Mercury, the smallest of the planets and the closest to the Sunis one of the five planets known since ancient times, those that can be seen with the naked eye: Mercury, Venus, Mars, Jupiter and Saturn.
Mercury is a bright dot above the Sunonly It is observed before dawn or at dusk and for a short timealways close to the Sun. We will never see it at midnight or at the highest part of the sky. That is why few people have seen it.
On September 1st, at dawn, east (where the Sun will “rise” minutes later), The Moon will be in conjunction with Mercuryto the left of the planet. You will be able to see them with the naked eye, they will be very close to the horizon from 5 am onwards.
The tiny planet takes 88 days to orbit the Sun. At some point, from Earth we see Mercury moving away from the Sun, up to a maximum distance, which we call Elongation.
On September 4, 2024 at dawn, looking east, Mercury will shine, reaching its Maximum Western Elongation (Well, move westwards.) MMercury will move away from the Sun but not too much, it will not even rise to the middle of the sky, will be located just above the horizon. And after this day it will descend, approaching the position of the Sun.
The next Maximum Elongation will be in the East on November 16, when Mercury will be observed at dusk, to the west And to close the year, on December 25 at dawn, in the east, Mercury will once again be at its Maximum Western Elongation.
These days are a good opportunity to observe the small planet with the naked eye. Remember that you can observe it a few days before and after these dates. If you use binoculars or a telescope, be very careful not to point them into the glare of the Sun, which is about to rise.
The phases of Mercury
Near elongation, Mercury exhibits dichotomy, an optical phenomenon observed only with a telescope. Mercury It will appear half illuminated (by the Sun) and half dark, like the Moon in the First Quarter or Last Quarter phases. The other planet with a dichotomy is Venus. This optical phenomenon is only available with telescopes and you will need to pay close attention to appreciate it.
It will be next September 5th at dawn, in the east, when Mercury will be in dichotomy. Once again it will be on November 20th at dusk, in the west, and then on December 20th at dawn, in the east. You can see this phenomenon just a few days before and after these dates.
In the case of Venus, the next dichotomy will occur on January 11, 2025, in the west, at dusk.
Mercury
It is the smallest of the planets, even smaller than Jupiter’s moon Ganymede (5268.2 km) or Saturn’s Titan (5149.5 km). Mercury measures only 4879.4 km in diameter, which is slightly larger than our Moon (3474.8 km).
Mercury takes 88 days to orbit the Sun, which would be its year.While its day lasts 58 Earth days, it takes the Earth 24 hours to rotate once on its axis.
The small planet is located 57 million km from the Sun, almost a third of the Earth-Sun distance of 150 million km.
Mercury has no moons, has a rocky surface full of craters and its temperature ranges between 430° C and -180° C.
And, to everyone’s surprise, in 2001 they discovered he had a tail!
This feature is typical of comets and some asteroids, but planets?Yes, Mercury has a faint tail, and Pluto, the largest of the dwarf planets, also has one.
In the case of Mercury, The solar wind (particles from the Sun) excite the atoms on the surface (they gain energy), which rise up forming a layer of gas around the planet.it is a kind of atmosphere but so tenuous that it He prefers to call it the exosphere. It is composed of oxygen, sodium, hydrogen, helium and potassium.The solar wind pushes these atoms into space, generating a tail up to 24 million kilometers long (yes, you read that right).
Mercury’s tail is not obvious, it was discovered only in 2001, and it is only observed in long-exposure astronomical photographs and special filters that detect sodium. Astrophotographer Sebastian Voltmer captured a beautiful photograph of Mercury, its sodium tail and above, the star cluster The Pleiades in Taurus..
Take advantage of Mercury’s elongation to admire it with the naked eye. If you have a telescope, try to observe the dichotomy, but be very careful because the Sun is nearby.
german@astropuebla.org