Searching for extraterrestrial life – Part 2

In this post we will focus on finding the intelligent life in outer space.

Unfortunately, it is not possible to distinguish between an intelligent life and another non-intelligent life away from us, except for the technology used by the former. So let’s focus on finding the technologically advanced intelligent life in this post.

As we said in the previous post, the prerequisites are more restrictive if we are to find planets where technologically advanced intelligent life can emerge. The main thing is that we need to have a solid surface and a liquid surface also, which excludes the large gaseous planets from our list, leaving as options in our own solar system only: Venus, Earth, Mars and perhaps some satellites and dwarf planets.

We consider as a technologically advanced intelligent life the one that have, at least, a language, a writing system, a radio communication technology and a transport technology (such as chariots, carriages, cars, boats, ships, submarines, airplanes or spaceships). Which implies knowledge about eletricity and probably a mass production system.

Basically our proposal to find technologically advanced intelligent life is the same as in our proposal presented in the previous post, but replacing light by radio broadcasts.

Any technologically advanced intelligent life will need to create some communication technology and will use radio waves to transfer signals like voice and data from one place to another far away. These radio waves will continue to propagate through the Universe and can be captured by us.

So the goal here is to find radio emissions that can be established as having origin near the orbit of the planet and that can not be explained by natural processes, such as radioactive decay, such as our own artificial (man-made) radio emissions, .

If we find artificial radio emissions coming from near the orbit of the planet, it is because we have some form of intelligent life living there.

To precisely determine the origin of an artificial radio emission it is necessary to capture it by several radio telescopes all over the world in order to triangulate precisely the position of the radio source. This is the main difficulty in doing this search. We need to point out not just one radio telescope, but several radio telescopes, to the same sky position, away from each other, to prevent our own emission interfering with the results.

But any signal that is captured by all of them at the same time must have come from far away from us, because if it were generated near us, they should be captured at different times by the antennas. Ideally, these antennas should be located on different continents around the globe instead of many antennas in the same location.



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Searching for extraterrestrial life – Part 1

As we discussed in the previous post, to increase our chance to find life, we should look for planets where we can find a liquid surface and near to these planets. We are unlikely to find life away from a liquid planet.

But the liquid does not mean water. At least not only water, but any liquid, including methane.

Of course, that planets with liquid water will be more likely to find life more similar to ourselves, but we must keep in mind that there may be forms of life that are completely different from ourselves, including some based on silicon rather than carbon.

If we was searching for simple lives like bacteria and viruses, we must include very cold planets in our portfolio. In our solar system all planets except Mercury must be included. A solid surface is not needed to allow these organisms to emerge, only a liquid surface that can be composed of gas under pressure, making Jupiter, Saturn and Uranus possible candidates as well.

So, when we was searching for extraterrestrial life outside our solar system, we need to consider not only planets with solid surface and liquid water but those with solid surface and any liquid surface and large gaseous planets, including those very cold to have liquid water and even those too hot too, if the pressure of your atmosphere can create a liquid surface somewhere on the planet.

To find places that can support intelligent life the prerequisites are a bit more restrictive. We will discuss this in our next post.

But the question is what to search for on those planets that may suggest that some life is living there?

Should we search for organic components in the atmosphere?

It may be a target, of course, but as we discussed in our previous post, these components can be made by chemical reactions inside the planet, but this quest excludes the possibility that we find life based on silicon or life forms completely different from what we know.

What to search for then?

Light is the answer.

On Earth we have bioluminescent organisms and the light they produce is totally different from sunlight. We have a lot of organisms that produce light, including some algae and the light reflected by the plants also differ from the sunlight.

The hard thing to do is that we need to separate the light reflected by the planet from its own star from that produced within the planet itself. If we find in the middle of the light reflected by the planet radiation of a quality or color different from that emitted by the star, that light can only be produced by the life inside the planet.

To do this, we need to compare the composition of the frequency of the light emitted by the star with the composition of the frequency of the light reflected by the planet and subtract the effect of its atmosphere and any solid and liquid surface that can exist in the planet and the difference is the effect of the life there. A simple and beautiful solution.

This is our best chance to search for life in outer space away from us and it should be our choice, at least before we can make space travel and go there to check, because it is easy to implement and is unquestionable and undoubtedly, being scientifically very solid.

To gain experience on it, we should try to use this technics to infer the presence of life on the planets and satellites in our own solar system, including the Earth where we know that the life exists.

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