Is magnetism a source of green energy?

Anyone who's ever tried to hold twomagnetstogether has felt the surprising power of magnetism. If the magnets have opposite poles, they'll attract each other so forcefully that they may leap from your grip and go skidding across the floor. On the other hand, if they share polarity, they'll repel each other. With such huge stores of invisible power, isn't it likely that magnetism could be a source of efficient, green energy?

Harnessing magnetism to produce energy is an idea that's been around for years. Several companies on the Internet claim to have produced magnetically poweredperpetual motion devices那完全是无限地独立运行的，没有停止。物理学家长期以来一直警告说，这种设备是不可能的。机器可以发挥能量而不先被某些外部来源动力的想法违反了热力学的第一定律。此外，据说无限期运行而没有摩擦且无需冷却系统的机器违反了热力学的第二和第三定律。

Even though perpetual motion generators are a theoretical impossibility, new research suggests that magnetism may play an important role in a number of other emerging clean technologies. Recently, scientists at the University of Michigan concluded that it may be possible to use magnetic fields to collectsolar energydirectly without the need for semiconductors, potentially reducing the cost of solar power [source:EPOnline].

Researchers are also working on a number of other green technologies involving magnetism. Some day soon, we may be able to recharge magnetic batteries with a few vigorous shakes. Yale researchers have also invented a lead-free solder that uses a magnetic field to melt a tin-silver alloy. Removing lead solder from household electronics would make them considerably cleaner, greener and more recyclable. Last but not least, engineers at Columbia University are experimenting with nanomagnetic materials to make computer chips more energy efficient.

So, is magnetism a source of green energy? Sort of. Magnetism by itself may not provide a new source of green energy. However, it's clear that it could play a big role in lowering costs and improving efficiency for a number of renewable energy sources.

Feel drawn to the next page? There's lots more information after the jump.