Imagine it's the 1800's and a cowboy is riding his horse across the plains of Montana. A buddy rides up to tell him he's heard that people are inventing ways to move faster, get around quicker. Now, that cowboy is imagining a faster HORSE or faster STAGE COACH, he's not imaging a Boeing 747 no less even a Model T car - how could he? His idea of "fast" is confined to what he already knows can move along at some speed. Horses.
Jump ahead to now, where people say alien craft from other galaxies, or even from a planet in THIS one, have travelled here many times, watched us, perhaps left something of their visits behind. Many would argue that no interstellar craft could possibly make a journey of hundreds of thousands of miles, over such vast amounts of space, and if they could they would've had to start eons ago, maybe far over 10,000 years in the past.
So I put it to that argument, that those folks are only seeing "speed" as they know it exists in this world, this dimension. Speed and force used in the Space Shuttle lift-off rockets, perhaps. We really have no idea of what "speed" might mean to an alien life form of far more advanced technology and intellect than humans. Who knows what such a civilization could've conquered in the way of what constitutes "movement" and the relation of that to the space-time continuum.
Many respected astronomers believe space contains "worm holes" through which a properly outfitted craft can navigate, and come out the other side in another galaxy. Kind of like a super-sonic space tunnel. A short-cut from the Milky Way to Andromeda, our nearest galaxy. Instead of taking 10,000 years it takes only 1 thousand. Which brings me to this:
WHY? Why would an advanced civilization in another part of the Universe, after finding abundant but very simple carbon-based life on this one planet in this tiny star(solar)system, in this one single galaxy, WHY would they want to come here? What would they gain? And if curiosity plays a role (making them more human than not) couldn't they have examined our world and its inhabitants in other ways, I mean if a being is that advanced to have conquered inter-stellar travel, perhaps somehow bending time itself, wouldn't they have safer ways to observe this planet than flying overheard in saucer-shaped objects? I can't help but think they know all about radio-astronomy, about satellites, and most certainly, inter-stellar speed.
And how much different would outerspace life be from us? Instead of thriving on water, alien life might live in a sea of liquid methane. Or instead of getting energy from a sun-star, they might thrive on hydrochloric acid. Right now, Titan, one of Saturn's moons, is the most likely place we'll find life. But if such life is assumed to be so much different from what we know as humans, what kind of craft would they need to leave their star-system, their galaxy, to take a look at us? Certainly not one which could "seat" pilots. Their anatomy may not require them to sit, as we know it. And again, I'd have to ask WHY would they need to "fly" here at all? We've had our "ears" on interstellar space for decades without leaving the earth, couldn't we assume other forms of life might be doing the same for alot longer? In other words, they would have no logical reason to come here, and more in fact to stay away.
To me, I believe that for HUMAN BEINGS the mother of intellect is curiosty. It may not be a factor for other life forms but it's what brought Australopithicus to Homo sapiens - our intense curiosity to know. If other life forms in other worlds possessed such an emotion, we'd have to assume then, that life started on other planets in far away galaxies much the same way it did here. An orderly yet random chaotic flash of electricty from lightening into the seas. If so, and it started long before 3 billion years ago, (age of earth) then they're older than us, managed to survive whatever demons they had to, and perhaps can arrive in this galaxy to observe this growing evolving experiment called life on Planet Earth.
Can an advanced race of beings learn from us? I can't think there's anything they'd NEED to know, but when I used to examine ant colonies I was fascinated at their orderly progression, the same with bees who collected pollen from my mother's flowers then returned with their pals. It amazed me. And certainly my intellect was on a higher scale than these insects. So it was human curiosity that drove me to study these "lesser" life forms. But I'm an earthing.
WOULD an advanced race of non-human outer space beings be curious about us? Let's suppose they are, and certainly after the first test of a nuclear weapon they might be! With their vast, far more intricate knowledge, wouldn't they have invented a method of observing that didn't involve these "saucer" crafts or mutilation of cattle, or people being "beamed aboard" a great ship, or any of the other suspiciously similar reports we get from around the world? I don't doubt people believe what they say, but science and logic are more convincing to me. I WANT to believe, but as in any argument for and against something, you must have more proof to bolster your case, and in this one we have none. Not one true iota of solid evidence that a space craft from another galaxy visited our planet. Area 51 and Roswell included.
Like you (hopefully) I know life took hold on other planets in other star-systems in other galaxies at other times, far before ours, and some that started yesterday. Star nurseries are putting the chemical properties in place that will one day create whole planetary systems around one, two, even three sun-stars. This Universe is so large, still expanding.
I believe that when far-more intelligent life decides to visit this planet, it won't be in hiding or secret, for there'd be no logical need. If they've flown through our air space before, as reported by so many pilots, they know we have rocket capabilities but we're incredibly slow. Ponderously slow. They have nothing to fear from us, so a visit to Earth from planet Xenon may involve the introduction and interacting of two species of life, both eager to know the other, both wanting to learn, an event like no other before it.
The possibility exists, but only if we can last, as a species.
The images of various Nebulae are courtesy of JPL, HUBBLE, & NASA. These are huge areas of space where new stars are forming. Did you find the small picture of Horsehead Nebula?