If aliens attacked us, that would also mean that they can master interstellar travel.

This means that they are at least a hundred years ahead of us, technologically. Most probably even more than that (several centuries or millennia ahead of us).

We would have as much chance against them as a tribe of Homo Habilis would have against a couple of Apache attack helicopters. And that is none.

Science fiction tends to put humans on a more equal footing against aliens, but in reality superior technology and unbelievably advanced science will favor the aliens on a massive scale.

At least, that’s what a clever bunch of parasitical human aliens would be doing. Aliens from outer space, now, might use other methods. But the aim would be similar: subjugation in the short term, extermination and replacement in the long term.

This comment is by a previous answerer.

“Last comment. IF an alien race could make it to Earth, it is very unlikely they would attempt to kill us, and if they did its probably because we deserve it. In order to make it that far on an evolutionary scale (develop interstellar travel with the means of personally making it) than they were able to peacefully research, they didn’t do what it looks like we will, and only develop better means of killing one another. Because if they had, they would be dead with that level of technology.”

That’s utter nonsense. What bogs down advancement is a surfeit of tolerance, not an excess of violence. Almost all life subsists on other life, and the one thing no race can tolerate is a rival. The reason is that both your race and the rival race will grow in numbers until the combined population is resource limited. Thereafter, either race can continue to grow only at the expense of the other. If one of the races decides to do “the responsible thing” by using birth control, the chances are pretty good that the same idea won’t seem as wise to the members of the other race. When the population of the birth control race becomes inferior to that of the non-birth control race, the larger group will attack, defeat, enslave and exterminate the smaller one, thereby gaining all the resources for their own use and further growth.

And, of course, it is better to exterminate rivals while they are relatively small and weak, rather than allow them to grow into a formidable foe against whom victory will not be certain, and would be, at best, expensive.

When groups actually do exterminate their rivals, they gain resources and clear the land for their own use. The important rule is: when you have an overwhelming advantage: STRIKE. History is not a static thing, and having possession of unbeatable position is not a situation which endures forever, and perhaps not for long. Enemies will gain from you technology they do not presently have, and then they will turn your own weapons, the military labors of your own minds, against you. Demonstrating the “golden rule” does not reform a parasite, an exploiter. Peace is what people want when they are either too demoralized to fight or too weak to win.

This comment, by another answerer, is also nonsense:

“Aliens would never attack. Any species advanced enough for interstellar travel would understand that aberrant behavior has no place in the universe.”

The rules of nature’s game do not vary with the intelligence or the resources of the race involved. Greater intelligence only permits a more complete grasp of the possibilities afforded by those rules. More resources makes it possible to act on a larger scale. Our planet is a rare thing: a liquid water world with moderate gravity and an oxidizing atmosphere. The Earth is to the galaxy what a large diamond would be in a desert of ordinary sand. Of course those aliens would attack. In some way or other. You’ll understand that they might be clever about it. They might have our diplomats come up to their spaceship for dinner and arrange to collect tissue samples while they are there, so that afterward the aliens can study human DNA and prepare a nasty virus to exterminate all humans at some future time.

But, yes, they would certainly intend to remove us from Earth.

I say this not as fact, but to illustrate such a conflict has soooo many variables no one can anticipate what will happen. Any sentence starting with, “Since they can travel to the stars…” is instantly suspect. We just don’t know what they can or can’t do. If they are indeed like us we are in deep trouble. But that’s only “if”.

Any species advanced enough for interstellar travel would understand that aberrant behavior has no place in the universe.

BTW don’t worry about this happening anytime soon, I know there is life out there, but where and what it is are a mystery, and will remain such because this Universe is VAST. Think looking at the ocean if you were the simple primate we only JUST evolved from, it doesn’t matter if there is better food on the other side cause there is no way you can get to it. We just aren’t smart enough yet.

Last comment. IF an alien race could make it to Earth, it is very unlikely they would attempt to kill us, and if they did its probably because we deserve it. In order to make it that far on an evolutionary scale (develop interstellar travel with the means of personally making it) than they were able to peacefully research, they didn’t do what it looks like we will, and only develop better means of killing one another. Because if they had, they would be dead with that level of technology. SO they would either not want to harm us (or even make contact because it would interfere, much like we TRY not to interfere with natural events) or would simply be killing us because we needed to be killed. And if they thought we needed to be killed, they are smart enough for me to say “Please do, I wouldn’t want us to screw this up”

Aliens only exist in Hollywood.