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Thursday, October 4, 2012

The Exobiology and the Astrobiology

The Exobiology and Astrobiology is the study of the possible presence of life on other planets.

In the study involving geologists, chemists, oceanographers, astrophysicists, molecular biologists, zoologists and paleontologists.

In 1998, NASA established the Astrobiology Institute, which has been instrumental in the consolidation of this new science.

The search for extraterrestrial life has been too often trivialized, and this has led extremes of absolute skepticism or credulity in these matters.

If we knew the conditions required for the emergence of life, appreciate how difficult it is that it arises somewhere in the space, which makes it even more difficult the emergence of beings in our image and likeness (common appreciation for the human race, which denotes his selfishness and self-centeredness).

But what we mean by life?

Life is difficult to define, but easy to appreciate and recognize when we observe it.

The problem comes when we move into the boundaries between life and non-life prompted many opinions and controversies.

There are some organisms called extremophiles.

These are very simple organisms adapt to extreme situations with ease.

Bodies of this type appear in our country in the area of ​​Huelva (Rio Tinto), being the main feature of this river being adverse habitat for life.

However, it has grown from 500,000 years ago significant biodiversity of microorganisms (more than 2,500 species of bacteria), which exist in extreme conditions similar to those of Mars, leading us to believe that in our neighboring planet-like organisms may exist.

Therefore, the search for extraterrestrial life brings us, at first, to think in simple organisms and simple.

The existence of life is a series of conditions that are considered universal (we assume the basis of life beyond Earth will follow the same pattern that has followed it and need the same items), need:

A liquid where chemical reactions take place.
An element to form compounds easily.
A source of energy.

In the case of the Earth these elements were water, carbon and energy processes derived from electrical shock and ultraviolet radiation.

It is logical conditions similar to Earth, since they are the only references we have, and work without reference is impossible.

Anyway, you think of other solvents such as liquid ammonia and methyl alcohol and other elements other than carbon and silicon.

Given the above, life could exist on other planets, including satellites of our own solar system, so it is asking about what conditions make a planet habitable?:

Have abundant chemical elements like carbon, hydrogen, oxygen and nitrogen, mainly.

The orbit of the planet around its sun is circular and is at a distance appropriate.

Otherwise, there would be very hot or very cold, as the zoom in or out planet to its sun.

There is an almost inexhaustible energy source that maintains a temperature adequate to allow the formation of complex molecules.

That the planet has a magnetic field to deflect radiation deadly particle from its star.

That gravity is strong enough to maintain an atmosphere and weak enough to not crush the living beings on the planet.

That atmosphere would regulate the global temperature of the planet and protect its surface radiation
destructive molecules.

Additionally, a rotation would help regulate the planet's global temperature.

Once above the planetary conditions for habitability of a planet, we must stand to wonder whether in our solar system there is a candidate or candidates for any habitable agency.

We as possible candidates: Mars, Europa and Io (moon of Jupiter), Titan (moon of Saturn) and Triton (satellite of Neptune). 

Let's briefly look at these candidates:

Mars is the planet most like Earth.

It has atmosphere and features that have made the subject of countless stories and speculation about the existence of life.

Its atmosphere is less dense than the Earth, composed mostly of carbon dioxide, with 2.5% nitrogen and 1.5% argon.

It also contains water vapor and oxygen in trace amounts.

It is believed that in the past may have had a denser atmosphere, with water on its surface.

Recently, NASA has found evidence of underground water.

Regarding the temperature is never above 30 degrees below zero.

Their conditions are not favorable for life.

Despite this, gets a lot of ultraviolet radiation from the sun and contains volcanoes, active before, which means a large amount of energy that would have favored the emergence of life have been liquid water, life could have adapted microorganisms gradually to changes in weather and still survive in current conditions.

Europe : a satellite of Jupiter, and more suggestive of the satellites by the extensive range of
life to exist there.

In recent years it has exposed serious cracks in its icy surface, indicating the existence of water oceans under the surface.

On its surface have discovered large amounts of sulfuric acid, which when oxidant would be a good source of energy.

Besides sulfuric energy sources would be the tides raised by Jupiter on Europe, the electrons from the magnetosphere of the planet, and radioactivity and solar radiation.

Despite his condition, apparently invalid for life, it is thought that under the ice there is a large lake inhabited by microbes.

To justify this hypothesis, we look similar habitats on Earth, being the most ambitious study of Lake Vostok buried in Antarctica.

Io : This is another of the satellites of Jupiter, which Galileo probe has confirmed the existence of
volcanic activity.

Not rule out the possibility that there is subsoil water and thus the possibility of life.


Titan : Saturn's moon has an atmosphere similar to Earth and although its surface is very cold, scientists have high hopes that microscopic life exists.

Its atmosphere is composed of nitrogen and methane, the latter in liquid, so that life would be in a liquid is not water.

As the planet's temperature is very low and the solar energy received is less than that of Earth, chemical reactions must be slow, so that life must be of a microscope.

Triton :
Neptune Satellite organic compounds present on the surface.

Despite being the coldest object in the solar system, from its interior materials are ejected into space, which proves that there must be some source of energy that allows this process.

But what criteria are followed in the search for life?

The search for life is based on the fact that the laws of nature do not change according to the
place.

Spectroscopy trying to determine what molecules are in space and which are not because these molecules have patterns that define them.

In the past 30 years have identified many compounds of carbon, an element that gave rise to simple molecules, which then won in complexity and thus gave rise to terrestrial life. 

Logically, the greater the degree of complexity of the molecules found, the easier the leap into life.

At the moment, and found 100 and 200 molecules of carbon atoms and even some amino acids such as glycine.

There is a theory known as panspermia defending that life originated on Earth, but come from other places and came to Earth via comets and meteorites that hit Earth.

This theory involves, at least in the distant past, the existence of life on other planets.

It is also believed that comets and meteorites brought water to Earth, especially in the beginning, when the frequency of crashes was higher.

It is believed that comets, most of which hit the Earth at high speeds, transporting materials rich in carbon.

The next step is to analyze and understand the evolution on Earth, as this can lead to understand what is happening elsewhere.

Originally, the system of molecules began playing obtaining energy from chemical reactions and the Sun

During the first stage of its life, the Earth was subjected to continuous impact and the sun radiated a 30% less heat than now, which kept the earth at the edge of freezing.

However, primitive organisms proliferated, some 3,500 million years.

Later, the oxygen produced by photosynthetic changed the primitive atmosphere of CO2 by oxidation, thus facilitating the emergence of more complex organisms.

Appeared once living organisms, their evolution and biodiversity are the result of the constant interaction between them.

Then, if we accept that intelligence is the ability to adapt to the world that surrounds the living, intelligent beings everywhere are beginning to proliferate.


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