Understanding just how much a kilo-something, mega-this, giga-what or terra-anything is can be quite confusing.  In my classes, I’ve found, when talking about megabytes and gigabytes, using an illustration can be quite helpful.  Most new computers today have in excess of 1 gigabyte of memory installed and today’s newest hard drives are terabytes in size (raid devices -in the petabytes!). 

In order to better understand the immensity of these numbers, I’ve made a comparison sheet using distance and the thickness of a standard CD as an example.  I hope you find it entertaining, if not mind-boggling!

FYI- the prefixes, in order from smallest to largest, are: deca, hecto, kilo, mega, giga, terra, peta, exa, zeta, yotta…yotta, yotta!


The thickness of a CD is approximately 1.2 mm or .048 inches. 

[Not a stack] 1 CD  = 1.2 mm or .048 inches.
Not much to see here; look at one on your desk

[Decastack] 10 CDs stacked = 12mm or .48 inches
Almost ½ of an inch!
[Hectostack] 100 CDs stacked = 120mm or 4.8 inches
You’ve seen this many in spools on shelves in stores

[Kilostack] 1,000 CDs = 1,200mm or 48 inches
As tall as the average 5-6 year old

[Megastack] 1,000,000 CDs = 1,200,000mm or 47,244.1 inches
3,937 feet, ¾ of a mile long

[Gigastack] 1,000,000,000 CDs = 745 miles
The distance from NYC to Chicago -less 50 miles

[Terrastack] 1,000,000,000,000 CDs = 745,645 miles
Over three times the distance from the Earth to the Moon

[Petastack] Lots of CDs = 8.2 Astronomical Units (AU)
The distance from the Sun, past Jupiter -almost to Saturn

[Exastack] Oh My! CDs  = 8021.5 AU
.12 of a Light Year or 706 billion miles!

[Zetastack] You can’t even imagine! CDs  = 126.8 Light Years
38.9 Parsecs. A little over a 10th the length or our galaxy

[Yottastack] Fahgetaboutit! CDs = 38,889 Parsecs
All the way across the Milky Way -Plus!

Now, how many mp3s can fit on that many discs AND can you fit them on your iPod?


[tags] kilo, mega, giga, distance [/tags]
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