New Calculation Shows We’ll Make Contact With Aliens in About 1,500 Years

The disturbing Fermi Paradox suggests we should have made contact with an extraterrestrial civilization by now, yet we haven’t. By applying a 500-year-old philosophical principle, a Cornell University researcher has shown that the Great Silence is not unexpected—we just need to give it more time.

In a new study that will be presented at an American Astronomical Society meeting later this month, astronomers Even Solomonides and Yervant Terzian combine the Fermi Paradox with the Mediocrity Principle to show that we shouldn’t expect to hear from aliens for another 1,500 years. The reason has to do with the vastness of the Milky Way Galaxy, the time it takes radio signals to propagate through space as well as the apparent “averageness” of humanity in the larger scope of things.

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Even though this is probably in the wrong topic heading, I couldn't let an assertion made with nearly infinite uncertainty go without adding some of my own.

If there is or were persistent, intelligent life in the Galaxy they would have visited earth by now. But only if there were sufficient way stations along the route. I would estimate that it should take on the order of 500,000-1,000,000 years (others have estimated 50,000,000 years --it dosen't matter) to populate the galaxy once a civilization became maybe 1000 years more advanced than we are now. The Milky Way Galaxy is perhaps only 100,000 light years in diameter. I believe the estimate of the age of the Universe is close to 14 Billion years ( at least ). Thus there would be time for colonization if a civilization refrained from destroying itself long enough to become technically sophisticated. We are probably 50,000 years removed from the cave-man level and arguably 5 to 6 million years removed from the apes from which we branched off on the evolutionary tree. So it appears that there would be adequate time for the development of super-intelligent life once a habitable planet produced a variety of fauna. So to echo Enrico Fermi. "where are they or where are the signs of these visitations?"

If a civilization became advanced early on, and were near the center of the Milky Way they could easily meet these time schedules for exploration of Earth. The stumbling block would be if great distances between the habitable planets were a fact. This state of affairs would require multi-generational trips to possibly unknown regions. I conclude, therefore, that habitable planets are spaced more than 10 and maybe as much as 100 or more light years apart. Or perhaps we are in such a place in the galaxy that does not have a "chain" of nearby habitable planets that extend back to an advanced civilization. 1000 year trips would be too daunting for us and our alien friends (assumes one tenth the speed of light travel speed). I suspect that in 1000 more years we would be willing to launch a 100 Year trip if we knew where to go. It wouldn't do us much good if the nearest planet of interest were 100 light years away. So even if there were a large sprinkling of civilizations in our Galaxy, could we detect them if they were 100 light years or so away? In fact there is of the order of maybe a few thousand stars within 100 light years from earth--this does not bode well for eavesdropping--we may well detect only a powerful beacon from distances greater than this.

For sure, the dinosaurs lived as long as 250,000,000 years ago. The Earth has been around for maybe 5 billion years and habitable for maybe a billion or so at some level. Perhaps we should look for signs of this visitation right here on earth. Or do we conclude that we are the most advanced form of life at least out to 100 light years or so. If we can rule out a visit here on Earth then this would tell us a lot about what we may expect to find doing SETI and what the spacing between habitable planets must be.

Of course we could also conclude that we are among the most advanced civilizations right now and not enough time has gone on for inter-stellar space travel to have become a scientific possibility.

As usual, XKCD to the rescue...

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I'd say somewhere between now and then is a good guess.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.