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--- blog:articles:how_big_is_the_universe [2019/02/16 14:11] – Phil Ide
+++ blog:articles:science:how_big_is_the_universe [2019/03/06 10:37] (current) – Phil Ide
@@ Line 1: / Line 1: @@
 ====== How Big Is The Universe? ======
 {{blog:HDFWF3.jpg?400|Hubble deep Field Image}}\\
-I recently came across a youtube video explaining a method for multiplication that was quite different from long multiplication. To explain why this was so interesting, let’s first talk about long multiplication and what’s wrong with it.
+I recently came across a youtube video explaining a method for multiplication that was quite different from long multiplication. To explain why this was so interesting, let’s first talk about long multiplication and what’s wrong with it, and then we'll calculate the size of the visible universe in centimeters.
-Although long multiplication is fairly easy to teach, it has drawbacks. Firstly, you need to generate one interim result for each of the digits in the multiplier, and then sum these interim results. This takes up a lot of space when the multiplier is quite large, and takes a bit of time. The final result derives the least significant digits first – that is, the rightmost digit.
 === ===
+Although long multiplication is fairly easy to teach, it has drawbacks. Firstly, you need to generate one interim result for each of the digits in the multiplier, and then sum these interim results. This takes up a lot of space when the multiplier is quite large, and takes a bit of time. The final result derives the least significant digits first – that is, the rightmost digit.
 The other method only ever produces two interim results, and it generates them at the same time. The final result is generated beginning with the most significant digit, and in fact you can begin reading off the result before you have finished the calculation. Pretty awesome huh?
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 That result is 29 digits long, and is several orders of magnitude larger than a 64-bit computer can actually understand is a number.
+You can download the PHP code, including a test script that calculates the size of the visible universe on the [[:blog:aardvaark:downloads|downloads]] page.
+~~socialite~~
+~~DISCUSSION~~