Downloading the Web in an Afternoon

That's the equivalent of what Caltech recently accomplished.

Bandwidth is a measure of how much data can be sent across a network in a set amount of time. It's what you experience online when waiting for a web page to load.

But recently, Caltech reached a stunning milestone in how fast data can be sent, transferring 475 terabytes of data in 24 hours. That's fast enough to download the entire Web as indexed by Google in an afternoon. (Cool idea too. Can you imagine having your own personal cache of the web, updated every couple of hours in the background while you surf with no page load waits?)

OK, for math heads, here's the figures I used rounded to the nearest sanest numbers:

475 terabytes (the amount of data transferred in 1 day by Caltech), divided by 156 terabytes (the size of Google's web) = (roughly) 3.

More math? OK here is how I determined Google's size:

I did a Google search with my preferences set to return 100 pages. I searched for everything using *.* (Note: This search query doesn't work anymore. Use a creative seach of your own with common words like "home" or "welcome").
From those 100 hits, I added up the size of each page for a total of:
1721 k
and then divided that by 100 to get the average size of each page.
That gave me an average of 17 K per page
Multiply that by the number of pages on Google (9,180,000,000)
and that gives 156,060,000,000,000 Bytes or 156 terabytes.