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The solar corona behavior is still not known precisely and is one of the biggest open questions on solar physics. Nevertheless, the Parker Solar Probe, launched in 2018 by NASA, may provide more information about its origin.

Doubtlessly, the Sun is the star that has received the most attention over human history, and its significance has been recognized in all cultures. We are going in-depth on this topic later in chapter VI about the ancient worldview of eclipses.

Solar corona during a total eclipse of the Sun. Behind the moon’s shadow, redlined, we can see the solar flares, typical phenomena of the chromosphere.

• • • STARS ARE MADE UP OF ATOMS BUT HOW TO KNOW WHICH ATOMS ARE IN EVERY SINGLE ONE OF THEM?

Astronomers research the material that stars are made up of. To do so, they can only see the light they emit. Fortunately, the light produced at the center of the stars pass through their atmosphere and approach us, acting just like the light we produce on Earth. Also, their atoms behave the same way in the star as in the laboratory, which means that first, we study the kind of light atoms produce on Earth, and the colors they emit, and also how bright is every color.

For instance, if the gas of an element is heated, the brightness of its color is always the same. So, thanks to the laws of quantum physics, we can precisely calculate how much energy that brightness means. Atoms can emit or absorb light only on those specific colors.

Astronomers, on their behalf, scatter the light coming from the stars (leaving it as a rainbow), and they observe which colors are NOT there. Later, using spectroscopy, which is a technique used in every natural science, they compare the colors missing with the ones that atoms emit. 34 • • •