To err is human, which is not really an excuse.
And getting it wrong as a scientist is worse, of course, because relying on science is supposed to be the best way to make sure people are right. But since scientists are human (most of them, anyway), even science is never free of errors. In fact, errors are quite common in science and most scientists tell you that they would not have it otherwise. That’s because making mistakes is usually the best way to progress. An erroneous experiment can inspire new experiments that not only correct the original error, but also identify new previously unsuspected truths.
Still, sometimes the mistakes of science can be quite embarrassing. Recently, much hype has accompanied a scientific report on the possibility of life on Venus. But the instantaneous review of reproduction has now raised serious concerns about the conclusion of that report. Tests of phosphine gas, a chemical that supposedly could only be created by life (either microbes or well-trained human chemicals), began to look a little unstable. (See the story of well-trained Science News journalist Lisa Grossman.)
Although the final verdict on phosphine is yet to be pronounced, it is a good time to recall some of the other famous mistakes of science. Here we are not talking about fraud, or even bad ideas that were worth floating, but failed, or false initial positives due to statistical chance. Instead, let’s list the 10 erroneous scientific conclusions that received a lot of attention before being refuted. (With one exception, there will be no names, the purpose here is not to embarrass.)
10. A strange way of life
A report in 2010 claimed that a strange life form incorporates arsenic in place of phosphorus in biological molecules. This one looked pretty suspicious, but the test, at first glance, looked pretty good. Not so good at first glance. And arsenic-based life has never reached textbooks.
9. A strange form of water
In the 1960s, Soviet scientists claimed that they had produced a new form of water. Ordinary water that was poured through narrow pipes became denser and thicker, boiled at higher than normal temperatures, and froze at much lower temperatures than usual. It seemed that the water molecules must have been coagulating in some way to produce "water polia." In the late 1960s chemists around the world began vigorously pursuing water polishing experiments. Soon these experiments showed that the properties of water pulley came from the presence of impurities in ordinary water.
Sign up to receive the latest from Science News
Headlines and summaries of the latest Science News articles, delivered in your inbox
8. Neutrinos, faster than light
Neutrinos are strange flyweight subatomic particles that pass through space faster than Usain Bolt in PEDs. But not as fast as scientists claimed in 2011, when they timed the time it took neutrinos to fly from the CERN atom destroyer near Geneva to a detector in Italy. Initial reports found that neutrinos arrived 60 nanoseconds before a ray of light would arrive. The faster-than-light neutrinos picked up some headlines, evoked disbelief in most physicists, and induced Einstein to turn in his grave. But sanity was restored in 2012, when the research team found out that a loose electrical cable disconnected the experiment clocks, explaining the error.
7. Gravitational waves of the primitive universe
All space is invaded by microwave radiation, the excess glow of the Big Bang that threw the universe into action 13.8 billion years ago. A popular theory that explains details of the primitive universe – called inflation – predicts the presence of blips in microwave radiation caused by primordial gravitational waves from the early epochs of the universe.
In 2014, scientists reported finding precisely the expected signal, simultaneously verifying the existence of gravitational waves predicted by Einstein’s general theory of relativity and providing strong evidence that favors inflation. However, suspiciously, the reported signal was much stronger than expected for most versions of the inflation theory. Indeed, the analysis of the equipment did not correctly count the dust in the space that skewed the data. Primordial gravitational waves remain undiscovered, although their most recent cousins, produced in cataclysmic events such as black hole collisions, have been detected repeatedly in recent years.
6. A universe of a single galaxy
In the early twentieth century, astronomers disagreed on the distance of the Earth from the swirl-shaped diffuse cloud spots (called spiral nebulae). Most astronomers believed that spiral nebulae resided within the Milky Way galaxy, at a time when it was believed to comprise the entire universe. But some experts insisted the spirals were much farther away, entire galaxies like the Milky Way or "island universes." Alleged evidence against the idea of the island's universe came from measurements of internal movement in spirals. It would be impossible to detect such movement if the spirals were really far apart. But by 1924, Edwin Hubble established with certainty that at least the sound of spiral nebulae were in fact island universes, at great distances from the Milky Way. Those measures of internal movement were difficult to make and proved wrong.
5. The super fast pulsar of a supernova
Astronomers rejoiced in 1987 when a supernova appeared in the Large Magellanic Cloud, the closest stellar explosion to Earth in centuries. Subsequent observations looked for a signal from a pulsar, a rotating neutron star that should reside in the midst of the debris of some types of supernova explosions. But the possible pulsar remained hidden until January 1989, when a rapidly repeating radio signal indicated the presence of a supernova leftover superspinner. It emitted radio beeps almost 2,000 times per second, much faster than anyone expected (or could explain). But after a night of constant pulsation, the pulsar disappeared. Theorists rushed to devise intelligent theories to explain the strange pulsar and what happened to it. In the early 1990s, telescope operators rotated a TV camera (used to guide the telescope) back into service, and the signal appeared again, around a different supernova remnant. So the supposed signal was really a peculiarity in the guidance camera electronics, not a message from space.
4. A planet orbiting a pulsar
In 1991, astronomers reported the best case for the existence of a planet around a star other than the sun. In this case, the "star" was a pulsar, a neutron star orbiting about 10,000 light-years from Earth. Variations in the time of the pulsar's radio pulses suggested the presence of an accompanying planet, orbiting its parent pulsar every six months. However, then astronomers realized that they had used an inaccurate value for the position of the pulsar in the sky in such a way that the signal anomaly did not result from a planet, but from the movement of the Earth around the sun.
3. Age of the Earth
In the 1700s, the French naturalist Georges-Louis Leclerc, the Count of Buffon estimated a terrestrial age of about 75,000 years, although he acknowledged that it could be much older. And nineteenth-century geologists believe it is even older (hundreds of millions of years or more) to account for layer-by-layer observation of Earth’s buried history. After 1860, Charles Darwin's new theory of evolution also involved a very old Earth, to give time to the evolution of species diversity. But a supposedly final ruling against such an old Earth came from a physicist who calculated how long it would take an originally molten planet to cool. He applied an age limit of about 100 million years and later suggested that the actual age could even be much younger than that. However, his calculations were a mistake, not because he was bad at math, but because he didn’t know about radioactivity.
The radioactive decay of Earth elements added a lot of heat to the mixture, prolonging the cooling time. Finally, estimates of the age of the Earth based on rates of radioactive decay (especially in meteorites that formed at the same time as the Earth) provided the correct current estimate of the age of 4.5 billion years or so.
2. Age of the universe
When astronomers first discovered that the universe was expanding, in the late 1920s, it was natural to wonder how long it had been expanding. By measuring the current rate of expansion and extrapolating backwards, they found that the universe was less than 2 billion years old. However, measurements of radioactivity had already established that the Earth was much older and it was highly doubtful (as in ridiculously impossible) that the universe could be younger than Earth. However, those early calculations of the expansion of the universe were based on distance measurements that depended on Cepheid variable stars.
Astronomers calculated the distances of the Cepheids based on how quickly their brightness fluctuated, which in turn depended on their intrinsic brightness. Comparing the intrinsic brightness to the apparent brightness provided by Cepheid’s distance, just as you can measure the distance of a light bulb if you know its power (oh yes, and what kind of light bulb it is). However, it turned out that, like bulbs, there is more than one type of cepheid variable, which contaminates the spread rate calculations. Today convergent methods give an age of the universe of 13.8 billion years, making the Earth a newcomer to the cosmos.
Bartolomeu Velho (public domain)
1. Earth in the middle
Okay, let’s name and blame Aristotle for this one. He was not the first to say that the Earth occupies the center of the universe, but he was the most dogmatic about it and believed that he had established it as incontrovertibly true, using logic. He insisted that the Earth must be in the middle because the earth (the element) has always sought to move toward its “natural place,” the center of the cosmos. Although Aristotle invented formal logic, he apparently did not notice a certain circularity in his argument. It took a while, but in 1543 Copernicus firmly argued that Aristotle was wrong. And then, in 1610 Galileo's observation that Venus went through a complete set of phases sealed the case for a sun-centered solar system.
Now it would be nice if there was a lesson in this list of mistakes that can help scientists improve them in the future. But the whole history of science shows that such errors are really inevitable. However, there is a lesson based on what the mistakes on this list have in common: they are all on a list of mistakes that are now known to be mistakes. Science, unlike certain political philosophies and cults of personality, corrects its mistakes. That is the lesson and that is why respecting science is so important to avoid mistakes in other areas of life.