Gizmodo asked astrobiologists about what aliens might look like. The experts' answers are available on the publication's website.
“Sharks and dolphins have similar body shapes, although they are distantly related, some of which are fish and others are mammals. We shouldn't be surprised to see a similar convergence of body shape when we face life in other worlds,”says Douglas Vacoh, President of the METI (Messaging to Extra-Terrestrial Intelligence) International program.
According to him, "we should not expect duplication of Homo sapiens, as we seek life outside the Earth." The expert did not rule out that the multicellular inhabitants of the subsurface oceans of the satellites of the gas giants (primarily Europe and Enceladus) may resemble giant terrestrial tardigrades.
Astrobiologist from NASA Rocco Manicelli disagrees with him, who stated that multicellular life is unlikely to exist on Enceladus.
The chief astronomer of the SETI Institute (Search for Extra-Terrestrial Intelligence) Seth Shostak believes that insects are visually the "most alien" life forms on Earth.
Astronomer Kaitlyn Ahrens from the University of Arkansas (USA) believes that alien life may not be based on carbon, like earth. In particular, sulfur can be the main chemical element for it.