I think the idea that the aliens could be leaving an exhausted planet seeking somewhere new to settle is very possible. There may be millions of those migrations happening at this moment. The only thing stopping it would be FTL travel, which I believe is possible.
And wouldn’t it come down to an “us or them” decision if they found our planet suitable for settlement and we were not as strong as them? We’d probably do the same if Earth was in the same position. The decision would come down to letting human race die, wandering space forever, or taking over a paradise and educating the “savages.”
The fact that c represents an absolute limit in our universe is not a gulf in our knowledge, it’s the sumnation of it. If we’re wrong about that, we have to be wrong about a whole load of other things too.
If we’re going to decide whether or not to respond to the aliens on the basis that they might have something we, after much research, have concluded is fundamentally impossible, then we’re not even in a position to comprehend the question.
What if we’re completely wrong about radio waves too? - And what we merely think is a radio message from extraterrestrials is in fact a ham sandwich?
Well, no less than Prof. Hawking says (in the above link) that there could be things that we don’t grasp in the same way that a chimpanzee can’t begin to grasp quantum physics. Far from knowing the answer, we wouldn’t even know the question, or even understand that there’s a question to be asked in the first place.
ETA: ok, not in the linked story, but on another site covering the same story I read . . .
The only thing of substance we have that an alien would want is our planet itself.
Stars don’t last forever. If humans and aliens are to survive through hundreds of millions of years in whatever forms we/they evolve to then they must expand to new star systems as their stars die out. Even our earth is only good for another billion years or so before it starts getting too hot here. A billion years seems like a long time - but it isn’t really be cosmological standards. And by the time life evolves on a different hypothetical planet the star cycle may be much closer to causing problems.
So it is possible that alien species are out there looking for new stable and habitable planets to colonize for long term survival of their species. If they discounted planets currently inhabited by primitive lifeforms then they would seriously handicap their search. And even it it takes 100,000+ years to journey to earth, if they have the technology to do why wouldn’t they - given the alternative of staying with a star making home life unlivable.
Once they get here it would be prudent for them to ‘displace’ the residents (humans in our case) so as to remove a competitor for resources.
Maybe. But like you said, if they can travel between solar systems or galaxies, they probably don’t need to come into our atmosphere to kill us anyway.
I agree -
If I were the aliens having travelled a large x number of years to get to Earth - one simple way to deal with humans would be to just nuke us from orbit (after all - its the only way to be sure).
Then just wait a few more years/decades in orbit until the radiation levels are good to go. If you’ve travelled for a thousand+ years a few dozen more are not going to make much of a difference.
Based on what? We’re only just beginning to develop the technology that would be able to detect small, rocky planets outside our system and early indications are…they’re common.
And in any case, I still don’t see how earth’s the prize.
To move a reasonable amount of stuff from one star system to another…you’re talking either hella energy or Generation Starships.
So we’re already talking a species that either has the energy to pretty much produce any atmospheric conditions they want, on any planet they choose…or has the technology to make an indefinite home anywhere.
If I were writing a sci-fi novel, I might postulate that Earth just happens to have some resource that we’re unaware of. Because all the things precious to us should be abundant to a species that can traverse interstellar distances.
A race that has the tech to produce generational starships doesn’t necessarily have the power to create atmosphic conditions at will.
For example - how could any advanced alien possibly make the moon habitable? You’d have to somehow bring in impossible amounts of H, O, N, C, S etc. In order to have a planet that you can even terraform you have to have something to work with. A Mar’s type planet would be difficult to rework well since it has little water. It is always going to be a desert there. It might be far easier to just find a planet that has lots of organic molecules - like Earth.
And they may well need to terraform Earth to fit their needs too. Perhaps they happily breath an atmosphere that has much more/less nitrogen for example. But at least Earth has life’s basics in plenty to start with.
They can either propel a heavy ship close to c – hella energy.
Or they can make generation starships – tech to live anywhere.
OK, there are other options than this either-or – stasis, multitude of ships, FTL tech. But my point is simply that the things that supposedly make earth the prize often don’t seem such when you think about what it would take to get here.
Sure, but putting supplies together for a few hundred beings on a generational starship to reach Earth after a few 1000 years+ is no doubt incredibly technologically difficult - but it is easier than living on said starship indefinately. That starship would have either stop or at least resupply at some point. And machines can’t last forever either. Perhaps an advanced society makes the starship with a 5000 year warranty - but at some point it will break down.
My point is - when their planet/star is dying - a alien species (and humans too) will need to go somewhere else if we/they want the species to continue. That is a plausible reasons an alien would go to the huge expense of travelling to earth - to simply live here in our place.
Would aliens really want our planet? It would be nice to find a planet with just the right temps, atmosphere and gravity, but what are the odds? And wouldn’t aliens advanced enough to travel between stars also have the capability to just reprocess an asteroid belt into some sort of little Ring World kind of colony? Seems like once you get good at living in space, there’s no pressing reason to move back down a gravity well all infested with bugs.
No one can truly know whether any particular aliens would really want our particular planet - but it is certainly plausible.
Sooner or later, in trillions of planets and over billions of years - I believe some species will probably come along that is very aggressive - (aggresive like the Borg say). They will ruthlessly expand across the galaxy for their own reasons. I remember reading in the book ‘Five Ages of the Universe’ it might take about 50 million years for an advanced alien with generational ships to colonize the entire galaxy - travelling at a small fraction of the speed of light (Milky Way is 100,000 light years dia). A long time - but nothing in cosmological scale.
As for us - would most humans choose to live on another planet - or live forever in space? I could think of a few compelling reasons for a species to be living on planets whenever possible:
Where is it safer for a species to live (from radiation, impacts) - in a spaceship/asteroid or a earthlike planet?
Where is it easier to obtain organic molecules from which to make water/air/food - in a spaceship/asteroid or a earthlike planet?
Where is there less wear/tear on your machines, with easier maintenance to fix things?
Where is it more pleasant to live?
And again - at some point a star dies and sticking around in the star system is just a super bad idea as it goes through its death cycle - even if you are in a space ship. Aliens/humans will need to go somewhere else - so why not somewhere with another habitable planet. If there are already inhabitants there - kill them and take over.
Is anyone actually reading this as Hawking stating that FTL travel may be possible? If so, that’s bigger news than the topic of whether we should respond to aliens and quite possibly bigger news than anything else he’s ever said.