Are all portions of the Moon visible from Earth?
No. only one side of the Moon is visible from the Earth at all times. The rear or “far side” of the Moon cannot be seen from Earth.
Why is the far side of the Moon not visible from Earth?
Only one side of the Moon is visible from the Earth because the Moon rotates on its axis every 27.322 days, hence keeping the same face constantly towards Earth.
How is it possible to know about the far side of the Moon?
Spacecraft launched from Earth have gone behind the Moon and transmitted images of the far side of the Moon. We know about the far side only from these images.
When was the far side of the Moon first photographed?
In 1959, the Russian Moon probe Lunik first photographed the far side.
What are the names of the four quadrants of the Moon?
The four quadrants are first or northwest, second or northeast, third or southeast and fourth or southwest quadrant.