When will we find extraterrestrial life?
Possibly when one of Trump's supporters passes away and they do an autopsy on them ?
Actually , I'm pretty sure they have already done so , and long ago . Our government is not in the habit of exposing any possible technology they gain or have access to due to militarization aspects , and any alien species that arrived here would have technology we'd only dream of .
Plus , no government will willingly admit that they are not able to control our skies from more advanced species .. for that would lead to chaos and loss of control over the population . Any admission of finding other races in the universe or visiting us would come from leaks and whistleblowers , which has happened multiple times .
The government has a vested interest in the status quo as far as the population not fearing or seeking to align themselves with the unknown ... alien cultures would change or destroy many peoples ‘realities of life' , such as religions and obedience to the government as being the greater power over them .
So , all the evidence of them being here for some time has at least some probability of being true ... and the government will likely deny it Until they have no other choice but admit it .
I think within the next 50 years we will discover strong evidence of Extraterrestrial Life from:
A) Analyzing light spectra from some Exoplanets which are not explainable by "Natural " means.
B) Probes on Planets and/or Moons within our Solar System which will show bacterial or other simple life forms .
C) Hard Photographic evidence of actual Extraterrestrial Craft near Earth which is very difficult to refute, such as a prolonged Radar Report confirmed by Military Pilots from 2 or more countries and/ or Satellite Data and including eyewitness Video recordings .This is the most interesting possibility and based on the remote but distinct possibility that Advanced Aliens have been here, know that we are here, know that we are not emotionally ready for a full confrontation and do not wish to scare us . However ‘ They' are giving us clues to their existence which will become stronger on a gradual basis.
All three of the above are not really based on Science ...just pure speculation on my part but definite possibilities IMO.
You could just as easily ask, "When will we cure cancer". It either will happen or never happen.
But if it does, it will happen when we least expect it, a lot longer in time than we wish and with none of our current technology.
By the time we cure cancer, we likely would have discovered a form of unrelated technology (e.g. antigravity) that coincidentally cured something totally unrelated, like cancer. Breakthroughs happen like that, when serendipity and curiosity bring divergent ideas together, like discovering X-rays and penicillin, and the invention of plastics, microwave ovens and potato chips.
In my experience, it's best to abandon hope and embrace curiosity.
It could easily be never.
It's not that intelligent ETs don't exist, they almost certainly do just because there are hundreds of billions of galaxies and each one of them has hundreds of millions stars. So it is certain that intelligence exists in many parts of the universe.
The problem is not them - it's us.
We think we are searching for them but we are not. For example the latest results from Greenbank Breakthrough Listen shows that only 600 or so stars were searched over a miniscual part of the spectrum and then for a small amount of time each.
So, we understand the scale of the problem but, so far, lack the commitment and follow through.
Could be never at this rate.
Honestly, nobody knows. We just don't quite know enough about reality to be able to say how probable life is.
If I have to pull a date out of my arse, I would say we will find extraterrestrial life in about 200 years. I think by then we will have self-replicating Von Neumann probes, and will have charted several thousand planets. Eventually we will find one with some kind of unicellular life.
And it will be a joyous day indeed. I hope I am still alive to see it.
Statistically, we have more chances to be discovered by them than we have to discover them...
Mainly because they must be more advanced... Unless, of course, we look at microbes... In this, it will take forever. But NASA current discovery of a 7 planet system with 3 telluric ones in the green zone could be what we needed. But we'll need at least 2 more years to detect their atmosphere and some potential biomarkers like Methane and oxygen...