The central peak or mountain that forms inside an impact crater like Tycho isn't formed directly *inside* the crater, but rather in the center of the uplifted area surrounding the crater. Here's a breakdown of how it happens:

1. Impact: A large object (asteroid, comet) slams into a celestial body (like the Moon).

2. Shockwave: The impact generates an enormous shockwave that travels through the impacted surface.

3. Uplift: The shockwave causes the area around the impact point to be uplifted, pushing the material upwards and outwards.

4. Crater Formation: The impact creates a depression (the crater) in the center of the uplifted zone, while the surrounding material gets pushed outwards and eventually settles.

5. Central Peak Formation: The uplift creates a central dome-like structure in the middle of the uplifted area. As the surrounding material moves outwards, the central dome collapses on itself, forming the central peak.

Think of it like this: Imagine pushing a finger into a soft piece of dough. The dough surrounding your finger will be pushed upwards and outwards. The dough directly underneath your finger will be compressed and pushed upwards, creating a small mound in the middle of the indentation you created.

Why Tycho is a good example:

Tycho is a classic example of an impact crater with a central peak. Its relatively young age (around 108 million years old) means it hasn't been significantly eroded, allowing us to clearly observe the structure.

In summary: The central peak in a large impact crater like Tycho is not a direct result of the impact itself, but rather a consequence of the rebound and uplift of the surrounding material caused by the shockwave of the impact.