Here's why:
* Distance: Neptune is the farthest planet from the Sun, making it incredibly faint.
* Size: While it's a giant planet, its size is dwarfed by its distance from Earth.
* Brightness: Neptune reflects very little sunlight, further contributing to its faintness.
While Uranus can be glimpsed under exceptionally dark skies, it's generally considered too faint to be consistently seen without optical aid.
