On December 14, 2020, the moon’s shadow ran over Chile and Argentina, throwing a thin ribbon of land into the short, midday darkness.
Those on the trail of this total solar eclipse watched the solar system move. During a solar eclipse, the Moon passes between the Sun and the Earth, covering the bright face of the sun. Weather permitting, a complete eclipse of the Sun’s hidden, pearly-white atmosphere, known as the corona, will appear.
One week earlier, a group of scientists predicted what the corona would look like during this particular eclipse. The corona moves in response to the evolutionary magnetic field of the sun. Superhot gases – known as solar wind – gust from the corona and wind through the solar system. This flow shapes the conditions in space called space weather. Corona modeling is a key part of understanding and ultimately predicting space weather, which will affect astronauts, satellites, and everyday technology, such as radio and GPS.
It is easy to predict when and where a full supply of eclipse will occur. But predicting the appearance of the corona is much more difficult, since the solar magnetic field is so wide and complex. By comparing corona predictions with eclipse images from the ground, the researchers can test their models and identify where they could be improved.
Used by Predictive Science Inc. – a private research company based in San Diego, California, and with support from NASA, the National Science Foundation, and the Air Force Office of Scientific Research – data from NASA ‘s Solar Dynamics Observatory, or SDO, to develop it. the prophecy. The accounts were supported by NASA’s Advanced Supercomputing Division (NAS) at the agency’s Ames Research Center in Silicon Valley, California, as well as the National Science Foundation.
The sun is always boiling. Energy and magnetic fields churn through the star. Knowing where they are going is crucial in predicting the behavior of the sun, but it is a difficult question – like asking where a grain of rice will rise and fall in a pot. winding. For now, the researchers ’model relies on SDO magnetic maps of the sun’s surface to capture how the magnetic field shapes the corona over time.
Currently, the sun is becoming more active, which makes the action more difficult. When the sun is active, the appearance of the corona can shift in just days. The activity of the sun rises and falls over the natural cycle of about 11-years. The sun passed its lowest in December 2019, marking the transition to a new solar cycle.
When the December 14 eclipse came, the corona was more dangerous and calming than expected. The prediction showed marked structures, which, although close to the correct location, were clearer than what actually appeared.
“With the activity of the sun rising, it was interesting to see how an eclipse day changed,” said Predictive Science researcher Cooper Downs.
Data sampling could explain the differences. The team’s data included a strong area of magnetic activity. Two weeks before the eclipse, a solar eruption and an anemone-like eruption erupted from this area. Later, the region weakened, enough to weaken that part of the corona before the day of the eclipse. But the team’s data did not include the decay that followed, so there was a stronger magnetic field and a more precise corona on that side.
Blisters from a solar eruption, also known as coronal mass ejection, are also visible at the base left of the corona – another sign of sunrise activity. The eruption appears to have erupted from the Sun just hours before the eclipse.
Ideas from Solar Orbiter could help develop these models. Currently, researchers are limited to measurements from Earth’s view in the ecliptic plane – the space belt, largely parallel to the equator, through which all the planets pass. When Solar Orbiter, launched in February 2020, finds measurements of the magnetic field elsewhere, and finally, at the north and south poles of the sun, researchers get a more complete view of our star.
The research group has made predictions for each eclipse in recent years, making adjustments and improvements each time. In 2017, they used data from NASA and the Ames Pleiades supercomputer to predict the appearance of the corona during the Aug. eclipse. 21, 2017 across the United States. SDO’s observations of filaments – snake-like structures on the surface of the sun – helped to update the model. For the 2019 eclipse, the researchers developed their modeling of the solar magnetic field at the poles, which will at least have a strong influence on the shape of the corona.
One change they made this year is a more accurate model of corona temperature. Instead of making the solar material electrically charged in their simulation all at one uniform temperature, they allow separate temperatures for different types of grains. After the eclipse, the group compares their model to the reality and continues to change the simulation.
“We put ourselves out there to move the model forward,” Downs said. Disadvantages between the prediction and the actual show the importance of eclipses to moderators, he said. “If he doesn’t agree well, that just tells you what more we need to go.”
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