Many natural phenomena lead a human being to look to the sky. Just a few days ago, an unusual episode of polar auroras captivated the population of the Canary Islands (and also the rest of Spain). Mobile phones and digital cameras in hand were able to echo for the first time how a geomagnetic storm tinged the sky in the islands with reddish colors. However, only a group of privileged experts were able to see it from one of the most important astronomical observation centers in Europe.
Mar Carretero Castrillo is an astrophysicist from Lanzarote who is studying a doctorate on high energies at the Universitat de Barcelona. During the recent episode of northern lights in the Islands, Carretero was working on an investigation at the Roque de los Muchachos Observatory in La Palma and was able to capture how the auroras were reflected from the MAGIC telescopes.
These telescopes are part of a collaboration led by different countries, including Spain, Italy, Germany, Japan, and Brazil. "In the telescopes, there are scientific members from all these countries, and every month they send a group of four people to observe through the telescopes," she says.
This year, Mar Carretero is in charge of leading and controlling the operators who arrive for the first time at the telescopes in La Palma. At the same time, she continues to do her research work on her own.
In physics, there are different types of radiation known as electromagnetic waves, although not all are of the same type or intensity. For example, "we have the typical light that we can all see, but then there are others like radio waves, microwaves that we use to heat food, or X-rays from when we have an X-ray," she explains. Within all branches of astrophysics, hers is dedicated to the study of the "most energetic phenomena in the universe," which are measured in gamma rays.
That's where her research comes in. Compared to other types of astrophysics specializations, her work involves analyzing black holes in the Universe and, specifically, in the study of "high-energy binary systems," where a star much larger than the Sun is next to a black hole, orbiting each other. These "phenomena are more violent because the black hole is eating the material that is nearby and produces explosions that give rise to these gamma rays."
For the moment, the Canarian astrophysicist explains that only nine high-energy binary systems have been found in our galaxy and in the Universe in general. "They are very few for how big the galaxy is," she indicates. Her research seeks to find more systems of this type, analyze their behaviors, and discover why they generate such high energies, which cannot be created on Earth.
"The question is: what is in these objects that allows such powerful, strong energy to be created? Something is happening that accelerates the particles to a very high speed and emits gamma-ray energy. Basically, it is understanding how these objects move and behave, what is happening there, how these high energies are created," she details her research.
The work of this astrophysicist from Lanzarote is being well received. She has already published a scientific article on the subject and is also about to send a second report. The good reception in the scientific world has already led her to give more than a dozen conferences in Barcelona, Germany, Chile, several in the Canary Islands, France, and Argentina.
Among the recognitions she has received is that of the International Astronomical Union, the most important organization worldwide in Astronomy, which has invited her to give a lecture this summer during the celebration of an event in Cape Town (South Africa).
Canary Islands, epicenter of space observation
Annually, Mar Carretero spends from 15 days to a month in La Palma, the astrophysicist completely changes her routine and moves to the highest point of the Canary Island, at 2,396 meters of altitude. From there, she spends the nights, from when the Sun sets until it rises again, to investigate plots of space and taking observations.
In that time, she has a calendar that indicates an order with the points to look at during the different hours of the night. "At this time you have to observe this galaxy, then you are going to focus on this other object that is a star, which next to it has a black hole, for example, or on a supernova that is a star that has exploded," she highlights.
Then, she moves to the Universitat de Barcelona, where she analyzes and studies the results.
The Canary Islands are one of the points in the world where the skies are best observed, because the islands concentrate different conditions that make it possible. The La Palma Observatory joins those of "Tenerife, Chile, Hawaii, and South Africa as the points on the planet where there is better observation."
Among them, the height of islands like Tenerife or La Palma, the luminous quality of the skies of La Palma, given the lack of large cities, and the possibility that the sea of clouds leaves phenomena such as storms at lower levels makes this place a privilege.
The unusual episode of polar auroras in the Canary Islands
The extraordinary phenomenon of northern lights in the Canary Islands, which was photographed by Mar Carretero, originated as a result of a solar storm. "The Sun sometimes has ejections of particles from its mass due to solar storms, and if the Earth is aligned with the Sun when this eruption occurs, it reaches the Earth and interacts with the Earth's magnetic field, creating these lights," says the astrophysicist from Lanzarote.
In this line, she explains that "normally, these phenomena occur in the high latitudes of the Earth, which are those of the north and south of the planet, because there the magnetic field is more intense and closer to the surface."
For the auroras to form in the Canary Islands, closer to the Earth's equator than to the north pole, "the solar storm that occurred was very intense, much more than normal."
In the case of the Canary Islands, the lights that could be seen were red. "In the Canary Islands, basically the particles from the Sun that are interacting to create these colors interacted with oxygen at high altitudes," she says, while in other locations that interaction occurred closer to the ground.
Solar storms have their maximum activity every eleven years, coinciding precisely in this period 2024-2025. These storms can produce not only auroras but also failures in satellites and radio communications. However, on this occasion, it has been stronger than in previous periods.
At this moment, the scientist from Lanzarote managed to photograph this phenomenon with her mobile phone, with the Milky Way behind the telescope.
