If University of Barcelona cosmologist Fergus Simpson is correct, your basic intelligent alien from another planet is heavier than a grizzly bear -- and hopefully, less inclined to eat us when we finally meet.
We didn't notice the "or more" part at first. Yikes! We might have to look further up on our chart of animal weights to a moose, a Grevy's zebra, or a Bactrian camel.
How did Simpson come up with this estimate? Is it science or speculation? According to Newsweek:
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.
Makes sense, as far as it goes, though it doesn't take into account one important variable: A planet's surface gravity relative to Earth's. A smaller planet with a weak gravitational pull probably would tend to have larger forms of life than a Jupiter-sized planet with crazy-strong gravity.
So if the aliens are huge and full of bad intent, our only hope may be our planet's gravitation. Hopefully, we won't have messed that up before the times comes.
This story, "They might be giants: Scientist theorizes that intelligent extraterrestrials are huge" was originally published by Fritterati.