SETI stands for the Seek for Extra-Terrestrial Intelligence. Kindly note that the word ‘radio’ appears nowhere in that phrase, yet searching for synthetic radio transmissions from extraterrestrial civilizations seems to be close to synonymous with SETI, as bolstered by way of the popular film “Contact” (based on Carl Kruse SETI Profile Sagan’s novel). Now there is nothing incorrect with radio SETI. The seek for radio waves has been well thought out and would appear to supply up the maximum chance for success. However, there are more ways to skin the SETI cat (because it had been), and after 49 years of searching primarily through radio, I suggest that some more ways be adopted and explored. Any a part of the electromagnetic (EM) spectrum is suitable and up for investigation, equivalent to optical SETI (looking for laser beams) or infrared SETI (searching for Dyson Spheres) or just on the lookout for alien artifacts (as within the novel/film “2001: A Space Odyssey”). From that, we note that one can strategy the research of UFOs and/or historical astronauts as representing a form of SETI. Whatever investigation tells you that extraterrestrial intelligence (ETI) exists, or once existed, or would not exist at all (and a negative result is as essential as a constructive one) is SETI.
Why do SETI in any respect? That’s an apparent first question. Thankfully, there are lots of good answers to that question. There’s pure scientific curiosity for starters – exploring just for the sake of exploring. Then there’s the more philosophical approach in that SETI helps to higher decide our place in the cosmos. A negative reply is just as necessary as a optimistic answer in determining whether humanity is unique, high of the heap, one of the great unwashed cosmic crowd, or the new boy on the block. SETI has a practical side too in figuring out the existence of potential neighbors which may very well be sources of profit and/or threats to us. Obviously, a choose few scientists, SETI lovers, have long felt that SETI was, and is, worth doing. Radio SETI is (as of this writing), a quite mature science now forty nine years old.
Now if seven is a lucky number, then seven occasions seven ought to be even luckier, yet, some 49 years after the first radio SETI experiment (Project Ozma) was performed by Dr. Frank D. Drake, there’s be no luck in detecting any signal of another technological extraterrestrial civilization (49 years as I write this – it is even longer now). What does this counsel to us as a life type with an advanced technological civilization? Where are our ‘kin’ on the market among the many stars?
Firstly, it suggests that radio SETI is not going to be fairly as straightforward as first envisioned. The number-crunching back in those early days recommended that ETI with a suitable detectable technology (radio emissions or somewhat transmissions) can be pretty common. Even though solely a relative few of those haystack stalks have been sifted for that needle, it is becoming clearer that type of SETI is not going to be straightforward; N (the number of technologically radio speaking ETI within the cosmos) isn’t going to be an extremely large number. So, some constraints on the SETI concept and logic have come home to roost.
By way of the search so far, it’s clear (to me anyway) that there aren’t any Type III civilizations (able to harness the energy output of an entire galaxy) in any galaxy even remotely ‘shut’ (in cosmic terms) to us. If there were any Type 2 civilizations (potential to command the energy output of a whole star) almost in our own galaxy it ought to have proved pretty obvious by now. There have been of course many false alarms, but additionally a number of cases that regarded like a positive signal was received. Alas, all have been one-offs and have never been picked up again. Without verification, those ‘wow’ signals remain enigmas, but not proof optimistic of extraterrestrial intelligence (ETI).
Firstly, my rationalization as to why we’ve not detected ETI through radio-SETI forty nine years on. I consider it unlikely in the extreme that any ETI would deliberately target our dad or mum star and photo voltaic system. We’re just too average. There is not any compelling reason to target Sol versus hundreds of thousands of other stars. Even if they did, what are the odds that their targeting us would just occur to coincide with our evolving the requited know-how to detect similar? What if we have been focused, however thousands, maybe tens of millions of years ago? ETI gave up the ghost and targeted elsewhere!