MESSAGE OF THE MONTH
How I proved the Moon landing wasn’t faked
An elderly acquaintance asked me about the famous Apollo 11 lunar footprint photo. I don’t think she had totally erased from her mind the idea that the whole lot was faked. I had a quick think, and in the course of the discussion on the regolith I was repeatedly interrupted by comments that ‘there’s no water on the Moon’ (the implication being that the surface cannot be – or behave like – clay or mud) and that ‘sand won’t stay put’ – so I couldn’t possibly come up with an explanation.
Well, I wasn’t going to be beaten by this. I did some research and ascertained that the thin layer of fine dusty regolith that overlays the coarse stuff has a mean particle size of 72 + m and a bulk density of about 1.5. I decided to do an experiment. With lunar gravity at about one-sixth that of Earth’s, I needed a material with one-sixth the density of regolith, comparable particle size, and a surface that would generate pretty ordinary Van der Waals forces (the small electrical forces that make all matter stick together very slightly).
Bread flour has a mean particle size of about 50 + m and a bulk density of 0.48: a ratio of regolith/ flour of about three, so I really wanted a material with about half the density of flour. I have kept a bottle of Lycopodium powder for the past half century in case it came in useful sometime. I looked on the internet again and found that Lycopodium spores are about 40 +m – ideal. But nowhere could I find the bulk density, except in a blog that read “an ounce will fill more than a half cup volume measure”. Apparently this American cooks’ measure is 8.3 fluid ounces, near enough the volume of 8.3oz of water. So Lycopodium will have a bulk density of approximately one divided by 4.15, which equals 0.241. So, the ratio of densities regolith/ Lycopodium is 1.5 divided by 0.241, which equals 6.2, near enough identical to the ratio of Earth/ lunar gravity. But unfortunately, in my hour of need, I was unable to locate the bottle!
So, it was back to bread flour. Spacesuits are heavy: I looked up the weight of the kit and it was 91kg. Kitted up, an astronaut weighed about twice an average man, but in reduced lunar gravity this would have been about one-third of that weight – the final piece of data for my experiment.
I suffer from hot feet, and wear sandals year-round. It would be a disaster if a pair were to collapse in winter, so I keep an unworn pair in stock. I filled a small tea tray with flour and made an impression with a pristine sandal, with a pressure of about 15kg (one foot: they jump, not walk, on the Moon). In five minutes I had a perfect fake lunar footprint, but it took 10 minutes to clear up the mess, and get the flour back into the bag for its intended use. I gave the photo to my acquaintance, along with an explanation of what I had done. John Kemp, Whitstable
A truly thorough experiment John. It seems you have well and truly proved your point: but did your acquaintance see the light? – Ed