Why would a very advanced intelligent species travel whatever vast distances just to destroy us? Seems to me the wrong thing to worry about...
I agree, but this is a foundational sci fi theme and there's literally dozens of "motivations" for interstellar aliens being a human existential threat. There's the "too violent to be allowed to spread" theme which has at least four different plot threads. there's the "take from savages" colonialism treatments, there's the "cultural superiority/species gestalt" theme with at least a dozen different plot threads, there's the "enslavement/livestock" theme with at least six threads. I could go on, but you get the drift. But they ALL impute human motivations to their aliens. I personally believe that any interstellar culture that came to Earth would be curious and eager to study such a young and primitive sapient civilization, and rather indifferent to any "earthly" threat. Not that I think they'd take any of our usual crap directed at them.
Referencing some sci fi theme for fun, I'm thinking the encounter will unfold much like the movie Earth Girls Are Easy; https://www.imdb.com/title/tt0097257/ In the past, and even today, on Earth there has been too much fighting and conquering and power struggles and macho bravado usually rooted in fear-mongering, when coupled with most people's encyclopedia, the TV, it's no wonder many of us fear meeting up with aliens. A huge portion of us are scared to death of the aliens crossing our borders so those who appear from the sky...they must be evil! After all we surely know that all alien craft will be equipped with phasers and proton torpedoes...
Using Earth as an example, 99.99999999999999999999% of all life that lives now or has lived in the past is not intelligent at least compared to us. Literally only a handful of primate bipeds out of all the billions of different species that have lived on this planet have evolved into intelligent life and all but one of those is extinct now. If Earth with all that it has going for it only has an infinitesimal chance of spawning intelligent life why would it be any different anywhere else?
Life could be rare, intelligent life could be rare, both could be common, we simply have no idea. The problem is that we can't even apply the basic scientific method to this issue because we only have one sample to take which is our own planet. So it is impossible to conclude anything having only one sample. We can make educated guesses but until we are able to take accurate samples to pit against our own planet we will simply never know if life on Earth is rare or common or if intelligent life like us is rare or common. Earth may very well be an anomaly. Our whole planet with all of our life on it could be the result of a freak accident in the Universe that didn't happen anywhere else. Europa or Enceladus could have full flown Atlantis style cities underwater with intelligent life swimming around. Or maybe just microbes, or maybe nothing at all. We just don't have the technology to research anything thoroughly enough except for our own planet and until we do all we can do is speculate. Earth had an infinitesimal chance of spawning intelligent life. That doesn't necessarily mean that everywhere else has the same tiny odds. Many years from now we may discover other worlds with multiple species of intelligent life and our planet would be seen as abnormal for only having humans with cognitive thought. Or we may never find anything at all. Point is, no matter how advanced humans become we still have a very small chance of actually meeting anybody else because the Universe is just so huge. Even if we colonize the entire Milky Way galaxy and find out there is nothing else here but us we still couldn't even rationally conclude that there IS nobody else. There may just not be anybody in the Milky Way, which is just one galaxy, just like the Earth is just one planet. From what we understand so far the laws of physics apply to the whole Universe as far as we can tell thus far. But that doesn't mean the laws of evolution on planet Earth apply everywhere. They very well may just apply to planet Earth. We can conclude that the laws of physics apply everywhere because we can actually observe them applying everywhere we look. We can't "observe" evolution past our own planet so we have no idea how evolution works anywhere but Earth or if it even works anywhere else at all. For all we know this little rocky water planet of ours that spawned life could be a freak of nature with intelligent species living primarily in Gas Giants or something. Aliens may have been staring at our Solar System for millennia, staring at Jupiter or Saturn looking for life "as they know it" and completely dismissing the little water planet because "nothing can live on a planet like that".
Using Earth as an example, If Earth is one of 8 planets in the only solar system we truly know, and there are 100 Billion other solar systems in our galaxy which sits among hundreds of billions of galaxies but intelligent life developed here then as far as we "Know" intelligent life exists in every solar system in the Universe.
In terms of SETI, intelligent life was defined as those who possess technology enough to emit radio waves which are detectible signals. On Earth, we have the technology to emit radio waves but obviously there are other forms of intelligence...excluding our federal government. So if we're talking SETI, then ever how intelligent life can be defined, it needs to be detectible by 'others'. It might be considered a waste of time and money to travel to another solar system only to find some 'intelligent' chimpanzees...
For those of us who believe all the building blocks of life need is the right environment, and some time, and some luck, as is happening here on Earth, then it seems logical to me to assume this same process can happen throughout the Universe. Earth is not 'special'...Earth is just one of the possibilities...
"Their research revealed there is a 30 percent chance that humans are alone in the Milky Way galaxy." That means there is a 70% chance humans are NOT alone in the Milky Way galaxy.
But where in the Milky Way, assuming we beat those odds? If intelligent life is not somewhere in our quadrant, it might as well not be there at all unless warp drive becomes a reality :/
Actually statistically Earth is extremely special. Currently there are some 250 identified things necessary for life to form, not the handful you mentioned in your earlier post to me. It takes a hell of a lot more than just ingredients and time. You need a planet with a rotating core for protection against solar radiation which is harmful to ALL life. This is why Mars does not have any life on it. You need large gas giants in the system to vacuum up stray debris or planets will be constantly bombarded forever, our sun is unique in that its not a dwarf star and also that it is a single star. Astronomers now believe that most star systems are in fact binary star systems which are less likely to form life because of the massive amounts of radiation thrown off from one star devouring another star. If someone told me we were alone I would believe that as much as someone telling me that there are 10 intelligent civilizations in the universe and I would except that as well. Someone that told me there are thousands or tens of thousands of advanced civilizations I could not take seriously.
Sure it is, it just takes years, but that's not what I was talking about. I'm alluding to a technology that we don't have.
You think that we can reach places thousands or millions of light years away without time or speed? That technology is science fiction.
Several planets in our own Solar system have magnetic fields. SETI is finding large gas giants. Binary star systems are common and no reason why planets with life cannot exist. I suggest you be more open minded about how many planets in our Universe might have intelligent life...
It would seem you believe all life is as "We Know It" which is not in evidence and unlikely to be accurate. We humans simply do not and cannot know what is out there or needed to create life or even what "Life" might be. For all we know there are living sheets of life in Ethane lakes of Titan and floating helium thingys in the clouds of Jupiter....use your imagination as it is as good as anything else in this situation.
That is technology. Interstellar travel flies in the face of the laws of physics. Maybe the laws of physics are wrong but you can't reasonably compare the two things.
Yes. Technology. As for your understanding of physics, you might want to catch up on the last 50 years. Example: https://cosmosmagazine.com/physics/...lain-dark-matter-dark-energy-and-the-big-bang