5 facts about planet Earth. Quick reference

    Earth, Terra, Earth, Erde, all peoples have different names for the same world in which we all live. Having visited all known worlds of the solar system, we sincerely began to understand how unique our own world is. In this review, I will introduce you to little-known facts about the unique physical and climatic features of our stone giant that determined our very existence.


    We all know the main features of our planet, which have not yet been observed on other planets - namely, the oceans of liquid water on the surface and of course the existence of life. However, many will be interested to learn about the other unique features of our planet, thanks to which the existence and evolution of life on it has become possible.


    Iron Stone Giant

    Planet Earth is not only the largest of the rocky planets of the solar system, but also the most massive (in the solar system it is larger, it does not always mean more massive). The mass of the Earth is estimated at 5.97x10 24 kg, while the mass of its "sister" Venus is less than 1.1x10 24 kg. To increase the mass of Venus to the mass of the Earth, we would not even have enough of all the material of Mercury, Mars and the Moon together (5.8610 24 kg in total). And only adding to this planetary “salad” Ganymede, the largest and most massive satellite of the planet in the solar system (Jupiter), we could “outweigh” the stone giant. And that is only ½%.

    The largest "stone" planets and satellites of the solar system


    A similar difference in mass is also achieved by the fact that the Earth is also the most dense planet of the solar system (5.51 g / cm 3 ). The acceleration of gravity (g) at its equator is similar to that at the imaginary surface of most giant planets (with the exception of Jupiter, where g is 2.5 times greater).

    Speaking of the principle “larger does not mean more massive”: Ganymede is twice as massive as the Moon, and its diameter is 8% larger than that of the planet Mercury (5300 km versus 4900 km), however it is inferior to the latter by more than two times its mass!

    Natural Nuclear Reactor

    Almost all lovers of physics and related sciences (such as astrophysics) are well acquainted with the energy sources of stars like the sun, where the thermonuclear fusion of fusion of hydrogen and helium nuclei occurs. Active processes of "production" and energy transfer occur inside large planets, but due to diametrically opposite processes.
    During the formation of our planet, the heaviest and most dense elements, such as iron, nickel and radioactive isotopes descended to the center of the planet, the lightest remained closer to the surface. Thus, the differentiation of the inner layers of the planet took place. Therefore, large celestial bodies are distinguished by the relative scarcity of heavy elements at their surface (one of the main reasons for the interest of earthlings to Mars). As a result, an iron-nickel core was formed in the center of the planet that was heated by the decay of radioactive elements to 5700 ° C.

    Earth's bowels: 1-2 The inner and outer core (total mass 28.5 masses of the moon); 3 mantle (52 masses of the moon). Earth's lithosphere (4) together with the hydrosphere and atmosphere make up no more than 1/3000 of the planet


    All this heat is transferred through the liquid outer shell and passes into the mantle. Actually the movement of molten metal in the outer core and generates the Earth's magnetic field. Through convection processes in the mantle, energy reaches the Earth's crust - the continental drift known to us is the result of constant movements of lithospheric plates forming the earth's crust.
    Those. The Earth is not just a gigantic lump, which is active only at the surface, but a colossal nuclear reactor, with active heat transfer systems and powerful magnetic field generators.

    Magnetic shield

    The above mentioned magnetic field of the Earth is also not typical for the planets of the earth group. More precisely, a magnetic field of a similar nature was also found in Mercury, however, the magnetosphere of the Earth in its characteristics is more reminiscent of the magnetospheres of giant planets. In terms of strength at the equator, it is second only to Jupiter (10 times), superior to Saturn and Uranus and comparable to the magnetic field of Neptune (0.3 G at the equator). However, in size of the magnetosphere and dipole magnetic moment, it is significantly inferior to all of them.

    Earth magnetic field diagram. The ionosphere appears when the molecules of the upper atmosphere are ionized by solar radiation. It is present in almost all planets with relatively dense atmospheres and can deflect part of the charged particles arriving from the surface of the Sun


    Magnetic field strength (Gauss) expresses the force with which a given field acts on charged particles.

    Unlike the magnetospheres of the giant planets, the magnetic poles of the Earth do not correspond to the geographical ones, the northern magnetic pole of our planet is located in the southern hemisphere, and the southern, respectively, in the northern hemisphere. The reasons for this geographical location of the magnetic poles are their constant inversions at the geological time scales (associated with chaotic processes in the liquid outer core of the planet). Magnetic poles, traveling along the surface of the Earth, alternately approach the geographical poles of the planet. The whole process takes from 1000 to 10 000 years, during which the "polar" auroras in certain periods can be observed at any latitude of the planet, up to the equator. During such inversions, the planet’s magnetic field temporarily weakens, which can lead to an increase in the background radiation on the Earth’s surface.

    Inversions of the Earth’s magnetic poles over the past 5 million years. Black inversions are similar to modern ones. White color indicates the periods of reversal (magnetic poles lie in the corresponding geographical).


    Scientists do not have data on a positive correlation of the attenuation of the magnetic field during its inversion with the mass extinction of species. However, in any case, such a weakening of the "magnetic shield" of the Earth will not take humanity by surprise:
    “The last time the inversion of the magnetic field occurred about 780 thousand years ago. If homo sapiens arose 240 thousand years ago, this means that our species has never experienced geomagnetic inversions. Moreover, most scientists agree that the process itself from start to finish takes several thousand years - from 2-3 to 7-10 thousand years. In this case, however, the most active stage can occur within a millennium-long time interval. On the other hand, some experts believe that some of the polarity reversals in the history of the Earth could last tens of thousands of years. In any case, these are not years or decades ”
    (c) The most popular scenarios of the end of the world in December 2012.


    A month of stability

    While chaotic processes in the Earth’s core cannot guarantee a stable orientation of the Earth’s dipoles, the natural satellite of our planet has been providing stable orientation of its geographical poles relative to its orbital plane of revolution around the Sun at an angle of 23.5 ° for 4.5 billion years (varying within 3 ° with a period of 100,000 years). Such stability of the rotation axis of the planet is capital to provide relatively constant conditions for the evolution of life on our planet. For example, the planets Venus or Mars are doomed to randomly change the angle of inclination of the axis of rotation to the plane of revolution, under the influence of the tidal forces of large planets and the sun. However, the Earth's axis of rotation is subject to the so-called precession .

    The rotation of a celestial body is characterized by its movement around its own axis of rotation, while the revolution expresses the actual movement of one celestial body in orbit around another celestial body. Thus, the Earth does not revolve around the sun, but turns for 365 daily rotations of the Earth.

    The existence of such a heavy "stabilizer" in the orbit of our iron-stone giant also brings it closer to gas and ice giants. The moon has a transverse diameter of 3476 km and is the fifth largest satellite in the solar system (after the largest satellites of Jupiter and Saturn). Its matter would easily be enough for 5 planetoids weighing Pluto, and the remainder would be enough for two more asteroid belts between the orbits of Mars and Jupiter!

    The relative sizes of the Earth, the Moon and Pluto


    The Earth-Moon system has the smallest mass ratio of the planet and its satellite in the solar system (previously belonging to the Pluto-Charon system), the Earth in this respect exceeds the Moon “only” by 81 times. For example, Saturn surpasses the mass of Titan almost 3,000 times!

    A speck-sized universe ...

    The large mass of the Earth, combined with a powerful magnetic field and a large natural satellite, made the main contribution to the climatic diversity of our planet. Many people remember how in fantastic sagas heroes traveled to different worlds in which only a certain type of climate dominated. These are the rocky planets of the Star Trek Volcano, the hot Tatooine, the frozen Hut and the giant satellite of the giant Endor in Star Wars. Of course, this is only a simplification of the authors, and inhabited planets can show great climatic diversity, as on Earth. Our iron-stone giant has a place for the whole universe of all kinds of landscapes - for endless oceans, and impenetrable forests with a jungle, and, of course, for the endless dazzling ice surface of the poles.

    On this final (but not the last), amazing and unique feature of our planet, I would like to finish this brief review. However, it would be more correct to give the floor to Karl Sagan, who had long left us, but left a solid intellectual legacy:

    “Take another look at this point. It's here. This is our house. This is us. Everyone you love, everyone you know, everything you ever heard of, all people who ever existed lived their lives on it. A lot of our pleasures and sufferings, thousands of self-confident religions, ideologies and economic doctrines, every hunter and gatherer, every hero and coward, every creator and destroyer of civilizations, every king and peasant, every couple in love, every mother and every father, every capable child, inventor and traveler, every ethics teacher, every lying politician, every “superstar”, every “greatest leader”, every saint and sinner in the history of our species lived here - on a speck suspended in the sunbeam.

    Voyager 1, 1990, distance - 6 billion km


    Earth is a very small scene in a vast space arena. Think of the rivers of blood shed by all these generals and emperors, so that, in the light of glory and triumph, they can become short-term masters of a piece of sand. Think of the endless cruelties committed by the inhabitants of one corner of this point over the barely distinguishable inhabitants of another corner. About how often disagreements between them, how they crave to kill each other, how hot their hatred is.
    Our posturing, our imaginary significance, the illusion of our privileged status in the universe - they all pass in front of this point of pale light. Our planet is just a lone speck of dust in the surrounding cosmic darkness. In this grandiose void, there is not a hint that someone will come to our aid in order to save us from our ignorance.
    Earth is the only known world that can support life. We have nowhere else to go - at least in the near future. To visit - yes. Colonize - not yet. Whether you like it or not - Earth is now our home.
    Astronomy is said to instill modesty and reinforce character. There is probably no better demonstration of stupid human arrogance than this detached picture of our tiny world. I think she emphasizes our responsibility, our duty to be kinder with each other, to preserve and cherish the pale blue dot is our only home. ”
    - Pale blue dot


    My publications are close to the topic:
    Extreme sister of the Earth. Past and Future of the Morning Star
    Earth Rising on the Moon ... commonplace
    What killed the “terrible dinosaurs”? About generators of mass extinctions

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