根据《物理评论快报》实验报道(http://focus.aps.org/story/v22/st20), 当光离开光纤时，给光纤一个推力，而不是拉力。作为揭示一种新的物理现象，这个实验是很成功的。但如何解释这种现象，引起了很多爭异。
A series of laser pulses is sent into the fiber, and each causes it to bend. The research team interprets this as a recoil of the fiber as the light gains momentum when it hits the air. This result supports the claim that light's momentum is less in a material than it is in air--one side of a century-old debate on the true momentum of light in transparent materials.
按我的看法，是由于动量守恒引起的，和光在介质中特别是在透明介质中的动量大小没有什么关系，就像自来水离开塑料软管一个道理。
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