There is an introduction to the nature of the “Hubble tension” in the first part of this article, which covers measurements based on the distance ladder (see https://physbang.com/2026/07/28/hubble-tension-part-1-the-distance-ladder/). This article looks at how the Cosmic Microwave Background (CMB) can be used to calculate the expansion of the Universe – and therefore the Hubble constant. But … Continue reading Hubble Tension Part 2: Baryon Acoustic Oscillations
Hubble Tension Part 1: The Distance Ladder
The term “Hubble tension” refers to discrepancies in the value of the Hubble constant, which in turn indicates the rate of expansion of the Universe. In particular, the “tension” arises because two different techniques for calculating the constant give significantly different values. For a brief introduction to the Hubble constant, see https://physbang.com/2026/04/26/red-shift-and-the-age-of-the-universe/ or NASA’s summary … Continue reading Hubble Tension Part 1: The Distance Ladder
Astronomy in a Nutshell
There are no equations in our Astronomy module - just a bundle of facts, models and theories. To make learning (and revising) easier, the knowledge that you need can be linked into seven pairs of ideas as listed below; 1. Models of the Universe: Geocentric versus Heliocentric 2. Observing the Universe: Naked Eye versus Using … Continue reading Astronomy in a Nutshell
How did the Universe begin?
As was the case when we considered models of how the Universe is structured, when it comes to explaining the beginning of the Universe you again need to know about two competing ideas. You also need to know about the evidence that either supports or questions each theory. One theory is the Steady State Theory. … Continue reading How did the Universe begin?
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