For many centuries, people have been interested in the question of the origin of the Universe and, in particular, our planet - the Earth. Have you ever thought about where everything that surrounds us came from?
During the development of science, many versions have been put forward: from objectively absurd to quite probable. Currently, there is one generally accepted version of the origin of the Universe, called the Big Bang theory.
The essence of this theory is that billions of years ago there was a huge fireball in outer space, the temperature of which exceeded millions of degrees. At some point, this ball exploded, scattering particles and matter throughout the Universe at enormous speed.
Since the temperature of the fireball was incredibly high, the particles scattered throughout the Universe had quite a lot of energy. Therefore, for the first time after the explosion, they did not attract and did not interact in any way.
However, after about a million years, the particles began to cool, and atoms began to form from them through mutual attraction and repulsion. From atoms later, first elementary chemical elements (such as helium and hydrogen) appeared, and then more and more complex ones.
Over time, cooling more and more, the newly formed elements began to unite into huge clouds of dust and gas. As a result of gravitational attraction, small objects began to be attracted to large ones, the particles either collided with each other, or scattered, forming more and more new parts of the Universe. Thus, stars, galaxies and planets appeared.
This is how our planet appeared. Its core gradually compressed, releasing a huge amount of thermal energy. As a result of this, the rocks that made it up melted, and the substances separated from the core formed the earth's crust.
After about a billion years, the Earth cooled, the earth's crust hardened and formed the outer shell of our planet, and gases periodically ejected from the bowels of the Earth, thanks to the earth's gravity, subsequently formed the earth's atmosphere. Some of the gases from the atmosphere condensed on the surface of the Earth, and oceans appeared. Thus, all the conditions were created for the emergence of life on Earth. The same principle applies to all living things.
Today, scientists have proven that the Universe continues to expand, new elements continue to form on the Sun, and our Earth is also undergoing significant changes. Nothing stands still, everything develops, dies and is reborn. This has been proven over more than one million years, by scientific research and observations of processes occurring on the planet.
Mountain formations are gradually shifting, the planet is changing its axis of rotation, due to which changes in climate occur, solar flares are becoming more frequent. This all just means that millions of years ago everything happened according to the same scenario in order to open new horizons for the existence of the Universe, planets, stars and galaxies.
That's a very difficult question. And it is hardly possible to give an exhaustive answer to it. At least for now. The Earth itself preserves its past, but there is no one to tell about this past - it was so long ago.
Scientists are slowly “questioning” the Earth through the study of radioactive rocks and are getting some answers. But the known past of the Earth is not final, but goes into an even more distant past - what happened before it solidified? Scientists compare planets with each other in their present state and try to judge from them the evolution of the Earth. Understanding the world is a long and not so easy process.
There are many hypotheses about the origin of the Earth and other planets, some of which we will consider separately on our website.
Modern hypotheses about the origin of the Solar System must take into account not only the mechanical characteristics of the Solar System, but also take into account numerous physical data on the structure of the planets and the Sun.
In the field of cosmogony, a stubborn ideological struggle has constantly been and is being waged, since the worldview of scientists is dramatically affected here. Proponents of the theory of creationism, for example, believe that the age of the Earth is no more than 10,000 years, and supporters of the theory of evolution measure the age of the Earth in billions of years.
Thus, there is not yet a hypothesis that answers all questions about the origin of the Earth and other planets of the solar system. But scientists increasingly agree that the Sun and the planets were formed simultaneously (or almost simultaneously) from a single material medium, from a single cloud of gas and dust.
There are the following hypotheses about the origin of the planets of the solar system (including the Earth): the hypothesis of Laplace, Kant, Schmidt, Buffon, Hoyle, etc.
Basic modern scientific theory
The emergence of the Solar System began with the gravitational compression of a gas and dust cloud, in the center of which the most massive body, the Sun, was formed. The matter of the protoplanetary disk gathered into small planetesimals, which collided with each other and formed planets. Some planetesimals were ejected from the inner regions into the Kuiper Belt and the Oort cloud.
Kuiper Belt- the region of the Solar System from the orbit of Neptune to a distance of about 55 AU. e. from the Sun. Although the Kuiper Belt is similar to the asteroid belt, it is about 20 times wider and more massive than the latter. Like the asteroid belt, it consists mainly of small bodies, that is, material left over from the formation of the Solar System. Unlike asteroid belt objects, which are primarily composed of rocks and metals, Kuiper belt objects are composed primarily of volatile substances (called ices) such as methane, ammonia, and water. This region of near space contains at least three dwarf planets: Pluto, Haumea and Makemake. It is believed that some satellites of the planets of the solar system (Neptune's satellite Triton and Saturn's satellite Phoebe) also arose in this area.
Oort cloud- a hypothetical spherical region of the Solar System that serves as a source of long-period comets. The existence of the Oort cloud has not been instrumentally confirmed, but many indirect facts indicate its existence.
The Earth formed about 4.54 billion years ago from the solar nebula. Volcanic degassing created the primary atmosphere on earth was created as a result of volcanic activity, but it had almost no oxygen, it would have been toxic and not suitable for life. Much of the Earth was molten due to active volcanism and frequent collisions with other space objects. One of these large impacts is believed to have tilted the Earth's axis and formed the Moon. Over time, such cosmic bombardment ceased, allowing the planet to cool and form a solid crust. The water delivered to the planet by comets and asteroids condensed into clouds and oceans. The earth finally became hospitable to life, and its earliest forms enriched the atmosphere with oxygen. For at least the first billion years, life on Earth took small and microscopic forms. Well, then the process of evolution began.
As we said earlier, there is no consensus on this matter. Therefore, hypotheses about the origin of the Earth and other planets of the solar system continue to arise, and old ones also exist.
J. Buffon's hypothesis
Not all scientists agreed with the evolutionary scenario for the origin of the planets. Back in the 18th century, the French naturalist Georges Buffon expressed a hypothesis, supported and developed by the American physicists Chamberlain and Multon. The hypothesis is this: once upon a time another star flew in the vicinity of the Sun. Its gravity caused a huge tidal wave on the Sun, stretching in space for hundreds of millions of kilometers. Having broken away, this wave began to swirl around the Sun and disintegrate into clumps, each of which formed its own planet.
F. Hoyle's conjecture
The English astrophysicist Fred Hoyle proposed another hypothesis in the 20th century: the Sun had a twin star that exploded. Most of the fragments were carried into outer space, a smaller part remained in the orbit of the Sun and formed planets.
Creation theory
Creationism- a theological and ideological concept according to which the main forms of the organic world (life), humanity, planet Earth, as well as the world as a whole, are considered as directly created by the Creator, or God. The term "creationism" became popular around the end of the 19th century, meaning concepts that recognize the truth of the creation story set out in the Old Testament. It should be noted that there are several directions in the theory of creationism itself, but, for example, Templeton Prize-winning geneticist, evolutionist and former Dominican Catholic priest Francisco Ayala believes that there are no significant contradictions between Christianity and evolutionary theory, and evolutionary theory, on the contrary, helps explain both the perfection of the world created by God and the cause of evil in the world.
Protodeacon A. Kuraev in the book “Orthodoxy and Evolution” he writes: “Those who vaguely think that God becomes unnecessary if we extend the process of creation are naive. Equally naive are those who believe that the creation of the world in more than six days diminishes the greatness of the Creator. It is only important for us to remember that nothing interfered or limited creative action. Everything happened according to the will of the Creator. But whether this will was to create the world instantly, or in six days, or in six thousand years, or in myriads of centuries, we do not know.”
Our planet appeared approximately 4.54 billion years ago. Scientists cannot accurately describe all the features of its formation, but the generally accepted theory of the birth of the Earth has numerous scientific confirmations.
At first, on the site of the solar system there was a huge molecular cloud. It split and from one part of it a protosolar nebula was formed, which began to shrink under the influence of gravity. In the core of the nebula, thermonuclear reactions began, from which our Sun was formed.
The young star was surrounded by a dense protoplanetary cloud consisting of gases and dust. In this gas and dust formation, local centers of gravity began to form, and protoplanets (planetesimals) were born.
Protoplanets collided and attracted the remains of gas and dust matter. As a result, the Earth, Mars, Neptune, Venus, etc. were formed.
How the planet appeared: video
How the Earth was formed: educational video for children
Another eight hundred million years passed and life arose on the cooled Earth.
Planet Earth is the only known place where life has been found so far, I say for now because perhaps in the future people will discover another planet or satellite with intelligent life living there, but for now Earth is the only place where there is life. Life on our planet is very diverse, from microscopic organisms to huge animals, plants and more. And people have always had the question - How and where did our planet come from? There are many hypotheses. Hypotheses for the origin of the Earth are radically different from each other, and some of them are very difficult to believe.
This is a very difficult question. You cannot look into the past and see how it all began and how it all began to emerge. The first hypotheses of the origin of planet Earth began to appear in the 17th century, when people had already accumulated a sufficient amount of knowledge about space, our planet and the solar system itself. Now we adhere to two possible hypotheses for the origin of the Earth: Scientific - The Earth was formed from dust and gases. Then the Earth was a dangerous place to live after many years of evolution, the surface of the planet Earth became suitable for our life: the Earth's atmosphere is breathable, a solid surface, and much more. And Religious - God created the Earth in 7 days and settled here all the diversity of animals and plants. But at that time, knowledge was not enough to weed out all other hypotheses, and then there were much more of them:
- Georges Louis Leclerc Buffon. (1707–1788)
He made an assumption that no one would believe now. He suggested that the Earth could have been formed from a piece of the Sun, which was torn off by a certain comet that hit our star.
But this theory was refuted. Edmund Halley, an English astronomer, noticed that our solar system is visited by the same comet at intervals of several decades. Halley even managed to predict the next appearance of the comet. He also found that the comet changes its orbit a little each time, which means it does not have significant mass to tear off a “piece” from the Sun.
- Immanuel Kant. (1724–1804)
Our Earth and the entire solar system were formed from a cold and collapsing dust cloud. Kant wrote an anonymous book where he described his hypotheses about the origin of the planet, but it did not attract the attention of scientists. Scientists by this time were considering a more popular hypothesis put forward by Pierre Laplace, a French mathematician.
- Pierre-Simon Laplace (1749–1827)
Laplace suggested that the solar system was formed from a constantly rotating gas cloud heated to enormous temperatures. This theory is very similar to current scientific theory.
- James Jeans (1877–1946)
A certain cosmic body, namely a star, passed too close to our Sun. The sun's gravity tore some mass out of this star, forming a sleeve of hot material that eventually formed all of our 9 planets. Jeans spoke about his hypothesis so convincingly that in a short time it won the minds of people and they believed that this was the only possible emergence of the planet.
So, we looked at the most famous hypotheses of the origin, they were very unusual and diverse. In our time, they would not even listen to such people, because we now have much more knowledge about our solar system and about the Earth than people knew then. Therefore, hypotheses about the origin of the Earth were based only on the imagination of scientists. Now we can observe and conduct various studies and experiments, but this has not given us a definitive answer about how and from what exactly our planet originated.
Only relatively recently did people receive factual material that makes it possible to put forward scientifically based hypotheses about the origin of the Earth, but this question has worried the minds of philosophers since time immemorial.
First performances
Although the first ideas about the life of the Earth were based only on empirical observations of natural phenomena, nevertheless, fantastic fiction often played a fundamental role in them rather than objective reality. But already in those days, ideas and views arose that even today amaze us with their similarity to our ideas about the origin of the Earth.
So, for example, the Roman philosopher and poet Titus Lucretius Carus, who is known as the author of the didactic poem “On the Nature of Things,” believed that the Universe is infinite and there are many worlds similar to ours in it. The ancient Greek scientist Heraclitus (500 BC) wrote about the same thing: “The world, one of all, was not created by any of the gods and by any of the people, but was, is and will be an eternally living fire, naturally igniting and naturally extinguishing "
After the fall of the Roman Empire, a difficult time of the Middle Ages began for Europe - the period of the dominance of theology and scholasticism. This period was then replaced by the Renaissance; the works of Nicolaus Copernicus and Galileo Galilei prepared the emergence of progressive cosmogonic ideas. They were expressed at different times by R. Descartes, I. Newton, N. Stenon, I. Kant and P. Laplace.
Hypotheses about the origin of the Earth
R. Descartes' hypothesis
So, in particular, R. Descartes argued that our planet was previously a hot body, like the Sun. And subsequently it cooled down and began to look like an extinct celestial body, in the depths of which fire still remained. The hot core was covered by a dense shell, which consisted of a substance similar to the substance of sunspots. Above was a new shell - made of small fragments resulting from the disintegration of the spots.
Immanuel Kant's hypothesis
1755 - the German philosopher I. Kant suggested that the substance from which the body of the solar system consists - all the planets and comets, before the start of all transformations, was decomposed into primary elements and filled the entire volume of the Universe in which the bodies formed from them now move. These Kantian ideas that the solar system could have formed as a result of the accumulation of primordial dispersed scattered matter seem surprisingly correct in our time.
P. Laplace's hypothesis
1796 - French scientist P. Laplace expressed similar ideas about the origin of the Earth, knowing nothing about the existing treatise of I. Kant. The emerging hypothesis about the origin of the Earth thus received the name of the Kant-Laplace hypothesis. According to this hypothesis, the Sun and the planets moving around it were formed from a single nebula, which, during rotation, broke up into separate clumps of matter - planets.
The initially fiery liquid Earth cooled down and became covered with a crust, which warped as the depths cooled and their volume decreased. It should be noted that the Kant-Laplace hypothesis prevailed among other cosmogonic views for more than 150 years. It was on the basis of this hypothesis that geologists explained all the geological processes that occurred in the bowels of the Earth and on its surface.
E. Chladni's hypothesis
Of course, meteorites - aliens from deep space - are of great importance for the development of reliable scientific hypotheses about the origin of the Earth. This is because meteorites have always fallen on our planet. However, they were not always considered aliens from outer space. One of the first to correctly explain the appearance of meteorites was the German physicist E. Chladni, who proved in 1794 that meteorites are the remains of fireballs of unearthly origin. According to him, meteorites are pieces of interplanetary matter traveling in space, probably fragments of planets.
Modern concept of the origin of the Earth
But not everyone shared this kind of thoughts in those days; however, by studying stone and iron meteorites, scientists were able to obtain interesting data that was used in cosmogonic constructions. For example, the chemical composition of meteorites was clarified - it mainly turned out to be oxides of silicon, magnesium, iron, aluminum, calcium, and sodium. Consequently, it became possible to find out the composition of other planets, which turned out to be similar to the chemical composition of our Earth. The absolute age of the meteorites was also determined: it is in the range of 4.2-4.6 billion years. Currently, these data have been supplemented with information about the chemical composition and age of the rocks of the Moon, as well as the atmospheres and rocks of Venus and Mars. These new data show, in particular, that our natural satellite the Moon was formed from a cold gas and dust cloud and began to “function” 4.5 billion years ago.
A huge role in substantiating the modern concept of the origin of the Earth and the Solar system belongs to the Soviet scientist, academician O. Schmidt, who made a significant contribution to solving this problem.
Thus, bit by bit, based on isolated isolated facts, the scientific basis of modern cosmogonic views was gradually formed... Most modern cosmogonists adhere to the following point of view.
The starting material for the formation of the Solar System was a gas and dust cloud located in the equatorial plane of our Galaxy. The substance of this cloud was in a cold state and usually contained volatile components: hydrogen, helium, nitrogen, water vapor, methane, carbon. The primary planetary matter was very homogeneous, and its temperature was quite low.
Due to gravitational forces, interstellar clouds began to compress. The matter was densified to the stage of stars, at the same time its internal temperature increased. The movement of atoms inside the cloud accelerated, and, colliding with each other, the atoms sometimes united. Thermonuclear reactions occurred, during which hydrogen was converted into helium, releasing a huge amount of energy.
In the fury of powerful elements, the Proto-Sun appeared. His birth occurred as a result of a supernova explosion - a not so rare phenomenon. On average, such a star appears in any Galaxy every 350 million years. During a supernova explosion, enormous energy is emitted. The matter ejected as a result of this thermonuclear explosion formed a wide, gradually denser gas plasma cloud around the Proto-Sun. It was a kind of nebula in the form of a disk with a temperature of several million degrees Celsius. From this protoplanetary cloud, planets, comets, asteroids and other celestial bodies of the Solar System subsequently emerged. The formation of the Proto-Sun and the protoplanetary cloud around it occurred perhaps about 6 billion years ago.
Hundreds of millions of years have passed. Over time, the gaseous matter of the protoplanetary cloud cooled. The most refractory elements and their oxides condensed from the hot gas. As further cooling continued over millions of years, dusty solids appeared in the cloud, and the previously hot gas cloud became comparatively cold again.
Gradually, a wide annular disk formed around the young Sun as a result of the condensation of dusty matter, which subsequently disintegrated into cold swarms of solid particles and gas. From the internal parts of the gas and dust disk, planets like the Earth began to form, consisting, as a rule, of refractory elements, and from the peripheral parts of the disk, large planets rich in light gases and volatile elements began to form. A huge number of comets appeared in the outer zone itself.
Primary Earth
So, approximately 5.5 billion years ago, the first planets, including the primordial Earth, arose from cold planetary matter. At that time, it was a cosmic body, but not yet a planet; it did not have a core or mantle, and there were not even solid surface areas.
The formation of the Proto-Earth was an extremely important milestone - it was the birth of the Earth. In those days, the usual, well-known geological processes did not occur on Earth, which is why this period of the planet’s evolution is called pre-geological, or astronomical.
The proto-earth was a cold accumulation of cosmic matter. Under the influence of gravitational compaction, heating from continuous impacts of cosmic bodies (comets, meteorites) and the release of heat by radioactive elements, the surface of the Proto-Earth began to heat up. There is no consensus among scientists about the magnitude of the heating. According to the Soviet scientist V. Fesenko, the substance of the Proto-Earth heated up to 10,000°C and, as a result, passed into a molten state. According to the assumptions of other scientists, the temperature could barely reach 1,000 ° C, and still others deny even the very possibility of melting the substance.
Be that as it may, the heating of the Proto-Earth contributed to the differentiation of its material, which continued throughout subsequent geological history.
The differentiation of the Proto-Earth substance led to the concentration of heavy elements in its internal regions, and lighter elements on the surface. This, in turn, predetermined the further division into the core and mantle.
Initially, our planet did not have an atmosphere. This can be explained by the fact that gases from the protoplanetary cloud were lost in the first stages of formation, because at that time the mass of the Earth could not retain light gases near its surface.
The formation of the core and mantle, and subsequently the atmosphere, completed the first stage of the Earth’s development - pre-geological, or astronomical. The earth has become a solid planet. After which its long geological evolution begins.
Thus, 4-5 billion years ago, the solar wind, hot rays of the Sun and cosmic cold dominated the surface of our planet. The surface was constantly bombarded by cosmic bodies - from dust particles to asteroids...
