Puny Earthlings, your planet is not worth invading

by John MacBeath Watkins

It seems Earth is a much less common sort of planet than we have supposed in the recent past. This means that any aliens who evolved in a more common sort of solar system would find our planet too cold and our atmosphere too thin to sustain life.

You can blame Jupiter, which seems to have wiped out the early inner planetary system before retreating to
The alien warlord is ready for his closeup (okay, it's a water bear.).
the sidelines.

We've discovered about 500 other solar systems with planets, and most solar systems don't resemble ours at all. They tend to have giant inner planets with atmospheres hundreds or thousands the pressure of earth's, closer to their suns than Mercury.

They would probably be hot enough on the surface to melt lead.

Our solar system was likely similar to this before Jupiter came into low orbit around the sun and destroyed such inner planets as had formed, until Saturn formed, and drew Jupiter out to a wider orbit.

This would explain why the three inner planets, Mercury, Venus, and Earth, are younger than the outer planets. They would have formed from the debris left over from Jupiter's destructive juvenile period of acting like a wrecking ball in the inner solar system.

Imagine an alien warlord from a more normal system, looking for new worlds to conquer.

"Any habitable planets in this system, Lackey?" he would ask the science minion.

"None of these planets could support life as we know it, sire," Lackey replies, "but there is something funny..."

"Funny peculiar, or funny 'ha-ha?'" the warlord demands to know. Warlords like a laugh as much as anyone.

"Well, sire, the third planet out is so cold that it has dihydrogen monoxide oceans covering most of the planet, and if you dropped lead into them it would become solid. The gravity is very low, and it retains only a wisp of an atmosphere, and the pH level is so alkaline that there is hardly any sulfuric acid in the rain. Yet there is a thin layer of life on it."

"But not, of course, intelligent life?" the warlord inquires imperiously.

"Well, there seem to be some large hives, and they are generating chemicals intended to make the planet hotter and put more acid in the rain, so it's possible they are trying to make their planet more habitable for life adapted to a normal atmosphere. However, they are so far from the sun and the gravity is so low, I doubt they will succeed."

"Amazing! The poor, doomed creatures are trying to evolve into a decent life form, but there's no way their planet can be properly turned habitable by higher life forms," the warlord observed. "Put it down for further study, low priority. I've little use for pure science, but it might amuse my nerdy youngest son."

And so, the alien warlord passes on, looking for decent planets to conquer.



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