what are aliens

Aliens, also known as extraterrestrial life, are life forms that do not originate from Earth. No extraterrestrial life has yet been conclusively detected, but it is believed that such life might range from simple forms such as prokaryotes to intelligent beings, possibly bringing forth civilizations that might be far more advanced than humanity. The science of extraterrestrial life is known as astrobiology. The possibility of extraterrestrial life has always fascinated humans, and people have speculated about alien life on Mars and other nearby planets ever since we realized they were different from the other points of light in the night sky. Although the lack of evidence of life beyond Earth doesn’t mean we don’t have any idea what could or should be out there, the presence of aliens on Earth has never been proven. Most scientists believe that for another planet to have life on it, it must be similar to Earth in several ways, such as having an atmosphere, water, and orbiting a star like the Sun at a good distance.