American President Jimmy Carter goes to Denver on May 3, 1978 to the Solar Energy Research Institute.
On the other side of the country, on the same day, dozens of people gathered at Cadillac Mountain in Maine, the place where the sun's rays supposedly touched the United States for the first time.
In New York, Robert Redford told the crowd that "no country can put an embargo on the Sun." All these events in the United States, but also in 22 other countries of the world, had something in common - that year, World Sun Day was celebrated for the first time, on Carter's initiative.
Since then, scientists have been using every moment to learn as much as possible about the star that made Earth populous.
What do we know about the Sun?
The Sun is about 4,5 billion years old, according to the National Aeronautics and Space Administration (NASA). They will sow, scientists estimate, even more.
"Stars like our Sun shine for about nine to ten billion years. So our Sun is about halfway through its life," say NASA scientists.
"When those five billion years are up, the Sun will become a red giant."
"That means it will get bigger and cooler at the same time. When that happens, it will be different from the Sun we know today. "It will become about 2.000 times brighter than it is now."
This star is 109 times the diameter of Earth and weighs 330.000 times.
However, every second it loses several tons of its own mass when converting it into light and energy. The temperature of the Sun is an incredible 15 million degrees Celsius. This temperature is estimated to be in the very core of the Sun.
Although we perceive the Sun as yellow, this star does not actually have one color, but is a mixture of several. Because we look at it through the atmosphere, we see it as blindingly white. The Sun is made up of two-thirds of hydrogen, while one-third goes to helium. It takes eight minutes for the sun's rays to reach the Earth, and the distance is almost 150 million kilometers.
What else are we investigating?
The fascination with the Sun continues. Scientists are constantly trying to find out something new - so in 2020, they photographed the star in stunning detail.
The images were taken from Hawaii - with the Daniel K Inouye Solar Telescope.
They show an area of only 30 kilometers. This time-lapse video shows how the surface of the Sun changes over the course of 10 minutes. It is the highest-resolution image of the Sun to date, and its appearance is closest to that of constantly shifting glowing lava. The color ranges from yellow to red. Just when we look at the Sun, but with the naked eye, we can notice that it is sometimes red. Why is that?
"The bottom line is the scattering of sunlight - and it's not scattered evenly," says astronomer Edward Blumer, from the Royal Museums Greenwich.
"Each color has a different wavelength and that's why each shade looks the way it does."
For example, violet has the shortest wavelength, while red has the longest.
The next step is to understand our atmosphere, the layers of gases - like the oxygen we breathe - that surround our planet and make life possible.
As sunlight passes through different layers of air - each with gases of different density - it is refracted and separated as if passing through a prism. Also, there are particles that remain in the air, which in turn cause scattered light to bounce and reflect off of them. When the sun rises or sets, its rays strike the upper layers of the atmosphere at a certain angle. And that's where the "magic" happens.
Bonus video:
