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Physicists Lift Tiny Wing Using Light
物理學(xué)家利用光使微小的翼狀物飛起

Think about flying and you no doubt think about air. The wind in your face, the wind at your back, the wind beneath your wings. Now physicists note that light can also give you a lift. Their work appears in the journal Nature Photonics.
一說到飛翔，你必定會(huì)想到空氣。風(fēng)拂過你的臉頰，吹過你的后背，托起你的雙翼。現(xiàn)在，物理學(xué)家們注意到，光也可以搭你一程。他們的研究成果發(fā)表在《自然光子學(xué)》雜志上。

Staying aloft is a matter of dealing with pressure. In the case of a plane, it’s the difference in pressure on the top and bottom of its wings that keeps the craft afloat. But air isn’t the only way to generate pressure. Light can do the same. When photons pass through or reflect off of something, they give that object momentum. That’s why comet tails always point away from the sun. Solar radiation and wind push them that way.
懸浮空中取決于對(duì)壓力的利用。以飛機(jī)為例，它雙翼上方與下方的壓力各不相同，正是這不同的壓力使得飛行器保持懸浮。但是空氣并非產(chǎn)生壓力的唯一途徑。光也做 得到。當(dāng)光子穿過某物或由某物反射時(shí)，就會(huì)給該物體一個(gè)動(dòng)量。這就是為什么彗尾總是背離太陽(yáng)的方向。太陽(yáng)輻射和太陽(yáng)風(fēng)使其如此。

So physicists got to wondering whether radiation pressure could be harnessed to help an item soar. The craft they deployed was a wing-shaped rod the size of a bacterium. They plopped this rod into a beaker of water and hit it with a laser beam from below. And found that the rod moved upward and to the side—a sign of optical lift. The finding could aid the design of solar sails for interstellar sojourns. And perhaps give new meaning to the phrase “traveling light”.
因 此，物理學(xué)家開始忖度能否利用輻射壓力使物體高飛。他們?cè)O(shè)計(jì)的飛行器是一個(gè)細(xì)菌大小的翼狀桿。他們讓這個(gè)翼狀桿落入盛有水的燒杯中，并用激光束從底部擊中 它。研究結(jié)果表明，該翼狀桿會(huì)向上運(yùn)動(dòng)，移到一旁——這標(biāo)志著是光造成的上升運(yùn)動(dòng)。這一發(fā)現(xiàn)可以為星際旅居設(shè)計(jì)太陽(yáng)風(fēng)帆?；蛟S，還會(huì)為短語(yǔ)“輕裝旅行 （traveling light）”賦予新的意義。

—Karen Hopkin

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