Everything in this life begins with a rotation, everything eventually comes full circle. Everything starts with movement. Space is no exception, its knowledge begins with the rules and order of movement in space of all its objects. This mechanism has a complex organization.
Orbit is not an easy circle…
All people know from birth that cosmic bodies, primarily planets, rotate in an orbit that is a circle. But in this case, it's a relative term. The fact is that not a single circle along which a cosmic body passes its way around the Sun is ideal. In one way or another, they are all close to an ellipse. Such distortions give all the planets an additional unique component, because in each part of the orbit the Sun will affect them differently, sometimes significantly affecting the climate and other indicators. This effect is especially noticeable at two points. What?
Aphelion and perihelion
These are sections of any orbit that are located on opposite sides of it. The circumferential distortion causes the planet to be closer or farther from the Sun.
What is perihelion?
This is the point where a planet, comet or asteroid is closest to the sun. Such moments for some of them may be considered a full-fledged summer, while for others they may not bring much change.
For example, the difference between the minimum and maximum distances of the Earth is relatively small, only 5 million km. Therefore, people do not even notice these periods. However, to clarify, it is worth noting that the Earth passes perihelion on January 4-5 annually. In the northern hemisphere, at this time, the height of winter is in full swing, and in the southern hemisphere - quite a normal summer.
And if you imagine that there would be an opportunity to be on Mercury, then the difference could be felt, because its orbit is much more different from an even circle. As with the Earth, the moments of closest approach are not relevant for Venus, Jupiter, Saturn, Uranus and Neptune.
Aphelios
At this point of the circle, the space object moves away from the Sun as much as possible. It does not matter for all those planets that were discussed in the previous section. It is worth noting that in fact the name "aphelion" appeared later. Initially, this point was called "apohelion". It's just that once upon a time in the records, someone decided to split the word into two parts, shortening it: ap.helios. When reading, the dot between the parts of the word was not noticed, and someone read the combination of letters ph as "ph", as it is read in English. Since then, the name "aphelion"entered and fixed in various languages. Earth passes this point every year on July 4-5.
These orbital centers are important points not only for astronomers, perihelion and aphelion in astrology also occupy not the last place. They are used to make forecasts and predictions of global events.
And how did the orbits of Mercury, Mars and Pluto differ?
Nothing special, except that their orbits are more different than the others from a circle and more like a full-fledged oval. This means that the moments when they pass aphelion and perihelion are especially important for them.
Mercury
The range of distances from the sun is quite wide - from 46 to 70 million km. This planet has no seasons, because its axis has almost no tilt, but you can notice a significant change in daytime temperature. When Mercury is at its maximum distance from the Sun, the temperature during daylight hours is less than + 300 degrees Celsius, and at the moments of closest approach it increases to almost + 430.
Mars
Its orbit is more rounded than Mercury's. But significant changes do occur during the periods of passage of aphelion and perihelion. They are manifested by the fact that the seasons in one hemisphere will differ from the other in duration and temperature. When summer begins in the northern hemisphere, the planet is at its maximum distance, so it is not as warm, but longer. In the south - on the contrary, shorter, butwarmer, because during this period Mars passes perihelion.
As for temperatures, it is difficult to talk about them, because they change dramatically not only in relation to winter and summer, but also during the day, which are almost the same as on Earth. For example, at the equator during the day the planet can warm up to +28 degrees, but at night the temperature can drop to -40 and below. The minimum temperature at the poles is close to -150 degrees.
Pluto
It has its own paradoxical features. Orbit is one of them. It is almost as oval as that of Mercury. The point of closest removal is at a distance of almost 50 distances from the Earth to the Sun, and when approaching the star, Pluto turns out to be closer to Neptune, at that time it is separated from the star by 29 distances from the Earth to the Sun.
Although it intersects with Neptune, it cannot collide with it due to the different inclination of their orbits.
Knots of planets
This is the name of the point where the planet's orbit crosses the celestial equator in the direction from south to north and back. They are of no particular importance. However, the nodes of the Moon are popular with astrologers, who consider them to be important karmic points and use them when interpreting a horoscope. According to their location, the optimal path of personality development is determined. Believe it or not - everyone decides for themselves.
Astronomically, the lunar nodes are eclipse points that occur when the night luminary at the moments of the new moon or full moon coincides with one ofthem.
Conclusion
Any path is full of mysteries and surprises, especially when it comes to planets. In this case, a simple circle is a treasure trove of interesting information. Knots, perihelions and aphelions help to create a more complete understanding of the concept of "orbit".
