The numbers
- Why we cannot see it
- The Moon spins while it goes around us
- How much stays hidden
- 41%Less than half, thanks to the wobbles
- First photograph
- October 7, 1959, by the Luna 3 probe
- First human eyes
- December 24, 1968, with Apollo 8
- First landing
- January 3, 2019, with Chang'e 4
To get an idea
The part truly never seen from Earth is not half the Moon but a little more than four tenths.
On that face the dark seas are almost missing, and the craters are much more crowded.
Fun facts
These are not in the book: there was no room on paper.
The first human beings to look at it were the Apollo 8 astronauts, on Christmas Eve.
The first landing on that face happened in 2019, with a Chinese mission.
To talk to the Earth, that mission had to use a relay satellite in orbit.
People have thought of building a base right there to study the universe without Earth's interference.
On the far side the dark seas are almost missing, and the surface is much more cratered.
Test yourself
The first question is the one printed under the QR code, with the answer the book did not give. The other four only exist here.
Question 1 of 5★ is the one from your book
Why do we never see the far side?
Question 2 of 5
Does the far side get sunlight?
Question 3 of 5
How much of the Moon really stays invisible from here?
Question 4 of 5
Who saw it first?
Question 5 of 5
What is the far side like?
Riddles
I am not dark, even though everyone calls me that: the Sun warms me just as it warms my other half, only at different times. I am invisible because of angles, not light. What am I?
No human being looked at me for all of history, until a Christmas a few decades ago. Before then, only a machine sent from far away had photographed me. What am I?
I should be exactly half of something, and instead I am a bit less: a slow wobble lets people peek beyond my edges. What am I?
Try it yourself
Do it again while always facing the same direction instead: this time they will see all your sides. That is what would happen without synchronous rotation.
Look for a photograph of the far side and compare it with the Moon you see in the sky: it is so different it looks like another world.
The words
- relay satellite
- A satellite that passes signals between two points that cannot see each other.
Sources: Wikidata (Q194235), Wikipedia (Faccia nascosta della Luna).