It's an interesting thought, fun to consider, but the most enjoyable part of this recent Slashdot post was a very creative comment/mini-post made by the user lexsird [Slashdot] in which the user suggests "It already happened" [Slashdot].
Aliens did land here to destroy us, but they were small and insect like and the bug exterminator guy killed their entire galactic fleet, thinking they were some "weirdo bug infestation". A second attempt was tried by another species, and aquatic one, but it got ate by sharks. A third one came, land based and they were bigger, but were ate by the wild life. A fourth came and the RF that we are immune to quickly burned out their brains, and they too were ate by wild life.What a fantastic and fun evaluation of our interaction with the world (and Universe) around us. To the user lexsird, if you're reading this, thank you for your few minutes of creative musing.
A mechanical race came and was destroyed by a thunderstorm, when a bolt of lightning struck their ship and it exploded. Of course there have been several small missions which end up in races being consumed by just the biological aspects of our planet. Germs, viruses, and an assortment of microbes tend to make short work of them if they don't use the proper environmental protocols.
Not to mention we are a biological weapon to 99.9999999% of the species in the known universe. Many in the galaxy speculate that the "creator" an extra dimensional entity that instilled the creation codes, was being some kind of a dickhead when he instilled the planetary creation code for this planet. Many speculate and fear that we are doomsday weapon made by said "creator", some want to destroy us, others think we have some special link with the "creator" and should just stay away at least.
Considering we breath poisoned gas, we are mostly water, which is a universal solvent that eats through many species on contact. We live near oceans of water which scare most species. We are larger than most species by far and are physically more capable. We have lived in a constant state of war with each other since before our history, hence we are really good at it and durable, some how we fight each other so hard, yet our species is over populated. Which is a terrifying aspect of us, we breed so fast compared to most species.
Most species pray that we will just kill ourselves off. Others are convinced we will achieve the technology to travel about the universe, hence over running it in a matter of eons. But it's galactic law that nobody gives us any aid, and any species that tries to cultivate us is punished. Often rich juveniles from a species will buzz Planet Earth to impress a mate or mates, only to get shot down, spotted or crash; many escape, but its still risky behavior that if caught gets severe punishments.
Mostly we are immune to solar radiation, in fact we bath in it to get a tan. Our Sun puts out enough EMP to burn up the nervous system of some delicate species before they even get near Earth. Our skin though we think it's thin in contrast to some of the beasts of the planet, is incredible to most species. It's chemical resistant, radiation resistant, and waterproof which baffles everyone. Shooting an Earthling with an alien water cannon only amuses them. They in fact stole several water cannons and reproduce them as toys under the "Super Soaker" line. An Earthling child with a water gun chills the bones of the hardiest of galactic warriors.
Lastly, what we can eat is frightening as well. What we eat and drink frightens most species away alone. Most of them would be on our dinner plate, as a delicacy. Not to mention our waste byproducts are the most foul bits of toxic waste in the universe. They have watched us poke and prod everything on our planet and try to eat it. We have even ate each other, which is a horror that most minds can't comprehend in the universe. Not to mention we skin other species and wear them as clothes and trophies.
Then some have tried to understand us, they have figured out that TV is some form of entertainment to us, not educational, not some history archive. This process drove many species insane. One species was found in some insane collective nightmare after watching Gilligan's Island episodes, they fell into some logic loop and have been catatonic as a species ever since. They have concluded that we as a species are quite insane and it's illegal to attempt to figure us out psychologically.
Its now been a much debated subject of trying to destroy Earth. Most figure its an impossibility and that we will do it ourselves. Others fear failure and we will at last notice, get angry and come hunt them down. The last species made it all the way to Earth's orbit only to get pelted with micro meteors, lost EMP shields, then burned up in the atmosphere. It's always bad luck coming here.
