Mysteries of the Universe |  Automatic translation | | | | | Astronomy - The curiosity that characterizes humanity, has enabled man to understand the major astronomical phenomena and it now gives a dramatic sense stronger what is happening before our eyes. In the solar system, the Sun has captured 99.86% of the total mass of dust and gas from the original nebula. Jupiter, the largest planet in the system, has captured 71% of the remaining mass. The other planets are shared residue gravitational this development, ie 0.038% of the total mass. Earth is the result of this interstellar dust.
At the heart of a nebula of gas and dust, the gravitational pressure and heat will initiate nuclear reactions. A star is born and around the system, revolve planets, asteroids, comets, small objects, gas and residual dust. The matter is organized around the universe in the same way and bearing the diversity of objects and stellar systems is surprising. | | The dust are the building blocks of planets, they stick together to form small bolides, that collision in collision form objects, which grow to the detriment of their neighbors. Their masses and gravity increase, attracting themselves more matter. Collisions liberate large amounts of heat, the atoms disintegrate themselves and expect cooling to assemble molecules.
On Earth, much later, there will be assembly of simple molecules and complex molecules to reach this wonderful DNA molecule will now reproduce and store information, opening the way for biological evolution that we know.
« It is absolutely possible that beyond what our senses perceive, hide unsuspected worlds. »
Albert Einstein (1879-1955), Nobel Prize in Physics in 1921 for his interpretation of the photoelectric effect. | |
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Eclipses
An eclipse requires an alignment of three celestial bodies, the
Sun, Earth and Moon. Lunar eclipses are occultations of the Moon by the Earth's shadow while solar eclipses are eclipses of the sun in the shadow of the Moon.
These celestial concordances are frequently observed, at least one of each (lunar eclipse and solar eclipse) every 6 months. The Moon appears to us with phases, ie in different lighting of the Lunar sphere. As the moon only reflects light from the Sun, the only visible part of the Moon is one that is geared to both the Earth and to the Sun. The periodicity of phases of the moon is 29.5 days, or a lunation or lunar month although there are several lunar month.
Eclipses take place at syzygies, ie when there is a quasi alignment between the Sun, Earth and Moon. The solar eclipse occurs at new moon, the lunar eclipse occurs at full Moon.
Cycle periodicity of eclipses is known as
Saros. A cycle that obeys surprising coincidences and average an Saros contains 84 eclipses, 42 solar eclipses and 42 lunar eclipses. Indeed, during this cycle, there are the same number and the same type of eclipses, total, annular, partial every 223 lunations or every 18 years. More precisely, the Saros is a period of 585.32 days or 18 years, 10 or 11 days and 8 hours, depending on the interval contains 4 or 5 leap years.
But the three Saros cycle is even more interesting because the eclipses return to the same position in the same geographic area on earth, with the same thickness of the shade, with the same apparent diameter, etc.
A Saros is equal to 18 years, 10 or 11 days and 8 hours so 3 Saros is equal to 54 years, 34 or 35 days depending on the interval contains 13 or 14 leap years, this cycle is called Exeligmos.
There is therefore a nearly perfect periodicity of eclipses of about 54 years. |
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