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  • When we think of looking for extra-terrestrial life, we tend to focus onearth-like

  • planets, that is, planets with conditions that are similar to our own. “Life exists

  • on earth,” the logic goes, “so earth-like conditions are probably a good bet to find

  • more life.”

  • And yet.

  • There are hundreds of billions of galaxies in the observable universe, each with billions

  • if not trillions of stars, and most stars have planets orbiting them. That's roughly

  • a million billion billion planets. The enormity of this number means it's probably safe

  • to assume that there are many many *many* other planets with life - even intelligent

  • life.

  • And this, together with some basic physics and fancy statistics, implies it's more

  • likely that species of intelligent extraterrestrials will live on habitable planets unlike earth

  • and will be unlike humans. More precisely, they'll be bigger than us and live in smaller

  • groups on smaller planets.

  • Now, I know it sounds crazy that with only one data pointus – we can make any

  • predictions at all about aliens we don't even know exist. But we can – here's

  • how:

  • A basic result in statistics is that there's a big difference between the properties of

  • a typical *individual* and the properties of an individual in a typical *group*. The

  • majority of humans, for example, live in countries with a population of at least 180 million

  • people. But the majority of countries have populations of less than 6 million.

  • And the majority of *religious* humans are members of religions with more than a billion

  • followers, while the majority of *religions* have fewer than a million followers.

  • And the majority of people who follow the English Premier league are fans of teams with

  • hundreds of millions of fans like Manchester United, while most *teams* have just a few

  • million fans each.

  • It doesn't matter how many individuals you have, or how you make the groups – they

  • can be religions, or fans of sports teams, or the ingredients of this trail mix. It is

  • a mathematical fact that the group that the median individual belongs to will be at least

  • as big/bigger than the median group. Or, simply put, any time groups are not all the same

  • size, most individuals will be members of groups that are bigger than most of the other

  • groups.

  • The takeaway is that an individual should expect to be a member of a large group, not

  • an ordinary one. If you don't know what group you fall into (like, I don't know

  • what my blood type is), the most likely groups to be in are the biggest ones – I'm probably

  • O or A positive.

  • And when it comes to intelligent life forms, we humans don't know what kind of group

  • we fall into. So statistics tells us that we, as individuals, should expect to be members

  • of a large group of intelligent beings. That is, we should expect that our species has

  • a higher population than most other species. And just knowing that we probably have a high

  • population tells us a lot.

  • For example, individual living beings require space to live – I mean, the countries with

  • the biggest populations tend to have large land areasso earth, with its high population,

  • is probably bigger than most other planets with intelligent life.

  • Similarly, smaller living creatures need less space and energy per creature, and accordingly

  • tend to have higher population densities: that's why there are way more ants on earth

  • than elephants. So humans, with our high population, are probably physically smaller than most

  • other species of intelligent life.

  • In fact, we should expect to be abnormal among intelligent aliens when it comes to anything

  • that influences overall population size. Like, easily available energy makes it easier to

  • maintain higher populations, so we should expect our sun to be somewhat hotter and brighter

  • and closer than the stars of most intelligent alien species; and we should expect our atmosphere

  • to be more transparent to our star's light; and so on.

  • If this all sounds a bit unspecific, well, with just a few more simple and reasonable

  • assumptions based on basic physics, we can be more precise. Researchers have predicted

  • that the population of most intelligent alien species should be below 20 million individuals;

  • the majority of planets with intelligent life should have less than 80% the radius of the

  • earth; and the individuals of most intelligent alien species should be at least as massive

  • as polar bears.

  • So instead of looking for nearby intelligent extraterrestrials onearth-like planets”,

  • the intelligent approach might be to look for habitable planets slightly smaller, darker,

  • and hazier than our own. In short, we should expect to be the Manchester United

  • of the universe, searching for AFC Wimbledon.

When we think of looking for extra-terrestrial life, we tend to focus onearth-like

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B1 intelligent intelligent life population earth majority expect

Aliens: Are We Looking in the Wrong Place?

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    Summer posted on 2021/02/18
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