Sun Opposition Mars in Depth
Across the wheel, and near the Mars opposition
One hundred eighty degrees between Sun and Mars means that at your birth Mars was opposite the Sun in the sky, rising as the Sun set and visible all night. This is the point in the Mars cycle when the planet is closest to Earth and at its brightest, which happens roughly every twenty six months. If you have this aspect natally you were born within weeks of a Mars opposition, and Mars was probably retrograde or close to it.
Allow seven to nine degrees. The retrograde detail is worth checking, because it turns the aspect inward and often describes someone whose considerable force is aimed at themselves before it is aimed anywhere else.
Conflict arrives through other people
Oppositions externalize. Where the square generates its own friction internally, the opposition tends to find you a live opponent. People with this aspect frequently report that they are not aggressive but that aggressive people keep turning up in their lives. Some of that is genuinely bad luck. Most of it is a stance, a slight forward lean that others read as a challenge and answer.
The useful question is not who started it. It is what you are doing that reliably recruits the same character into every workplace and friendship group.
The turn
This aspect has a clear developmental arc and most people move through it in roughly the same order. First stage, you are in conflict and it is always their fault. Second stage, usually somewhere in the thirties, you notice the pattern and overcorrect into avoidance, which tends to produce low grade depression because the Mars energy has nowhere to go. Third stage, and this is where it becomes an asset, you learn to engage deliberately with things worth opposing.
The mature version is a good advocate. Someone who can be in direct conflict on behalf of a cause or a person without needing to win personally is doing this aspect properly. The advocate version also tends to be a better strategist than the earlier stages, because it has finally stopped needing the other side to be wrong.
Timing and practical handling
Transiting Mars opposes your natal Sun about every two years, holding orb for four to six days, and can stretch to weeks if it stations in that part of the zodiac. Those stretches usually deliver a specific person to argue with. Knowing it is coming does not prevent the argument but does let you choose whether to have it.
One concrete habit helps more than any other. In a confrontation, ask what the other person actually wants before stating what you want. It costs one sentence and it converts a large number of standoffs into negotiations, because the opposition's real problem is that both parties have already decided the other is the obstacle.