> But how do you interpret astronomical observations? By using the currently understood laws of physics, of course, so it becomes a bit of a circular argument.
One of the best ways to measure this is to use quasar absorption spectroscopy to probe the precise energy level spacing of atoms (like iron, magnesium, and so on) from billions of years ago with the energy level spacings found in the same atoms of today.
If the fine-structure constant (for example) were different by some amount in the distant past, its effect is calculable -- and the spectroscopic signature of a different fine-structure constant is distinct from any other physical effect (redshift of the spectrum, etc.).
There are some intriguing results that have come out over the past decade or so, with new information coming in all the time.
One of the best ways to measure this is to use quasar absorption spectroscopy to probe the precise energy level spacing of atoms (like iron, magnesium, and so on) from billions of years ago with the energy level spacings found in the same atoms of today.
If the fine-structure constant (for example) were different by some amount in the distant past, its effect is calculable -- and the spectroscopic signature of a different fine-structure constant is distinct from any other physical effect (redshift of the spectrum, etc.).
There are some intriguing results that have come out over the past decade or so, with new information coming in all the time.