Humans have reached the moon and are planning to return samples from Mars, but when it comes to exploring the land deep beneath our feet, we have only scratched the surface of our planet.

This may be about to change with a $1 billion mission to drill 6 km (3.7 miles) beneath the seafloor to reach the Earth's mantle -- a 3000 km-thick layer of slowly deforming rock between the crust and the core which makes up the majority of our planet -- and bring back the first ever fresh samples.

Electricity is the lifeblood of many aspects of our world. Without volts and amps, many of our technological innovations would cease to exist. Even our bodies wouldn't function without an electrical charge zipping through our cells. But what electricity gives, electricity can take away.

Although this form of energy is vital to so much of our lives, it's one of those things that are only good in the right amounts. Too much electricity can electrocute people. Likewise, it can kill our modern electronics and machines.

But thanks to Michael Faraday, the brilliant 19th-century scientist, and one of his namesake inventions, the Faraday cage, we humans have developed plenty of ways to control electricity and make it safer for our computers, cars and other inventions -- and for us, too.

The thermostat has been a straightforward appliance for years. The man who invented the iPod, however, believes that it needs a bit of a makeover both aesthetically and environmentally. David Pogue reports.

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