The Earth's core is important because it generates the planet's electromagnetic field - which seems to be weakening.

BBC: Planet Earth

It uses an electromagnetic field, rather than carbon brushes, to accelerate from standstill to up to 100, 000 revolutions per minute within 0.7 seconds.

BBC: Dyson launches all-in-one hand-drying Airblade water tap

Using a conductive capacitor that is integrated as part of the pen, it connects to an electromagnetic field generated by an excitation coil in the digitizer.

ENGADGET: N-trig's Digital Pencil plays pen and fingertip roles, claims mastery of both

Also, the Modbook Pro's SSDs are fine-tuned to not interfere with its high-resolution pen tablet interface (whereas the electromagnetic field emissions of HDDs are notoriously difficult to control).

ENGADGET: Modbook Pro to launch with SSD storage, up for pre-order October 3rd

With each changing minute, an electrical pulse generates an electromagnetic field that changes the position of the crystals on the face of the watch, to elegantly display the passing time, while producing a distinctive sound unique to the Phosphor Reveal digital watch line.

ENGADGET: Phosphor's Reveal wristwatch uses Swarovski crystals to tell time, bedazzle you

Bursts toward earth can cause electromagnetic storms when they react with the Earth's magnetic field, resulting in an explosion of color in the sky.

CNN: Northern lights dazzle Northern Hemisphere