Measurements by shooting laser beams, today allow researchers to find out details about the moon
Dr. Noah Brosh
Although the moon has been thoroughly studied for many decades, there are still quite a few topics that are not completely understood about this celestial body, which we often observe at night.
At the end of the 60s of the last century (the 20th), the astronauts landed on the moon, in the "Apollo" operation - and brought rock samples from there. They left various devices on the moon, which measured, for example, the "moon tremors" as well as the moon's reaction when other celestial bodies hit it.
These were mainly meteors - and the most important of them was the one that hit the far part of the moon, hidden from the earth, in 1972.
The impact caused considerable shock. The body that hit the moon was one meter in size. The event allowed researchers to reconstruct the surface of the moon, up to a depth of 1100 km. It turns out that part of the moon is still in molten form (lava).
Another experiment of this type was done when one of the rockets from the Apollo system was aimed to crash into the moon. It was a controlled experiment, where the energy of the collision was known in advance to the scientists.
The detector system, the sesmo-meters, which was left on the surface of the moon, stopped working about 25 years ago. Since then we have no information about moonquakes.
These days, a new series of measurements has begun - using components previously left on the moon by the astronauts from the Apollo mission. This confirmed the assertion that part of the moon is still in a molten state.
The measurements in this matter focused on the reaction of the moon's surface to the gravity of the earth and the sun. These forces are well known on Earth. Create the phenomenon of "tides and low tides" in the days. The sea level rises and falls at a constant rate, twice a day.
The tides on the Earth are created due to the difference in the gravitational force of the Sun and the Moon, between the point that is under one of these bodies, and the opposite point, on the other side of the Earth, relative to the attracting body. The farther the opposing point is from the attracting body - the force exerted on it is smaller than at the point below the body, from where the attracting factor is seen, "above the head".
The difference between the force of gravity, at the near point and this force at the far point, is felt on the earth as a force that tries to "stretch" it along the line connecting the center of the sphere, and the attracting body.
This phenomenon takes on an easily visible expression when the outer surface can change its state
Easily - and this is what happens especially in the oceans.
There is also a phenomenon of "tides and low tides" in the crust: the solid surface of the earth rises a little when the moon or the sun passes over a certain point, and they fall a little when the bodies move away from that point.
The new measurement examines the same phenomenon, regarding the surface of the moon. When the bodies that create tides in rocks are the earth and the sun. The measurement is performed by firing a very short pulse of a laser beam, towards the places on the moon where the astronauts from the "Apollo" mission left special boards where laser radiation reflectors were installed.
Measuring the time that passes from the execution of the shot to the reception of the light reflection, determines the distance between the facility on the moon and the ground station.
This measurement is carried out these days, with an accuracy of a few centimeters. From the series of measurements it is possible to decipher movements that occur on the surface of the moon, in the same order of magnitude as those caused by the tidal force exerted by the earth and the sun.
These measurements confirmed the existence of the molten zone inside the moon. They should get better
In the portrait during the year, when it will be possible to take into account, for example, the effects of deformation that occurs in the Earth's atmosphere under the influence of solar radiation.
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