Who Is Number 1?

And for how long?

China surpassed Japan as #2. Is the US next? Does it matter?

If China were to replace the U.S. as the largest economy on Earth, it could mean big changes for America. Right now, the U.S. economy is three times bigger than China's -- $15 trillion compared to $5 trillion. But China is catching up fast. NPR's Planet Money team has a story today from the near future -- on what life would be like for the U.S. if it were to become No. 2.

Audio Embed: All Things Considered 8/19/10, Reporters: Chana Joffe-Walt and David Kestenbaum.