Scientist David Catling from the University of Washington proposed a new way to search for extraterrestrial civilizations. In his opinion, their existence may be indicated by an abnormally low amount of deuterium.
Extraterrestrial civilizations need a lot of energy. Fossil fuel reserves are limited, solar and wind power produce no waste but are not as efficient, and nuclear fission power depends on stockpiles of fissile material and has the problem of getting rid of spent fuel. Thus, we can assume that any advanced alien species will eventually turn to nuclear fusion (unless, of course, there are some more efficient energy processes unknown to us).
One of the simplest forms of nuclear fusion is the fusion reaction of deuterium and tritium nuclei. Deuterium, also known as heavy water, is found in small amounts in Earth’s oceans. Its commercial extraction will cause the ratio of deuterium to ordinary hydrogen in water vapor (D/H) to begin to decrease. This change can be detected by Earth-based telescopes and is a sign that advanced life exists (or existed in the past) on it.
David Catling and his colleagues used the Earth and a fusion power about 10 times greater than that predicted for humanity by 2100 as the basis of their model. The simulations showed that the D/H ratio in water vapor would decrease to values smaller than in the local interstellar medium over 170 million years. If we are talking about a land world with a small ocean that is only a couple percent of Earth’s, it would take no more than 10 million years.
According to Catling, this method could well be used for technologically advanced civilizations. If astronomers manage to find a world where the concentration of deuterium is significantly lower than the values in the surrounding interstellar medium, it will immediately attract a lot of attention. One of the main advantages of the method is that the abnormal D/H ratio will remain even if evolved life becomes extinct or leaves their home.
Earlier we reported on whether a fusion engine could help humanity reach the stars.
Provided by Phys.org
