Now that NASA no longer has a manned space program, and the U.S. government has bowed out of the space exploration business leaving $100 billion in tax-payer funded hardware up in orbit for the use of whomever can make it up there to use it, the agency now appears to be in the business of speculating on various reasons why space faring aliens might want to destroy human civilization.
Any interstellar space faring race that makes it to Earth is obviously going to be highly advanced; much more so than we. The United States, having just retired its only manned spacecraft, the Shuttle, can’t even make it to orbit, much less back to the moon, much less anywhere else.
Many scenarios have been advanced by Hollywood as to why aliens from space might want to off the human race; everything from stealing our water, harvesting our resources, and coveting our women to exterminating the vermin (us) prior to colonization, or even simply using us to fill appetizer space on an alien menu.
But all these project onto aliens, particular end goals that we humans might think of. To a human, for example, it may seem reasonable that aliens might desire our female population, but to a bug eyed scaly tentacled green monster, that attraction might not seem as obvious. Such things might be good enough for the masses, but, say intellectuals, a truly advanced species would certainly concern itself with truly advanced concepts; things that all intelligent beings would naturally be concerned with; things that the majority of humanity, lacking the proper intellect, would probably overlook.
Enter NASA’s latest report on why we should curb greenhouse gasses in our atmosphere. With the whole global warming thing going up in smoke for various reasons, what better threat to jolt us back on the path of reason than to ring in the possibility of alien nasty’s getting medieval with us because we can’t seem to keep from pooping in our food dish?
“It may not rank as the most compelling reason to curb greenhouse gases, but reducing our emissions might just save humanity from a pre-emptive alien attack, scientists claim…
The authors warn that extraterrestrials may be wary of civilizations that expand very rapidly, as these may be prone to destroy other life as they grow, just as humans have pushed species to extinction on Earth. In the most extreme scenario, aliens might choose to destroy humanity to protect other civilizations.
“A preemptive strike would be particularly likely in the early phases of our expansion because a civilization may become increasingly difficult to destroy as it continues to expand. Humanity may just now be entering the period in which its rapid civilization expansion could be detected by an ETI because our expansion is changing the composition of the Earth’s atmosphere, via greenhouse gas emissions,” the report states.
Hmmm. So let’s think about this one for a minute. Aliens from space watching from afar note a change in the composition of Earth’s atmosphere. “Aha!” they say, “this must be due to the activity of some hither-to-for unknown alien species mucking up its atmosphere. Quick! Let’s go kill them before they breed some more!”
This presupposes several things. First, some alien species has the Earth under continuous observation and has had us under continuous observation for some time. There are an awful lot of planets out there. We have just begun to be able to find planets around stars relatively close to us and most of them have been Jupiter sized or bigger. It is unlikely that we will spend our currently scarce resources keeping any of them under continual observation for the next 150 years.
Second, the carbon dioxide content of an atmosphere is always a constant. There are no natural phenomena that could cause atmospheric carbon dioxide to increase or decrease. This is unlikely. One only has to look at our own planet over time, before humans were here to muck things up, to see that this is not true.
Third, the alien civilization has the means to get here and snuff us out. Of course if they didn’t the entire exercise would be academic, so I suppose we have to give them that one.
So I guess we are now postulating a race of xenophobic aliens who search the heavens for any up-and-coming race, using their atmospheric pollution as a marker to determine where the competing intelligence is arising. Or alternatively, the alien equivalent of Greenpeace with an attitude, searching the heavens for interstellar polluters they can annihilate before said polluters can escape from their planet and pollute other star systems.
Of course, it might also be that our radio/TV wave front has reached them, and they are sick and tired of our soaps, sitcom reruns, and reality TV shows inundating their planet.
The fun part of “what if” though is playing “what if” on the “what-iffers.” “What if” is a game that all can play, and who is to say that my “what if” isn’t just as valid as your “what if?” That being the case…
What if the aliens have already arrived? What if they stopped by say in 1947 or so and decided that we were just too dangerous to be allowed to escape from our planet, but being from an advanced civilization and such, they couldn’t just wipe us out. So instead they found the “environmental movement” to help us along in offing ourselves in an “environmentally friendly” manner.
What if Hollywood has been infiltrated by space aliens? What if the absolutely terrible movies and television shows they pump out on a regular basis are actually the space alien’s way of reprogramming our thought processes, dumbing us down, and keeping us out of their hair?
What if the space aliens really don’t care, being as we pose absolutely no threat to them in the first place. Space is an awfully big place. Currently, the United States is incapable of even reaching low Earth orbit with any sort of manned spacecraft. Voyager 1, the farthest man-made object in space moving fast enough to escape the solar system’s gravitational pull, is not headed towards any particular star. However in about 40,000 years it will pass within 1.6 light years of the star "AC+79 3888, which is at present in the constellation Camelopardalis. That star is generally moving towards our Solar System at about 119 km/s (430,000 km/h; 270,000 mph). Note that currently, Voyager 1 is only 16.12 light hours away from Earth; thus in 40,000 years it will be still be over 6000 times as far away from AC+79 3888 as it currently is from Earth.
Even if by some stretch we were to invent a star drive tomorrow, and somehow summon the national willpower (and cash) to actually build a ship to travel to another star in a reasonable amount of time, said space aliens would still have an enormous technological jump on us and plenty of time to wipe us out should they so choose.
One would think NASA would have better things to do. Then again, what does a space agency do when it no longer has space faring capability – or a mission in life even remotely related to space exploration? 
Perhaps this study is an attempt to market a screenplay to Hollywood; if so maybe those employed there can do so on their own dime instead of using taxpayer money. Like other useless government money sinks, I am ready to put NASA on the chopping block. Someday, if this nation is ready once again to venture out into space, maybe then we can think about resurrecting it; meanwhile it is an agency in search of a meaningful mission and at this juncture that is a luxury we can no longer afford.