Alien Scientist 44: Divining the Sun
Stephen Marshall, a former resident of Tsukuba, has been writing Alien Scientist articles for the Alien Times since 2001. Even though he no longer lives in Tsukuba, he is still a regular contributor to the magazine. Here is his latest intergalactic report.
If an alien scientist knew the galaxy well enough to find its way to Earth, then the chances are that it would know more about the Sun than any of the locals. Of course, how much the Earthlings knew would depend on who – or what – was being consulted, at what point in history.
Any creature with senses must surely have some sort of visceral awareness of the sun, as a warm, bright presence – or perhaps direction – at least among creatures living at the surface of the Earth. The more visually aware surface dwellers would surely be conscious of the sun as a big glowing ball in the sky whose presence or absence would signify day and night.
Human imagination allows extrapolation beyond these simple experiential truths, to hypothesise (correctly) that the disc that sets in the evening is the same object as the disc that rises again the next morning; and (wrongly) that the sun, along with the moon and stars, follows a track in the sky centred on the Earth. Other human traditions have it that the sun is made of a celestial substance that is different in kind from the matter found in our terrestrial world. The ancient Egyptians went further, believing that the sun was a god, variously ruler of heaven and earth, and identified with the creator of the world.
Modern Earthlings can now agree with alien scientists that the sun is just another star; and that planets – once considered to be ‘wandering stars’ – are in fact satellites of the sun, just like Earth, which is no longer the central focus of the universe. But while we have known the sun’s role as an astronomical object for centuries, it is only relatively recently that we have worked out what the sun is actually made of, and how it works.
For most of history, the sun has just been taken for granted as a sort of big fiery ball. But what do we mean by a fiery ball? Certainly the sun can be regarded as roughly ball-shaped, at least to the extent that it appears as a disc in profile; and to the extent that anything ‘fiery’ could be considered ball-shaped. But when we say fire, what kind of fire? The sun does not burn the way a fire does, by combustion – otherwise, how could it burn for so long, in the vacuum of space? We now know that the sun works by the process of nuclear fusion. If we allow burning to include the nuclear reactions in the sun, then we can allow that the sun does, in a sense, ‘burn’. So we can graciously expand the meaning of ‘burn’ and ‘fire’ to include the sun, and keep with it all the warm, cosy associations of fire found in human traditions, rather than looking at the sun with a new cold gaze as a kind of nuclear-technological apparatus, as if it were invented in the twentieth century.
This brings us to the question of what the sun is made of. The sun is made up almost entirely of two elements – seventy per cent hydrogen, and twenty eight per cent helium. But when we look more closely, we see that these substances are not simply composed of atoms in a conventional sense, but form a plasma, in which protons, neutrons and electrons are flying around as independent agents, not bound together in the form of atoms. Unlike solids, liquids or gases, plasma must be considered as rather alien stuff – that is, unfamiliar to us as a natural state of matter on Earth. From this point of view, our biggest heavenly neighbour is not, in one sense, strictly made up of the same kind of matter as down here on Earth, but features a state of matter only found naturally in the interiors of stars, or as we might say, in the heavens.
Indeed, by its process of nuclear fusion, the sun may be said to create atoms, the heavy elements that our familiar world is made up of. In this sense, the sun is, in a manner of speaking, a creator of the world we know. As an alien scientist might agree with an ancient Egyptian.