{{Pause=2}} CHAPTER 18 {{PAUSE=1}}Early Visits To Earth {{Pause=2}} Lya said to me: "As you know, the atmospheric perturbations that frequently are registered on your planet come from space. It is there where the innumerable climactic changes are born. Nevertheless those are the result of major phenomena - some natural, others artificial." She paused a moment and then continued: "Space offers an infinite accumulation of surprises. When we came here for the first time, you were registering on your calendar the year 1249, and the planet, absolutely, was very different from what you find today. We crew members of the ship exhibited our surprise at the simplicity of the people - utilizing rudimentary weapons when we already possessed a technology that would have evoked great surprise among those inhabitants of each one of the societies that we encountered at that time in conflict." In the manner that you arrived before?" I asked without believing that she had heard me. "Yes, but my charge was not the same as it is now... Then we simply studied and my first trip was only exploratory." "And now - your trip is likewise to explore?" "Not necessarily, but you will know later why. Now let me continue explaining the atmospheric changes with relationship to the forms of life existing between the years 1200 and 1350. During this lapse of time we made various trips, at least one each twenty years. We discovered that the climactic changes curiously influenced the comportment of the Earth people. Your planet, Professor, belongs to those inhabited ones of the group that you call the Milky Way, and it is an extremely fickle body. There is a great diversity of climate around this tiny world. This is because of modifications in your solar system. Well, as a result of those changes being analyzed we discovered some surprises in space. Cosmic clouds, or intermittently radioactive clouds, as we call them, were encountered with unusual frequency. They almost drove us away step by step. They are not detectable by the human eye. Our sensors locate then and we evade contact, we have special sensors for our space navigation. For us, these clouds (because of the ability to detect and avoid them) are not dangerous, and thus represent no threat. With the objective of protecting ourselves we open a compartment door and expel a neutralizing gas whose principal component is highly concentrated oxygen. Nevertheless for you it is offensive. It would damage your world. It would provoke change in radio waves, turbulence in the air and in your electricity', and would generate problems by the alteration of the energy wavelengths. But the most important damage would be to your neurons." {{PAUSE=2}}