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.

The scientific mistake in Tökland

The mystery of Tökland Island is one of the best-known novels of the Spanish writer Joan Manuel Gisbert, which in 1980 won him the Lazarillo Award.

In the first part of the book, a millionaire is trying to find the right person, who in the second part should help him unveil a tremendous secret, and so he builds an underground labyrinth in the depths of the fictional Tökland Island, offering a grand prize to the person who will manage to solve all the problems posed by the successive rooms of the maze.

At first, all who try to solve the challenge posed by the maze fail ignominiously. At last, the protagonist of the novel decides to attempt the adventure, but as he does not trust himself to solve every problem alone, he prepares a team of collaborators, specialists in various fields, who will contact him from a ship that will remain close to the island, and while he goes through the labyrinth will help him solve the problems he finds there.