A Radio Telescope on the Moon

One of the most interesting radio frequencies for radio telescopes is that emitted by hydrogen atoms when excited by an energy input. Upon returning to its ground state, the atom emits a photon with a frequency of 1.42 gigahertz. This frequency corresponds to the microwave region, which ranges from 300 MHz to 300 GHz. If we focus a radio telescope on a cloud of gas and dust in our galaxy, which is composed mostly of hydrogen, this frequency is easy to detect.

But what happens if we try to detect this frequency in very distant regions of the universe? The expansion of the universe affects these waves by lengthening them (that is, decreasing their frequency), in the same way as the frequency of the cosmic microwave background radiation, which was initially in the visible and infrared regions of the spectrum, is now in the microwave region, with its peak at a frequency of 160.2 GHz.

Does the Moon influence people?

Astrologers have been answering this question in the affirmative since time immemorial. It’s true that astrology has been discredited since a few centuries ago, to the point that another name had to be found for the science dedicated to the study of the stars (astronomy = laws of the stars). Despite which, in this supposedly scientific age, the mainstream media dedicate significant space to horoscopes and other astrological products.

Sometimes the influence of the moon has been confirmed. Since ancient times it was observed that the tides are related to the position of the moon in the sky, although it was not known how this influence could take place. To support the theory of Copernicus against that of Ptolemy, Galileo formulated a theory, according to which the tides are not due to the attraction of the moon, but to the translational movement of the Earth around the sun. In this case Galileo was wrong, because the influence of the moon is real, although it was not explained until Isaac Newton formulated the theory of universal gravitation.

Thirteen months in one year?

After talking about days and hours, this is the turn of the month. Like the day, it corresponds to a natural cycle: the revolution of the moon around the Earth. As we know, seen from the Earth, the moon does not seem to rotate around its axis and always shows us the same face. However, if we take as a reference point a star or the sun, a rotation can be seen. An observer located on the sun would see successively all the points on the surface of the moon, therefore would see it rotating around itself. It could also be observed that its period of rotation is the same as its revolution around the Earth. This is why it always shows the same face towards our planet.

Space as a point of concord for humanity

Start of a V-2 rocket in 1943

The exploration of space began some seventy years ago, as a continuation of the Third Reich’s war effort to develop ballistic missiles (the V-2 rocket) to bombard Britain and other places without the need of airplanes.

At the end of World War II, the two new great powers (the United States and the Soviet Union) recruited the scientists and technicians who had carried out the German advances in that field, took them to their respective countries and started programs of space exploration, whose first objective was, of course, to obtain military advantages in the cold war that had just begun. As a result of Operation Paperclip (the US recruitment program), German scientists as important as Werner von Braun went to work in the United States. An equivalent Soviet program (the Operation Osoaviakhim) did the same with other German scientists, perhaps less known, but equally efficient. With their help, both superpowers began a space race that would last several decades.

The Chinese on the Moon

The hidden face of the moon

On January 2, a Chinese spacecraft landed on the opposite side of the moon.

The fact that the moon rotates around its axis in the same time that it revolves in an elliptical orbit around the Earth has the consequence that our satellite always shows us the same face. For several centuries, the hidden face of the moon was an enigma. In 1870, the science-fiction novel Around the Moon, by Jules Verne, leaves open the possibility that in the hidden face of the moon there could be air, water, life, and even intelligent inhabitants. While the three travelers pass over the hidden face during the lunar night, unable to see anything on the surface, a sudden flash of light caused by a meteor shower illuminates for a moment the hidden area and shows them clouds, seas, forests... or at least that’s what the dazzled observers think they have seen.