This year we are visited by the “COMET OF CHRISTMAS” – THE MOST LUMINOUS


In many cities, you can already see the streets lit by Christmas lights and the large malls that have become festive. The sky this year has also thought of us, giving us a bit of poetry and Christmas imagination. A bright and highly suggestive show for a comet passage just in time for Christmas.

The celestial visitor is a comet, the 46P / Wirtanen, appears every 5.4 years, in our sky and bears the name of the American astronomer Carl Alvar Wirtanen, who discovered it in 1948.

The nucleus of the comet has a diameter of more than 1 km and when it passes closer to the Sun, it will develop its characteristic ionic tail. However, it cannot be observed at the sight, for the perspective we have from the Earth.

We’ll have to be happy to at least see a kind of big nebula twice the moon. Not bad as a Christmas present. Since we have not always seen his passages near the Earth, around 12 times total.

At this moment, it is approximately 23 billion km from Earth, in the constellation of Fornace, a group of stars located in the southern horizon of it.


His arrival is expected in mid-December, just in time for the Christmas holidays. Concretely, the next December 12 will go to the minimum distance from the Sun and 16 will be at the point closest to the Earth, to 11.5 billion km approximately. But already at the beginning of December you can see the first images with telescopes.

THE CHRISTMAS STAR - A tradition in our Nativity Scene

Astronomers say that a star or comet did not shine on the Bethlehem nativity scene, but rather a conjugation of planets.

It was Giotto who, impressed by the passage of Comet Halley, introduced it for the first time onto the nativity scene of Bethlehem, in the fresco of the Scrovegni Chapel in Padua.

Tradition sometimes imposes itself strongly and so above the nativity scene there is always a comet or a star instead of a group of planets.

But out of these poetic considerations, Comet Wirtanen has all the credentials to go down in history as one of the most spectacular comets of recent times.


The 46P / Wirtanen is a periodic comet, which means that it goes around with a certain frequency, in this case every 5.4 years. It is expected to arrive approximately mid-December.

It belongs to the Giove comet family. Its orbit carries the right comet out of the orbit of the Earth, within the Jupiter road around the Sun.

Since astronomer Carl Alvar Wirtanen discovered it in 1948, Wirtanen has passed close to Earth on 12 occasions.

Instead, despite being one of the brightest known, its light is reflected relatively and tenuously, since it extends over a great atmosphere of comets. Its light is fluorescent in the sunlight and with a green reminiscence in some points of the atmosphere of its tail.

For the moment it is the brightest and brightest, but not enough to see it easily at sight.

However, it is possible that it can be seen when approaching the most to the Earth and the Sun. More or less 30 times the distance of the moon. At that moment he expects it to be even brighter and can be seen at least in some places with very dark skies.


In history, the register of a comet that has passed closer to the Earth is that of 1 / Lexell, in 1770, it seems that it came to pass less than 6 times the distance between the Earth and the Moon in that year.

Another comet that came to us recently is the 21P / Giacobini-Zinner which passed on 9 and 10 September 2018 and left a light rain of meteors in its passage.


We all want to see it, but due to the orientation of the Earth and its difficult perspective at the moment of its approach, it is difficult for its famous tail of ions to be clearly seen.

The tail will be fluorescent green due to the composition of its atmosphere. Obviously it will remain leaning behind the comet and its size will be even bigger than that of the planet Jupiter.

More or less is estimated to appear even larger than the diameter of the Moon, and perhaps twice more.

But that will be determined with astrophotography, since the area to be evaluated includes the outer area of the tail and of course will be weaker each time in brightness as it moves away from the nucleus of the comet.

So, already at the beginning of December, enthusiasts and fans to see Comet 46P / Wirtanen can install telescopes and enjoy the images.

It is possible that together with it you can also see in slow motion, one or more masses close to the field of the comet. These. objects will appear very slow, and they will look like asteroids. Instead they are not space rocks, but control satellites.

This will happen because Wirtanen will enter the space area where they are located in orbital ring around 450 active geostationary satellites.

It means that, a group of meteorological, television and communications satellites orbiting our planet about 35,786 km above the Earth’s equator.

As these satellites orbit the speed of the Earth, the satellites appear motionless, fixed in one position. But it’s not like that. They are located in a higher position, and therefore more illuminated by the Sun, for this they will see better.