Last chance to enjoy a rare astronomical phenomenon that will not occur again until 2038.

GenevaThis Saturday, September 20, Saturn's main satellite, Titan, will cast its shadow on the ringed giant. It will be the last time it will do so for the next 14 years. These eclipses are extremely rare and only occur for a few months every fifteen years or so, when Titan's orbit aligns it with the Sun and Saturn. From November 2024 to October 2025, eclipses occurred every sixteen days. However, we will have to wait until 2038 to see the Saturnian satellite cast its shadow again on this fascinating world, the second largest after Jupiter and the only ringed one visible from Earth. This strange periodicity of eclipses is mainly due to the high inclination of Titan's orbit with respect to the planet's orbit around the Sun.

Eclipses are one of the astronomical phenomena that arouse the greatest passion, even among those who are not particularly fond of astronomy. Just look at the excitement generated by the total solar eclipse that It will take place next August and will be visible from Catalonia.Although solar eclipses, where the Moon comes between our star and Earth, may seem rare, we can observe a couple of them from different points on the planet over the course of a year. However, if we look at other parts of the solar system, eclipses are an even more frequent occurrence. Jupiter, for example, with its four large moons, experiences eclipses almost every day.

Possible source of life

Titan is Saturn's largest moon and the second largest in the entire solar system after Ganymede, one of Jupiter's main moons. In fact, Titan accounts for 96% of all the mass orbiting the planet, including its rings.

The arrival of NASA's Cassini probe to the ringed giant in 2004 provided fundamental information buried beneath Titan's dense golden atmosphere. Today, this moon represents one of the most fascinating objects in the solar system. It is the only celestial body, except Earth, where stable liquids have been found. Intense hydrocarbon rains feed the rivers of methane that run across its surface and fill large, transparent lakes. Gravimetric observations show that beneath its surface, filled with icy dunes, there may be vast oceans of water and ammonia. These characteristics, as well as its chemical composition, cause an inverse greenhouse effect; that is, the atmosphere allows heat to escape, and only 1% of sunlight reaches its surface. This causes the average temperature to be around minus 183 degrees Celsius.

Currently, Saturn and its moons represent an essential source of information for understanding not only the formation of the solar system but also the emergence of life on Earth. Recent NASA research has demonstrated their presence in methane lakes in vesicles, a type of organelle that makes up cells. Astrobiologists are questioning whether, just as water appears to be an essential element for the development of life on our planet, Titan's lakes could also be a potential source of life, albeit with characteristics different from those on Earth.

Observing this beautiful and rare astronomical phenomenon from Earth requires a relatively powerful telescope with high magnification and a large aperture. Advanced astrophotography techniques are also necessary to obtain a sufficiently sharp image of Titan's shadow. Another option is to visit a nearby astronomical observatory, as they likely have scheduled observations.