Re: Do laws of nature last forever?

Hello Yevgeniy,

We have no solid evidence that the laws of nature have changed since the Big Bang, and no suggestion that they will change in the future.

It wouldn't take too much of a change to destroy life in the Universe. A fairly-small change in the constants of the Strong Interaction or the Weak Interaction, for example, could make stars burn much more quickly or much more slowly. A change in the electromagnetic force would have similar effects, as well as disrupting (for example) the chemistry of carbon.

There are sort of three classes of experiments which deal with long-term changes in the laws of Nature.

• First, one can do very precise laboratory measurements, repeat them from year to year, and see if the results change. One such experiment (see this web page) measured, at the same time, a certain wavelength of light emitted by a hydrogen atom and that emitted by a rubidium atom. If the strong-nuclear force changes over time, it would affect the rubidium wavelength but not the hydrogen wavelength. No such effect has been observed yet (although I have heard rumors of a new experiment in Germany which may see something; stay tuned.)
• One can look at the isotopes left over from very old nuclear reactions. The main example is a uranium deposit in Gabon, West Africa, under the river Oklo. This deposit is so uranium-rich that, two billion years ago, it underwent a "natural" chain-reaction and behaved as an open-air nuclear power plant. The unusual isotopes left behind by these reactions are still there in the deposit. Several important isotopes are found at Oklo with the same abundances with which they are found in modern nuclear reactors; this tells us that the behavior of these nuclei (i.e., the cross-section that produces them in the reactor) has not changed in two billion years.
• You can look at distant stars and galaxies and study absorption and emission lines in the light. In some rare cases, you can measure the properties of atoms in the distant sources; since the light was emitted so long ago, this tells you something about the laws governing the atom at the time the light was emitted. One recent study (see this paper) claims that the wavelengths emitted by zinc, chromium, and iron atoms in 10-billion-year-old quasars are different than those emitted by the same atoms today, and that they believe that the electromagnetic force was 0.006% weaker 10 billion years ago. This result is very controversial, and we hope for it to be either strengthened and confirmed, or refuted, by more observations in the upcoming few years.

-Ben