The plane of the ecliptic of the solar system. Ecliptic – Magazine "All about Space". When to watch

The study of the properties of interplanetary space far from the ecliptic plane is of great importance. scientific interest. Deviation from the ecliptic plane requires additional energy costs. These costs vary sharply depending on which region outside the ecliptic plane we wish to explore.

The easiest way to penetrate into areas distant from the ecliptic plane is to do this on the outskirts of the solar system. To do this, it is enough to place the artificial planet into an outer elliptical orbit, inclined at a small angle to the ecliptic plane. Even a slight tilt will remove spacecraft on large

distances from the Sun to tens of millions of kilometers from the ecliptic plane.

It is much more difficult to penetrate into the space “above” and “below” the Sun. Let's assume that we are trying to launch an artificial planet into a circular orbit perpendicular to the ecliptic plane. Moving in such an orbit, the artificial planet should meet the Earth six months after launch.

Rice. 134. Artificial planets in circular orbits of radius 1 AU. e. when bending:

The heliocentric speed of exit from the sphere of influence of the Earth must be equal in magnitude to the speed of the Earth. Construction in Fig. 134, but shows that the geocentric exit velocity From here the initial departure velocity We obtained an even greater value than the fourth escape velocity.

Flight in an elliptical orbit lying in a plane perpendicular to the ecliptic, with perihelion located behind the Sun near its surface, would require an initial speed only slightly exceeding one-fourth the cosmic speed, but the maximum distance of the spacecraft from the ecliptic plane (halfway from the Earth to the Sun) would be equal to 0.068 a. i.e., i.e. 10 million km. The value is too small on the scale of the Solar System, and the launch speed is almost unattainable!

But it turns out to be quite easy to explore areas that lie many millions of kilometers “above” and “below” the Earth’s orbit. To place an artificial planet into a circular orbit of radius 1 AU. e., the plane of which is inclined at an angle to the ecliptic plane, we need a geocentric exit velocity. For the angle, we will find where. As we can see, the speed of departure from the Earth turned out to be small, and yet it allows the artificial planet, 3 months after launch, to move away from the Earth to a maximum distance of 26 million . (Fig. 134, b). Note that such an artificial planet, moving side by side with the Earth (albeit outside the sphere of action),

must be subject to a noticeable disturbing influence of our planet.

Launching with an initial speed equal to the third cosmic speed (allows the spacecraft to be placed into a circular orbit of radius 1 AU, inclined to the ecliptic plane at an angle of 24°. The maximum distance of the device from the Earth (after 3 months) will be 60 million.

From the point of view of solar research, it is of interest to achieve high heliographic latitudes, i.e., a possible greater deviation from the plane of the solar equator, and not from the ecliptic. But the ecliptic is already inclined to the solar equator at an angle of 7.2°. Therefore, it is advisable to exit the ecliptic plane at the ecliptic node - the point of intersection of the Earth’s orbit with the plane of the solar equator, so that the deviation of the probe’s orbit from the ecliptic plane is added to the already existing natural inclination of the ecliptic itself. Since the axis of the Sun is inclined towards the point of the autumnal equinox, the launch should be carried out in the middle of summer or in the middle of winter, when the axis of the Sun is visible “from the side”.

A collection of interesting problems and questions

A.

At the pole, the Sun is above the horizon for half the year, and below the horizon for half the year. And the Moon?

B.

To answer the question, you must first thoroughly understand why the Sun at the pole does not leave the sky for six months and how it behaves.

IN.

The orbit of the Moon and the orbit of the Earth are approximately in the same plane, called the ecliptic plane. This plane is inclined at a certain angle to the plane of the celestial equator, so half of the ecliptic is above the equator (i.e. in the northern hemisphere of the sky), and the second is below the equator. At the pole, the plane of the celestial equator coincides with the plane of the horizon. Since the Sun, moving almost uniformly along the ecliptic, describes a complete apparent revolution around the Earth in a year, it is above the equator (and the polar horizon) for half a year and below the equator for half a year.

The Moon completes a full revolution around the Earth in almost the same plane in about a month. This means that it remains in the polar sky for half a month, then goes below the horizon for half a month.

The sun at the pole appears in the sky on the day of the vernal equinox (more precisely, three days earlier due to atmospheric refraction). Due to the daily rotation of the Earth, the Sun describes circles above the horizon; due to its movement along the ecliptic, the Sun rises higher and higher until the moment of the summer solstice. As a result, it describes an upward spiral in the sky for three months (which gives about ninety turns). After this, the Sun begins to descend in a similar spiral and on the day of the autumnal equinox (more precisely, three days later) it descends below the horizon.

The plane of the ecliptic is clearly visible in this image taken in 1994 spaceship lunar reconnaissance Clementine. Clementine's camera shows (from right to left) the Moon illuminated by the Earth, the glare of the Sun rising over the dark part of the Moon's surface, and the planets Saturn, Mars and Mercury (three dots in the lower left corner)

Ecliptic (from (linea)ecliptica, from ancient Greek. ἔκλειψις - eclipse) - a large circle of the celestial sphere along which visible annual movement occurs. Respectively ecliptic plane- the plane of revolution of the Earth around the Sun (terrestrial). A modern, more accurate definition of the ecliptic is the section of the celestial sphere by the orbital plane of the barycenter of the Earth system - .

Description

Due to the fact that the Moon's orbit is inclined relative to the ecliptic and due to the Earth's rotation around the barycenter of the Moon-Earth system, as well as due to disturbances in the Earth's orbit from other planets, true sun is not always exactly on the ecliptic, but may deviate by a few arc seconds. We can say that there is a path along the ecliptic "average sun".

The plane of the ecliptic is inclined to the plane of the celestial equator at an angle ε = 23°26′21.448″ - 46.8150″ t - 0.00059″ t² + 0.001813″ t³, where t is the number of Julian centuries that have passed since January 1, 2000. This formula is valid for the coming centuries. Over longer periods of time, the inclination of the ecliptic to the equator fluctuates around the average value with a period of approximately 40,000 years. In addition, the inclination of the ecliptic to the equator is subject to short-period oscillations with a period of 18.6 years and an amplitude of 18.42″, as well as smaller ones; the above formula does not take them into account.

In contrast to the plane of the celestial equator, which changes its inclination relatively quickly, the plane of the ecliptic is more stable relative to distant stars and quasars, although it is also subject to slight changes due to disturbances from the planets of the Solar System.

The name “ecliptic” is associated with the fact known since ancient times that solar and lunar eclipses occur only when the Moon is close to the points of intersection of its orbit with the ecliptic. These points on celestial sphere are called the lunar nodes, the period of their revolution along the ecliptic, equal to approximately 18 years, is called the saros, or draconic period.

The ecliptic plane serves as the main plane in the ecliptic celestial coordinate system.

Angles of inclination of the orbits of the planets of the solar system to the ecliptic plane

Ecliptic plane

The ecliptic plane is clearly visible in this image taken in 1994 by the Clementine lunar reconnaissance spacecraft. Clementine's camera shows (from right to left) the Moon illuminated by the Earth, the glare of the Sun rising above the dark part of the Moon's surface, and the planets Saturn, Mars and Mercury (three dots in the lower left corner)

The name “ecliptic” is associated with the fact known since ancient times that solar and lunar eclipses occur only when the Moon is near the points of intersection of its orbit with the ecliptic. These points on the celestial sphere are called lunar nodes. The ecliptic passes through the zodiacal constellations and Ophiuchus. The plane of the ecliptic serves as the primary plane in the ecliptic celestial coordinate system.

See also

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See what “Ecliptic plane” is in other dictionaries:

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In popular science articles on the topics of space and astronomy, you can often come across the not entirely clear term “ecliptic”. In addition to scientists, this word is often used by astrologers. It is used to indicate the location of space objects distant from the Solar System, to describe the orbits of celestial bodies in the system itself. So what is the “ecliptic”?

What does the zodiac have to do with it?

The ancient priests, who were still observing the heavenly bodies, noticed one feature of the behavior of the Sun. It turned out to be moving relative to the stars. Tracking its movement across the sky, observers noticed that exactly one year later the Sun always returns to its starting point. Moreover, the “route” of movement is always the same from year to year. It is called the “ecliptic”. This is the line along which our main luminary moves across the sky during the calendar year.

The stellar regions through which the path of the shining Helios ran in his golden chariot drawn by golden horses (this is how the ancient Greeks imagined our native star) did not go unnoticed.

The circle of 12 constellations along which the Sun moves is called the zodiac, and these constellations themselves are usually called zodiacal.

If according to your horoscope you are, say, Leo, then do not look in the sky at night in July, the month in which you were born. The Sun is in your constellation during this period, which means you can see it only if you are lucky enough to catch a total solar eclipse.

Ecliptic line

If you look at starry sky during the day (and this can be done not only during a total solar eclipse, but also with the help of a regular telescope), we will see that the sun is at a certain point in one of the zodiacal constellations. For example, in November this constellation will most likely be Scorpio, and in August it will be Leo. The next day the position of the Sun will shift slightly to the left and this will happen every day. And a month later (November 22), the star will finally reach the border of the constellation Scorpio and move to the territory of Sagittarius.

In August, this is clearly visible in the figure, the Sun will be within the boundaries of Leo. And so on. If we mark the position of the Sun on a star map every day, then in a year we will have in our hands a map with a closed ellipse marked on it. So this very line is called the ecliptic.

When to watch

But to observe your constellations under which a person is born) will be possible in the month opposite to the date of birth. After all, the ecliptic is the route of movement of the Sun, therefore, if a person is born in August under the sign of Leo, then this constellation is high above the horizon at noon, that is, when sunlight won't let you see him.

But in February, Leo will grace the midnight sky. On a moonless, cloudless night, it is perfectly “readable” against the background of other stars. Those born under the sign of, say, Scorpio are not so lucky. The constellation is best visible in May. But to consider it, you need to be patient and lucky. It’s better to go to the countryside, to an area without high mountains, trees and buildings. Only then will the observer be able to discern the outline of Scorpio with its ruby ​​Antares (alpha Scorpio, bright star blood-red in color, belonging to the class of red giants, having a diameter comparable to the size of the orbit of our Mars).

Why is the expression “ecliptic plane” used?

In addition to describing the stellar route of the annual movement of the Sun, the ecliptic is often considered as a plane. The expression “ecliptic plane” can often be heard when describing the position in space of various space objects and their orbits. Let's figure out what it is.

If we return to the diagram of the movement of our planet around the mother star and the lines that can be laid from the Earth to the Sun at different times, put together, it turns out that they all lie in the same plane - the ecliptic. This is a kind of imaginary disk, on the sides of which all 12 described constellations are located. If you draw a perpendicular from the center of the disk, then in the northern hemisphere it will rest on a point on the celestial sphere with coordinates:

• declination +66.64°;
• right ascension - 18 h. 00 min.

And this point is located not far from both “ursae bears” in the constellation Draco.

The Earth's rotation axis, as we know, is inclined to the ecliptic axis (by 23.44°), due to which the planet has a change of seasons.

And our “neighbors”

Here is a brief summary of what the ecliptic is. In astronomy, researchers are also interested in how other bodies in the solar system move. As calculations and observations show, all the main planets revolve around the star in almost the same plane.

The planet closest to the star, Mercury, stands out the most from the overall harmonious picture; the angle between its plane of rotation and the ecliptic is as much as 7°.

Of the planets in the outer ring, Saturn’s orbit has the greatest inclination angle (about 2.5°), but given its enormous distance from the Sun - ten times further than the Earth, this is forgivable for the solar giant.

But the orbits of smaller cosmic bodies: asteroids, dwarf planets and comets deviate from the ecliptic plane much more strongly. For example, Pluto's twin, Eris, has an extremely elongated orbit.

Approaching the Sun at a minimum distance, it flies closer to the luminary than Pluto, at 39 AU. e. (a.e. is an astronomical unit equal to the distance from the Earth to the Sun - 150 million kilometers), to then again retire into the Kuiper belt. Its maximum removal is almost 100 a. e. So its plane of rotation is inclined to the ecliptic by almost 45°.