There’s an article on the i09 website entitled Is it Time to Accept that We’re Alone in the Universe. The article claims that Our galaxy, at 13 billion years old, has been around long enough for aliens to explore and colonize it many times over by now (recent work shows it should take less than a billion years, perhaps even as little as a few tens of millions of years). Clearly, we should have seen somebody by now.
It then goes through the “logical” reasons of the exclusive presence of “non-existent spacefaring” aliens could be attributable to any number of things, including a reluctance to explore space, or owing to technological intractability. But it could also imply that aliens simply don’t exist. Indeed, despite all the recent discoveries of potentially habitable exoplanets, along with the general feeling that our universe is primed for life, there are many reasons to suspect we’re truly unique in the large scheme of things.
Thus it concludes that we need to accept the fact that we are alone in the Universe.
Yet in my view, this is a rather shortsighted and narrow-minded attitude. Simply because we haven’t met or discovered anything “alien”, does not mean they don’t exist. Our own spacefaring endeavours have been limited. We have only landed on the Moon which is a mere 384,400 km from Earth since we first sent humans into space – 46 years ago. All our other missions have been with unmanned vessels, and even these have been limited and few between.
When one considers the vast distances between not only our own planets within our solar system, but also between stars themselves, one has to question how anyone can assume we are alone. For example, the nearest planet to Earth is Venus which is 38 million kms away. To even get out of our solar system one needs to go beyond Pluto which is 7.5 billion kms from Earth. The nearest neighbouring star to us is Proxima Centauri which is 4.24 light years away, which when you consider the speed of light is 299,792,458 meters per second, you can fathom how truly far that is.
Further, the fastest unmanned vehicle humans have developed is the twin Helios probes that were sent into orbit around our own Sun. Their speed? A mere 252,792 km per hour. The fastest manned vehicle was Apollo 10 which managed to travel at 39,896 km per hour!
The argument can be made that okay, we haven’t got the technology, but surely other species out there would have developed the ability to travel vast distances. The question one would have to pose is this:
Why would any space travelling life form even consider coming our way? Our solar system is in one of the outer regions of the Milky Way galaxy, and no where near the center. They – like us – would explore the nearest celestial bodies to their home world, just like we have with the Moon, Venus, Mars and other planets, moons etc in our solar system. When we decide to go beyond our system, we will head for star systems that are near us.
The other question is in terms of communication. If aliens are communicating or sending signals out into space, would we even recognise it? Imagine the following scenario: would our own ancients [eg the Romans, Greeks or Egyptians] recognise the sounds of a jet flying overhead, or would they assume its thunder or something similar?
Even if alien life forms have sent “hi, we are here” signals at the speed of light, how long would it take to get here and for us to even understand or realise it is a signal?
How do we know for certain that we haven’t been visited or contacted, and us simply not realised it?
Rather than convincing ourselves we are alone and diverting our efforts inwards, we should take the view that there is life out there and make focus on trying to find it. After all, humanity has never really been a self-centred and focused species, for if we had, we would never have found out that our own planet is not a flat world with dragons and giant mountains that can never be crossed.