THE SOLAR SYSTEM IS THE Sun • Mercury • Venus • Earth • Mars • Asteroids • Jupiter • Saturn • Uranus • Neptune • Dwarf Planets • Comets • Kuiper Belt
Explanations: The location of the planets in space relative to each other and the Sun are shown in the picture completely conditionally — as a given.
The proportionality of the distances between the planets and the Sun is not observed.
The proportions of linear dimensions are partially observed for the planets of the Earth group with satellites: the Moon near the Earth, Phobos and Deimos near Mars, and separately for the giant planets (without satellites).
The proportions of the linear dimensions of Mars and the dwarf planet Ceres in the asteroid belt are partially observed.
The proportions of linear sizes (relative to each other) for the eight largest trans Neptunian dwarf planets: Eris, Pluto, Makemake, Haumea, Sedna, Orc, Quavar and Varuna, known as of March 2009, are partially observed.
go to the page Astronomy (initial) Units of measurement in astronomy
OUR PLACE IN THE UNIVERSE is now people quite" easily " imagine their place in the boundless expanses of Space.
They have been coming to such ideas for many thousands of years from the first questioning glances of primitive man at the night sky of the Earth, to the creation of the most powerful telescopes in all frequency ranges of electromagnetic vibrations.
Other types of wave processes (gravitational waves) and elementary particles (neutrino telescopes) are also used to study the properties of outer space.
Space scouts are used — interplanetary spacecraft that continue their work already outside the Solar System and carry information about our planet to those inhabitants of the Galaxy (Universe) who will become owners of these spacecraft in the future.
Studying nature (other Greek.
humanity had to move from simple contemplation and wisdom (natural philosophy) to the creation of a full — fledged science — physics experimental and theoretical (G. Galileo).
Physics was able to predict the future in the development of natural processes.
Physics is essentially the basis for all sciences, including mathematics, which cannot exist separately from nature, since it draws its themes from nature and is a tool for its research.
As the mysteries of the movement of the planets were solved, new sections of mathematics were created (I. Newton, G. Leibniz), which are now being used with great success in all sections of human activity without exception, including in the knowledge of the laws of the universe.
Understanding these laws allowed us to determine our place in the universe.
The process of cognition continues and cannot stop as long as a person and his natural curiosity exist — he wants to know what everything is made of and how it is arranged (galaxies, stars, planets, molecules, atoms, electrons, quarks...), where everything comes from (physical vacuum), where it disappears (black holes), etc.
For this, scientists create new physicomathematical theories, for example, superstring theory (M– theory) (E. Witten, P. Townsend, R. Penrose, etc.), which explain the structure and Macro– and Microcosms.
So, our Galaxy (the Milky Way) is part of the so called local group of galaxies.
The sizes of galaxies and the distances between them are huge and require special units of measurement (see the column on the right).
The parallactic ellipse described by the star looks from the Earth the same as the Earth's orbit, if we could observe it from the star <...
>The orbital motion of the Earth leads to the fact that during the year we find ourselves on one side of the Sun, then on the other, and as a result we look at the stars from slightly different angles.
On the Earth's firmament, this looks like the fluctuations of the star around a certain average position — the so called annual parallax.
The farther away the star is, the smaller the scope of these oscillations.
Having determined how much the apparent position of the star changes due to the annual movement, you can determine the distance to it using the usual geometric formulas.
In other words, the distance determined by parallax is not burdened with any additional assumptions, and its accuracy is limited only by the accuracy of measuring the parallactic angle.
< ...
> You can read about distances and ages in astronomy in Dmitry Vibe's article " How do astronomers know this?"
our neighbors from the local group of galaxies (enlarge picture)
Our Galaxy the Milky Way is a giant disk consisting of stars of different types, star clusters, interstellar matter consisting of various types of radiation, elementary particles, atoms and molecules, dark matter, over the mystery of which astrophysicists are now struggling.
There is a black hole (at least one) in the center of our Galaxy — another of the astrophysical problems of our time.
The diagram below shows the structure of the Galaxy (arms, core, halo), its size and the place occupied in it by the Sun, the Earth and other planets satellites of the Sun.
The movement of the Earth in orbit causes a one year parallax (the angle at which the radius of the Earth's orbit is visible from the sun, perpendicular to the ray of vision).
For nearby stars, it has a noticeable value, although it does not exceed 1".
In the old books, parallax was denoted by the Greek letter π ; in recent years, the Latin letter p is more often used.
If the parallax angle (p) is small and expressed in radians, and the length of the base perpendicular to the direction of the object is a, then the distance to the object is r = a / p .
If the parallax is expressed in arc seconds, then the distance to the object r = (1 / p ) parsecs = 206,265 (1 / p ) au.
the location of the solar system in the Milky Way Galaxy (diagram) enlarge the picture
To measure distances in the visible part of the universe, a parsec (from parallax + second) is used.
The distance to an object whose annual parallax is 1".
In the old books, the word "parsek" was abbreviated as ps.
After switching to the SI system, in order not to be confused with picoseconds, it is abbreviated as "pc".
1 pc = 3.26 holy years = 206,265 au = = 3,086·1016 m.
As a unit of measurement of distances between bodies in the Solar System, the astronomical unit (AU) is used — the average distance between the centers of the Earth and the Sun, approximately equal to the major semi axis of the Earth's orbit.
One of the most precisely defined astronomical constants: 1 AU = (149,597,870 ± 2) km.
The unit of distance sometimes used in astronomy, a light year is equal to the length of the path that light travels in a vacuum for 1 tropical year (365,242 days): 1 St. G. = 9.46·1015 m = 9.46·1018 cm = = 0.307 parsecs.
The distance from the Sun to the center of the Galaxy (the Milky Way) is approximately.
30 thousand sv.
years; the diameter of the Galaxy is more than 100 thousand sv.
years.
scheme of branches (branches) The Milky Way (the solar system is highlighted) enlarge the picture
COSMOGONY (Greek. κ ο σ µ ο γ ό ν ι α
from Greek. κ σ σ μ ο ο — order, world, universe and γ ο ν ν — birth origin of the world) is a section of astronomy devoted to the origin and development of celestial bodies.
THE ORIGIN OF THE SOLAR SYSTEM
THE ORIGIN OF THE SOLAR SYSTEM A full fledged theory of the formation of the Solar system still does not exist.
All hypotheses, starting with R. Descartes (1644), existed for a certain time, and when they could not explain some phenomena occurring in the Solar System, they were either completely rejected, or developed and supplemented by other scientists.
The first serious cosmogonic hypothesis about the origin of the Solar system was created and published in 1755 by the German philosopher Immanuel Kant (1724-1804), who believed that the Sun and the planets were formed from solid particles of a huge cloud that approached and stuck together under the influence of mutual gravity.
The second cosmogonic hypothesis was put forward in 1796 by the French physicist and astronomer Pierre Simon Laplace (1749-1827).
Taking Saturn's ring as a gas ring that separated from the planet during its rotation around the axis, Laplace believed that the Sun arose from a gas nebula, the rotation speed of which increased as it contracted, and because of this, rings of gas matter (similar to Saturn's rings) separated from the Sun, giving rise to planets.
This hypothesis has existed for more than 100 years.
However, like Kant's hypothesis, it was rejected because it did not explain the laws of the Solar system.
A reliable hypothesis should explain the following basic laws of the Solar system: 1) the planets revolve around the Sun in almost circular orbits, slightly inclined to the plane of the Earth's orbit, which is an angle of 7° with the plane of the solar equator (with the exception of the [dwarf] planet Pluto, whose orbit is inclined to the plane of the Earth's orbit by 17°);
2) the planets revolve around the Sun in the direction of its rotation around the axis (from west to east), and most planets rotate in the same direction (with the exception of Venus, Uranus and Pluto, rotating from east to west) 3) the mass of the Sun is 99.87% of the mass of the entire Solar system;
4) the product of the mass of each planet by its distance from the Sun and its orbital velocity is called the angular momentum of this planet; the product of the mass of the Sun by its radius and linear rotation speed is the angular momentum of the Sun.
In total, these products give the angular momentum of the Solar system, of which 98% is concentrated in the planets, and the Sun accounts for only 2%, i.e. the Sun rotates very slowly (the linear velocity of its equator is 2 km/s);
5) the physical properties of the planets of the Earth group and the giant planets are different.
The hypotheses of Kant and Laplace could not explain all these laws and were therefore rejected.
For example, Neptune is removed from the Sun by an average distance of d = 30 AU and its linear velocity in orbit v = 5.5 km / s.
Therefore, when the ring that gave rise to it separated, the Sun should have had the same radius and the same linear velocity of its equator.
Shrinking further, the Sun has consistently generated other planets, and currently has a radius of R≈0.01 AU.
According to the laws of physics, the linear velocity of the solar equator would have to be
that is, it is much higher than the actual speed of 2 km/s.
This example already shows the inconsistency of the Laplace hypothesis.
At the beginning of the XX century, other hypotheses were put forward, but all of them turned out to be untenable, since they could not explain all the basic laws of the Solar system.
According to modern ideas, the formation of the Solar system is associated with the formation of the Sun from a gas dust environment.
It is believed that the gas dust cloud, of which about 5 billion years ago, the Sun was formed, slowly rotating.
As the cloud shrank, the speed of rotation increased, and it took the form of a disk.
The central part of the disk gave rise to the Sun, and its outer regions gave rise to the planets.
This scheme fully explains the difference in the chemical composition and masses of the planets of the Earth group and the giant planets.
Indeed, as the Sun warms up, light chemical elements (hydrogen, helium) under the influence of pressure, the radiation left the central regions of the cloud, going to its periphery.
Therefore, the planets
formation of the planets of the Solar system (according to Laplace)
the Earth groups were formed from heavy chemical elements with small admixtures of light ones and turned out to be small in size.
Due to the high density of gas and dust, the Sun's radiation weakly penetrated to the periphery of the protoplanetary cloud, where the temperature was low and the incoming gases froze on solid particles.
Therefore, the distant giant planets were formed large and mainly from light chemical elements.
This cosmogonic hypothesis explains a number of other laws of the Solar System, in particular, the distribution of its mass between the Sun (99.87%) and all the planets (0.13%), the current distances of the planets from the Sun, their rotation, etc.
It was developed in 1944-1949 by the Soviet academician Otto Yulievich Schmidt (1891-1956) and subsequently developed by his employees and followers.
According to this hypothesis, the process of planet formation is represented as follows.
According to the idea of O. Y. Schmidt, the medium from which the planets were formed was a fragment of an interstellar gas dust cloud captured by the Sun in the Galaxy.
Numerous thickenings occurred in a disk shaped gas dust cloud due to the mutual collision of its particles.
Many small clusters were destroyed by mutual collisions, and others fell on large clusters, as a result of which they increased in size and compacted, gradually creating the embryos of planets (planetesimals).
Inelastic impacts during collisions of clumps led to the fact that the orbits of the embryos of the planets became close to the circles.
formation of the planets of the Solar system (according to Schmidt)
Over time, only those largest embryos that were located far from each other and did not have a significant mutual gravitational effect survived, so their orbits around the Sun became stable.
From these embryos, large planets were formed over hundreds of millions of years.
Between the orbits of Mars and Jupiter, where the significant gravitational influence of Jupiter prevented the growth of clumps and disturbed the stability of their orbits, small planets asteroids and meteoroids were formed, which often collide with each other and with planets in our era.
At the very periphery of the initial dust cloud, many long period comets emerged from the remnants of light gases and a small amount of dust.
Testing this very plausible hypothesis is still difficult, since we do not observe systems like ours and we have nothing to compare it with.
However, the constantly ongoing search gives hope.
Already now (July 31, 2009), astronomers know about the existence of 281 other planetary systems (extrasolar systems), with 357 planets (exoplanets).
Planets similar to Earth in their physical characteristics have been found.
There is an intensive study of exoplanets, various models are being tested, including the appearance of planets from gas dust nebulae.
Analysis of the content of radioactive elements in the Earth's crust, studies of meteorites and lunar soil, as well as geological data indicate the probable age of the Earth at 4.6 billion years.
The sun and its planets began to form about 5 billion years ago.
years ago.
Thanks to the calm evolution of the Sun, which moderately warms the Earth, there are about 3 billion people on it.
years ago, life was born, which during this long period of time evolved into a reasonable one.
Obviously, the formation of planets around stars at a certain stage of their development is a natural process.
Therefore, we have the right to believe that many stars have planets and, perhaps, life, including intelligent life, can exist on some of them.
Hypotheses (23) of the formation of the Solar System (list and information about the authors) July 2009
part of the gas dust nebula M16 (NGC 6611) in the constellation of the Eagle, bright blue stars continue to form in the dark columns of the Eagle Nebula.
The nebula became famous in 1995, when its photo was obtained by the Hubble Space Telescope.
Active star formation is taking place in the nebula.
In this image (0.8 meter telescope in the Canary Islands), a part of M16 is visible an emerging scattered star cluster.
Many details of the nebula's structure can be seen in this photo due to the fact that it was obtained in specially selected wavelength ranges, where hydrogen, oxygen and silicon atoms emit.
The bright blue stars of M16 have been continuously forming over the past 5 million years, the youngest of them were formed in the famous central pillars of gas and dust, which are called the "Pillars of Creation" and "Fairy".
The size of M16 is ~20 light years, and the distance to it is ~7,000 sv.
years.
The source of the text is here
The Great Orion Nebula (M42) The Orion Nebula is one of the most famous nebulae in the sky.
Glowing clouds of gas and hot young stars in this region of star formation are on the right in this clear and colorful image, mounted from two frames.
It also shows the smaller nebula M43 (near the center) and the bluish reflective dust nebulae NGC 1977 and its neighbors (on the left).
Located on the edge of an invisible giant complex of clouds of molecular gas, these beautiful nebulae represent only a small part of all the interstellar matter located in this region of the Galaxy.
In these well studied stellar nurseries, astronomers have also discovered numerous planetary systems that are still being formed.
This celestial landscape covers almost 2 degrees in the sky, which at a distance of 1500 light years to the Orion Nebula corresponds to ~ 45 light years.
The source of the text is here
sources:
M. M. Dagaev, V. M. Charugin "A book for reading on astronomy: Astrophysics" M.: Enlightenment, 1988 D. Layzer "Creating a picture of the Universe" M., "Mir", 1988 (David Layzer "Consolidating the Universe" New York. 1984) D. Vibe "How do astronomers know this?"
The origin of the Solar system according to Schmidt Our place in this world is Astronomy.
Encyclopedia for children.
Avanta, 1998 S. Hawking "The World in a nutshell", With Pb, Amphora, 2008
© Alexander Koval 2004-2016
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