We are more blind than we should be before the Sun

The Sun is our star, the source of life on Earth, yet it is still unknown in many ways. More than would be advisable, given that a solar storm directed towards our planet could knock down all the technology on which we depend. “We are more blind than we should,” admits the solar physicist Javier Trujillo Bueno (Alicante, 1959), whose main objective is to solve some of these mysteries from the Canary Islands Astrophysics Institute (IAC). “But science is moving fast and convincing the authorities that decide the financing is not easy,” he admits. Although he has succeeded: he has just entered the European scientific elite receiving an aid of 2.5 million euros from the European Research Council (ERC Advanced Grant) to unravel the secrets of the sun’s magnetism.

“It is fundamental that we can decipher how the magnetic field of the Sun’s atmosphere works, because it is the cause of all its explosive phenomena”

Despite the immense importance of the Sun, there is an almost unexplored territory in which Trujillo wants to focus his efforts: the polarization of sunlight that originates in the outermost layers of the star. “We want to find out how physical properties are in these outer regions of the solar atmosphere where as we move away from the Sun we pass from a gas to 10,000 degrees in the chromosphere to more than a million degrees in the solar corona. And that abrupt change takes place in a transition region of less than 100 kilometers, “says the scientist, noting that among these three regions is the key to understanding the magnetism of the Sun. And that is, in turn, the key to understanding How and why these solar storms occur, which, if they repeated the Carrington event of 1859 that overthrew the telegraphs, would be devastating in our digital and satellite present. “It is fundamental that we can decipher how the magnetic field of the Sun’s atmosphere works, because it is the cause of all its explosive phenomena,” warns Trujillo, research professor at the CSIC.

“It is the great mystery: how a magnetic field originates in the Sun, how it is possible that for weeks a gigantic structure of plasma, like a prominence, that should collapse, is there levitating. What is happening when suddenly that disappears and millions of tons of material are expelled into space? “Asks the researcher in reference to those formidable flashes that sometimes detaches the star. Trujillo and his team are looking for the keys to magnetism in the polarization of sunlight. When the light vibrates in a chaotic way, it is said that it is not polarized, but the presence of a magnetic field in the gas emitting it is something that leaves a trace and, therefore, observing and understanding the polarization of solar radiation helps us To decipher the complex magnetism of the Sun. “This is where the signature of the magnetic field of the solar atmosphere is. We need to measure the polarization that originates there, “says the researcher, who can sign up to six young researchers for five years thanks to the scholarship received.

“What we have is five minutes of observation and we need routine observations to know more in detail what happens”

He will do it from the IAC with his group of solar physics in Tenerife, the island where he grew up since he was a year old. It is not the only recent success of this equipment: in December they received from NASA a “gift of Kings advanced”, in the words of Trujillo. They will help them send back to the space, in a brief mission of few minutes, a telescope that looks to the Sun to look for these rays of polarized light. You have to go outside and look for them, because the Earth’s atmosphere absorbs ultraviolet light. This experiment, called CLASP, served to demonstrate in 2015, in its first flight, the results of the theoretical calculations that the team of Trujillo had published in 2011. “They were theoretical articles based on the atomic physics in which it was predicted that they could be captured Linear measurable polarization signals, “he describes. In collaboration with European colleagues, Japanese and NASA, designed and sent the telescope that could demonstrate, in a few minutes, that Trujillo and his group were right. After climbing 300 kilometers, the telescope returned to Earth intact, which will allow them to repeat experience without much expense to learn more of that magnetism. “The cost of a telescope launched by a rocket like that is about ten million euros. A space telescope, which is dedicated to constantly looking at the Sun as we need, is 500 million euros, “says the researcher as an example of the small steps with which his science advances. “What we have is five minutes of observation and we need routine observations to know more in detail what happens,” he complains.

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