Light is granular, can you climb up along the beam?

There is a joke that describes a scene: a person turns on his flashlight at night and a light beam appears. One person said to another:? Climb this post? . The other one didn't climb, saying, I climbed up, and as soon as you turned off the flashlight, I fell down. ?

Jokes are jokes. If they are more serious, the light beam can really lift or move objects. Because light has particles and photons have momentum, light pressure will be generated when hitting an object, and light pressure can drive the object.

Remember Hawking's ambitious dream before his death? Hawking wants to explore Alpha Centauri four light years away with a light sail spacecraft. Hawking's idea is to use a powerful laser to accelerate a pocket spaceship with a huge sail to one-fifth of the speed of light, so that you can receive information from Alpha Centauri in your lifetime. Hawking's idea of a spacecraft that can fly at one-fifth the speed of light has not yet been developed, but a spacecraft with the same principle has entered space.

In addition to designing and manufacturing light sail spacecraft, there is also a very effective tool, namely optical tweezers. Commonly used mechanical tweezers can hold small objects, and some basic operations are often carried out with the help of mechanical tweezers during experiments or maintenance. When people's research goes deep into the field of macromolecules with only tens of microns or even tens of nanometers, people need a more precise optical tweezers, which can have similar processing and even other advantages as mechanical optical tweezers.

Optical tweezers can manipulate objects, and this manipulation is non-contact and it is not easy to cause mechanical damage to the manipulated objects. In the field of single cell and single molecule research, optical tweezers have played a great advantage, which can cut the cell wall and operate the organelles inside. You can even use the transparency of the cell membrane to operate the organelles directly without opening the cell membrane.

As for manipulating objects as big as people, or moving people from one position to another on a beam of light, humans do not have this ability at present. However, this idea does not violate the known scientific principles, and there may be such high-power optical tweezers in the future.