per second, which would take ~584.542 billion years!!

Either way it's likely longer than the universe has been around.

Last fiddled with by gd_barnes on 2021-06-01 at 04:23

2021-06-01, 11:47   #10
Xyzzy

"Mike"
Aug 2002

2×23×179 Posts

Quote:
 Everywhere is within walking distance if you have the time.
- Steven Wright

 2021-06-01, 12:57 #11 xilman Bamboozled!     "πΊππ·π·π­" May 2003 Down not across 2×5,387 Posts I'd like to see you walk from the Earth to the Moon.

 Similar Threads Thread Thread Starter Forum Replies Last Post mickfrancis Math 16 2017-03-01 07:17 CRGreathouse Probability & Probabilistic Number Theory 15 2014-08-13 18:46 aketilander Operazione Doppi Mersennes 1 2012-11-09 21:16 henryzz Math 7 2012-05-23 01:13 literka Factoring 5 2012-01-30 12:28

All times are UTC. The time now is 16:41.

Fri Jul 30 16:41:43 UTC 2021 up 7 days, 11:10, 0 users, load averages: 1.81, 1.92, 1.83