I bet you didn't know that this thread would have a part 2

There's a full moon out tonight. We've all seen it before, but tonight, if you get a chance between the clouds, have a look up at it and think about this -

When you can see a full moon from earth, that means that you can see a full earth from the surface of the moon.

The moon is 2150 miles across. The earth is 7910 miles across. So roughly speaking, the earth is 3½ times the diameter of the moon.

That means that the earth in the moon sky tonight will appear 3½ times wider and 3½ times taller than the moon appears in the earth sky. Or in other words, it will take up 13 times the amount of sky that the moon does tonight.

And there's no atmosphere on the moon, which hazes and distorts the moon seen from earth - so it would be not just much bigger than we see the moon, but also much clearer. And because we never see the far side of the moon, the earth as seen from the near side never sets.

It must be a truly electrifying sight. Yet it's possible no-one's ever seen it. Man has only spent about 12 days on the moon, but the full earth, like the full moon, only appears once every 28 days. And I think all the Apollo visits were timed at the same phase of the moon to fit the required trajectory.

So you'll just have to make do with this spectacular photo taken in 2015 by NASA's Lunar Reconnaissance Orbiter - and as I say, have a look up at the full moon tonight and try imagine seeing the view of a full earth for yourself.

One last Apollo snippet before I move on to a new book!

This is an Apollo toilet -



Operation was straightforward -

1) Find a quiet corner of the spaceship. Zero-g actually created more such corners - you could float up to the ceiling and turn upside-down, for example
2) Drop the cacks
3) Tape the open end to your arse
4) ****e

Now the problem with step 4 is that gravity plays a key role - it's what causes the drop into the toilet bowl on earth. Without gravity - well, you can guess. So step 5 then is to put your finger into the finger-sized slot on the side, poke around and help things on their way.

On with the steps so -

6) Remove bag - being careful not to pull out too many hairs
7) Wipe with wet-wipe - the small square on the left - and pull up trousers
8) Insert the contents of the black bag into the toilet bag and mush everything up by hand. The black bag contains a chemical element designed to neutralise the bacteria in the toilet contents.

Part of the recorded transcript of Apollo 10 is the three astronauts blaming each other for a floater in the cabin (133:29:44 to 133:30:44 here if you're really interested). And one astronaut on Apollo 8 had the 24-hour bug - diarrhoea and vomiting - and again, there were bits floating around. When Apollo 8 splash-landed (if you'll pardon the pun!), the navy officers who opened the hatch recoiled at the smell from inside.

For anyone interested on reading more about the Apollo missions, I can absolutely recommend Andrew Chaikin's A Man on the Moon, which covers all the Apollo missions and features interviews with every Apollo astronaut and a hell of a lot more people besides. I'd go so far as to say it's a really important book - only 4 of the 12 people who've walked on the moon are still alive today - and a brilliant account of an incredible period.

Next in my reading pile is my own book. :eek: I've already spotted a typo on page 2...