A grey seal: Or is it a woman?

The Falling Sky

Pippa Goldschmidt
Freight Books, £8.99, ISBN: 9781908754141, PP256
by Pippa Goldschmidt

SRB Diary: In Orkney

November 18, 2016 | by Pippa Goldschmidt

I’M heading north to Orkney, where I’m scheduled to take part in this year’s science festival. As the Hamnavoe ferry approaches Stromness I stand outside on the deck, so I can watch as it changes direction to line up with two red navigation lights on the town’s Hellihole road. This manoeuvring is essential for the ferry to follow the correct course through the harbour entrance, and it’s a reminder of how closely land and sea are linked here.

This is the twentieth year of the science festival and it attracts speakers from all over the world. In contrast the audiences tend to be local (the tourists from the ever-present cruise ships anchored off Kirkwall seem more interested in ice-cream and bus trips to Maes Howe).

First stop on my science festival tour is Lyness, on Hoy. Lyness was one of the bases of the Royal Navy until 1957 and the remnants of this military use still dominate the landscape. A vast oil drum now houses part of the exhibit at the local museum, and there are gun batteries, barracks and a naval cemetery (where some of the victims of the Royal Oak bombardment are buried). The houses in Lyness appear to have been built in the spaces left vacant by the naval infrastructure.

I give my talk on fictional explorations of astronomy and afterwards we go outside to consider the night sky. It should be ideal for seeing the stars, as dark as anywhere in the British Isles, but the nearby flare at Flotta oil terminal does a depressingly effective job at lighting up the eastern part of the sky. We try and shield our eyes from this light and pick out some stars. I’m ashamed to admit to the others that I have never witnessed the Northern Lights, surely this should be a rite of passage for astronomers? The wind is unusually absent for Orkney, and the midgies triumph. We’re soon driven back indoors.

* * *

ON my return to Kirkwall I spend an afternoon at Orkney Grammar School listening to some other science festival talks. A billed highlight is Professor Martin Hendry from the University of Glasgow who tells us about the recent discovery of gravitational waves by the LIGO instruments in America (LIGO is short for Laser Interferometer Gravitational-Wave Observatory – actually two vast laboratories each with two perpendicular laser beams stretching for miles). The physics department at Glasgow was one of the pioneers of the exceedingly complex technology needed to do this type of science and is rightly proud of its close connection to this discovery.

Martin explains that gravitational waves are a key prediction of general relativity, first conjectured by Einstein in 1915. These waves are understood to be ripples in space-time caused by the motion of massive objects. Nobody (including Einstein himself) thought it would actually be possible to detect these waves because their predicted amplitude was so minute. Nobody, that is, until the 1960s when an American physicist, Joe Weber, claimed he’d found them by tuning bars of aluminium to the right frequency. These detections were false (although Weber himself would never admit defeat), but influential in that they encouraged other people to consider better ways of doing the experiment.

General relativity is a theory that has never been proved wrong since its first experimental confirmation by Arthur Eddington in 1919. This latest discovery by LIGO actually confirms the theory in two different ways, firstly through detecting gravitational waves with the predicted characteristics, and secondly because the objects causing these waves seem to be a pair of black holes – and black holes are another phenomenon predicted by general relativity. As two black holes circle each other and fall inwards, they emit gravitational waves at the same frequency as a chirping noise, and in his talk Martin is able to persuade us to impersonate a black hole and chirp at him.

But whilst LIGO’s result is beautiful, and has been celebrated by physicists everywhere, one aspect is slightly alarming. General relativity is a classical theory born out of nineteenth-century physics and mathematics. It’s not written in the same language as the other great revolutionary idea of twentieth-century physics, quantum mechanics, and so far nobody has found a way of connecting the two theories. Sooner or later the cracks in general relativity must show, so LIGO’s precise and definite confirmation of the waves only puzzles the theorists even more.

The next talk is a historical one by Dr Alec Mackinnon (also from Glasgow University) about the Scottish physicist C.T.R. Wilson, who invented a device called the cloud chamber about a hundred years ago. Cloud chambers were a pioneering technology enabling scientists to see sub-atomic particles such as electrons. Much of the apparatus of physics – be it cloud chambers or LIGO’s more modern interferometer – renders the invisible world visible.

* * *

WHEN I was last in Orkney a few months previously, I went for a walk at Birsay, on the north-west corner of Mainland. Birsay has an island (the Brough) that is connected to the mainland at low tide by a short causeway. At high tide, the causeway is covered and the Brough is cut off. As I walked along the beach, a pod of seals rested in the water nearby with their upturned faces facing the sun. I had with me new and powerful binoculars and I was keen to try them out, so I looked through them at one of the seals.

The seal was in fact a woman. Through the lenses I saw quite clearly the shape of her head and the strands of her long wet hair flowing over her shoulders. I lowered the binoculars and the woman turned back into a seal.

Traditionally, selkies are found in liminal places between the land and the sea. Places that themselves change identity, such as islands that are not always islands, depending on the tides and the weather.

Physics has accustomed itself to the fact that what we see of the world depends on our technological abilities. But it has become uneasily aware that language also influences our observations. In 1877 the Italian astronomer Schiaparelli announced that he had made detailed observations of the planet Mars and discovered ‘canali’ on its surface. ‘Canali’ was duly translated into English as ‘canals’. This was then interpreted by a minority of astronomers, such as Percival Lowell, as meaning that Mars had inhabitants capable of building canals to conduct water from the ice caps on Mars to its red deserts (presumably to irrigate those deserts).
But ‘canali’ simply means channels, a more neutral word with no overtone of the artificial or alien-made. And while the majority of astronomers didn’t agree with Lowell’s claims, some remnant of them lasted in the collective consciousness until the first space mission to Mars in the 1960s showed no evidence for any sort of channels and the ‘canali’ theory was finally laid to rest.

* * *

BACK in Kirkwall I give my talk about the quantum physicist Schrödinger and his wave equation which he derived while on holiday in 1925 with a mystery woman (her identity has never been resolved, all we know is that she definitely wasn’t his wife). What interests me is how this equation has been interpreted in different ways. Its prevailing use – as a way of quantifying probabilities of future events – was anathema to Schrödinger himself, who remained convinced that his wave was a physical reality and not a mathematical device. He thought he’d made a great discovery, other physicists regarded his equation as more of an invention. The audience and I talk about what it must have felt like for Schrödinger to come up with a brilliant piece of physics, to be fêted for it (he won the Nobel prize) and yet not know what it meant.

* * *

AT the ferry office in Kirkwall harbour I check the times of the ferry to Eday where I’m giving my next talk. On the window-ledge of this office I find two skeletons, apparently positioned so that they’re sheltered from the prevailing wind. One skeleton is larger than the other but they are both clearly of the same species. I can’t even tell if they’re animal or bird. Google says ‘sea bird’ but doesn’t narrow it down any more than that. I replace them on the ledge, and the next day when I go to look for them again, they’ve disappeared.

Eday is an island almost small enough to see the sea on the other side, and when I step off the ferry I still feel surrounded by water. The island’s community lives along its coast, facing outwards, and a high percentage of that community comes to the planned talks at the local school.

The first talk is by Anne Strathie who tells us about Scott’s Terra Nova expedition to the South Pole in 1910-1913. The expedition is commonly seen as a failure because Scott was beaten in the race to the Pole by Amundsen, and because all five men died on the return journey. But Anne is more positive as she emphasizes its extensive scientific legacy in many different areas of geology, meteorology and biology. Scott and his men insisted on lugging a heavy sample of rocks on their return journey, the weight of which may have contributed to their deaths. These rocks were discovered with the men’s bodies and the fossils they contained were subsequently used to demonstrate the validity of the Gondwana supercontinent theory.

On the final boat journey to Gills Bay, we’re accompanied by gannets who easily keep pace with us. The sky is invisible behind the mist and rain, and I try and fail to spot any seals.

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