The current views on extraterrestrial life
Today, enough astronomers believe that there must be a high probability that we will find life beyond Earth. Among the indirect evidence they have found in support of this modern belief includes the number of planets discovered outside our solar system, not to mention the vast number of sun-like stars in the Milky Way (and, by implication, every other galaxy in the universe). Add to this the availability of the right raw chemical elements and molecules to build life throughout the universe, and it would take a very brave soul to deny the possibility of ETs.
As we speak, astronomers have discovered more planets orbiting other suns than they can count on their fingers. In fact, we are talking conservatively in the hundreds, with more being detected almost on a daily basis. As the instruments for detecting planets around other distant stars get more sensitive, astronomers are discovering that some planets around other stars are about the size of our Earth. it won't be long before another new type of instrument is built by NASA to detect the atmospheres of these planets to determine whether oxygen (a tell-tale sign of life) is present in reasonable quantities.
Then the astronomers tell us that our Earth orbits an ordinary medium-sized yellowish sun not unlike the hundreds of millions sauntering about the Milky Way. And given that the Milky Way is just one of billions of galaxies roaming the universe, the same numbers game is used by scientists today when we ask about the likelihood of finding ETs..
Among many sensible and open-minded scientists in the 21st century, there is considerable belief in the likely existence of extraterrestrial life. Even among the general public, the belief is growing steadily by the year. For example, the late Jean Cocteau (1889-1963), famous poet and member of the Acedèmie française, said prior to his death on 1 October 1963:
"The astonishing thing would be if they [ETs] did not exist." (1)
In the early 21st century, engineer Bill Stone of Stone Aerospace contracted by NASA in 2007 to build the space probe to search for alien life, gave his positive support when he said:
"If you want an experience at being humbled, go look at the NASA Hubble deep space image that looked into the darkest, darkest, little tiny segment of the sky. And what they saw back in that picture to me was the most devastating news of all for people who think we are important. What you saw were clusters of light that were not stars, they were galaxies. And there were thousands and thousands of galaxies in that little picture of the darkest part of the universe. If you think there is not other life out there, think again." (2)
However, for the more rational members of society, discussions about the number of stars and the growing number of planets around other stars are usually never enough to convince them that ETs should exist. More solid proof for the existence of extraterrestrial life is needed.
NASA understands this point very well. Finding direct evidence for ETs remains a fundamental issue in this whole ET debate. Because if you can find just find one instance of ETs somewhere beyond the Earth, the great ET debate can be finally resolved. As a result, NASA is sending probes to other planets and moons in our solar system to see if life might exist, or has existed. And the scientists are not expecting anything too complex or advanced. A single bacterium thriving on another world is enough to convince them of the existence of ETs.
Even so, can we be sure that a single supposedly alien bacteria will be seen as enough evidence to convince every single rational person that ETs exist? Probably not. Of particular concern in this regard is how our innocent efforts to visit other worlds may have inadvertently carried, or soon will carry, Earthly bugs to those places. These bugs have the potential to contaminate other worlds and affect our results to such an extent that it would still be questionable whether we had actually truly found ETs, especially if we start to wonder why the bacteria we might discover on neighbouring worlds look remarkably like those on our own planet. It only takes one bacteria to contaminate another world no matter how hard we clean our scientific space probes.
Not even space is enough to stop a bacterium from surviving the journey. All it needs is a sufficiently protected spot on a spacecraft to remain in suspended animation in the cold of space (apparently it can survive indefinitely in this state) and when the next spacecraft will build plunges into liquid water on another planet or moon, this is enough to thaw out the little critter and help it to survive in its new environment. Then before you know it, the bacteria will thrive and multiply to such an extent that any analysis of the water will soon reveal countless numbers of the little lifeform.
How do we know for sure whether a bacteria on another world is truly alien? Or should we be looking for more advanced and complex life of a size that we can clearly observe with the naked eye and then we can say, "Hey! That's definitely alien"? and "Yep, there is no chance we could have created it."
Looking for bacteria in the solar system could potentially be undermined should scientists discover that the location is contaminated with our Earthly bugs from a previous spacecraft visit, or even an asteroid that hit the Earth 65 million years ago could see some materials ejected from Earth reach a planet like Mars and possibly carry with it some bacteria. At some point, we must seek larger and more intelligent forms of life in the universe, just to be absolutely certain. Furthermore, if aliens are hiding from us, there is a distinct risk that scientists may not be looking in the right area for the evidence (especially if we put all our eggs in the "alien radio signal" or "alien bacteria" baskets, hoping to find an alien civilisation sending signals to us, or anything that looks remotely alien if it is found on another world).
Come to think of it, given how long the search for alien radio signals has taken, you would think that the universe would have thrown at us at least one alien radio signal to keep us busy and solve our problem of whether we are alone. Apparently none as we speak. Extraordinary. But what if the Australian CSIRO astronomer, Dr Kelvin Wellington, is right when he said:
"There's a joke around that everybody might be listening, nobody sending." (3)
Maybe ETs have a good reason for not sending radio signals into space.
Surely this quote shows the importance of expanding the search to other areas where ETs might exist. In which case, how about UFO reports? A logical next step one might think. However, for most scientists, they assume that nothing will eventuate from a study of UFOs.
A very poor decision as our research has shown.
However, since we already have the answer and know the importance of UFOs to the SETI situation, the remaining part of this discussion will now involve a look at the probability of finding life in the universe based on the key aspects needed to build life in the universe and where such life is likely to be found, and using this probability to estimate the number of planets with life in our Milky Way and how many of these are likely to become technically advanced alien civilizations. Then we will look at whether there is enough time for one of these alien civilizations to reach our planet. And finally, we will look at a reasonable explanation for why alien civilizations might choose to keep quiet with us.
Of course, all this work to discuss the topic of ETs may not be necessary given what we know from the UFO reports. But for now, and as a useful information service to the public, it is important that we at least give an indication of the probability of finding ETs without the help of UFO reports. Let us see just how likely we are alone based on observations of the Earth and the universe through our telescopes.\