I recently took my 5-year-old daughter to visit the Prado Museum and we inadvertently, by mistake, passed by the room of Goya’s black paintings. Although I wanted to get her out of there quickly, she kept looking at a couple of them, she even wanted to see one again that she later told me she never wanted to see again, “Saturn devouring her children”. Tremendous painting, but it is that Goya was more right than we might think, in several ways. Indeed, Saturn is devouring his children: the rings, between you and me, nor the diamonds that an advertisement from decades ago said, are forever.
It’s been 412 years since we earthlings discovered Saturn’s rings. In 1610 Galileo Galilei wrote a letter to his patron Cosimo II de’ Medici to tell him that the famous planet Saturn was not alone, he had a couple of companions on each side. Two years later, those two prominences that Saturn had “like ears” were no longer there, and Galileo wondered what Goya painted 200 years later: has Saturn eaten his children? We can imagine how Galileo freaked out in 1613 when the “offspring” of the planet appeared again.
Four decades passed before Huygens in 1655 came up with the idea that what they were seeing were rings of matter around the planet. At first he was unsure of his theory, and so that no one would step on it while he did further testing, he wrote what is known as an anagram, “a change in the order of the letters of one word or phrase that gives rise to another.” different word or phrase. He wrote: “aaaaaaacccccdeeeeeghiiiiiiillllmmnnnnnnnnnooooppqrrstttttuuuuu.” No, my keyboard has not gone crazy, rearranging those letters in 1659 Huygens told us “annuto cingitur, tenui, flat, coherent nusquam, ad eclipticam inclinato”. Translated: Saturn “is surrounded by a thin, flat ring that does not touch the planet and is inclined with respect to the ecliptic.”
We explain it. In the plane defined by Saturn’s equator, perpendicular to the planet’s axis of rotation, Saturn has what we know as rings. This is a very flat structure, which can be as long as 1 kilometer, when the planet has a diameter of about 120,000 km. Saturn revolves around the Sun (more or less) in the same plane as the Earth, which is known as the ecliptic (which in the sky is an arc through which the constellations of the zodiac follow one another), which we could think of as a pool table where the planets move around the center of mass of the system, which is close to the center of the Sun (but not exactly). Saturn also revolves around an axis, but this is inclined with respect to the ecliptic, in a similar way to that of the Earth, so both planets have their days and nights and their seasons. The angle formed by the axis of rotation of Saturn with respect to the ecliptic is almost 27º, compared to the 23º inclination of the axis of rotation of the Earth with respect to the plane of the ecliptic.
Imagine two spinning tops rotating with a certain inclination, different for each one of them, and both spinning relative to each other. At each moment one spinning top will see the other in a different way. If we are in one of these spinning tops, sometimes we will see the other tilted towards us, others to the other side, others as if it had no relative inclination with respect to us. If we include the presence of a ring in this system, the result is that sometimes Saturn’s rings are on edge with respect to Earth, and because they are so thin, we don’t see them. Other times they form an angle with our line of sight and are perfectly distinguishable with small telescopes.
The fact that Saturn’s rings can be distinguished is not without spectacularity, we are talking about a very fine structure compared to the planet, they must contain about 10 million times less mass than the planet itself, but they shine as much as it thanks to its extension (they have a size equal to a third of the radius of the planet itself), its composition (mainly water ice), and the light of the Sun, which is what is reflected in that water ice allows us to see the rings. Well, not only have we seen the rings thanks to the reflected light of the Sun, the Cassini spacecraft uniquely managed to take pictures of the rings of Saturn with the Sun in the background, it was there, something that no mortal right now I’m afraid we will be able to see in situ, we have not met the expectations of Arthur C. Clarke in “2001, a space odyssey”.
Where do those rings come from? Are they perfectly circular? Have they always been there? Will they last forever? We focus only on the last question, of the several that we have mentioned and the many that we could ask ourselves. The fact is that on Saturn it is raining and/or snowing rings of water, once again the word rain falls short. Little by little Saturn, to be more precise, its gravity, but also its magnetic field, is devouring its “ring children”. Not only that, solar radiation, in the form of photons and energetic particles, what is called solar wind, and also micrometeorites are destroying the water molecules of the rings and releasing hydrogen and oxygen, in fact the rings have a kind of atmosphere of oxygen around you.
The calculations on the destruction of Saturn’s rings are made with not much data available, the most important being those provided by the Voyager 1 and 2 probes, which passed through there a whopping 45 years ago. I am a little ashamed to give these data, I think the time that has passed since we were able to explore that planet from right there seems tremendous. It is like saying that in 45 years we have not visited Granada and seen one of the wonders of the world. In any case, it is estimated that the rings will disappear in 300 million years and have been there for 10-100 million years. What a fork!, but it is that studying the rings is not easy.
On human, or even life-on-Earth, scales, those times are tremendous, implying that perhaps the first primates didn’t see Saturn’s rings (if any made a telescope), but on a planetary scale it’s less than 10% of that. Saturn life. This also implies that perhaps Jupiter once had rings as or more spectacular than Saturn’s, and not like the ones it has today, which along with those of Uranus and Neptune, are quite unknown among the general public. But look at the JWST’s latest images of Neptune! And don’t take long to see the rings of Saturn! Just as it happened to Galileo, they are now turning on edge and will disappear from our vision in a couple of years, to return in all their splendor from 2027. And at some point In millions of years, the rings will disappear, never to return, devoured like Goya.
Cosmic Void is a section in which our knowledge about the universe is presented in a qualitative and quantitative way. It is intended to explain the importance of understanding the cosmos not only from a scientific point of view but also from a philosophical, social and economic point of view. The name “cosmic vacuum” refers to the fact that the universe is and is, for the most part, empty, with less than one atom per cubic meter, despite the fact that in our environment, paradoxically, there are quintillions of atoms per meter cubic, which invites us to reflect on our existence and the presence of life in the universe. The section is made up of Pablo G. Perez Gonzalezresearcher at the Center for Astrobiology; Patricia Sanchez Blazquez, full professor at the Complutense University of Madrid (UCM); Y Eva Villaverresearcher at the Center for Astrobiology.
You can follow SUBJECT in Facebook, Twitter and instagramor sign up here to receive our weekly newsletter.
#long #Saturns #rings