In Search of Planet Vulcan – Richard Baum and William Sheehan

Cover of In Search of Planet Vulcan


In Search of Planet Vulcan
Richard Baum & William Sheehan
310 pages including index
published in 1997

The classic idea of the universe was that it was geocentric: the Earth in the centre, with the planets, moon and the sun circling around it and the fixed stars as background. Over the centuries that central idea had to be modified with increasingly complex epicycles as the theory had to be adjusted to observational evidence. It was only in the sixteenth century that Copernicus, Kepler and Bruno challenged this Ptolemaic model and replaced it with the truth: that all the planets, including Earth revolved around the Sun. Copernicus was the first to propose this, Bruno would die at the stake for his advocacy but it was Kepler who figured out how the planets revolved and what governed their orbits. more than half a century later Isaac Newton formulated his laws of gravity, joining Kepler’s laws with more mundane events on Earth, finally providing a complete model of the workings of the Solar System. From then on, any planetary orbit could be calculated with the right observations and the use of Kepler’s and Newton’s laws.

except for one. The orbit of Mercury remained, as the subtitle of Baum and Sheehan’s book has it, “the ghost in Newton’s clockwork universe”. Time and again, no matter how carefully the observations were made and how intricate the calculations were, the two just would not line up. Even the best astronomers in the world, with the best observations could not make Mercury’s orbit confirm to what it should be according to Newtonian physics. It wasn’t until Einstein reformulated the laws of gravity that the reason why became clear. Newton’s laws break down near massive objects like the Sun and although “good enough” for most situations, Mercury’s orbit was just too close to the Sun and Newtonian physics just wasn’t accurate enough. Of course, until Einstein found the real answer, astronomers sought for other explenations for Mercury’s wrong orbit — and the most likely candidate was an undiscovered planet even closer to the Sun: Vulcan.

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The State of the Universe – Pedro G. Ferreira

Cover of The State of the Universe


The State of the Universe
Pedro G. Ferreira
320 pages including index
published in 2006

I felt the need to reacquaint myself with modern astrophysics as it has been far too long since I’ve read anything about it. Sure, I do watch The History Channel’s Universe series whever I catch it, but that doesn’t tell me much I don’t know already, while following the vast array of astronomy blogs out there is no real substitute, as they do assume a certain familiarity with the current state of the art. Long live the public library therefore, for providing quick access to what looks like exactly the book I need: The State of the Universe: a Cosmic Primer. Written by Pedro Ferreira, a lecturer in Astrophysics at Oxford, it’s meant as a layperson’s introduction to what astrophysics thinks the universe looks like and what makes it tick.

The State of the Universe is built up logically from first principles. Ferreira starts with a short overview of classical Ptolemaic cosmology, with the Sun revolving around the Earth and how it was succeeded by the heliocentric cosmology of Copernicus and Gallileo. Over several chapters he then shows how our knowledge of the size and complexity of the universe expanded, from what was once thought to be no bigger than our Solar System, through an understanding of how big our Galaxy actually and finally to an appreciation of the idea that all those galaxy shaped nebulas are actually galaxies as well. Then he goes on to the other end of the scale and explains the physics of the universe: the fundamental forces that shape it (gravity, electromagnetism, the strong and weak force), a quick sketch of the whole zoo of the particles that make up the matter and energy in it and how it all sits together. From the classic Big Bang idea of the evolution of the universe he finally moves on to the cutting edge of current physics, where it all gets a lot less clear what’s real and what’s just clever theorising.

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