Ulrich Dobramysl
Ulrich's posts
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The 2015 Nobel Prize in Physics was awarded jointly to Takaaki Kajita and Arthur B. McDonald "for the discovery of neutrino oscillations, which shows that neutrinos have mass." ﻿
New Horizons

I am constantly amazed by the patience and endurance as well as the incredible sense for details that is required to send spacecraft to distant planets/planetoids/rocks. New Horizons travelled for 9.5 years (!) with an average speed of 16 kilometers per second (!) over a distance of 5 billion kilometers (!) to hit a target area for the Pluto flyby with roughly 100 square kilometers (!!). That amounts to hitting a target of the size of roughly 2 micrometers across a football (soccer) field, while traveling 200 nanometers per second. The former is incredible precision, while the latter requires incredible patience. And that is before you consider the care that has to be given towards designing the instruments, making them space-hardy, designing the schedule of experiments taking place and sending the data over an extremely constrained downlink, while making the system flexible enough to accommodate any changes necessary due to new information over 9.5 years.
#plutoflyby   #newhorizons﻿
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This is truly sad. I have tremendous respect for his achievements and for his ability to overcome his demons.﻿
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This is interesting!﻿
So, I was reading about why we have 60 minutes in an hour and 60 seconds in a minute. It's because of the Babylonians, who were fascinated by the number 60 because it has more factors than any smaller number. And, when you think about it, 60 is rather nifty because you can divide it up in all the ways humans like to divide things up. You can divide it in half (half an hour is 30 minutes), in thirds (20 minutes), in quarters (15 minutes), in 5ths (12 minutes), in 6ths (10 minutes), and in 10ths (6 minutes). What other ways do humans like to divide up an hour? Hard to think of any.

So I decided to explore this idea of "numbers that have more factors than any smaller number". So I wrote a computer program that calculates the number of factors for every number, and outputs numbers that have more factors than any number that comes before it. The number 60 has 12 factors, which, if you want to count them to verify I'm not making this up, are: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60. This is more than any number before it; for example 59 has 2 factors (it's prime), 58 has 4 factors (1, 2, 29, and 58), 57 has 4 factors (1, 3, 19, and 57), and so on.

I decided to call these numbers "Babylonian special numbers" so as not to confuse them with regular special numbers in mathematics. Actually I've never heard of "special numbers" in mathematics, but I figured somebody at sometime in history must've dubbed something "special numbers."

Anyway, I discovered these "Babylonian special numbers" are pretty sparse. There are 3 1-digit Babylonian special numbers, 5 2-digit numbers, and 6 3-digit numbers. (See table below.) Curious, I decided to continue. I found there were 5 4-digit numbers, 9 5-digit numbers, 9 6-digit numbers, and 9 7-digit numbers. So they're pretty few and far between, as numbers go.

I noticed that while we use 12 and 24 (which are also Babylonian special numbers) for our 12- and 24-hour clocks (which is also due to the Babylonians), we skip over 36 and 48 before getting to 60. I figured this was because 36 and 48 don't have 5 as a factor. We humans like to be able to divide by 5s and 10s. So it's no wonder the Babylonians liked the number 60 -- it's the smallest number that divides everything humans like, including 5s and 10s, and is the only 2-digit number to do so (there are no more Babylonian special numbers between 60 and 100 -- the next is 120).

So I decided to also note on the table when a new prime number is introduced as a factor. I decided to call these "Babylonian extra special numbers."

Here's the table. Note that 360, the number of degrees on a compass, also appears on the list.

1: number of factors: 1
2: number of factors: 2, first appearance of 2 as a factor (extra special)
6: number of factors: 4, first appearance of 3 as a factor (extra special)
12: number of factors: 6
24: number of factors: 8
36: number of factors: 9
48: number of factors: 10
60: number of factors: 12, first appearance of 5 as a factor (extra special)
120: number of factors: 16
180: number of factors: 18
240: number of factors: 20
360: number of factors: 24
720: number of factors: 30
840: number of factors: 32, first appearance of 7 as a factor (extra special)
1260: number of factors: 36
1680: number of factors: 40
2520: number of factors: 48
5040: number of factors: 60
7560: number of factors: 64
10080: number of factors: 72
15120: number of factors: 80
20160: number of factors: 84
25200: number of factors: 90
27720: number of factors: 96, first appearance of 11 as a factor (extra special)
45360: number of factors: 100
50400: number of factors: 108
55440: number of factors: 120
83160: number of factors: 128
110880: number of factors: 144
166320: number of factors: 160
221760: number of factors: 168
277200: number of factors: 180
332640: number of factors: 192
498960: number of factors: 200
554400: number of factors: 216
665280: number of factors: 224
720720: number of factors: 240, first appearance of 13 as a factor (extra special)
1081080: number of factors: 256
1441440: number of factors: 288
2162160: number of factors: 320
2882880: number of factors: 336
3603600: number of factors: 360
4324320: number of factors: 384
6486480: number of factors: 400
7207200: number of factors: 432
8648640: number of factors: 448﻿
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I really like the idea of having a flag representing all of earth. How do we get everyone to ratify that?﻿
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This is the right kind of mixture between cute and primal fear inspiring.﻿
The cute-but-terrifying Australian Pygmy Cheessum!

h/t  who got me to seek out the artist (Sarah DeRemer) and their FB page :)﻿
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This should be obvious to anyone who at some point has been a child.﻿
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An amazing accomplishment!﻿
Welcome to a comet! Rosetta’s lander Philae is safely on the surface of Comet 67P/Churyumov-Gerasimenko, as these first two CIVA images confirm. One of the lander’s three feet can be seen in the foreground. The full panoramic from CIVA will be delivered in this afternoon’s press briefing at 13:00 GMT/14:00 CET.

http://www.esa.int/spaceinimages/Images/2014/11/Welcome_to_a_comet

#cometlanding #Rosetta #Philae #67P  ﻿
Do a Google search for "Bletchley Park" - it's a cute easter egg. ;-)﻿
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That must be one of the stranger conversations with TSA...﻿