Our brain works by generalizing. This is how we understand the patterns and trends of this world of ours that surrounds us. We do it for everything, both for what we should and for what we shouldn’t, and this is how the mathematization of science is born, but also prejudices. The fact is that, sometimes, generalizing is almost impossible. For example, we only know of the descendants of a single life form. How varied others could be and we, who would generalize from a single case, could hardly imagine. Well, something like that is what happens with our planet.
If we look up at the firmament we will see some points of light that, even though they disguise themselves as stars, are also planets. Neighbors of our solar system. We’ve gleaned quite a bit of information about them, but there’s still a lot we don’t know. What’s more, if we restrict the questions to rocky planets, like ours, of a similar size and characteristics, the number of known cases is further reduced and, of course, generalization becomes even more difficult. Therefore, in many cases our attempt to generalize planetary issues is based on a single case: that of the Earth. This is how the question that brings us here is born: is it common for planets like ours to have a magnetic field?
The answer is especially important for understanding life in the universe. The magnetic field protects us from some of the dangers of the universe and prevents solar winds from sweeping through the atmosphere, stripping us of air. As expected, our planet is protected by a magnetic field. In fact, the Earth’s heat is capable of producing molten iron currents in the outer layers of its core. Like the air in a room, the hottest iron rises, gradually cooling until it sinks again, thus increasing its temperature and starting the cycle again. They are convective currents that, as if it were a gigantic dynamo, produce a magnetic field that escapes from the Earth through the south pole, enveloping it in all directions and re-entering through the north pole.
Furthermore, a planet’s magnetic poles meet at the places where the magnetic field crosses its surface as perpendicularly as possible. In any case, that is our shield, the magnetosphere, an area around the planet under the influence of the magnetic field generated by its core. The place where the battle between the Earth and the Sun takes place. When the electrically charged particles of the solar wind reach our magnetic field lines, they change their direction and begin to follow them, as if they were roads. This is how they end up concentrating at the poles, massively hitting the atoms in the atmosphere in such a way that they absorb that energy and, when they release it, they do so in the form of visible light that we know as “auroras”.
The question, therefore, is not easy to answer. We know, for example, that some large planets (the size of Jupiter) do have a magnetic field, but identifying it on rocky planets of our size that are many light-years from here is not exactly what we would say “a triviality”. Since the magnetic field is not directly visible, researchers have to look for alternatives. Consequences of their presence that we can measure. And, if the experts are not mistaken, that is what they have found in YZ Ceti b, an exoplanet that is 12 light years from us.
It all started when researchers Sebastián Pineda and Jackie Villadsen observed a repeating radio signal from the star YZ Ceti using the Karl G. Jansky Very Large Array, a radio telescope operated by the US National Science Foundation’s National Radio Astronomical Observatory. This radio signal could have to do with the interaction of YZ Ceti’s magnetic field with that of its star, which was precisely the reason why experts were focusing their studies on planets very close to their stars.
It is possible that what scientists have detected is a kind of aurora borealis, but not from the planet, but from the star itself, partly influenced by the magnetic field of YZ Ceti b. It will be necessary to continue investigating other cases to be sure that there are no other more parsimonious or accurate explanations.
DON’T GET IT:
- In theory, the same YZ Ceti b is not habitable, but it doesn’t matter. That’s not what the researchers were looking for. What this study allows us is to reaffirm our suspicions that there are other very distant planets with their own magnetic field and that, even if it is not habitable, it will surely make other planets in less hostile places in space more habitable.
REFERENCES (MLA):
- Coherent radio bursts from known M-dwarf planet-host YZ Ceti nature astronomy 10.1038/s41550-023-01914-0
Discussion about this post