Apple Inc. celebrated a huge milestone today as iTunes sold its 10 billionth song.
Let's put that in perspective.
That's approximately 32.8 songs per American, since there are just over 300 million of us now. There are only about 6.8 billion humans on Earth, so we've downloaded about 1.4 songs each. There have been about 240 million iPods sold (counting every model in the line), which works out to about 41.6 songs each.
How long would it take to listen to those songs?
Since the average American pop song is, according estimates, almost exactly four minutes long, that's 2,400,000,000,000 seconds of music. There are 31,556,926 seconds in a year, which means that, if you played every iTunes song ever sold back to back it would take 76,053 years to get to the end of the playlist.
That's a really long time. The ancestor scientists have called our "Y-chromosomal Adam" lived sometime around 75,000 years ago.
The Toba Catastrophe is supposed to have happened between 70,000 and 75,000 years ago, so, by rough estimates, if a member of the species Homo erectus had hit the little gray arrow button on that playlist in the year BCE 74,043 -- listening to ABBA when a super-volcanic eruption wiped out all but as few as 10,000 members of the species anyone reading this belongs to -- we'd be getting to ZZ Top's "Legs" around now.