Michio Kaku presented an Ask Me Anything (AMA) on Reddit, where he answered questions regarding aliens, what they may look like, and how they might act. As viewers sent in questions, the astrophysicist postulated answers about the nature of alien life forms and civilizations.
Extraterrestrial beings able to travel to Earth from other solar systems, by definition, have technology far in advance of our own. This means they have survived long enough to get past the time when they became able to destroy their world through war or negligence. This might suggest that any technological civilization capable of interstellar flight would be unlikely to be violent.
“However, they still might be dangerous if they simply don’t care about us and we get in the way. In War of the Worlds, the aliens did not hate us. We were simply in the way. In the same way that a developer is a threat to forest animals because he can pave the [forest], the danger there is from someone who sees that we are just in the way. But for the most part, I think they will be peaceful, but view us like we view forest animals,” Kaku wrote during the AMA.
Aliens would likely have two eyes, providing them with binocular vision, Kaku stated. They would also be descended from predators, the astrophysicist speculates. Here on Earth, most intelligent species of animals, including humans, chimpanzees, and dolphins are capable of hunting other animals and consuming meat. However, less than two percent of the diet of chimpanzees consists of animals, and elephants are herbivores, showing this may not be a prerequisite of an intelligent species.
Kaku also believes aliens will have opposable thumbs, allowing them to manipulate materials and build tools. However, many animals here on Earth, including dolphins, crows, elephants, otters, and octopuses, are able to make and use tools without opposable thumbs.
“The veined octopus apparently can stack coconut shell halves that people discarded just as one might pile bowls, sits atop them, makes its eight arms rigid like stilts, and then ambles the entire heap across the seafloor, using them for shelter later when needed,” Live Science reported in 2009.
Language is one aspect of life that we will likely share with aliens, regardless of their origin. However, the means they use to communicate could be wildly different than the way we use sound. Visual communication, smells, chemical tracers, or some form of telepathy are all possible. But, language in some form is, more than likely, a prerequisite for an advanced species. It is also almost certain they will understand mathematics, since it would be nearly impossible to build and pilot an interstellar spaceship without such knowledge.
Chemists know of tens of millions of chemical compounds. In 2015, the American Chemical Society announced they had cataloged 100 million known substances. Of these, roughly half are based on carbon. This element bounds to a wide variety of other substances, in many structures, leading to diverse molecules. Due to the nature of chemical bonding, it is more than likely that most, if not all, alien beings would be based on carbon.
Aliens on other worlds will, most probably, be based on carbon, and have a language. However, the form or shape of their bodies could be radically different than our own. Imagine trying to communicate with octopus-like beings with a radically different language – much like the movie “Arrival.”
If aliens do arrive on Earth, there are only a few things we are almost certain to have in common with them. However, organic chemistry, language, and an understanding of mathematics is likely to be among our commonalities. However, they will have grown beyond their “technological adolescence,” meaning they would be unlikely to intend harm to those of us on Earth.
Astronomers currently estimate that one in five planets in our solar system is accompanied by one or more Earth-like planets. This would mean The Milky Way is home to between 20 and 80 million other Earths.
The original AMA with Kaku took place on February 21, 2018.