Experts define the UFO as an unknown body or light in the sky or on the Earth’s surface, whose appearance, flight path, general dynamics and luminescence properties can not be explained in a conventional manner.
In the meantime, the deceased astrophysicist J. Alien Hynek, a longtime American advisor
In the UFO area, has created a classification system for UFO observation, according to which it can be divided into the following groups:
NL Nocturnal Light – The simplest explanatory processes in the night sky are most often explained as UFOs. Experienced UFO investigator, on the other hand, at first glance, often recognizes that the objects seen mostly from a long distance are satellites, meteorites, landing lights for planes, planets, balloons and the like.
DD Daylight Discs – The day-to-day UFO shape is mostly described as oval or disc-shaped. These objects are categorized as DD. They are also seen from a long distance. Naturally, this class may also include NL phenomena appearing over the day, but it can not be said with certainty. Most DRO images are depicted on most UFO images.
RV Radar / Visual (Radar / Visual) – Unknown flying objects that were only radar-localized should not be classified as UFO phenomena because radar echoes can be caused by a number of natural causes. Interestingly, radar signals are confirmed by sensory perception – or vice versa. The natural causes that can cause radar echo include, but are not limited to, technical errors, rare meteorological influences, or bird fowl.
CE-1 Close Encounter of First Kind – This category includes all closely observed objects that do not cause interaction with the environment. Under close observation is a distance of up to 150 meters. The boundary of this distance may, of course, change in individual cases. In any case, the observer should be able to distinguish substantial details from the object. For this reason, CE-1 cases are not easy to explain.
CE-2 Close Encounter of the Second Kind Here comes physical and psychological interactions with the environment, for example in people in the form of paralysis, nausea, burns, fever and depression. In addition, traces of landing and traces of burns as well as power outages can be found. Observations of the CE-2 type are among the most interesting because the findings can be scientifically investigated.