Are we Alone?

Posted on July 20, 2010

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We started the emission of radio signals 100 years ago when the Canadian engineer Reginald Fessenden transmitted his message through the air on December 24, 1906 from Brant Rock, Massachusetts. The quantity of man-made emissions (radio and TV) increased a lot since than. Today the Earth is like a big buzz. It appears like a living organism. Now it can be recognized somehow.

As the radio and TV signals (which are the only intelligent signals that are broadcasted from us into the space) travel with the speed of light, than in this moment the Reginald’s message is about 100 light years away from Earth into the space (that signal is very, very weak but it exists, and it travels out there).

And if we ask an Astrophysicist: Could you please give me an estimate of the amount of stars located within 100 light years from earth? He will probably reply: Well there are about 3496 stars within that distance from the Earth.

But, since all stars are not cataloged this number can be much grater and according to some other sources it can reach to 8000 stars. So in this case we are going to speculate with roughly 3500 – 8000 solar systems in the space that received and they are receiving our broadcasting. At this point probably it will be good to mention that in those solar systems there are planets revolving around their suns.

Having said that if we throw in the fact that The Milky Way is estimated to contain 200 billion, or up to 400 billion stars, than the picture is getting clearer. So, is there any tool or way to predict or estimate the number of planets within the Milky Way that might have intelligent form of life? Yes there is, and it’s called Drake equation:

N = R* × fp × ne × fl × fi × fc × L
N is the number of civilizations in our galaxy with which we might hope to be able to communicate
R* is the average rate of star formation in our galaxy
fp is the fraction of those stars that have planets
ne is the average number of planets that can potentially support life per star that has planets
fl is the fraction of the above that actually go on to develop life at some point
fi is the fraction of the above that actually go on to develop intelligent life
fc is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L is the length of time such civilizations release detectable signals into space.

Considerable disagreement on the values of most of these parameters exists, but the values used by Drake and his colleagues in 1961 were:

R* = 10/year (10 stars formed per year, on the average over the life of the galaxy).
fp = 0.5 (half of all stars formed will have planets)
ne = 2 (2 planets per star will be able to develop life)
fl = 1 (100% of the planets will develop life)
fi = 0.01 (1% of which will be intelligent life)
fc = 0.01 (1% of which will be able to communicate)
L = 10,000 years (which will last 10,000 years)

Drake’s values give N = 10 × 0.5 × 2 × 1 × 0.01 × 0.01 × 10,000 = 10.
THERE ARE ONLY 10 PLANETS with extraterrestrial civilizations in our galaxy with which we might come in contact? Gee.

This number can be much bigger but the point is that there are 200 – 400 billion stars in our galaxy (and planets in those solar systems) and probably there are only 10 planets with intelligent life form. So far we sent our message to only 3500 – 8000 stars… What do we expect? To be heard and seen? So far we sent our massage only to a tiny, little insignificant corner of our galaxy (3500 compared to 200 billion is insignificant), and the chances that in that corner there are planets with intelligent life form, are probably close to ZERO.

The answer is: NOBODY knows that we exist.

It is more than clear that Drake equation could be extremely inaccurate tool for estimating the number of extraterrestrial civilizations in our galaxy with which we might come in contact and it is obvious that there are great numbers of assumptions involved. After all it is only a speculation.

Let’s follow these skeptic scientists and say that Drake calculations are absolutely wrong. Drake says that only 10 planets in the whole Milky Way are populated with civilizations with which we might come in contact. Let suppose that number is much greater, 10 times greater. That leaves us with 100 lively planets, right? But the Milky Way has 200 – 400 billion stars and around them there are many planets orbiting. Let assume that there are only 2 planets per star (which is not likely, that number is greater). That means we have approximately 400 – 800 billion planets in our galaxy. For the sake of simplicity let’s play with the number of 600 billion planets in the Milky Way.

So we have 100 planets with intelligent life form from 600 billion planets in total, right? That means every 6 billionth planet is populated with intelligent life form. Wow. And we sent our messages only to 3500 – 8000 stars which means to maybe 16000 planets so far. That number is so insignificant in comparison with 600 billion planets. And do you think that the 6 billionth planet will be somewhere among those 16000 planets. The chances are so small for that.

Let’s go further and assume that Drake made a terrible mistake, and the number of lively planets is 10000. That means Drake made a mistake by thousands (which is truly questionable). Cool. Even than it turns out that every 60000th planet is populated with intelligent life form. Still the chances that this planet will be among those 16000 which are close to us are very, very small.

The point is that we already sent our message to such an insignificant corner of our galaxy and that corner is very, very small compared to the whole galaxy so it is very possible that nobody knows that we even exist.

For comparison imagine that you are confined in some house. You are writing SOS notes on the paper and you are throwing those notes out of the window. At the beginning they end up in the backyard. Nobody will know that you are in the house. Nobody will read those notes because nobody is in the backyard. However, by the time passes you become more skilled with throwing those notes and you start making paper-planes out of them. You throw them out of the window and now they end up on the street. But still the chances that somebody will notice those notes are small, because the street is not frequent at all. It may happen if you are lucky but the chances are very, very small. Finally you are so skilled that you paper-planes are flying to the nearest houses and buildings. Now the chances are greater and maybe somebody is living in those houses. But since that is abounded suburb your effort will be futile. Nobody is living there. And at the end if your paper-planes can glide all over the city it is sure that someone will spot them. Nice. Maybe this analogy isn’t perfect but it can illustrate.

As I said earlier, even if we assume that this calculations are totally wrong, with doing that we will end up with assumption that there are 10.000 planets with intelligent life form in our galaxy (1000 times more than Drake thinks).

Even if that is the case, that number is really insignificant compared to the total number of planets in our galaxy which is around 200.000.000.000. On top of it we already sent our broadcasting (which is the only proof that we exist) to only 16.000 planets so far (100 light years away from Earth), it will turn out that we sent our message to only about 0.00000008 % of our galaxy.

Our signals will reach the center of our galaxy about 27000 years from now. That is 270 centuries from now.

We started to scream 100 years ago. For our galaxy 100 years are nothing. We are still babies. Nobody knows that we exist.

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