Life

 At the outset, my goal of this article was to list the various theories reached by science regarding the emergence of life on planet Earth. With the passage of time and within the period of research with which I worked to collect sources, I found that it is more appropriate to shift the direction of the article from merely listing theories to a more comprehensive view and listing the natural factors that exist on planet Earth in particular and space in general that must exist to form life.. This is if we assume that life is a natural process that results automatically as soon as the appropriate conditions are provided. I would like to note that this article does not explain how life began, as we still do not know the answer to this scientific riddle, and everyone who claims to know the answer is claiming to know something without evidence or proof. We can identify and refute the factors necessary to shape life, but we do not know how it began in a proven way. I hope to consider this research as a humble attempt to summarize a group of scientific research on the subject of life in the solar system. I will first search for what are the conditions of life, then I will project these conditions on the planet and examine its biological system, and then I will compare these conditions within several possible stations for the existence of life in our solar system.

Definition of life:

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Some scientists define life as any system capable of reproduction, others define it within the systems capable of energy metabolism and reproduction, and others define it as the system capable of sustaining itself. In this article, I will rely on the definition adopted by the US space agency NASA. The NASA definition used says that life is "a sustainable chemical system subject to Darwinian evolution." Let us analyze this definition quickly: - First: a chemical system means that it is a system composed of organic chemistry and does not include systems made of electronic circuits or the like. Second, the condition for sustainability revolves around energy metabolism and reproduction. Third: the ability to develop through natural mechanisms.

an introduction:

In this article I am looking at the conditions for life on planet Earth. But it is very important that we do not limit our imagination and assume that life is limited in its inception in its present earthly form. But by virtue of that we are on Earth and that we are alive, we must study this phenomenon that occurred at least once in the history of the universe, which is the emergence of life on planet Earth, and through it we analyze the factors that led to this phenomenon. In this stage, I will list the factors separately and then relate them to a form that explains their collective impact on the planet

Planet Earth:

Planet Earth is about 4.5 billion years old and is part of a solar system consisting of 7 other planets (8 total) all orbiting a second-generation hydrogen star. The distance between the Earth and the Sun's star is 150 million kilometers, which allows the formation of chemical elements in their triangular forms (liquid, gaseous and solid).

The formation of this triad of states of matter is one of the most important conditions of life, and I will delve more deeply into this topic later

Magnetism and the sun:

Earth's structure is made up of several layers that make up the total mass of the planet. We live on the crust, but there are several layers of ground beneath us until we reach the core. Earth's core is formed of two layers, a liquid metallic layer and a solid mineral layer. The presence of iron and nickel in the core of the Earth has a very important effect, which is the formation of a geosphere around the planet. The magnetosphere extends about 65,000 kilometers from the surface of the Earth. That is, the Earth is surrounded by a magnetic dome 65,000 kilometers deep from the surface of the Earth into space.

This atmosphere is very important for life on Earth because the magnetic field works to hold the atmosphere together, which forms a closed ecosystem within the planet. Also, one of the benefits of the magnetosphere is that it protects the planet from solar radiation harmful to life and that causes the disintegration of many of the organic elements important to life if they reach the earth.

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The solar wind that reaches us from the sun is expressions of positively charged and very hot particles that are launched towards the earth in the form of plasma, and as it approaches the earth, it wraps around the Earth's magnetic envelope and appears in beautiful colors we call the twilight lights. Aurora borealis can be observed near the Earth's poles.

Next time you observe the aurora borealis with its beautiful colors, remember that it is a very important natural phenomenon in the development of life and its survival on the globe. Note: Many people confuse the magnetosphere with the force of gravity.

The magnetosphere is an effect related to electromagnetism, and gravity relates to mass and its effect on spacetime. There is also a difference between the magnetosphere and the atmosphere, as the atmosphere represents the cover composed of the earth's gaseous elements and is responsible for the survival of the Earth within a closed ecosystem. The magnetosphere is what holds the atmosphere together and stays around the earth.

Appropriate attractiveness:

Gravity is appropriate in a way that allows life to be formed and developed in ways that do not collapse in on itself. For example, if life was found on a planet with a gravity several times stronger than Earth’s gravity, life would not have evolved in the form of bodies with protrusions such as limbs or wings. So the size of the planet and its mass type is very important because of the effect of gravity on the elements on the planet. This, of course, has a direct impact on the formation and diversity of life.

The gravitational pull of Jupiter is twice and half the Earth's gravitational pull. This means that the earthly life in its current form based on the data of the Earth's gravity will not be suitable for Jupiter even if all life conditions are available. The strength of the bones and muscles will not be sufficient to withstand the difference in gravity. So the force of gravity has an important role in the shape and quality of life's development.

Note that I am not saying that life is impossible on a planet with a high gravitational influence, but rather that it will be very different from what we know about life today. For example, scientists classify the planets within the influence of the theoretically acceptable gravitational force, provided that it does not exceed 13 times the gravity of Jupiter because this type of gravitational force will cause hydrogen to fuse into heavy hydrogen and turn the planet into a brown dwarf star.

 

So the search is for planets whose gravity does not exceed this maximum gravitational (33 times the Earth's gravity).

Tectonic plates:

In a previous paragraph, I mentioned that the earth consists of ground layers. The top layer of the Earth is the "crust", which is not a single piece but rather is made up of large plates (8 large plates and many small plates). This phenomenon was discovered by the German scientist Alfred Wegener when he proposed the theory of continental drift in 1912.

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These movements within the lithosphere result in the creation of different conditions and cross-fertilization between elements and materials, and mixing them with different forms and important factors shaping life. I will delve more deeply into this topic within the axis of theories of the emergence of life on planet Earth. Many people think that sunlight is the only source of energy on the planet, but in fact many of the organisms that live at the bottom of the oceans do not get sunlight at all, but rather derive their energy from the volcanic craters at the bottom. So the latent heat in the earth's layers is an important source of energy in addition to sunlight.

Solar stability:

The presence of a relatively stable star for a long period of time allows the natural factors formed to develop in a stable and regular manner. There is no doubt that life began quickly on the surface of the earth, as it began approximately 500 million years after the formation of the planet and continued to this day, but due to the stability of the sun's star, this life was able to develop within 4 billion years without being affected by cosmic natural disasters. If the sun was one of the stars that explode more quickly, or it is larger, or its fusion is halomeric instead of hydrogen, or it is less stable in general, the Earth would not have been able to maintain its electromagnetic atmosphere, and the Earth would not have formed an atmosphere that isolates the Earth from outer space.

Habitable range:

Planet Earth is 150 million kilometers away from the sun (this distance is called a solar unit). Within any solar system, and based on the type of star, there is a distance called the habitable zone, which determines the acceptable distance for the formation of the elements within the three forms (liquid, gas, and solid). The existence of planet Earth within this appropriate distance for the formation of water is one of the main reasons for the formation of life and that is due to the importance of water in the formation of life as we know it. The solar unit is an appropriate distance with respect to the sun's star and the planet, but it is not a general measure as the size, type, age, planet type and chemical composition of the star affect the estimation of the habitable range distance. Today, after 4 billion years, the Earth is at the boundaries of the range and started to go outside it towards the sun. Researchers estimate that Earth will be completely out of range in approximately 1.7 billion years.

Purchaser:

Jupiter is very important for the formation of life on Earth, as it represents the guardian of the solar system from comets and large bodies through its gravitational force. Jupiter constitutes a buffer for comets and other bodies that may approach the planet, so the presence of a planet with strong gravity within the outer range of the solar system works to protect the planets within the internal range and contributes to the stability of the development of their ecosystems without being exposed to geological disasters.

It should be noted that a comet hit the planet 65 million years ago and caused comprehensive extinctions of living things, and among the most important of these extinctions were the dinosaurs. The extinction of the dinosaurs was an important reason in the evolution of mammals and then the great apes until reaching humans.

the moon:

The moon is 384,400 kilometers away from Earth today. But the moon is separated from the earth by a distance of 3.8 cm every year. This means that if we go back to the period of the emergence of life on Earth (approximately 4 billion years) and consider that the ratio of the divergence between the earth and the moon is the same, then this means that the moon was much closer than it is today, and this means that the effect of the lunar gravity was much greater on Earth.

This point is very important in the study of the formation of life because the moon is an important source of energy due to the force of its attraction. Imagine with me how the ocean water is constantly moving due to the moon’s gravitational pull, which contributes to mixing the organic carbon materials together.

succession of night and day:

The alternation of day and night on the globe means that the temperature is not cold or hot for long periods. For example, a day on the planet Venus takes 116 days on Earth. As I mentioned earlier about the importance of energy for the emergence of life, I add that any variable factor is a positive factor, especially if the change is regular for long periods that allow parasitic systems to form on this energy.

Day and night are the result of an astronomical phenomenon, as the planet rotates around itself, so they are the result of energy expended in the form of the movement of the planet. The temperature fluctuations between day and night prevent the elements from taking a certain shape for long periods. If the duration of the day on Earth was similar to planet Zahra, the water would have evaporated within a short period of time, and if the night was as long as Zahra, the water would have frozen. That is why the existence of day and night alternations is important for obtaining all three types of matter (solid, liquid, and gas) and from them obtaining various environmental systems on the planet.

Life conditions:

-Elements:

When we delve into the properties of the atom and the mechanisms of its connection between them, we can understand the basic laws responsible for the formation of chemical elements. Atoms are linked together to form chemical elements, for example two hydrogen atoms are bonded with one oxygen atom, resulting in our water element.

One carbon atom with two oxygen atoms gives us carbon dioxide. A silicon atom with two oxygen atoms that produce glass. Each material has different properties by how it bonds with other materials, and these properties are related to the number of electrons surrounding the nucleus of an atom.

 

Without going into these details, it is important to mention that carbon is one of the most important elements in the composition of chemical elements. The "desire" of carbon to have four additional electrons means that carbon can bond with four other atoms at the same time.

This makes carbon the backbone for building the inorganic and organic chemical elements. All living things depend on carbon for their basic structure due to its property of bonding elements with each other.

So the presence of carbon in the environment is a prerequisite for building organic compounds capable of metabolizing energy and replicating themselves. That is why we find that scientists and researchers for life in space are very interested in the presence of carbon within the ecosystem, which means the diversity of the chemical elements in that system.

-energy:

Energy is an external influencing factor on an indoor, isolated system. The refrigerator has to dissipate heat energy in order to produce internal cold in the box. The sun has to burn hydrogen in order to send its photons towards the earth and warm it. The moon’s mass has to affect the space-time between the moon and the earth to cause ocean waters to move in the form of tides, roots and waves. In order for anything to happen, there must be movement and movement represented by the types of energy.

So the first condition for the formation of life is the existence of energy sources capable of emitting movement within the environment. Examples of energy on planet Earth: the sun's heat, the sun’s gravity, the moon’s gravity, the latent heat within the earth’s layers and the geological movements and their effects from volcanoes, earthquakes, rivers, and water erosion.

So if we want to assess the conditions for the formation of life, we have cosmic conditions related to the location of the planet and its astronomical position, and local conditions related to the existence of systems in which carbonic organic materials and energy sources are able to influence and mix these organic materials continuously. Now we reach the last paragraph of this axis, which is stability in the system, which allows these interactions to develop cumulatively without exposure to cases of total annihilation.

Assuming that meteorites and space objects collide on the Earth continuously when the Earth's environment is stable, so chemical elements develop into biological systems. As I mentioned earlier, the presence of a gas giant planet like Jupiter in the solar system prevents large objects from reaching and colliding with Earth. Also, the relatively stable condition of the sun allowed the stew of life to simmer over a gentle flame.

 

So if we are assessing the ability of a new planet to host life, we must evaluate the general stability around the planet and the duration of this stability if it is estimated in millions of years for life to evolve.

Hypotheses of the emergence of life:

After spending a long time reading and researching these hypotheses, I would like to mention an important idea before going into the details, which is that there is no single scientific hypothesis capable of explaining the origin of life. In every theory there are ambiguities that the theory cannot answer or scientific contradictions with evidence from other theories, but if we relate all these theories and put them within a comprehensive theory, we may have come close to reaching some answers, but the road is still long.

Please separate the study of the causes and mechanisms of the emergence of life, and the study of the conditions and existence of life. By simply refuting the conditions responsible for the origin of life, we become able to actively search for life in space even if we do not understand how this life began.

One of the biggest problems that we suffer when trying to solve the mystery of life is that the event of evolution occurred a very long time ago, about 4 billion years ago. That is why we do not have a clear idea in which to describe the environmental situation of the Earth at that time. The chemical composition of the atmosphere was different from the current composition (now nitrogen and oxygen), the distance of the moon was different (the effect of gravity is much greater) and the sun's temperature was different (colder).

So we are working on building a virtual template and we are working through the template to discover influences that may lead to the transformation of organic chemicals into protein systems capable of replicating themselves and metabolizing energy.

We will search in some hypotheses about the emergence of life in brief. Personally, I do not think that the answer is within any of these hypotheses, and I think that the answer lies in a premise composed of all these hypotheses and some secrets that we have not yet discovered. Therefore, I will not spend much time describing or defending these hypotheses.

Or the first simple mixture: Primordial soup In 1924, the scientist Alexander Ovrin developed this hypothesis, which says that life began due to the interaction of some chemical elements on the surface of lakes and oceans through exposure to electric shocks due to thunder.

 

The interaction of these chemical elements with the electric thunderbolt was what produced the amino acids, which are the main building block in the formation of nucleic acids and which later embody the protein bodies. This hypothesis was not accepted by scholars at the beginning. In 1953, scientists Miller-Urey conducted a famous scientific experiment at the University of Chicago, where they prepared a hypothetical environment that simulated the environment on planet Earth 4 billion years ago. The elements of hydrogen, methane and ammonia were used in a water container, and then the vessel was subjected to electric shocks, along with thunderbolts.

The result of the experiment was the emergence of new organic elements, just as the scientist Alexander Ufren had assumed. The emergence of organic matter in this way is evidence that the organic matter and protein-forming amino acids can be created under certain natural conditions.