On July 16, 1945, in the Jornada del Muerto desert in New Mexico, the explosion of the first atomic bomb in history took place. The Trinity test began the era of nuclear weapons that would have its world premiere in Hiroshima, Japan, less than a month later. Those artifacts of death and destruction were the culmination of the Manhattan Project, the first major plan of applied science in history, designed to convert into pure power the knowledge obtained on the subject during the previous decades. The atomic bomb was, possibly, the worst publicity that has ever been given to science, but not all the practical fruits of the work of the physicists have been used for evil, far from it. The atomic age has had significant benefits for humanity. Here are some of them.
1. Radiation that cures cancer
Many people have in their heads that radioactivity causes cancer, but perhaps not as many know that it also cures it. Since the late 60s, what are known as gamma knives have been used all over the world. These machines use the ability of these rays, made of ultra energetic photons, to destroy living tissue. Just as people exposed to radiation may get cancer because these rays damage their cells, the application of this device focused on the harmful tissues end up destroying them in a selective way.
The origin of these gamma rays is cobalt 60, a radioactive element that continuously emits photons. This feature means that it must always remain isolated and that handling it is hazardous. This is why the source of radiation is being replaced by particle accelerators that can emit radioactivity only when needed.
Nuclear technology, as well as serving to treat disease, has become a valuable diagnostic tool. One example is positron emission tomography (PET). This system allows for the reconstruction of images of what is happening inside the body. To achieve this, the patient ingests a radioactive drug with a very short life in order to avoid radiation damage. The system then detects the gamma rays emitted by the patient.
2. Trips to the edge of the Solar System
In the vicinity of the Earth, where we use orbiting satellites for communications or to predict the weather, solar panels are the primary source of energy. The Rosetta probe, now studying the comet 67P/Churyumov-Gerasimenko, is capable of operating at 800 million kilometers from the Sun, but requires two giant solar panels of 14 meters each, with which to squeeze out every last photon of the low solar energy available.
Beyond this, to explore the gas giants like Jupiter or Saturn or to try to reach the edge of the solar system, nuclear energy is necessary. The atomic propulsion produced with radioisotope thermoelectric generators (RTG) is the most effective way to reach those places where the sun is too weak for a solar panel system.
This technology, which converts the heat energy produced by the disintegration of plutonium-238, kept the pioneer Viking probes exploring Mars for years. The Galileo probe, with a similar power system, revolutionized our knowledge of Jupiter and its moons, and Cassini has already spent ten years rediscovering Saturn and its moons, photographing the geysers of Enceladus or analyzing the subsurface ocean that lies beneath the surface of the satellite Europa.
The most extreme case of the potential of nuclear power for space exploration is the Voyager probes. Launched in 1977, they have now reached the edge of the solar system and continue to send signals as the most distant human emissaries from Earth.
3. An unknown application in energy production
The fundamental civil use of nuclear technology came almost a decade after its use as a weapon. In 1954, the Soviet Union launched the first nuclear reactor fueling the electric grid. Today, although only 31 countries have nuclear power plants, more than 12% of the world’s electricity is produced in such facilities.
But power is not the only contribution of radioactivity to energy production. As in medicine, the ability to cross the field of ionizing radiation has found wide uses in industry. Among these is the exploration of oil wells to check if they will be commercially profitable.
To reduce the risks of the investment required to drill an oil well, a source of neutrons or gamma rays is introduced inside the well in order to understand its geological features. In addition, a radiation detector is used to collect the information emitted by the source and its interactions with the environment. The neutron activation analysis, for example, is able to analyze the presence of more than 40 elements, providing essential information to assess the value of a well.
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