Ask Ethan #29: The Most Famous Failed Science Experiment

So, then, the reasoning went, if light is a wave — albeit, as Maxwell demonstrated in the 1860s, an electromagnetic wave — it, too, must have a medium that it travels through. Although no one could measure this medium, it was given a name: the luminiferous aether.

Sounds like a silly idea now, doesn’t it? But it wasn’t a bad idea at all. In fact, it had all the hallmarks of a great scientific idea, because it not only built upon the science that had been established previously, but this idea made new predictions that were testable!

Ethan does a pretty thorough job of this, as usual, with the possible exception of not fully explaining that the observation of aberration was how scientists knew we couldn’t be at rest with respect to an aether — in their paper, Michelson and Morley specifically mention how their null result refutes Fresnel’s model of aberration (involving partial aether dragging and which was backed by an experiment carried out by Fizeau in 1851).

What I really object to here is the notion that this was somehow a failed experiment. The hypothesis failed, but it was not their hypothesis! While it’s quite likely that Michelson and Morley expected a result that was consistent with us moving through an aether, the more idealized view an experimentalist is supposed to take is to not expect a specific result at all, lest one become biased in gathering and interpreting data. That the experiment was clever and thorough enough to be able to refute an incorrect hypothesis means it was wildly successful, rather than a failure.

Kelvin, Rutherford and the Age of the Earth: I, the Myth

This all seems clear enough. Rutherford is referring to Kelvin’s cooling argument. But this argument is invalid, because it assumes no new source of heat, and such a source exists, namely radioactivity. Or so says the popular myth. The truth is more complex, and more interesting.

Chernobyl’s Hot Mess, “the Elephant’s Foot,” Is Still Lethal

By the fall of 1986, the emergency crews fighting to contain the nuclear disaster at Chernobyl made it into a steam corridor beneath failed reactor Number 4. Inside this chamber they found black lava that had oozed straight from the core. The most famous formation was a solid flow that their radiation sensors firmly told them not to approach. With cameras pushed in from around a corner, the workers dubbed the dimly lit mass “the Elephant’s Foot.” According to readings taken at the time, the still hot portion of molten core put out enough radiation to give a lethal dose in 300 seconds.

The Elephant’s Foot could be the most dangerous piece of waste in the world.

via fine structure

Since we are not asking “What else floats in water?”

Use of ancient lead in modern physics experiments ignites debate

Unfortunately the story really doesn’t lay out the case for why ancient lead ballast falls into the category of “cultural heritage artifact” or why more than a small fraction of it would need to be preserved for study. Newly mined lead is contaminated with Pb-210, which has a half-life of about 22 years and is present because it’s in the decay chain of U-238. So Pb that’s been around for several hundred years (especially under water where it would better shielded against any kind of activation reaction) has been separated from the source of the unstable isotope that produces it (ultimately U-238, but realistically Ra-226, which is the “most recent” previous step along the decay chain with a half-life longer than a year) is more useful for shielding detectors, as it has essentially no sources of radiation that might cause spurious readings.

Good Old-Fashioned Technology

I don’t want to over-state the case because, actually, I love new gizmos that allow me to browse my music collection through my TV and to photograph the Orion Nebula in mere moments using the unbelievably sensitive ISO25600 setting on my camera. I wouldn’t want to halt the inevitable march of progress even if I could. But I would like to take this opportunity to mark the passing of some dearly loved and enlightening technology that has gone the way of all flesh.

I agree. New technology is amazing , but there’s something to be said about the older analog equipment, where you could tinker in ways that you can’t do anymore.

1842: Jean-Daniel Colladon guides light with water

The great thing about [total internal reflection] is that it can be done with other transparent, optically dense materials — such as a curved stream of water!