i agree on all points.. but the bolded one.
if they develop to be sentient and with high tech.. they must have something to spark the intelligence.. which is curiosity.
curiosity will make them explore their world and beyond.
curiosity will make them want to find life in the cosmos
curiosity will make them come here to study and eventually first contact.
if we found a plant far far away.. that have beings that are like medieval times... we would go study them.. but we would wait till they can understand what and why we are there before we expose them to us.
You are assuming that we are the most interesting thing in the universe to a species that has the ability to travel all over the universe. Even if you are correct though, how likely is it that they can travel here, but can't keep from being detected once they arrive?
Not clowing, not criticizing - but I think you guys might be overthinking this, and here's why.
Buzz Aldrin co-authored with
John Barnes the science fiction novels
Encounter with Tiber (1996) and
The Return (2000).
In the two books, Aldrin covers quite well how interstellar travel is possible using a solar sail and a commitment to multi-generational crews.
He also covers how exposure happened in his story - they messed up.
Not to put too fine a point on it - but the last time we were truly productive as a society as a whole was when we didn't care about perfection or image - we once understood the fine art of screwing up.
Instead of being organizations being top-heavy with viewgraph engineers using Powerpoint so that 80 people can pontificate over any idea beaten to death by one guy still thinking (I'm looking at you, NASA), we once had organizations where people would think they were smart, get almost there, screw up royally, have drinks at lunch until hair-brained ideas turned into solutions, and then get back, sober up, and get it right.
Our entire lunar mission in the 60s is a story of divine and magnificent serial screw-ups.
The revolutionary Americans used to drink beer for breakfast - the Guiness-thick stuff that was equivalent to eating a loaf of bread and catching the buzz you needed to overthrow the planet's reigning superpower.
How could Thomas Jefferson possibly have owned slaves yet doctrines on freedom? How did the founding fathers get something as incredible as our constitution put together? I'll tell you how - they were a bunch of royal screw-ups, that's how. Ben Franklin - when later our ambassador to France - was known as a drinker and womanizer, and we teach our young to revere the portly old boy in the granny glasses as mostly harmless. He was bombed and a skirt chaser and everyone knew it for a fact while he was on the government dole. Now - if that's not a screw-up, I don't know what is.
Kirk was a screw-up, as were his two buddies - products of a reflection of our lunar days.
Picard and crew walk around like they're in the mall and drink synthahol - and yet, in the modern ideals, that's how interstellar space will be done.
Wrong. Kirk's ship could take a beating, and his idea of diplomacy was a good belt of Saurian brandy, a phaser, and a smirk.
Picard's boat gets hit by a lesser force, the prime directive is discussed for 10 minutes, and then they get on the viewscreen and apologize their way thru a politically-correct negotiation, crafted to ensure no one screws up.
Any spacefarers acting like Picard and crew will be wiped by the first impatient and disgusted cavemen they meet. They won't get past the next solar system.
It'll be the Kirks that make it out.
Any of them that can make it here _must_ be detectable - because if they try to avoid it - I guarantee by what made it possible for them to get here in the first place -
They'll screw it up.
And btw - why would they _want_ to visit us in the first place? OK, let's talk about curiosity.
Before space travel, they would have invented movies and tv shows, and they'd take a bunch along to watch on the long voyage. And by the time they got here, their curiosity might not even extend to anything more complicated that the plot in
Earth Girls Are Easy.
A few generations on a space boat seeing the same old faces, and then you hit a planet - yep - great-grandma's mission plan is now replaced by whatever the crew votes to really do - and screw-ups are a certainty.
Don't expect Klaatu to land in Washington - expect the three stooges to land in New Mexico.