Science Shrugs

Boris Johnson

The Michelson-Morley experiment of 1887 disproved the ether, a hypothetical medium that permeates the universe. By using an interferometer with perpendicular arms, Michelson and Morley demonstrated that the speed of light is the same regardless of how the direction of the light is oriented relative to our motion through the supposed ether. Their null result set the stage for Einstein’s theory of Special Relativity and is often lauded for heralding the new age of physics. At least that’s how the story goes. In reality, it was more complicated.

Thing is, Morley himself was not convinced of the results of his seminal experiment. Together with a new collaborator, Dayton Miller, he repeated the measurement a few years later. The two again got a negative result.

This seems to have settled the case for Morley, but Miller went on to build larger interferometers to achieve better precision.

Indeed, in the 1920s, Miller reported seeing an effect consistent with Earth passing through the ether! Though the velocity which he inferred from the data didn’t match expectations he remained convinced to have measured a partial drag caused by the ether.

Miller’s detection could never be reproduced by other experiments. It is today widely considered to be wrong, but just what exactly he measured has remained unclear.

And Miller’s isn’t the only measurement mystery.

In the 1960s, Joseph Weber built the first gravitational wave detectors. At a conference in 1969, he announced that he had measured two dozen gravitational wave events, and swiftly published his results in the Physical Review Letters.

It is clear now that Weber did not measure gravitational waves – those are much harder to detect than anyone anticipated back then. So what then did he measure?

Some have argued that Weber’s equipment was faulty, his data analysis flawed, or that he simply succumbed to wishful thinking. But just what happened? We may never know.

Then, 40 years ago, physicists at the Heavy Ion Society (GSI) in Germany bombarded uranium nuclei with curium. They saw an excess emission of positrons that they couldn’t explain. In a 1983 paper, the group wrote that the observation “cannot be associated with established dynamic mechanisms of positron production” and that known physics is “unlikely match to the data at a confidence level of better than 98%”.

This observation was never reproduced. We still have no idea if this was a real effect, caused by an odd experimental setup, or whether it was a statistical fluke.

Around the same time, in 1975, we saw the first detection of a magnetic monopole. Magnetic monopoles are hypothetical quasi-particles that should have been created in the early universe if the fundamental forces were once unified. The event in case was a track left in a detector sent to the upper atmosphere with a balloon. Some have suspected that the supposed monopole track was instead caused by a nuclear decay. But really, with only one event, who can tell? In 1982, a second monopole event was reported. It remained the last.*

Today we have a similar situation with the ANITA events. ANITA is the Antarctic Impulsive Transient Antenna, and its collaboration announced last year (to much press attention) that they have measured two upward-going cosmic ray events at high energy. Trouble is, according to the currently established theories, such events shouldn’t happen.

ANITA’s two events are statistically significant, and I have no doubt they actually measured something. But it’s so little data there’s a high risk this will remain yet another oddity, eternally unresolved. Though physicists certainly try to get something out of it.

In all of these cases it’s quite possible the observations had distinct causes, just that we do not know the circumstances sufficiently well and do not have enough data to make a sober inference. Science is limited in this regard: It cannot reliably explain rare events that do not reproduce, and in these cases we are left with speculation and story-telling.

How did the world end up with Donald Trump as President of the United States and Boris Johnson as Prime Minister of the United Kingdom? In politics as in physics, some things defy explanation.

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* Rewrote this paragraph after readers pointed out the second reference, see comments.