See the number of vias on the PCB through the moon

Because the top side is the device;

The Bottom surface naturally sees more vias.

Since the moon's revolution period is the same as the rotation period, the moon always faces the earth with the same hemispherical surface (front). Humans cannot directly observe the back of the moon by visual or astronomical instruments. Therefore, humans guess that the back of the moon should be The same as the front. Since humans invented the cosmic detector to photograph the back of the moon, they realized their mistakes: the back of the moon is different from the front, and there are more craters than the front. There is no scientific explanation for this phenomenon for many years. In fact, it is very simple. As long as we think of an asteroid belt between the orbit of Mars outside the Earth's orbit and the orbit of Jupiter, the problem is solved. Whether it is the meteorite that has fallen on the earth or the meteorite that has fallen from the moon, it is basically an asteroid from the asteroid belt. We can divide the operation of the Earth and the Moon into a plan, and divide the lunar orbit into four zones, each zone is a 90-degree arc, that is, the Moonlight Zone, corresponding to the lunar calendar of fifteen; the plastic moon zone, corresponding to the first and second; The first half of the month, corresponding to the eighth day; the second half of the month, corresponding to around twenty-three. Also draw the direction of the sun and the direction of the asteroids (the opposite direction). Next we can do this analysis: Considering the two situations in which the moon is in the upper half of the month and the second half of the month, the probability of the aft of the moon and the front of the moon is the same; and when the moon is in the moon and plastic moon respectively In the district, since it is basically unaffected by the earth when it is in the Mochizuki area, the probability of the asteroid falling on the back of the moon will not decrease (if the earth is affected, the probability will increase slightly), while in the plastic moon area, it will be greatly affected by the earth. The asteroids that rushed to the moon first passed through the gravitational field of the earth, and some of the asteroids were captured by the earth, which reduced the probability of the asteroids falling on the front of the moon. In this way, the probability of asteroid falling on the back of the moon is greater than that of the front asteroid, causing more craters on the back of the moon than on the front.

See it: the top side of the moon (PCB) is the same number of vias as the Bottom face (unless the blind hole is buried). Only the TOP of the moon has the earth, blocking the meteorite. The TOP surface of the PCB is soldered to block the via. So it caused a visual difference. . . . .

I wish you all a happy Mid-Autumn Festival.