The North and South Lunar Nodes reference the Moon’s crossings of the ecliptic. The North Node is when the Moon goes above the ecliptic during its orbit of the Earth, and the South Node is when the Moon drops below the ecliptic. (Clear as mud, right?)
Okay, perhaps a little more background might be helpful here …
The Sun and major planets (Mercury through Neptune) originated in a rather flat, spinning disk of gas and debris. The center of the disk evolved into our star, the Sun. The other major planets evolved from the debris colliding and clumping together (called ‘accretion’). (Pluto and other ‘trans-Neptunian objects’ like Sedna and Eris formed a bit differently and are a separate subject not pertinent to the lunar nodes.) The original disk of gas and debris of our solar system is often called the ‘solar disk’.
Because the planets (and asteroids) formed from this spinning flat disk, they acquired the same relatively flat orbits around the Sun. They were like marbles rolling around on a dinner plate. This invisible ‘dinner plate’ is now referred to as the ‘ecliptic’, and the planets continue to roll around it.
Just like the other major planets, the Earth also rolls around this relatively flat ecliptic. And the ‘rolling’ of the Earth is actually the Earth spinning like a top. And as the Earth spins, the side facing the Sun is daytime, and the side facing away is nighttime.
Now, the ‘spindle’ of the Earth’s spinning, also called the ‘axis of rotation’, is not straight up and down. It is tilted at about 23 and a half degrees to this ‘flat plate’ called the ecliptic. This tilt is called the Earth’s ‘obliquity’. Because of this tilt, it causes uneven heating of the Earth and creates seasons in many parts of the world – Summer, Fall, Winter, Spring.
Okay, let’s bring the Moon into all of this. (Whew, it’s about time.) The Moon orbits the Earth very close to the Equator (but off by almost 7 degrees). With the Earth tilted by about 23.5 degrees to the Ecliptic, and the Moon’s orbit roughly in the same neighborhood of tilt. While orbiting the Earth, the Moon sometimes goes up and across the ecliptic. At other times, the Moon comes down crossing the ecliptic again. Where the Moon’s orbit intersects the ecliptic going up (‘north’ relative to the Earth), it is called the North Lunar Node (or North Node). Where the Moon’s orbit intersects the ecliptic going down (‘south’ relative to the Earth), it is called the South Lunar Node (or South Node).
Within Chaostrology, the house where the South Node sits signifies karmic problems from one or more past lives. The North Node then represents corrections for the past issues. The general term for karmic problems is ‘misuse’. The misuse can be either too much or too little of some character trait. For instance, karma related to the 1st House is typically either being impulsive or being lazy. Impulsiveness is too much initiative, and being lazy is too little initiative.
In the end, all character traits must be balanced for each of us to align with the Golden Rule – treating others as we wish to be treated. For the 1st House example, we must not be too impulsive nor too lazy. Our actions must be appropriate for each situation.