Sunday, June 8, 2025
800,000,000,000 Stars

Thursday, March 6, 2025
Sublime Numbers

Saturday, July 27, 2024
30,000
- 30029 = primorial prime
- 30030 = primorial[1]
- 30031 = smallest composite number which is one more than a primorial
- 30203 = safe prime
- 30240 = harmonic divisor number[2]
- 30323 = Sophie Germain prime and safe prime
- 30420 = pentagonal pyramidal number[3]
- 30537 = Riordan number
- 30694 = open meandric number
- 30941 = first base 13 repunit prime
https://en.wikipedia.org/wiki/30,000
1. Sloane, N. J. A. (ed.). "Sequence A002110 (Primorial numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
2. Sloane, N. J. A. (ed.). "Sequence A001599 (Harmonic or Ore numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
3. Sloane, N. J. A. (ed.). "Sequence A002411 (Pentagonal pyramidal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.

Wednesday, March 6, 2024
Large Numbers
In advance of Pi Day, March 14, New Scientist recently published an article describing some very large numbers: These 7 mathematical facts will blow your mind. The article includes some familiar numbers, such as Tree(3) and the Dedekind Numbers, and some additional curiosities including Penrose Tiles, mazes, and octonions (the 8-dimension cousin of quaternions.

Monday, December 11, 2023
The Monster: 808017424794512875886459904961710757005754368000000000
(Image: https://www.iconfinder.com/Spot)
While reviewing entries in the On-line Encyclopedia of Integer Sequences, I came across one of the larger integers that is a term of a sequence: 808017424794512875886459904961710757005754368000000000. It is the order of the 26th Sporadic Simple Groups and is also known as the Monster Group.
Grant Sanderson has a video on the 3Blue1Green series: Group theory, abstraction, and the 196,833-dimensional monster.
The OEIS sequence with this number is found here: https://oeis.org/A001228.
Other mathematicians posted videos about their favorite number over one million at: https://www.youtube.com/results?search_query=MegaFavNumbers.

Saturday, November 25, 2023
200,000,000,000,000,000,000,000 Stars
(Image: https://www.iconfinder.com/iStar_Design_Bureau)
I've seen several different estimations of the number of stars in the universe. Recently, The Conversation, an online independent news organization, published this article by Brian Jackson: How many stars are there in Space?
He estimates there are approximately 2 trillion galaxies with each having an average of 100 billion stars giving a total of 200,000,000,000,000,000,000,000 stars.

Thursday, November 23, 2023
The 9 Most Massive Numbers in Existence (Tia Ghose article in Live Science)
The website Live Science recently published an article by Tia Ghose, The 9 most massive numbers in existence. It covers many subjects that have been discussed in this blog, including Graham's Number, the scale of the universe, and prime numbers. Below is a link to the article:
The 9 most massive numbers in existence

Tuesday, November 21, 2023
Count to 9,192,631,770 in One Second
Counting to a very large number, such as 9,192,631,770, in on second may seem like an impossible task, but it is done on a very regular basis by atomic clocks. The International System of Units defines one second as 9,192,631,770 vibrations of the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom.
More on atomic clocks can be found here: https://en.wikipedia.org/wiki/Atomic_clock.
Official time in the United States is maintained by the U.S. Naval Observatory. A link to the official time is below:

Monday, October 2, 2023
3,628,800
This post is inspired by a recent puzzle published by Alex Bellos in the Guardian: Did you solve it? Puzzles you can do in the pub | Mathematics | The Guardian
The title of the post is 10! = 1x2x3x4x5x6x7x8x9x10 = 3,628,800. Interestingly, this value is the same number of seconds in six weeks. The challenge in Bellos's puzzle was to make the comparison without using a calculator.
One can confirm this without a calculator. Write out the number of seconds in six weeks as:
6 (weeks) x 7 (days) x 24 (hours) x (60 minutes) x (60 seconds)
Now one can cancel factors in the above equation by matching up with terms in the equation for 10!.
Cancel the 6 in both equations.
Cancel the 7 in both equations.
Cancel the 24 by matching with the 3 and 8 in the 10! equation
Reduce the 60 to 6 in the seconds equation by cancelling the 10 in the 10! equation.
Reduce the other 60 to 6 in the seconds equation by canceling the the 2 and the 5 in the 10! equation.
These canceling operations leaves us with 6x6=36 in the seconds equations and 4x9=36 in the factorial equation, therefore the number of seconds in six weeks equals 10!.
Alex Bellos is also the author of one of my favorite math books: Math Vacation: My Favorite Math Websites (jamesmacmath.blogspot.com)

Friday, April 1, 2022
The Very Small and the Very Big
In a prior post we considered how many digits of pi are required for a calculation, and I recently listened to a Lex Fridman podcast with guest Tim Urban, where they discussed if man is smaller than we are large or larger than we are small (Lex Fridman podcast).
Let's explore both extremes of
small and large.
Starting with the
characteristic size of a human, 1 meter. Most humans are taller than a meter
but are thinner and not at wide as a meter so for this discussion 1 meter will
be the scale of comparison we use.
Moving up in scale:
10 m
About the size of a garage or apartment
100 m
The length of athletic field or pitch
1000 m The span of a large bridge (The New York George
Washington bridge has a span of 1067 m)
10,000 m A 10k race in which many runners have competed
100,000 m A
distance typically traveled in an hour by automobile at highway speeds
106 m
A full day's driving on a long trip or traversing the north-south extent
of California
107 m
The distance from the north pole to the equator through Paris (by
definition of meter)
1011 m
The distance from the Earth to the Sun (One AU = 1.5 10x11m)
1012 to 1013 m
The orbit of Neptune is 30 AU
1016 m The distance to the Oort cloud (the
furthest extent of our Solar system)
1021 m The diameter of the Milky Way Galaxy
1027 m The radius of the observable universe
View this animation on the large scale of the universe: (1535) your mind will collapse if you try to imagine this | UNIVERSE SIZE COMPARISON - YouTube
Another good visualization is given here: https://bigthink.com/starts-with-a-bang/logarithmic-view-universe/
Moving down in scale
0.1 m
A human hand width
0.01 m A small finger width
0.001 m 1 mm or about the thickness of a credit card
0.0001 m A fine human hair or diameter of a human egg cell (the largest human
cell)
0.00001 m Diameter of a human capillary vessel
10-6 m The low end of the size of a bacterium
10-9 m Size of a molecule (one nanometer)
10-10 m
Angstrom - approximate size of a hydrogen atom
10-15 m Size of a proton
10-19 m Upper limit of the theoretical size of a quark
10-35 m The Planck length is 1.62 x 10-35 m (smallest
possible dimension)
Now, let’s consider the ratio of
the very largest thing, the observable universe, to the vary smallest,
theoretical size, the Planck length. The ratio is approximately:
1027 m: 10-35 m or 1062 to 1. Humans are
somewhat in the middle but closer to large end in the comparison given above.
If we only venture down to the size of a quark, then we closer to small end.

Monday, October 5, 2020
Tribute to Ronald Graham's Largest Number ...262464195387
What is the largest number? Any number that is offered can be bettered by that number plus 1. A common answer is infinity, although infinity isn't a specific number. "Infinite" describes something that is without bounds. Something could be infinitely large (set of integers) or something could be into infinitesimally small (as done in calculus).
Another approach to this question of the largest number is to ask what is the largest number used in a proof. In 1977 the mathematician Ronald Graham established the world record for the largest specific integer used in a mathematical proof. Graham's number is so large that if all the atoms in the universe were made into ink, the number could not be written. That is certainly disappointed for the readers of this post who wanted to see the number.
However, the last digits of Graham's number are: ...262464195387.
The actual expression of Graham's number uses hyperoperators which are higher order forms of exponentiation.
Since 1977, Graham's number has been exceeded by larger super-numbers used in proofs. One example is TREE(3).
Ronald Graham passed away in 2020 and was honored in a Numberphile podcast. An earlier podcast specifically described Graham's number. While the end digits of Graham's number have been determined, the first digit is unknown. Graham was asked what digit he would like it to be and he said he actually knew the first digit but only when the number is expressed in base-2 and then it is 1.
The icon I chose for this post is juggling because Ron Graham was an accomplished juggler. For a photo of Graham, see New York Times Obituary Link with photo.

Wednesday, June 10, 2020
One Trillion!

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