Problems with the “Old” Big Bang Theory⋆⋆

The problems of “criticality” and causality: Why is the Universe so flat and incomprehensibly homogeneous or uniform? The analogy of the surface of an inflating balloon. Fixed angular distances and varying physical distances. Possible but unpalatable initial conditions. The fate of open or close universes. The visible Universe, for us or for a diStant E.T. In passing, the “anthropic principle.”

Some Instruments of Micro-Physics

The destructive limits of microscopes. Ernest Lawrence’s first “cyclotron.” Linear and circular accelerators and colliders, their advantages and disadvatages, and how they work. Accelerating radio-frequency cavities, bending dipoles, and focusing quadrupole magnets. The accelerator comprex at CERN. The Large Hadron Collider (LHC).

The Scientific Method

The scientific method is defined and illustrated. This allows one to define empirically the concepts of mass (so often misinterpreted), energy, and momentum. Vectors and how to add them are introduced in passing. So are square roots, presumably quite unnecessarily. Whether or not E = mc2 is to be interpreted the way Einstein did it, is also discussed. The answer is “no”.

Physics as an Art Form

Beauty and simplicity, a scientist’s view. A first encounter with Einstein’s equations of General Relativity, space-time, and Gravity. Ockham’s Razor. Why the Universe is the way it is: The origin of the laws of Nature.

Dark Matter

What we know or do not know about dark matter. The evidence for its existence, first found by Fritz Zwicky. The “virial theorem” and the Coma cluster. The rotation curves of galaxies. Galactic dark-matter halos. Gravitational lensing and the May 1919 solar eclipse, a thiumph of General Relativity that propelled Einstein to his fame. The deflection of starlight by the eclipsed Sun. Gravitational lenses, Einstein rings, and Smilie. Gravitational-lensing and evidence for dark matter in the Bullet cluster of galaxies.

Limitations and Peculiarities of the Standard Models

Back to how peculiar the recipe to cook an inflationary universe is, with its mysterious cosmological constant and dark matter components. The arbitrary parameters of the Standard Model of particles are also many, and one of its predictions (the axion particle) still escapes detection. CERN’s CAST experiment, looking for—with no success—axions that the Sun could be emitting.

Where is the Cosmic Antimatter?

Matter and antimatter are basically almost identical (but for their opposite charges). How come there is practically no antimatter in the Universe? If matter and antimatter were once equally abundant, how come they did not annihilate each other? How come we are here? The baryon (proton plus neutron) to photon ratio. Ribbons in the sky? Almost complete annihilation.

The Direct Detection of Gravitational Waves

Gravitational waves emitted by black hole mergers. The first LIGO event: GW150917, the coalescence of two black holes of twenty nine and thirty six solar masses into one of “only” sixty two. The remaining three solar masses were emitted as energy in gravitational waves, a gigantic and perfect storm in the fabric of space-time. This is the dawn of a new era: The opening of the third “window” through which to look at the sky. Yet another triumph of general relativity. How much progress astrophysics has made since my time as a student.

The Discovery of Gravitational Wave Emission

Neutron stars, binary stars and pulsars. The Arecibo radio antenna. The discovery of the first binary pulsar (PS1913+16) by Husle and Taylor. This pulsar’s understanding in general relativity: A fantastic success.

A Parenthesis: Is Basic Science Useful?

Various opinions on the practical consequences of basic science. Some of the ones mentioned: The GPS, the HyperText Transfer Protocol (http), Sputnik, Hertz’s radio, nuclear reactors and Plato’s views on the subject.