A fun question :). Well assuming 10th century technology - we'd have proved the canals were probably real during the opposition of 1909 with good telescopes and photography, as that is when the Mars canal hypothesis was disproved historically. Martian canal. Or if not canals, if they didn't have them, we'd have spotted some other signs of agriculture - straight edged fields or whatever.
By the 1920s we'd notice that they have an oxygen rich atmosphere through spectroscopic measurement - as that is when we first proved that there is no significant levels of oxygen there - assuming they are oxygen breathers like us. That was when the technology was developed to distinguish the absorption lines of the Mars atmosphere from the absorption lines of our own atmosphere in light reflected from Mars.
We'd have spotted their agriculture - fields, houses etc, close up with the Mariner 6 and 7 probes around 1969.
And even if we hadn't spotted them by then, surely they'd discover our Viking 1 lander in 1976. The previous Russian landers also but they stopped transmission soon after landing. But Viking lasted for a long time and if they didn't accidentally or deliberately destroy the machines, perhaps we'd have had our first communications with them then. Viking 1
By the way though it would seem great to have neighbours like us there are some things that would make this unlikely.
We might, if we get to explore the galaxy find that in solar systems with more than one easily habitable world that when a technological ET evolves on one of them, it often goes extinct as a result of returning dangerous lifeforms when it first visits the other one.
By the 1920s we'd notice that they have an oxygen rich atmosphere through spectroscopic measurement - as that is when we first proved that there is no significant levels of oxygen there - assuming they are oxygen breathers like us. That was when the technology was developed to distinguish the absorption lines of the Mars atmosphere from the absorption lines of our own atmosphere in light reflected from Mars.
We'd have spotted their agriculture - fields, houses etc, close up with the Mariner 6 and 7 probes around 1969.
And even if we hadn't spotted them by then, surely they'd discover our Viking 1 lander in 1976. The previous Russian landers also but they stopped transmission soon after landing. But Viking lasted for a long time and if they didn't accidentally or deliberately destroy the machines, perhaps we'd have had our first communications with them then. Viking 1
By the way though it would seem great to have neighbours like us there are some things that would make this unlikely.
- If they had a chance of developing technology and just haven't got to it yet - then it is very very unlikely that we are both on the point of developing technology at the same time. To have a planet with intelligent beings without technology and without spaceflight I think they have to be incapable of developing technology (say like dolphins in a sea) - or else decided not to, with a firm resolve that lasts for millions of years s- or else - maybe they can do some technology but are not very strong or dextrous enough, not strong enough to build complex machines (say, like grey parrots might perhaps be??).
- In that situation we'd have wanted to rush over there, long before we had a reasonable understanding of issues of planetary protection. Or at least before we know enough about microbiology to do it properly. The US made attempts to protect Earth from lunar contamination - but apart from applying them in a rather half hearted way (hatch open and evacuated in a dinghy over open sea) it's now generally agreed that their provisions simply wouldn't have protected Earth at all if there were dangerous microbes on the Moon. They didn't know enough about possible lifeforms to protect us. Luckily there isn't any life there, we are pretty sure.
In science fiction stories of missions to visit lunar inhabitants of the Moon nothing like that. All I can think of is the H.G. Wells Martians. But it might well be that if they are independently evolved, that some lifeform on Mars is so good at metabolizing, say, that it out does any Earth life. Or vice versa.
We might, if we get to explore the galaxy find that in solar systems with more than one easily habitable world that when a technological ET evolves on one of them, it often goes extinct as a result of returning dangerous lifeforms when it first visits the other one.
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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