allineamento planetario gennaio

The alignment of planets on January 25, 2025 arrives, what it is and what we will really see in the sky

The great protagonists of the planetary alignment of January 25, 2025: Jupiter, Saturn, Venus and Mars.

Eyes rolling on Saturday evening January 25th to observe the spectacle ofplanetary alignment: around 7.30 pm the planets Mars, Jupiter, Saturn and Venus of the Solar System will all be visible to the naked eye at the same time in a “parade of planets” around the southern direction, arranging themselves along a curved line in the sky. The two outermost planets, Uranus and Neptune, will also be present in the sky, but they will only be visible with instruments such as binoculars or small telescopes but not with the naked eye. So in all it will be an alignment of well 6 planetsbut let’s say straight away that this astronomical phenomenon has no “special” meaning from a scientific point of view and, indeed, talking about “alignment” is slightly imprecise.

What will we see during the planetary alignment on January 25th and what is this phenomenon

In astronomy, a planetary alignment it is the situation in which at least three planets of the Solar System are visible in the sky at the same time. This means that the planets involved in the phenomenon are on the same side of the Sun as we are, therefore they all come into the field of view of that part of the Earth where it is night (in fact they would not be visible during the day).

What will be seen in the sky will therefore be the four planets observable with the naked eye: in order from east to west we will therefore have Mars, Jupiter, Venus and Saturn in the positions indicated by this celestial map.

January planetary alignment
Planetary alignment of January 25, 2025. Credit: Stellarium

As you can see, the planets they won’t actually be laid out in a straight line but they will follow a slightly curved line. This is absolutely normal: the same thing also happened in the planetary alignment of June 2024. This happens, among other things, because the planets do not orbit exactly in the same plane but have orbital planes slightly inclined to each other (up to a few degrees), enough for someone to appear “higher” and someone “lower” to us during an alignment.

Why it is imprecise to talk about “alignment”

Unlike solar eclipses and lunar eclipses, where our planet is actually aligned with the Sun and Moon, in a planetary alignment the planets are not really on the same line: they only seem so from our point of view. It is the same thing that happens with some constellations or asterisms: the three stars of the so-called “Orion’s Belt”for example, are not really aligned in space but simply appear that way in the two-dimensional celestial vault.

orion's belt
The three stars of “Orion’s belt”.

In any case, even the concept of “alignment” itself is not particularly special because in fact all the planets in the Solar System, including the Earth, orbit around the Sun approximately on the same level (with small variations, as we said above), said plane of the ecliptic (i.e. the imaginary line that corresponds to the projection of the Earth’s orbital plane onto the celestial vault). So in fact it practically always happens that the planets follow some line: it’s just difficult to have enough of them visible in the sky to be able to realize it!