In the northern hemisphere, today is the winter solstice. In the southern hemisphere it is the summer solstice. There are reasons for this and I will try to explain them as simply as possible. We will come out knowing more about the solstice or awfully confused.
The first thing we need to know about is that the earth orbits the sun.
The earth also rotates, which means it goes in a complete circle while it is orbiting around the sun. Because the earth rotates, it shows one side to the sun and then the other. Each rotation takes 24 hours. That’s why we have day and night.
The next reason is that the earth is pretty much round in shape and it is tilted. The earth s=doesn’t sit straight up and down like we would in a straight backed chair. It is at a tilt, with the top of the earth leaning back and the bottom of the earth leaning forward.
You can see the sunlight shining on the southern hemisphere more that the northern. In the arctic circle, it doesn’t really get light until the end of winter. In Antarctica, it doesn’t get really dark until the end of summer.
That’s the simple version. The next two pictures are sunsets.