Earth does not have any SI unit or even a unit.

There is SI unit of gravity or length.

While The astronomical unit ( AU) is just a unit of length (not even a SI unit ).

1 AU is equal to the distance from Earth to the Sun i.e., 150 million kilometres (93 million miles)

The SI unit of Earth is the Newton (N).

- What is the Newton?
The Newton is the SI unit of force. It is defined as the force required to accelerate a one-kilogram mass by one meter per second squared. In the case of Earth, the force of gravity acting on an object is typically measured in Newtons.

- How is the Newton related to Earth?
On Earth, the force of gravity is approximately 9.81 meters per second squared. This means that a one-kilogram mass on Earth experiences a force of approximately 9.81 Newtons due to gravity. This force is what keeps objects on the surface of the Earth and affects the weight of objects.

- Why is the Newton important for understanding Earth?
Understanding the force of gravity and its relationship to mass and acceleration is crucial for various scientific fields, including physics, engineering, and astronomy. By using the Newton as a unit of force, scientists and researchers can accurately measure and quantify the effects of gravity on Earth and other celestial bodies.

In conclusion, the Newton is the SI unit of Earth when it comes to measuring forces such as gravity. It plays a crucial role in understanding the dynamics of objects on Earth and in the broader universe.