Our former Vice President and Most Smartest Politician Evah before President Chicago came along stated on Conan O’brian that some new advances could tap geothermal energy a few miles down because the earth’s interior is “several million degrees”. John Derbyshire, someone who writes books on math as a side project, astutely corrects him:

The geothermal gradient is usually quoted as 25–50 degrees Celsius per mile of depth in normal terrain (not, e.g., in the crater of Kilauea). Two kilometers down, therefore, (that’s a mile and a quarter if you’re not as science-y as Al) you’ll have an average gain of 30–60 degrees — exploitable for things like home heating, though not hot enough to make a nice pot of tea. The temperature at the earth’s core, 4,000 miles down, is usually quoted as 5,000 degrees Celsius, though these guys claim it’s much less, while some contrarian geophysicists have posted claims up to 9,000 degrees. The temperature at the surface of the Sun is around 6,000 degrees Celsius, while at the center, where nuclear fusion is going on bigtime, things get up over 10 million degrees.

If the temperature anywhere inside the earth was “several million degrees,” we’d be a star.

I wouldn’t worry about it, its not like he has a history of making extraordinary claims that even his policy allies don’t believe.