If everyone on the earth at the same time with a laser pointer on the moon, what will happen ?

The first thing to consider is that all the people on earth are no way to see the moon at the same time. We must first pick a time to allow the most people to see the moon at the same time. Because 75% of the world's people live in the 0 degree warp to 120 degrees east longitude, so we choose the moon in the Arabian Sea near the time.

Then we have to consider whether it is full moon or new moon. Crescent is dark, so the effect of laser irradiation will be more obvious, but the new moon appears more during the day, so the observation effect was poor.

Regardless of the brightness, the United States Eastern Standard Time December 27, 2012 at 2 pm (Beijing time at 2 am) is the best time, when a full moon will appear in Mumbai and Islamabad, the world has 5 billion people can see it.But we still choose one and a half months, so that we can see the effect in the part of the cover

Originally December 21, 2012 is possible, but because according to the Mayan calendar earth will be destroyed in the day, so we chose Greenwich time on January 4, 2012 at midnight for half an hour. Ordinary output power is 5mw laser pointers, if the quality is good enough, then the laser can hit the moon all the way, of course, when the moon that beam will spread a lot of light. Earth's atmosphere also affects the light beam, but most of the light can reach the moon. The light beam will probably be scattered to the circle in the figure.

Assuming that all people can be stable aim, all the light can be distributed evenly on the surface of the moon. Half an hour at midnight, 5 billion people press the laser pointer at the same time. Why did not it work? Because the sun's exposure to the moon can reach more than 1000 watts per square meter. Because the moon cross-section is about 10 ^ 13 square meters, it can receive 10 ^ 16 watts of sunlight, an average of 5 billion people, then each person is 200 million watts per person, more than 5 milliwatt laser pen too much The. Although there are many factors that affect our efficiency in our system, these can not change the magnitude of the difference. 5mw really weak burst, and we can give a little force. 1 watt laser is dangerous stuff, it can not only blinding, but also burn the skin and lit something.

Suppose we spend nearly $ 2 trillion to 5 billion people each with a 1-watt green laser pen. This time we power 200 times, and because the green in the middle of the visible spectrum, so the human eye is more sensitive to green light. We use a green laser to illuminate a light beam with a width of 5 arcs and a brightness of 150 lumens, which is already brighter than most flashlights. The light to the moon surface illumination increased by half a lux, solar energy to provide 130,000 lux. Even if the 5 billion people all aim at a position, we can only 10% of the surface of the moon to increase the intensity of about 6 lux. With the development of lithium batteries and LED lighting technology, highlighting the LED flashlight market has a lot of power products, but the flashlight is certainly not enough, so we decided to give 5 billion people a "night sun" (Nightsun) You may have never heard of the name "night sun", but it should be seen in the film and television works. "Night sun" is installed in the police helicopter or the beach escort helicopter searchlight. It can reach 50000 lumens brightness, so that the night looks like the same day. The light of the night sun has several degrees wide, we need some lenses to focus the light column to about half.

Although it is difficult to see, but at least a little effect. The light of the night sun can provide 20 lux of illumination, than the moon that half of the black illumination twice. But the effect is still difficult to see, and the moon that half of the bright no effect.