I am curious as to why you think that the Earth is the only inhabitable planet?
Is that a logical determination or a gut feeling thing?
I do not think Earth is the only habitable place in the universe. I believe that there are billions of planets in our Milky Way Galaxy alone and millions are habitable by intelligent creatures. In the early sixties I made a probabilistic estimate of human like technological intelligent beings inhabitating those planets. With liberal calculations I came out with a figure of one million planets in our galaxy with intelligent beings capable to communicate with other intersteller intelligence by radio waves.
Even with all those intelligent civilizations the probability very small of contact, I calculated was one radio contact in 10 years. If I am off in my calculation say by half, one contact in 20 years. If off by tenth then one contact in 100 years, and so on, given that whole sky has been scanned as its now by SETI watchers. Therefore, even if the SETI watchers do not get any contact in the next hundred years, they should not stop, one day they will have contact.
I made the comment that the earth is the only place our human race can live in. No matter how much technologically we evolve, there is no chance that humans will be able to make intersteller journey. The distances between the stars is that great!If the human race go the way of dinosaurs, it will happen on this earth. Even if humans attain the capability for intersteller flight, they will kill each other before because with advancement they find more efficient ways to kill each other. Best regards,