By Robert Harrand
Every year, thousands of people worldwide report seeing UFOs, but what is the scientific view of an alien visitation?
Unlike belief in ghosts, psychic powers, or other paranormal activities, the notion of an alien craft visiting the Earth does not violate any physical laws. Some UFO sightings could be genuine alien visitors, and science has much to say on this subject.
The Problems behind Interstellar Travel
For an alien craft to visit the Earth, the first requirement is for an alien civilisation to exist somewhere in the universe. More specifically, a civilisation within a reasonable distance of the Earth.
Even at the fastest speed theoretically possible, the speed of light, it would take over 4 years to journey from the nearest star system to the Earth.
Perhaps aliens are willing to make a journey that takes hundreds or even thousands of years, in which case, many more star systems would be within range. Or perhaps, using laws of physics currently undiscovered to humanity, an alien craft could travel faster than light.
Assuming this possibility, the next question is why no trace of any alien radio signal has ever been detected. If life, and in turn intelligent life, is abundant throughout the universe, it would be expected for Earth’s radio telescopes to be hearing evidence of their existence. This is known as the Fermi Paradox.
No Signs of Alien Life
Explanations for a lack of signals include the idea that advanced civilisations use a form of communication that is currently undiscovered on Earth, that civilisations develop and destroy themselves in the blink of a cosmic eye, or that they’re simply not there in the first place.
The development of life may be incredibly rare, and the evolution of advanced life even rarer still.
UFO believers often quote the ‘Drake equation’ to support the idea of an abundance of alien life throughout the universe. This equation, devised by Dr. Frank Drake, gives an estimation of the number of advanced civilisations in the Milky Way Galaxy by using a number of parameters, all of which must be either estimated or guessed.
However, the result of this equation can be made large or small, based upon the optimism or pessimism of the person making the estimates.
Presuming that an advanced civilisation exists within transit distance of Earth, and that their radio signals have not yet been detected for some particular reason, the next question is motivation.
Why would such aliens make such an effort to travel to Earth, make the mistake of being spotted from the ground, and yet make no effort of establishing communication?
The explanation given by believers is that they have a motive for coming to Earth that is something other than formal contact.
The Rational Conclusion of UFO Claims
The sky is filled with human-built flying objects, including aircraft and satellites. These alone typically account for a large percentage of UFO sightings.
Unusual weather phenomena, lights on tall buildings, and tricks of the mind make up most, and possibly all, of the rest.
For there to be a remaining small fraction of sightings that are genuine alien craft, science clearly concludes that a large number of highly improbable events would have to out-weigh the possibility that the explicable sightings make up 100% of all UFO cases, rather than 99.999%.
For this reason, until extraordinary proof is obtained, alien craft in the skies above the Earth remain science fiction rather than science fact.
Robert Harrand
