Those who don’t believe that aliens are already living on Earth often ask the question, “Why haven’t they come here yet?” A recent answer was that they’re dead and no longer able to travel. Another possibility is that they don’t think Earth is inhabitable. Around 7.4 billion Earthlings ask, “Why would they think that and should we be worried?”
Astronomer Rory Barnes proposes this theory in his study that’s about to be released in The Astrophysical Journal. An astronomy professor with the University of Washington’s Virtual Planetary Laboratory, Barnes has developed a habitability index for analyzing the possibility of life on other planets. While previous formulas looked at whether a planet’s orbit around a star was in a circumstellar habitable zone (often called the Goldilocks zone) where it would have adequate atmospheric pressure for liquid surface water, Barnes goes much further.
The new index also takes into account how rocky a planet’s surface is and its eccentricity-albedo degeneracy – a ratio of energy reflected from the surface against the circularity of its orbit and how much star energy it receives. In simple terms, a habitable planet needs a good balance of light and energy between when it’s closest to its star and when it’s furthest away – a balance that’s served better by a more circular orbit.
Barnes fed Earth’s data into the formula and got some discouraging news – our planet only scored 82 percent on the habitability index. He explains the problem:
Basically, where we lose some of the probability, or chance for life, is that we could be too close to the [Sun]. We actually are kind of close to the inner edge of the habitable zone. If we spotted Earth with our current techniques, we would reasonably conclude that it could be too hot for life.
So aliens using viewing devices similar in power to our current telescopes might conclude that the third rock is too close to its sun and too hot to inhabit. Here’s what Barnes suspects the aliens might be thinking about Earth:
… it’s just this thing that dims some of the light around a nearby star when it passes.
Well, if that’s the way they feel, who wants them here anyway?