Friday, January 7, 2011

Science: Light Can Generate Lift

With the right design, a uniform stream of light has pushed tiny objects in much the same way that an airplane wing hoists a 747 off the ground.

Researchers have known for a long time that blasting an object with light can push the object away. That's the idea behind solar sails, which harness radiation for propulsion in space, for instance. ...

Light's new trick is fancier than a boring push: It created the more complicated force called lift, evident when a flow in one direction moves an object perpendicularly.

Optical lift is different from the aerodynamic lift created by an airfoil. A plane flies because air flowing more slowly under its wing exerts more pressure than the faster-moving air flowing above. But in a lightfoil, the lift is created inside the object as the beam shines through. The shape of the transparent lightfoil causes light to be refracted differently depending on where it goes through, which causes a corresponding bending of the beam's momentum that creates lift. [Emphasis added].

For more, see Light Can Generate Lift by Laura Sanders, January 1, 2011 at ScienceNews.

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