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  • Remember when Pluto was a planet?

  • Until very recently, Pluto's planetary status was an immutable fact learned by primary school kids the world over.

  • Pluto had an undisputed place in papierché models of the solar system and even its very own song lyric — 'And last of all there's Pluto too...'

  • But in August 2006, Pluto found itself cruelly demoted to a dwarf planet after failing to meet one of three criteria the International Astronomical Union uses to define a full-sized planet.

  • We are taught from an early age to think of scientific facts as, well, facts.

  • And it can be unsettling when this turns out to not be the case.

  • But does this uncertainty really mean that we can't trust science?

  • According to the Royal Society, the world's oldest independent scientific academy, the answer is quite the opposite.

  • Questioning established facts is actually at the heart of the scientific method.

  • Think of the whole process as a giant system of checks and balances based on raw information drawn from experiments or observations of nature.

  • Those experiments and observations lead to the formulation of a hypothesis which then goes through a rigorous process of checks by other scientists.

  • However, there isn't always enough information to draw the right conclusions.

  • Take for example Sir Francis Bacon, who noticed that the coastlines of West Africa and eastern South America looked like they were symmetrical.

  • He believed that nature was copying herself.

  • What he couldn't have known in the early 1620s was that the two coasts are two sides of a fault-line in an ancient supercontinent which split apart 140 million years ago.

  • Bacon's hypothesis remained gospel for centuries, until new discoveries about the science of plate tectonics emerged in the 1950s and provided a neat explanation for Bacon's observation.

  • There's also the fact that different experts examining the same raw data can draw different conclusions.

  • Spare a thought for poor Robert Plot who, in the 1670s, found a fossilised bone that he thought was that of a giant human.

  • At least he wasn't around when a geologist and zoologist proved it was in fact a Megalosaurus, a kind of dinosaur that roamed the Earth in the middle Jurassic.

  • Sometimes the scientific method is all about setting up ground-breaking experiments at the right time, in the right place to test theories.

  • In 1919, a blockbuster meeting of the Royal Society confirmed Einstein's theory of general relativity after a solar eclipse provided the perfect circumstances to measure the bending of starlight.

  • This showed that the gravity of a massive object, such as the Sun, could bend light around it.

  • Under the watchful eye of Sir Isaac Newton's portrait, the scientific community replaced Newton's previous theory with Einstein's newer and more general interpretation of gravity.

  • But even with evidence in its favor, Einstein's theory still can't be thought of as a fundamental fact.

  • It's even possible that in the future new breakthroughs will supersede our understanding of general relativity.

  • Uncertainty in science isn't enough if all the perspectives are the same.

  • Sometimes a lack of diversity in the system can skew the results.

  • Until the 1970s, primatologists were mostly men and tended to limit their studies to male primates.

  • They believed that the aggression observed in baboons meant human evolution had been driven by similar behavior.

  • That was until anthropologist Shirley Strumbegan observing both female and male baboons, disproving these earlier theories and facing a backlash for her troubles.

  • Scientists don't always get it right on the first go.

  • But rather than instilling doubt, it should inspire confidence that outdated ideas are replaced when new information becomes available.

  • It's the difference between upgrading your mobile and clinging to your old rotary phone because you don't want to be wrong.

  • And in most cases, newer breakthroughs would not be possible without the legwork that came before them.

  • While the rotary phone isn't the best available technology today, your smart phone wouldn't exist without it.

  • Uncertainty is baked into the scientific process.

  • It's the fundamental reason that progress is possible.

  • Ultimately, it comes down to who you trust more, the person who's certain they're right, or the person who's willing to be proved wrong.

Remember when Pluto was a planet?

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