According to Moore's Law, the price of computing power is slashed in half every two years — which helps explain why personal computers become outdated so quickly. But now, as Paul Krugman at The New York Times notes, the solar energy industry is experiencing a similar trend. The price of producing solar power continues to fall — thanks to technological improvements and heavy subsidies in countries like China — and this onetime punchline of an energy sector continues to expand. Will solar power eventually overtake oil as Earth's primary energy source? Perhaps. In the meantime, a look at the shrinking cost of solar energy, by the numbers:

Percentage growth experienced by the solar energy industry in each of the past five years

Percentage decline in the annual price of solar energy, adjusted for inflation

Percentage drop in the price of installing solar panels in the U.S. in 2010, says the Washington Post. "Solar companies are figuring out how to set up systems cheaply."

Gigawatts of solar power that were created or used in the United States in 2010. That's roughly equivalent to the output of 17 nuclear power plants.

Watts of power that the sun shines on every square meter of Earth

89 quadrillion
Watts of power shining on the Earth at any given moment. One quadrillion is a 1 followed by 15 zeros.

15 trillion
Watts of power used by "all of human civilization" each day. It may be a big number, but it's just "one six-thousandth" of the 89 quadrillion watts shining on Earth at any given moment, says Scientific American.

Seconds it takes for the sun to provide as much energy to Earth as humanity consumes in a day

Minutes it takes for the sun to provide as much energy to Earth as humanity consumes in a year

The year that analysts expect solar power to become affordable enough to compete directly with fossil fuels

The year that analysts expect solar power may satisfy more than half of the world's energy needs

$491 billion
Amount that U.S. drivers are expected to spend on gasoline this year

Sources: Forbes, Los Angeles TimesNY Times, Scientific American, Washington Post