The light emitted from quasars might help us find out.
Everything we know about the universe is based on laws of physics which we assume to be constant and unchanging. But are they? Astrophysicists are looking at the universal constants that underlie the laws of physics to see if they may have changed over the course of the universe’s history. Most of these constants, such as the speed of light, are almost impossible to measure for change, because all of our other measurements are based on them. But others, like the lesser known fine structure constant, may be possible to measure for change. This constant, known as alpha, characterizes the “strength of the electromagnetic interaction between elementary charged particles,” according to Wikipedia. Because we can measure alpha through spectrographs, it’s possible to look at the spectrographs of gasses that ancient, distant quasars have hit at different periods of time and to if alpha has changed.
The answer? We don’t know. Some studies have shown a slight change in alpha over time, while others haven’t. If alpha has changed over time, that could give us essential clues into whether the current grand unified theories of physics are valid.