I hadn’t intended to come back to this topic for a while, but last week’s article has led to some interesting discussion in a London-based Zoom group of which I’m a member. My friend Del Cotter suggested that the Sun is below the horizon in the lunar landing of Fig. 1, and the landscape and the Moonship are earthlit, which would explain why the ship is in different phase from the Earth’s.
Examining the still from 2001, a Space Odyssey more closely, I argued that the rim of the crater behind the ship, and its shadow, both indicate that the light is coming from the Sun, out of view to the right, so the phase of the ship should be the same as the Earth’s. Martyn Fogg, whom I cited in my review of Stephen Baxter’s Galaxias (ON, 30th August), suggested that those shadows are features of the terrain rather than the light source.
However, that closer examination has turned up more issues. The Moonship is bearing Dr. Heywood Floyd, who’s being rushed to the discovery site in the crater Tycho of a black monolith (Tycho Magnetic Anomaly 1). The Moonship Aries lands him in the crater Clavius, near the south pole of the Moon, and he’s taken north by Moonbus to Tycho, where the Sun rises over the monolith and activates it just as he arrives.
The phases of the Earth, seen from the Moon, and the Moon, seen from the Earth, are always complementary, adding up to a complete circle. (In 2010, Odyssey 2, Arthur C. Clarke points out that from the Jupiter-Io L1 point, where the Discovery is parked between the two books and films, Io and Jupiter would appear to be the same size and would make a perfect circle if their images were joined together without adjusting the scale. It’s a coincidental relationship, like the one which makes the Sun and Moon appear the same size at the current evolutionary state of the Earth-Moon system.) As Clavius is in the southern hemisphere of the Moon, south is at the top of Fig. 1 and if we could make out the features on the globe of the Earth, Antarctica would be uppermost. So the Earth’s phase in that image is waning gibbous, and the corresponding lunar phase would be waxing crescent. As Tycho is near the centre line of the Moon’s disc (Fig. 3), the Earth’s phase in Fig. 1 is not compatible with an upcoming sunrise at Tycho, unless Floyd is going to be delayed at Tycho for four Earth days or more.
Fig. 2 makes matters worse, showing the Aries in transit towards a Moon which is also waning gibbous, with both Clavius and Tycho in sunlight and the sunset line (the terminator) approaching them. Two mistakes have been made here: first, assuming that the phases of the Earth and Moon will be the same, rather than complementary, from a viewpoint between them, and second, unless I greatly mistake, making the Moon rotate the wrong way (as Larry Niven famously did with the Earth in the first edition of Ringworld). Fig. 4 shows the ship approaching the northern hemisphere of the Moon (still in the wrong phase), so presumably it makes a pass over the lunar Farside before coming in to land at Clavius – in which case the Earth should be ahead of it, not behind as shown. It would indeed be low on the horizon, but in the north.
As we see it from the surface on final approach (Fig 5), the Aries is nevertheless coming from the north, with the Earth behind it. And the phase of the Earth has been reversed, which at least means that the sunrise terminator is approaching Tycho, but it’s not going to get there for days. Remarkably enough, though, in Robert McColl’s poster painting of the same scene (Fig. 6), the Earth is at First Quarter, with south at the top, and that’s compatible with a sunrise shortly at Tycho (compare its position in Fig. 3) – the only one of these images that is.
Sure enough, when we get to Tycho we’re in trouble again (Fig. 7). The Earth is now in waxing gibbous phase, incompatible with the coming sunrise, and with the Earth on the horizon, we should be looking north. As the Moonbus has come from Clavius, nearer the south pole than Tycho, we should be looking south, as we are in Fig. 8. Perhaps the bus has made a partial circle around the excavation before coming in. But although the sunrise line is coming from the right, from the east, as it should be, it’s also spreading south. Maybe that is a quirk of the local terrain. However you look at it, sunrise happens much too fast – on the Moon, sunrise and sunset both take about two hours. But as Martyn Fogg said in last week’s discussion, what really comes across nevertheless is how good the landscapes are, overall, though the film was released two years before anyone had actually landed there.
Confusion between time zones occurs often in SF. One famous example was Anne McCaffrey’s ‘It was morning on Pern’ – as indeed it is on any planet, somewhere. But in another incident, a dragonrider leaps into the saddle with the cry, “The Red Star is overhead!” He then teleports half-way round the planet and raises the alarm with the cry, “The Red Star is overhead!” The late Dr. Jack Cohen was paid to sort out the astronomical confusions in Annie’s books, but couldn’t do it. He told me that for the Pern novels he had compiled a spreadsheet of her statements, with an average of three entries per box, and in each of them one statement contradicted the other two.
Another case was pointed out to me by Mark Hayward of the Whistlebinkies. In the fourth Terminator film, in order to synchronise their attacks, the rebels decide to make them all over the world at 4 p.m.. Try that and see how far it gets you!
Confusions over compass points are equally common, and I can’t resist giving two real-life examples. In the Bon Accord bar on North Street in Glasgow, I was once buttonholed by a chap who had noticed Sirius in the south and was sure it had to be the North Star, since it was the brightest. Eventually I managed to convince him that it’s the position that counts, and Polaris is only second magnitude, just happening to lie on the Earth’s axis. “So where would I find the North Star?” he asked. “Well, what street are we on?” I replied. He knew, but still didn’t get it.
On another occasion, my sister and her husband Dave Goulder took me to Rogart in Sutherland, where his ceilidh band was to play at the reception following the raising of the Canadian flag, on the remains of the croft where the first Prime Minister of Canada was born. I fell into conversation with a lady who told me she was very disappointed, because she had moved to Rogart nine years before in hopes to see the Northern Lights, but never had. I thought that was odd, so I asked her to point out her house. The Sun was setting, so I whipped off my wristwatch and took a quick bearing, after which I said, “But your house faces south, with a big hill behind it!” She knew that, but it had never occurred to her that to see the Northern Lights, you usually have to look northward.
Between 1954 and 1988 Sydney Jordan drew the world’s longest-running comic strip, Jeff Hawke, first for the Daily Express, then the Scottish Daily News, and then in a different version for the Daily Record called Lance McLane, which was recaptioned as Hawke for overseas syndication. He had to produce six episodes per week throughout, 10,208 of them in all, and under pressure he often had to take short cuts. One frequent one was that for lunar landscapes he would draw scenes which had already been painted by space artists such as Chesley Bonestell, R.A. Smith and Fred L. Woolf. In those the phases of the Earth were different, so in the strip the phase would jump about from day to day. In the story ‘Time Out of Mind’ (1959), for example, a US moonship lands in Mare Crisium near a monument commemorating the first Moon landing – and he got the date almost exactly right, ten years ahead (Fig. 9). He had forgotten about that, and when I pointed it out to the paper that eventually put us in touch. Project Apollo landings were made at sunrise, so hazards would be revealed by their shadows, and the half-full Earth is right enough for that, as is the sunset 14 days later (though again much too quick). But in between, the Earth goes through the full gamut of phases, from waxing crescent to Full to waning crescent, in no particular order.
Lance McLane was set mostly in an Earth-Moon system which had been wrecked by a cosmic catastrophe (Fig. 10). The Moon had a big divot taken out of it, but under pressure Sydney had real trouble remembering which side of the disc it was on, seen from here, and which body the debris ring was orbiting (Figs. 11, 12 and 13).
Another piece of artistic license which we simply had to wink at was the constant liberties he took with ‘synchronous orbit’. Around the Earth, synchronous orbit is only possible in the plane of the equator, at a height of 22,000 miles. Because of the Moon’s slow rotation it’s not possible at all there. At the L1 and L2 points, where the pulls of the Earth and Moon balance out, it is possible to maintain a stable position, but both of them are tens of thousands of miles from the Moon, and technically are special cases of orbit around the Earth. Yet in the strip, ships were in ‘synchronous orbit’ over locations from Australia to northern Europe, and over the Moon from Plato to Copernicus, at whatever height suited Sydney for story purposes.
The same mistake occurs constantly in Star Trek – but then, in the whole of the original series I have yet to find a single episode in which even the word ‘orbit’ is used correctly. Scotty’s constant refrain is, “The power has failed, Captain, we canna maintain orbit” – even in the episode where the Enterprise goes back in time and is ‘in orbit’ at a height where it can be intercepted by an F-104 Starfighter.
For my Interface stories, which were published in Galaxy and If in the early 70s, I had to work out the orbital characteristic of a ring of satellites orbiting the Earth, in the plane of the Equator, 6000 miles up. Those characteristics were plot drivers in two of the stories, as I explained in the Notes, while leaving the calculations ‘as an exercise for the reader’. One point that I made was that it would be very difficult to get from one to another. In Gravity the Hubble Space Telescope, the International Space Station and the Chinese space station are all in the same orbit (Figs. 15 and 16), unlike in real life, and Sandra Bullock gets from one to another simply by pointing at them and firing thrusters. If you try that, you will end up in either a higher orbit or a lower one, depending on whether the target is ahead of you or behind. As the late John Brunner said of such mistakes, in his novel The Shockwave Rider, “See you later, accelerator. Much later.”
The NASA Director saw Gravity in a public theatre. Interviewed subsequently, he said that he had been getting increasingly annoyed with the mistakes, until he realised that the women in the audience around him were agonising over how Sandra Bullock’s character had lost her baby, earlier in her career. “It made me realise that not everyone has the same perceptions that I do.”
(To be continued).
Duncan Lunan’s spaceflight SF stories are collected in his books, From the Moon to the Stars and The Other Side of the Interface, published by Other Side Books in 2019 and 2021, are available through Amazon or through bookshops, or from the publishers. For details and for his other books see Duncan’s website, www.duncanlunan.com.
Interested in the night sky? Check this out for October
1 reply »