Most people only know their sun sign, because it is the most vital part of a persons chart.
Our charts show the planetary positions of our birthtime and -place, as seen from the earth.
So, in an astrological chart, the earth is in the center of the solar system, not the sun.
This is not because astrologers don't know that we live in a heliocentric solar system, but because our birth charts show the planetary influences as seen from the earth.
And the influence the sun has on the earth is quite obvious:
Without the suns warmth and light, there would not be any life.
And that is why a persons sun sign is so important: It expresses our life energy, our self expression and how we act.
The Houses in the astrological chart stand for 12 life areas.
The Sun being our life energy, the house it is located in is our main life focus and the area of life where we feel most alive and we concentrate most of our energy on.
They are all dark, though, except for one: The sun is in this room: It shines its light, lighting and heating the room up.
There's life pulsating in this room and it shines bright, drawing all your attention to it.
That's how you could imagine the house your natal sun is in.
It is your main life focus and you put more attention and energy in it than any other life area.
We cannot possibly ignore this life area, we feel like we have to put special attention to it and be special in this area, express ourselves especially strong there.
Naturally, we overly focus on working and acting in this life area, which could also lead to us neglecting other parts of our lives and developing a need to be recognized for what we do in this life area, resulting in it being very important for our ego and self-confidence.