We are warned: We will see few extraterrestrials if a great many promising exoplanets are Waterworlds. Interestingly, Earth just missed being that type of planet. But while we’re talking about this stuff anyway:
Seriously, there is considerable evidence that the universe is fine-tuned for life. Maybe we should look at a simpler explanation than many we have considered:
Life has probably existed on Earth for four billion years but it is only in the last century and a half that humans have been serious about space travel. If other planets in our galaxy that could possibly host intelligent life are affected by the same physical constraints as Earth, their intelligent life forms could be on a schedule roughly similar to ours. They don’t visit us for the same reasons as we don’t visit them: They may suspect we’re out here. But they don’t have the technology to find out.
It’s nothing new. Around 600 AD, the Maya civilization in what is now Guatemala was highly developed. So was the Chinese civilization. They never interacted. They couldn’t. No one had the technology to cross the Pacific reliably so there was no way they could know each other existed. Today, Chinese tourists can visit Maya cultural treasures.
Most likely, the question of whether other planets in our galaxy feature intelligent life can only be resolved in the same way, by further advances in technology. It is, however, fun and useful to continue to develop hypotheses in the meantime.
News, “We won’t find ET on ocean planets, researchers say” at Mind Matters News
See also: Particle physicist offers 75 reasons we don’t see aliens. But Oxford’s Future of Humanity Institute gives high odds that we are the only intelligent beings in the galaxy. No matter whose theory about why we don’t see extraterrestrials is right, we are bound to go on wondering and searching.