2023-04-21 16:00:00
Luis Bellot, a solar physicist from the CSIC’s Instituto de Astrofísica de Andalucía, has been part of the scientific team responsible for the design of the European Solar Telescope (TSE) since 2009. What will be the most powerful solar telescope in the world, whose construction will soon take place in the Roque de los Muchachos, on the island of Palma, will provide an answer to many of the mysteries that we still do not know about our star, such as the action of the fields magnetic or solar storms.
National Geographic: A telescope of these magnitudes and with such sophisticated instruments is something unprecedented to date. Why is it so important to study the Sun?
Louis Bellot: First of all, we are interested in it because of a clear scientific interest: the Sun represents an incomparable physics laboratory in which physical processes occur at temporal and spatial scales that cannot be reproduced in terrestrial laboratories. The study of the Sun will allow us, for example, to open new paths in fields such as plasma physics, atomic physics or magnetohydrodynamics.
The second reason is that the Sun is a model star. It is the only star that is closest to us, it is the one that we can study in detail to understand how the others work, including those that are very far away and that we cannot know in such detail. The last reason is purely practical: the Sun is our source of energy and life, so it is important to know what processes take place inside it. For example, we know that a very dynamic celestial body changes rapidly in a matter of hours. When magnetic fields interact with each other, they release large amounts of energy, which can end up affecting us.
National Geographic: The European Solar Telescope will allow us to get closer to the Sun than ever before. What parts of our star will we better understand?
LB: The TSE and all its associated instruments are designed to study the magnetic fields in the different layers of the solar atmosphere. Not only in the photosphere (the luminous surface, the one we can see) but also in the upper layers, such as the chromosphere and the corona. Until now it has been impossible to simultaneously observe magnetic fields in all layers of the solar atmosphere. Something, however, very necessary, since what happens in the upper layers depends on what happens in the lower ones.
The TSE will be able to do this very efficiently for the first time, something that will represent a huge advance, since up to now we have inferred what happens on the Sun through extrapolations. From now on we will be able to measure the magnetic field in different layers of the solar atmosphere with enormous resolution. We will study regions as small as 20 kilometers, something very useful when it comes to understanding the physical processes that occur in our star. In summary, the main objective is to observe magnetic fields and see how they interact with each other and with the solar plasma. All this at very high resolution.
Photo: Luis Bellot
NG: When talking about studying the Sun, reference is always made to magnetic fields. Why are they so important?
LB: The magnetic field explains most of the processes that release energy in the Sun’s atmosphere. When we observe bright spots or structures in the atmosphere, they are most likely caused by magnetic fields. In the solar atmosphere there are very defined structures that are produced as a consequence of these fields, such as sunspots or solar prominences. Therefore, if we want to understand all the magnetic structures that we see in the solar atmosphere, we will need to characterize and measure the properties of all magnetic fields well. Its study is essential to understand everything that happens in our star.
NG: But magnetic fields are also responsible for the dreaded solar storms. How common are these episodes? Should we worry?
LB: News about solar storms that appears in the media is often sensationalized. The Sun is continually producing solar storms, especially when they are at their most active. However, most of these phenomena are of low intensity. When they reach Earth they usually generate some effects, such as auroras or interference with radio communications. More powerful solar storms sometimes occur, but this happens very infrequently. What we do know is that from time to time, when the Sun emits particles, radiation and plasma in the direction of the Earth, a geomagnetic storm can occur, although in general it does not have very serious consequences. In the event that it ends up leading to a more extreme phenomenon, it will be necessary to take measures, such as protecting the satellites -rotating or rotating them to protect them from solar radiation- or modifying air traffic near the poles. It is necessary to be prepared, but solar storms are not as dangerous as we are led to believe. They are not something that is going to end life on Earth, far from it. If an episode like the Carrington event of 1859 happened today, it would surely cause some damage, such as blackouts or loss of a satellite, especially in countries located at high latitudes. They would be specific problems, but in no case would it cause a cataclysm. Currently, measures have been taken to minimize all these effects, such as the construction of modular electrical systems to prevent an incident from causing a general blackout.
NG: In addition to taking measurements, it is crucial to know when a solar storm can occur. Is there a way to predict them?
LB: We can protect the satellites, or transfer the astronauts to armored modules. Of course, to take these measures we need to know when an episode is going to occur as far in advance as possible. We cannot predict in the future when a flare or coronal mass ejection will take place, but we can detect it at the moment it occurs on the Sun. From there we have a short period of time to react. For flares, it’s only hours, but when we’re talking about coronal mass ejections, we have up to a couple of days. We know that this is insufficient time, since it is necessary to take measures very quickly. The ideal would be to predict those events before they happen, and that is precisely what we are working on.
The European Solar Telescope, a window to the Sun
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