The bedrock of science itself is causality: stable, predictable effects flow from discernable causes for some rational reason. But since science (and science fiction) is also about always questioning assumptions, it’s fair to ask if causality is in fact an appropriate bedrock for science. This goes beyond modern philosophical complications regarding causality due to discoveries in relativity and quantum mechanics. What if the laws of physics themselves – relativity, quantum mechanics, and even Clarke magic – change with time, and generated effects now or in the future are different from those at the dawn of our universe? This most fundamental of questions is examined in an excellent April “feature article” over on Physicsweb.
Changing the laws of physics or nature implies that so-called “physical constants” in the universe must change as well. Some physicists have believed (and some still do) that the Universal Gravitational Constant or G has changed with time, allowing gravity to be stonger or weaker with time. Most current theorizing on this subject today deals with a different physical constant called the fine structure constant or “alpha”. Change alpha and you change the strength not of gravity but of electromagnetism – how high a given amount of static electricity will make your hair rise, or how far from the nucleus of an atom an electron will orbit. Change alpha too much, your hair would barely rise off your shoulders as you scuffed your feet on a carpet. Also, electrons wouldn’t orbit atomic nuclei properly, falling instead into the central nucleus of an atom – something that would be a pretty devastating thing for life, far worse than having a bad hair day. The universe may not care if alpha is varying, but the life in the universe certainly has a stake in the question.
So, is alpha changing? Precise measurements on the light from distant quasars suggest that the value of the fine-structure constant may have changed over the history of the universe. If confirmed, the results will be of enormous significance for the foundations of physics. And whether we will all be here next week. Too bad we can’t ask Q.