Just to say, I'm not going to answer the question directly, but rather its premises. This is a standard scenario in movies and science fiction, that there are alien planets close to Earth at the same stage of development. Where "close" could be half way across the galaxy if they have faster than light travel. But this is almost impossible in reality.
The thing is that it took us 4.5 billion years to evolve to the point where there are intelligent creatures with technology on Earth. And our star formed many billion years after the origin of our galaxy, even after the first stars able to have planets with a wide variety of elements like ours.
So suppose they evolved just half a billion years earlier, or their star formed half a billion years earlier? Their technology would be 500 million years ahead of us. But you almost never get science fiction stories where we meet ETs whose technology is 500 million years ahead. And it could be much more ahead than that.
For them to be only one million years ahead would be an extraordinary coincidence, though possible.
For them to be only a thousand years ahead, same technology as we will have a thousand years from now, is surely almost impossible.
The other assumption is that they could be aggressive. I'm not sure if they could be and still have space travel. At least - unless they are totally xenophobic, on friendly terms with their entire species and aggressive to all other species. Because if they fight wars amongst themselves, like we do - then once they find it really easy to get into space, they will be able to destroy each other much more effectively. They would have to develop a peaceful attitude to exploration and colonization to do that.
At any rate if they have technology a million years ahead of us, well if close by, they are here already, and are obviously are not only not aggressive, but have a "stand off" policy of not only not taking over Earth, or any of the other objects in our solar system that we know about including all planets, from Pluto inwards - they seem pristine - but even erasing all traces of their footsteps and tracks on Mars and the Moon (which we have imaged in high enough resolution to see such) so that we don't know they have been here.
And if they have technology a million years ahead of us, it's obviously no contest, they can make us all sterile (most humane solution if they just want to stop our galactic expansion, perhaps save a few to start the human species again) - or if they really want to kill us which I don't think an ethical ET is likely to want to do, it would be all over before we know it has begun, with nano technology we can't even see probably.
I also think that any sensible and forward looking ET would not want to colonize the galaxy unless they are sure they can do it in a peaceful and restrained and sustainable way, because of the risk that their descendants and their creations could themselves turn into monsters of the galaxy.
While any not sensible enough to do that would surely not be sensible enough to last long term in space because they would carve their solar system up into territories and engage in space wars that would soon destroy all the very fragile space habitats. Or if not, such a reckless ET that would try to colonize the galaxy without thinking about the consequences a few thousand years into the future would surely destroy its space faring capabilities earlier through some other reason. I think that's probably the reason we don't see a galaxy filled with ETs.
Hope you find this interesting, I know it's not directly answering the question but it's answering the premises underlying it. See also my
Will Anyone Ever Own Their Own Land In Space - And May We Get Wars In Space In The Future?
Why ET Populations Can't Continue To Expand For More Than A Few Millennia
The thing is that it took us 4.5 billion years to evolve to the point where there are intelligent creatures with technology on Earth. And our star formed many billion years after the origin of our galaxy, even after the first stars able to have planets with a wide variety of elements like ours.
So suppose they evolved just half a billion years earlier, or their star formed half a billion years earlier? Their technology would be 500 million years ahead of us. But you almost never get science fiction stories where we meet ETs whose technology is 500 million years ahead. And it could be much more ahead than that.
For them to be only one million years ahead would be an extraordinary coincidence, though possible.
For them to be only a thousand years ahead, same technology as we will have a thousand years from now, is surely almost impossible.
The other assumption is that they could be aggressive. I'm not sure if they could be and still have space travel. At least - unless they are totally xenophobic, on friendly terms with their entire species and aggressive to all other species. Because if they fight wars amongst themselves, like we do - then once they find it really easy to get into space, they will be able to destroy each other much more effectively. They would have to develop a peaceful attitude to exploration and colonization to do that.
At any rate if they have technology a million years ahead of us, well if close by, they are here already, and are obviously are not only not aggressive, but have a "stand off" policy of not only not taking over Earth, or any of the other objects in our solar system that we know about including all planets, from Pluto inwards - they seem pristine - but even erasing all traces of their footsteps and tracks on Mars and the Moon (which we have imaged in high enough resolution to see such) so that we don't know they have been here.
And if they have technology a million years ahead of us, it's obviously no contest, they can make us all sterile (most humane solution if they just want to stop our galactic expansion, perhaps save a few to start the human species again) - or if they really want to kill us which I don't think an ethical ET is likely to want to do, it would be all over before we know it has begun, with nano technology we can't even see probably.
I also think that any sensible and forward looking ET would not want to colonize the galaxy unless they are sure they can do it in a peaceful and restrained and sustainable way, because of the risk that their descendants and their creations could themselves turn into monsters of the galaxy.
While any not sensible enough to do that would surely not be sensible enough to last long term in space because they would carve their solar system up into territories and engage in space wars that would soon destroy all the very fragile space habitats. Or if not, such a reckless ET that would try to colonize the galaxy without thinking about the consequences a few thousand years into the future would surely destroy its space faring capabilities earlier through some other reason. I think that's probably the reason we don't see a galaxy filled with ETs.
Hope you find this interesting, I know it's not directly answering the question but it's answering the premises underlying it. See also my
Will Anyone Ever Own Their Own Land In Space - And May We Get Wars In Space In The Future?
Why ET Populations Can't Continue To Expand For More Than A Few Millennia
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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