This question is almost as old as the age of consciousness-laden humans, and that goes back tens of thousands of years. For a long time, under the influence of various religions, we believed that we were alone and the whole universe was created for us humans, God’s favorite creatures.
Following the Renaissance era of recognition that the stars do not revolve around us, but we, the earthlings, turn around a star, came the 20th century with the discoveries of physics, technology development and a new search for the meaning of life－We also saw 2 world wars, atomic bombs, and chemical weapons. Suddenly, people became captivated with extra-terrestrials, space travel and aliens on Earth. Initially these topics were the subject of science fiction and limited scientific curiosity. The 21st century, however, changed much of that, when the discovery of exo-planets (planets outside of our solar system) became a routine task. We also launched numerous observation spacecrafts, with the latest being James Webb Space Telescope (JWST). Furthermore, the power of our modeling and empirical data analysis and synthesis has increased by many orders of magnitude due to computing technology. In addition, UFO (Unidentified Flying Object) has become UAP (Unexplained Aerial Phenomenon) and has triggered serious follow-ups by US military and Intelligence. In other words, we have gone from ‘we are alone’ to ‘maybe or maybe not, but let’s investigate’. Nevertheless, in spite of efforts by organizations such as SETI (Search for Extra Terrestrial Intelligence), we have so far hit nothing－except for video shots of UAPs by serious pilots. But what if we identify a planet on another solar system on which we detect intelligent life? How can we travel to it, and how long will it take?
To start, let’s note that mankind’s fastest spacecraft to-date is the Parker Solar probe, which has clocked at 163 km per second (163 km/s). That’s pretty fast, but it is only 0.05% of the speed of light, and the closest star system to us is at a tiny 4.3 light-years away (Alpha Centauri). Consequently, our fastest craft will take over 8 000 years to get to the star system, and we have no evidence that Alpha Centauri harbors any intelligent life on any of its discovered planets.
Secondly, if we identify intelligent life in that star system, and send them a message of ‘Hi we are your neighbors’, it will take at least 8 and a half years to get a reply. Einstein’s special relativity implies this to be the shortest time possible, regardless of what technologies we develop in the future.
Now imagine by the end of this century, we develop technologies that speed up our spacecrafts by a factor of 200, say up to 10% of the speed of light. This means, the same journey will last ‘only’ 43 years, instead of 8 000+. So a round trip will last over 86 years. And that is only if we find intelligent life on Alpha Centauri. Other star systems at 10 or 20 light-year distances imply hundreds of years of travelling, even at a 200 fold increase in human space travel speed compared to our fastest current unmanned technology.
So are we alone? We cannot answer that question scientifically at this time, but we can be mostly sure the observed UAPs are not visitors in flesh from other cosmic worlds who have discovered us and sent researchers to investigate us. If so, they would be located in our ‘backyard neighborhood’, and our instruments would have already picked up the civilization’s ‘life’ footprint (oxygen, in particular). But then again, maybe there are other possibilities.
February 16, 2024, Cambridge,
Berta Seintan, PhD & Charlene Wardin, PhD