Non-believers should take into account the evidence of alien life forms, instead of making a dispute before looking at the possibilities in the theory; there are bystanders to back up the facts and findings of “Crop Circles” and other signs of their existence over the previous years.
“Particularly in the 1920s there had been occasional claims of extraterrestrial radio signals (see page 1196), but by the 1950s interest in extraterrestrial intelligence had largely transferred to science fiction (see page 1198). Starting in the late 1940s many sightings were reported of UFOs believed to be alien spacecraft, but by the 1960s these were increasingly discredited. It had been known since the mid-1800s that many other stars are much like the Sun, but it was not until the 1950s that evidence of planets around other stars began to accumulate. Following a certain amount of discussion in the physics community in the 1950s, the first explicit search for extraterrestrial intelligence with a radio telescope was done in 1960 (see page 1196). In the 1960s landings of spacecraft on the Moon confirmed the absence of life there - though returning Apollo astronauts were still quarantined to guard against possible lunar microbes. And despite substantial expectations to the contrary, when spacecraft landed on Mars in 1976 they found no evidence of life there. Some searches for extraterrestrial signals have continued in the radio astronomy community, but perhaps because of its association with science fiction, the topic of extraterrestrial intelligence has generally not been popular with professional scientists. With the rise of amateur science on the web and the availability of low-cost radio telescope