TMI: If all data were CD stack, it would pass moon

WASHINGTON (AP) -- How much information is there, really?

Well, according to a new study, humans were able to store 295 exabytes of information as of 2007.

Now what, you might ask, is an exabyte?

As you may recall, a bit is a single piece of information, "1" or "0," and a byte usually contains eight bits.

An exabyte is 1,000,000,000,000,000,000 bytes.

Martin Hilbert and Priscila Lopez of the University of Southern California say that if all that data were stored on compact discs, the stack of CDs would reach beyond the moon - if the stack didn't topple over.

That's a lot of data, and presumably we have collected a lot more since then. After all, Lopez and Hilbert estimate the storage capacity of the world's computers doubles every 18 months.

Their findings, looking at the growth of information storage capacity from 1986 to 2007, appear in this week's edition of the journal Science.

Naturally, it's coming out first in Thursday's online edition of the journal, with publication on paper to come later.

Hilbert and Lopez also calculated that:

- In 2007 people sent 1.9 zettabytes of information through broadcast technology such as televisions and GPS. A zettabyte is equivalent to 1,000 exabytes. And that's equivalent to every person in the world reading 174 newspapers every day.

- People shared 65 exabytes of information in 2007 through two-way communication systems such as cell phones - the equivalent of every person in the world communicating the contents of six newspapers every day.

- The year 2002 could be considered the beginning of the digital age. It was the first year worldwide digital storage capacity overtook total analog capacity. As of 2007, almost 94 percent of our memory is in digital form.