Mercury will be in its westernmost extension on May 29. There is no scientific evidence that it affects people’s lives in any way. But we still decided to figure out what it is and how it can be interesting.

1. What is elongation?

Elongation is an astronomical term used to describe the apparent distance of a planet, comet, or asteroid from the Sun in Earth’s skies. A more precise definition is the angle between the directions of the centers of two celestial bodies for an earthly observer.

In opposition, the elongation of the planet approaches 180°, but hardly reaches this value: the Earth is rarely exactly on the same line between the planet and the Sun, since the orbits of the planets are inclined to the ecliptic. On the contrary, if a celestial body passes through the solar disk, its elongation approaches zero.

2. Why is so much attention paid to the elongation of Mercury?

The elongation can be measured at any time for any planet in the solar system. However, when Venus and Mercury are mentioned, they are mentioned more. This is because they are closer to the Sun than the Earth. Only these two planets can be observed in the background of our star, and they never move far from the star in the sky beyond a certain maximum angular distance determined by the size of their orbits.

Mercury has the smallest orbit, so it is often too close to the Sun to be comfortably seen with a telescope. Therefore, the maximum elongation is the best time to observe it.

3. What is the difference between the eastern and western extensions?

The Eastern and Western extensions differ in exactly what their names imply. During western elongation the planet is west of the Sun, during eastern elongation it moves away from it to the east.

In the case of Mercury and Venus, it also determines the time of observation of celestial bodies. In the eastern elongation, they can be observed shortly after sunset in the evening, approximately above where it has just set, and in the western elongation, you should look for them in the early morning above the horizon. It had to rise.

4. What will it be interesting to see in the sky?

On May 29, Mercury will pass its maximum western elongation. This should mean the best conditions for his observation. But let’s not forget that the planets move near the ecliptic and are now positioned to rise very slowly in the south from the Sun’s rising point in the morning. Therefore, Mercury, which will be west of the luminary, will appear above the horizon a few minutes before sunrise and it will be extremely difficult to see it.

It is also difficult to see the eastern extensions of Mercury in our latitudes in autumn, when “lower” zodiac constellations such as Scorpio and Sagittarius reach their zenith in the evening. Instead, the spring evening elongation of the smallest planet on April 11 was quite favorable for observations, although the angular distance between Mercury and the Sun barely exceeded 19°.

5. How will Mercury’s maximum elongation affect events on Earth?

Mercury makes one revolution around the Sun in just 88 Earth days. This means that the earth can exceed the maximum elongation in the sky – east and west – up to seven times a year. Obviously, this phenomenon cannot be called unique.

Mercury’s maximum elongation does not mean it has become special or is somehow getting closer to Earth or the Sun. This is just a specific configuration of the three celestial bodies. Therefore, you do not have to worry that it will somehow affect at least some worldly events.