27 April 2011

V is for Very Very Very Big

We live on this planet we call Earth and when we stare up into the night sky we see little pinpricks of light.  From our early childhood education we know that each of these little pinpricks is in fact a star, just like our very own sun.  And in a quiet moment we may reflect on this and wonder to ourselves how many stars are there actually in the universe?  This post should hopefully give an answer to that question in a format that you can can comprehend.

When you stand in your suburban garden on a clear moonless night and look up into the night sky with your naked eyes, you may be able to see a few hundred stars. Journey into the country away from the effects of the city lights and you would count maybe 2000 stars.  2000 – not such a big number.  If you count really fast, you could probably reach it in about 10 minutes.  2000 is a number we humans are pretty comfortable with.

So what’s the big deal with the number of stars then?  Well, the number of stars we can see with the naked eye is a rather small amount compared to the number of stars that are actually out there.

Before I tell you how many stars there are in the known universe, just take a guess.  A million? A billion?  A trillion?  The answer is big.  Very big.  Very very ginormously hugely massively big.  It’s so big, a person is not able to comprehend the vastness of it by just looking at the number; there are just too many zeros!

The number is: 150,000,000,000,000,000,000,000 stars.

Before I get into describing how big that number really is, I’d like to talk about another interesting fact about stars.  Stars don’t just float around randomly in the universe.  They are instead clumped together in large clusters.  These clusters are called galaxies.  Our very own galaxy is called The Milky Way.  There are about 500 billion galaxies in the universe with each galaxy containing on average about 300 billion stars.  We as humans think we understand a billion.  We know it’s a big number.  But how big is big?

Well, since this is a blog about writing, I thought it might be fun to try put it into terms that a bookworm would be able to understand.  So here goes.

Let’s start with a standard paperback novel.  It has about 350 pages, each with 300 words per page, giving a total of about 100,000 words.  As authors, we can understand the sweat that goes into generating 100,000 words, and as readers we understand the time taken to read such a novel.  It’s not a trivial number.

Now let’s imagine we are standing in front of a bookshelf in a library.  The bookshelf is quite large - 1.8 metres (6 feet) high and about 3 metres (10 feet) wide – and it contains five shelves.  Now imagine us packing all 5 shelves of this bookshelf with brand new crisp paperback novels.  After the packing, each shelf ends up with about 100 novels.

The architect has built the library to be long and thin – similar in shape to Manhattan Island – so we decide to create 2 long aisles down the length of the building with a bookshelf to the left and right of these two aisles, giving us 3 bookshelves in a row.

To save space we place a second bookshelf back-to-back with each of the bookshelves already assembled. We then repeat this arrangement down the length of building.  In the end we manage to squeeze in 20 rows of double-sided bookshelves  And then we fill all the bookshelves with our novels.

That’s a big library of books we have there.  But we aren’t done yet, because we’ve still got more books to pack.  So we build another 80 floors onto this building, and we fill each floor with the identical arrangement of bookshelves and pack them full of novels.

And we are finally done!

Now you arrive at the library.  You take the elevator to the 62nd floor.  You walk down the second aisle, skipping 15 set of bookshelves before making a right turn into the next row.  You move to the bottom shelf and scan across until you find the 87th book.  You take the book out, and thumb through to page 238.  You scan down to the 5th line and locate the 4th word in that line.  That word is “home”.

That single word “home” represents The Milky Way galaxy – all 300 billion stars in it!  Every individual word taken from every novel in that library represents it’s own unique galaxy in our universe.  A galaxy brim full of stars.

If you then wanted to catalog every star in the universe, you would need to build a brand new 50-story building for each and every word in every novel housed in that 80-story building.  That is 500 billion new libraries you’d need to build.  And once you’d done that, each individual word from all the books in all those libraries would then represent a single star in our universe.

And that is how big the universe it.  It is a fantastically huge place.

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