Element 73

Sheldon: I made tea. 
Leonard: I don't want tea. 
Sheldon: I didn't make tea for you. This is my tea. 
Leonard: Then why are you telling me? 
Sheldon: It's a conversation starter. 
Leonard: That's a lousy conversation starter. 
Sheldon: Oh, is it? We're conversing. Checkmate.

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Just watched the 5th season of The Big Bang theory.  In an early episode of this season, I noticed Sheldon Cooper (played by Jim Parsons) wearing a shirt with the number 73 imprinted on it:

I recalled there being an earlier episode (Season 4, Episode 10, "The Alien Parasite Hypothesis") where Sheldon avowed his love of the number 73, but I couldn't remember why.  Then I did a quick internet search (my how the world has changed) and found this quote from said episode: 

"The best number is 73. Why? 73 is the 21st prime number. Its mirror, 37, is the 12th and its mirror, 21, is the product of multiplying 7 and 3.  In binary, 73 is a palindrome, 1001001, which backwards is 1001001."

73: The number, the myth, the legend...

Ah hah!  Behold the power of the number 73.  If you check out the wikipedia entry for "73 (number)" you'll find all of this as well:

- Seventy-three is the 21st prime number. The previous is seventy-one, with which it comprises the 8th twin prime. It is also a permutable prime with thirty-seven. 73 is a star number.

- 73 is the largest minimal Primitive root in the first 100000 primes. In other words, if p is one of the first 100000 primes, then at least one of the primes 3, 5, 7, 11, 13, 17, ..., 73 is a primitive root modulo p.

- 73 is the smallest prime congruent to 1 modulo 24.

- 73 is an emirp.

- The mirror of 73, the 21st prime number, 37, is the 12th prime number. The number 21 includes factors 7 and 3. The number 21 in binary is 10101 and Seventy-three in binary, 1001001, both are a palindrome. In addition, of the 7 binary digits representing 73, there are 3 ones. Also, 37+12=49 (seven squared) and 73+21=94=47*2, 47+2 also being equal to seven squared. Additionally, both 73 and its mirror, 37, are sexy primes twice over, as 31, 43, 67 and 79 are all prime numbers (sexy primes are primes that differ from their next prime number by a value of 6).

Tantalum: the 73rd Element

Pretty cool, huh?!  73 is pretty awesome.  

But what about the 73rd element on the periodic table?  Is there anything cool about Tantalum? 

Tantalum (symbol: Ta) is the 73rd element on the periodic table.  It was discovered in1802 by Swedish chemist Anders Gustaf Ekeberg.  It has an atomic weight of 180.9479 and it's most abundant isotope has 108 neutrons in the nucleus.  

One could do an internet search and find their fill of chemical and physical information about Tantalum, but here are a few of the most interesting aspects (at least, the ones that I find most interesting!):

- Tantalum has a melting point of 3290 K!  Only tungsten and rhenium have higher melting points

- Ekeberg named Tantalum comes from King Tantalus, father of Niobe, in Greek mythology. Tantalum is almost always found with Niobium in nature and Niobium was named after Niobe.

- Almost all of our tech devices (computers, smart phones, HD TVs, etc) have capacitors containing small amounts of Tantalum

- Tantalum is commonly used in the production of surgical tools, metal sutures, and rods and plates for mending broken bones and other injuries (since Tantalum tends to resist chemical reaction with other agents)

So there you have it! Some interesting things about the number 73 and the element 73. Perhaps 73 really is the best number. Or, at least, maybe just one of the best.