Aliens Are Enormous, Science Suggests

Aliens, if they exist, are likely huge. At least that’s the conclusion of a new paper by cosmologist Fergus Simpson, who has estimated that the average weight of intelligent extraterrestrials would be 650 pounds (300 kilograms) or more. ET would have paled in comparison to these interstellar behemoths.

The argument relies on a mathematical model that assumes organisms on other planets obey the same laws of conservation of energy that we see here on Earth—namely, that larger animals need more resources and expend more energy, and thus are less abundant. There are many small ants, for example, but far fewer whales or elephants.

Thus, throughout the universe, as is the case on Earth, there are likely more small animals than large ones, says Simpson, a scientist at the University of Barcelona. Since the number of planets inhabited by relatively small animals would outnumber the amount of worlds where large ones predominate, it is most likely that we find ourselves on a planet with relatively small animals—and are ourselves probably one of the smaller intelligent beings, he adds.