On significantly larger scales, the universe is still anisotropic. Consider,
for example, a sphere 3 AU in diameter, centered on your navel (Figure 2.2b).
Within this sphere, there is a preferred direction; it is the direction pointing
toward the Sun, which is by far the most massive and most luminous object
within the sphere. It is easy to determine the vector pointing toward the
Sun. Just step outside on a sunny day, and point to that really bright disk
of light up in the sky.