They’re already here
“If aliens are on this planet, they are likely using the ocean as a place to hide.” — Frequent-Muffin1
“Greys” are android avatars
“Greys aren’t fully biological, but rather remotely controlled androids, or that they are biological, but their “Grey” appearance is a suit and not the actual body.” — FZIdeas
They’re already watching us
“That if any civilization elsewhere in the universe had the technology to reach us, for any reason, they’d be very likely to be also be able to disguise their presence from our detection methods (i.e. they could observe us close up using nanotech, microscopic biological spacecraft etc and we’d never know)” — Zharan_Colonel
The aliens already died
“There are so many star systems with potentially inhabitable planets out there that the chances that we have been the only life in the universe is extremely slim. The question, instead, is whether life arising elsewhere has managed to survive destruction and remain alive today such that they might be able to contact us. That is to say, there have probably been countless civilizations for the past several billion years that simply haven’t made it.” — boulomai_mathein
They don’t fw us
“We don’t allow ourselves to contact lost tribes in the Amazon or other wild places. Extraterrestrials may have similar laws on a galactic scale.
We split the atom, but made weapons out of them instead of trying to reach the stars. They leave us alone out of fear that we’ll destroy ourselves if war accidentally breaks out.” — Throwitaltawayroot
We have no idea what aliens “are”
“That life in the universe could be so unrecognizable to us that we wouldn’t even register it as being alien life. What if life on another world was not carbon based, but another element? How would we even know what to look for since our definitions and descriptions of life are based on a completely different perspective?” — swheels125
We bore them
“They came, they saw, they weren’t impressed.” — SLObro152
They’re studying us
“Any species advanced enough to find us wouldn’t “make contact”. They’d study us the way we study animals. Ideally with minimal interference. Compare the average “abduction” story to the way we dart large animals, collect data and leave them to wake a bit groggy and confused but unharmed.” — thepizzapeople
We’re not nice
“Consider the fact that the human race is a divided mess of contradictory intents. We have the scientific community reaching out peacefully, yet if aliens do come into the airspace of any nation, the first to greet them would be the military. You can imagine what the response of the military would be when a UFO enters forbidden airspace. Given the declassified government files regarding UFOs, it is quite likely that contact has been attempted in the past and the results being tragic.” — CaptainPlanetZi
No one evolves long enough for inter-stellar travel
“Most civilization advanced enough to get even close to interstellar travel becomes too energy intensive and destroys themselves/their planet before they get far enough for interstellar contact.” — BattleBornMom
“UFO’s are higher dimensional objects moving through our dimension.
Like, if we moved a 3D object through 2D space, to a 2D being it would look crazy weird. A hollow sphere would start as a dot, then look like a hoola-hoop that starts small, gets big, then small again. They’d have no idea what they were looking at.
So wtf would a higher dimension object look like passing through our 3D dimension? It might rapidly change shape or appear to move at incredible speed as the (whatever) moved through our space-time. Gravity wouldn’t effect it (I don’t think). It wouldn’t appear to have any form of propulsion.” — mkultra123
We can’t comprehend them
“You can go insane trying to wrap your head around a 4th dimensional object passing through 3 dimensional space. Consider that a 4D being could look into our 3D bodies almost the same way we can see an amoeba through a microscope. It could literally reach in, and yank our organs out, or put something else in without ever breaking skin.
Also, it’s thought that it might be possible that we could catch a 4th dimensional being in the 3rd dimension. We couldn’t keep it in a room or a box, it would just walk out in it’s 4th degree of movement. But, we could harpoon it. We wouldn’t really be trapping the 4d being in our dimension, as much as we’d be tethering all of our slice of this 3rd dimension to a 4th dimensional being.” — theBytemeister
They are just too far away
“The movie “Contact” actually makes a good case that we haven’t been visited by UFOs or aliens.
Our most powerful broadcasts have traveled at best a few dozen light years from this planet. To put that into perspective…
If the Milky Way galaxy was the same size as North America, the Earth would be a speck of dust floating around a nick knack on a living room table in a house in Arizona. Our most powerful broadcast signals have made it to the end of the driveway, or at best across the street.
If there were a hyper-intelligent species two blocks over desperately listening for signs of intelligence in the neighborhood, they wouldn’t even know we existed for at least a couple thousand years.
When they finally picked up our signal (our first television broadcasts) it would take their response another couple thousand years to arrive here.” — gogojack
The universe is too young
“That there is no one else and we are those advanced aliens. The universe is still in its toddler stage in age and we are the first intelligent people.” — oatdaddy
We are the aliens
“You know that trope in sci-fi shows, where they stumble upon the networks of the “founders” or the “ancients” or the “architects”? A civilization so advanced, long ago, that traveled the stars?
That is us. We’re seemingly alone because we’re the first. Maybe they’ll stumble upon us in a million years.” — brainproxy
We’re the greys
“There is a very simple explanation as to why abductees independently described grey aliens as looking the same. There are no aliens and no abduction took place, but rather they are abstracting residual memories left over from being infants and looking up at adults. Before an infants visual cortex is fully developed, an adult human looking down at them would appear rounded and grey in color with large eyes. Cross that indistinct memory with a sleep state subconscious and standard psychological patterns and boom; alien abduction. It also explains the sensation of being lifted, examined and probed.” — Riccma02
“Aliens may percieve the passage of time differently than us. Our whole existence could play our before they’ve had their proverbial morning coffee or vice versa.” — ____REDACTED_____
It’s all a distraction
“The most logical theory I’ve ever heard is that 99% of alien sightings are set up by special intelligence agencies to distract from more nefarious things they are doing. the best theory I’ve ever heard is that aliens do want to make contact with us but they’re simply shy.” — dreamwithinadream93
They aren’t coming back
“Aliens landed once in Africa, got eaten by lions.
Planet now marked as dangerous by the Galactic Feds.” — SLR107FR-31
They live on Earth
“I don’t believe it, but that they live in underground caves and dwell primarily in Antarctica. I don’t remember the complete theory but people say they’re an advanced race adapted for life underground, and that they have advanced machinery because they have been living on the earth longer than humans.” — queen_in_the_north17