Speaking about UFO’s

We are in the third millennium, in the era of globalization, the Internet, telecommunications in real time, no only terrestrial, but inter-planetary. We have already been on the Moon, and have sent robotic equipment to Mars and as far as a satellite to Saturn!

So it turns a bit difficult to understand how there are still people who think that we are alone in the Universe.

It is not necessary to be astronomers, or to look through a telescope or a microscope, to realize that we cannot be alone: it is enough to look at our surroundings. At this grain of powder that is our Earth planet, there are millions and millions of different species, and as far as different forms of life: animal and vegetal.

Then, why thinking that we are alone?

If we cast a glance to the sky, we can quickly see that its aspect is uniform. There are no privileged zones. We see stars everywhere, all similar, all extremely far. By means of telescopes we can discover also that there are not only stars, but also other objects: the nebulas. Some are diffuse (as our clouds, to put it simply), others with regular and repetitive geometrical shapes, that induce to thing of something special and of a dynamics that governs them: they are the extra galactic "nebulas" or galaxies, that are not gas clouds, but conjunctions of stars, very similar to our galaxy, and obviously much further than the gas clouds that belong to our galaxy (the other galaxies, it is not necessary to say it, also have their own gas clouds and dust).

Looking further in the universe, we find out that the number of galaxies is huge, to the degree that, in the deepest photos, thousands of galaxies, and only galaxies can be seen. And each of them is a conjunction of stars that may have hundred thousand million stars.

Can we dare still think that we are alone?

I think that we cannot !

Nevertheless, there are still many more important reasons to demonstrate this thesis.

The universe is homogeneous: from wherever you look at it, we always see the same conjunctions, same movements, same elements, same compounds, same temperatures, and same phenomena. It is increasingly clearer that there are no privileged spots.

And as if this were not enough, there is no centre in the universe. Every observer wherever he is has the sense of being in the centre.

Maybe my example is too trivial, but saying that there is a centre in the Universe it would be like saying that the centre of the World is Buenos Aires or Madrid.

Then it would be not so meaningless to conclude that life in the universe has to be something not only common, but necessary and inevitable. What was said at the beginning, that is to say, with what variety of forms and with what predominance life exploits under conditions sometimes difficult, is another reason for thinking that life in the universe has to be a generalized phenomenon.

But beware! This should be properly understood!

This does not mean that we can find life in every corner of the Universe!

It is very well-known that there are living beings that endure temperatures of up to 2000 degrees, beings that endure extremely high pressures, and beings that live in total darkness.

But, for life to develop, certain conditions need to take place.

Let us analyze them.

We all know that in nature there are various forms of matter that are called elements.

We also know that some elements are so complex that cannot be stable, while others are simpler, and thus more abundant.

The simplest element is hydrogen, and still today, almost 13.5 thousand million years after the big-ban, 95% of matter that conform the universe is hydrogen.

Not much imagination is necessary to think that the first stars formed should be formed by hydrogen (though we will further see that this has not always been like that).

All stars have a complex evolution, and this is not the site to explain how it is developed: for the time being it is enough to know that this exists.

Nevertheless, it is necessary to know something more about stars; especially, how they are originated.

But: how is a star originated?

In the universe there are forces of all types, but the only one that often prevails, at least at local level, is always the gravitational force.

Let us imagine a huge hydrogen cloud (of tens of light-years), more or less homogeneous.

What may happen in that cloud?

If it is isolated in the space, due to the vacuum surrounding it, it should expand. But the gravitational force is stronger, and it tends to contract.

As it is not perfectly homogeneous, it starts dividing itself into many parts, each of them gets increasingly contracted, forming globules, that are possible to observe through telescopes.

As a consequence of this contraction, pressure, density and above all, temperature increase. Exceeding certain limit – around one million degrees – a thermonuclear reaction is automatically triggered, with the transformation of hydrogen into helium and the release of energy, and at the moment, a star is formed!

Alone? NO! (this, at least, is what I think).

When a cloud is contracted, in the dynamic universe, where there is no straight line, the particles that fall towards the centre, with increasing speed, do not move in the same direction. The formation of a whirlpool is inevitable, and the cloud starts to rotate, transmitting its rotation to the recently originated star and to everything surrounding it.

Creating a star producing no remnants is like building a house producing no debris.

Planets, satellites, asteroids, comets, etc., are this debris. When any of these "debris" exceeds certain dimensions, instead of a giant planet a second star will be formed, and we will be in face of a double star. Thirty percent of these observable starts are double, and among them, there are also triple, quadruple and multiple stars.

It turns very difficult, then, to image that a star may exist with no planets.

But, what may happen on these planets? The answer is: NOTHING, except for their movements. At least, on the planets belonging to second population stars (we will see later that there are also of first population).

In fact, in a hydrogen star, due to thermonuclear reactions, new elements can be produced. But on a planet, which temperature is much lower, no production of new elements can take place, and no evolution can take place.

Fortunately, stars are not eternal, and we have already said that they have a complex evolution.

Stars evolution is strictly linked to its mass, but not all are stable.

When a star is not stable, it can explode abruptly, and these events are very common in the universe. A star that explodes is called "Supernova".

We have already said that what feeds Stars is the thermonuclear energy.

There are two types of machines that use this energy: the nuclear reactor and the atomic bomb.

The reactor, generally, does not explode, and the operation of a star can be compared to a reactor.

The supernova, on the contrary, is a true bomb, a bomb bigger than the Sun, which glare, when it explodes in a remote galaxy, can exceed that of the galaxy that contains it!

Matter is thrown into the space at a speed of around 18 thousand km by second, and from the matter that is scattered in the space another nebula is formed, that contains this time not only hydrogen, but all the elements as well.

From the nebulas that had this origin, other stars of "first population" are formed in the course of time, which planets obviously contain a lot of elements that make evolution possible.

This is the first sine qua non condition for the development of life on a planet.

But it is not the only one; also the following conditions have to take place, among others:

1. The star has to be stable, for obvious reasons;

2. It does not have to be double or triple;

3. It does not have to be too hot, because its radiations would be deadly.

4. It does not have to be too cold, because its radiations would not be enough to generate life;

5. The planet does not have to be too close, because it would heat up too much;

6. It does not have to be too far, because it would be too cold;

7. It does not have to have a too elliptical orbit, because its variations would be unbearable;

8. It does not have to be too small, because it would lose its atmosphere immediately and there would not exist any liquids;

9. It does not have to be too big, because its gravity would be unbearable, as well as its atmospheric pressure;

10. Its axis has to have a convenient orientation; if it were perpendicular to the orbit’s plane, there would not be seasons, the polar circles would coincide with the poles, and the two tropics with the equator. If, instead, it were parallel to the orbit’s plane, as it occurs with Uranus, at a certain moment it would have the sun at the zenith in one pole, and six months later the zenith in the other pole, with the consequences that we can imagine;

11. For this reason it is necessary for it to have an adequate rotation period.

These are some of the necessary conditions for the development of life, and it is possible that there might be others.

But it is enough that any of these conditions does not occur to impede life development.

If we take into account that in our Galaxy there are hundreds of thousand million stars, according to calculations by specialists, there should not be more than 400 planets similar to ours in it.

It does not make a lot of sense stating of 400 are a few or a lot.

But, what does this mean?

If we start from the logic principle that the most probable thing is that these planets are distributed in the Galaxy in a uniform way, the most elemental calculation makes us conclude that the closest would be at around 10,000 (ten thousand) light-years.

This means that light would take 10,000 years to get to the closest planet, and the same time to come back. A total of 20,000 years.

If, having received a signal, we had the proof that on a planet at such a distance there is a civilization equal or superior to ours, and we had decided to send a message, by a radiotelescope, at the light speed, this would take 10,000 years to get there, and we would have the eventual answer in 20,000 years.

With respect to special spacecrafts, it is clear that they would be a bit slower…. But if we were able to send some at relativistic speeds (between 200,000 and 290,000 km per second) the simple collision of a spacecraft with an iron or silicon particle of one millimeter diameter would trigger as much energy as an atomic bomb, that if it makes the spacecraft explode, at least, it would perforate its tanks, computers, and the crew’s brains, with imaginable consequences.

Instead, a spacecraft that would travel "only" at 30,000 km per second (enough speed to reach the moon in 13 seconds!) would take obviously 100,000 years to get there, and other 100,000 to come back.

To all this we obviously have to add that it would not make any sense if in another planet there were a civilization as advanced as it was ours at the time of Hammurabi, or of Cicerone, or of Galileo..., because they would not be in conditions to communicate with us.

It would not make any sense, either, to answer a message sent 100,000 years ago by a civilization that has already disappeared … (it should not be forgotten that, in spite of the respectable age of the Earth, that is around 4,500 million years, our past history is one million times shorter, and the future, who knows, could be even shorter!

Setting this clear, let me now make you one question: Do you still believe in UFO’s?

I expect you will not answer affirmatively, because in this case, really, I would not have any other alternative than getting onto the first one that passes by and go to the planet 400 !!!