Oct 19, 2026 · 17 min · 11 segments
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Matt O'DowdHost
After all, it's hard to unravel the complexities of different parts of the universe if we don't know the basic rules.

But what if this is wrong? There is a hint of evidence that the fundamental constants that govern our universe may evolve over time, and even from one location to another.

The laws of physics are the relationships we observe between space and time and the fields and particles that occupy it.

Those relationships are often expressed as equations, but they're also governed by the constants within those equations.

For example, the standard model of particle physics is comprised of equations that predict the existence and behavior of the particle building blocks of our universe.

But the standard model also depends on a set of constants that cannot be predicted by that model, only measured.

Things like the mass of the electron and the relative strengths of the forces of nature.

Why the fundamental constants take the values they do is a very deep and unanswered question.

They predict that the fundamental constants may not be constant at all, and instead may vary over time and space.

Instead, we're gonna look at the experiments and the evidence, because there's a hint of evidence that at least one fundamental constant is, in fact, varying.

To measure changes in a fundamental constant, we first need to choose the right constant.

But was it always this value? It's been suggested that a changing speed of light might be an alternative to inflation theory or even to the apparent expansion of the universe.

For one thing, our definitions of the units used to define the speed of light are arbitrary and themselves depend on that speed.

The meter is officially defined as the distance light travels in one 299,792,458th of a second, and the second is defined in terms of a particular frequency of light emitted by the cesium 133 atom.

If the speed of light changes, the rulers we use to measure that speed change also.

The speed of light defines the relationship between space and time, so is it even meaningful to talk about it changing independently to its underlying dimensions? In fact, it may be impossible to interpret changes in any physical constant that has units.

After all, it's hard to unravel the complexities of different parts of the universe if we don't know the basic rules.

But what if this is wrong? There is a hint of evidence that the fundamental constants that govern our universe may evolve over time, and even from one location to another.

The laws of physics are the relationships we observe between space and time and the fields and particles that occupy it.

Those relationships are often expressed as equations, but they're also governed by the constants within those equations.

For example, the standard model of particle physics is comprised of equations that predict the existence and behavior of the particle building blocks of our universe.

But the standard model also depends on a set of constants that cannot be predicted by that model, only measured.

Things like the mass of the electron and the relative strengths of the forces of nature.

Why the fundamental constants take the values they do is a very deep and unanswered question.

They predict that the fundamental constants may not be constant at all, and instead may vary over time and space.

Instead, we're gonna look at the experiments and the evidence, because there's a hint of evidence that at least one fundamental constant is, in fact, varying.

To measure changes in a fundamental constant, we first need to choose the right constant.

But was it always this value? It's been suggested that a changing speed of light might be an alternative to inflation theory or even to the apparent expansion of the universe.

For one thing, our definitions of the units used to define the speed of light are arbitrary and themselves depend on that speed.

The meter is officially defined as the distance light travels in one 299,792,458th of a second, and the second is defined in terms of a particular frequency of light emitted by the cesium 133 atom.

If the speed of light changes, the rulers we use to measure that speed change also.

The speed of light defines the relationship between space and time, so is it even meaningful to talk about it changing independently to its underlying dimensions? In fact, it may be impossible to interpret changes in any physical constant that has units.
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