- Daniel Gonzalez Cappa
- BBC News World
The Sun is the largest source of energy in the solar system and what allows life to exist on Earth.
It is also the largest celestial body in our planetary system and the closest star to us.
Its mysteries, however, remain multiple, and this December 4 scientists will have another opportunity to study it: the total solar eclipse that will be especially visible from Antarctica.
The shadow that this will generate will pass precisely through the Unión Glaciar Joint Scientific Polar Station, an Antarctic summer base operated by the Chilean Antarctic Institute (INACH) and the country’s three armed forces from November to January.
And when that happens, Patricio Rojo, director of the Department of Astronomy at the University of Chile, and his team of scientists will be there to observe it.
“It is a unique opportunity,” Rojo assures BBC Mundo. Another eclipse with similar characteristics is not expected for a couple of decades. “Everything we observe will help us understand the great mysteries of the Sun”.
It is the reason why the team headed by this astronomer won the XXVI National Competition of Antarctic Scientific and Technological Research Projects 2020 of the INACH.
And it is precisely the characteristics of this eclipse that make it important.: the time and place in which it occurs and the fact that it is a total eclipse visible in this part of the planet.
Unraveling the mysteries
The Sun has been studied and analyzed for centuries. Its influence on the climate and temperature of the Earth and the seasonal change, among others, caused it to be seen as a deity by ancient civilizations.
In Egyptian mythology, for example, he was represented by the god Ra, the one who gave rise to life. And the Mexica had Tonatiuhtéotl, the leader of heaven.
Similarly, eclipses could be considered important astronomical events that were recorded. Archaeologists have found evidence in the form of clay tablets from periods as far back as 2,000 years BC.
Today it is known that a solar eclipse occurs when the Sun, the Earth and the Moon are aligned, the latter being among the first two.
If the Moon covers the Sun in its entirety (the Moon, being closer to the Earth, looks larger than the Sun) a total solar eclipse occurs.
In these moments of almost absolute darkness you can see the crown of the Sun, the outermost layer of the star, which is not visible to the naked eye.
And it is precisely in this crown that the scientists of the University of Chile will fixate, since it is the one that contains some of these solar mysteries that Rojo talks about.
For example, contrary to what one might believe and its distance from the photosphere (it extends more than a million kilometers away from the Sun’s atmosphere), the corona is hundreds of times hotter than the surface of the Sun.
But the corona is at the same time much much dimmer than the Sun itself, and this is because its density is about 10 million times less dense than the solar surface, making it less bright.
That is why one of the best times to study the solar corona is during a total eclipse Sun.It is in these few minutes that the solar disk is hidden by the Moon when the corona can be appreciated.
“The corona is always there, what happens is that it emits much less photons and therefore drowns in the sea of photons that come from the photosphere,” explains Rojo.
“So the eclipses are the great event that we have to be able to observe these tenuous areas. In fact, historically, through an eclipse, observing the corona is that the existence of helium was discovered,” continues the scientist.
4 basic facts about the Sun
- NASA describes the Sun as a ball made primarily of hydrogen and helium located about 150 million kilometers from Earth.
- Its severity is what holds together sistema sthey are; and not only to planets but also to other celestial bodies, such as asteroids, meteors, comets, and cosmic dust.
- It is the largest body in the solar system and the brightest. AND its volume is so great that it would take 1.3 million planets like ours to fill it.
- What we see of the Sun, what we would call its surface, is called a photosphere or photosphere. But actually the sun does not have a solid body Rather, it is a gigantic ball of superhot gas whose temperature can reach 15 million degrees Celsius.
An opportunity in 20 years
But the solar corona is not the only reason why scientists at the University of Chile are at the South Pole, where they face temperatures as low as -20ºC.
Red is interested in studying above all answer that have the sudden absence of light in the atmosphere in a place like Antarctica.
And is that the atmosphere in Antarctica, given the temperatures, is more compact than in other latitudes of the planet, so it has a lower alloy than the rest.
Being at the South Pole, Antarctica can experience months of sunshine or a total absence of sunlight. Being there during the austral spring, scientists will be able to see the king star permanently on the horizon without it being hidden.
But when the eclipse occurs and the shadow of the LOnce this part of the planet darkens, scientists expect temperatures to drop sharply. In Red’s words, it would be how to see the change of season but concentrated in just a few minutes.
“So what we are going to do is measure the response of the Sun on the atmosphere at different heights with the help of drones,” says Rojo.
For this they have to simulate the observation of the eclipse beforehand: make sure that the terrain is appropriate and that the hills do not cast shadows on them. Other scientists, such as René Garreaud and doctoral student Nitya Pandey, accompany them on the mission.
The last time the response of the atmosphere was studied during a solar eclipse with the same characteristics was in 2003. By then the mission scientists were able to observe the Sun’s corona but only at a surface level, not with drones.
Furthermore, scientists do not expect another solar eclipse in Antarctica until about 2039. It is an event that occurs every nearly two decades.
There is another reason that excites scientists: this eclipse also coincides with the change in solar variation, a cycle of electromagnetic activity that lasts approximately 11 years.
And it is the Sun, in the words of Red, has its own periods of greater or less activity. At this time, the Sun is ending its “quiet” cycle and a period of greater activity is expected to begin next year.
And it is that the Sun is not a body with a uniform movement. Their regions move at different speeds and create fluctuations that have visible effects, such as sunspots.
Sunspots are cooler areas on the surface of the Sun during this activity and make the solar magnetic field twists and createse explosions.
These explosions release particles in one direction. And sometimes they can reach Earth, affecting communications and damaging satellites.
For example, in March 1989, the province of Quebec in Canada suffered an electrical blackout caused by a solar storm that had been seen by astronomers days before.
“The intention in the background is to know more about the magnetic field and the effects on our planet,” says Rojo. “Astronomy is not an applied science, but everything that we observe will help us to understand the great mysteries of the Sun.”
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Eddie is an Australian news reporter with over 9 years in the industry and has published on Forbes and tech crunch.