One of the main things which drives scientific progress is admitting when you're wrong. From our perspective on the world, things might seem one way, but if all the evidence points in another direction, it's time to reconsider.
Scroll on for five examples of mistaken beliefs about humanity's place in the universe which were once held to be true, and discover the science which disproved them...
Magnetic Black Hole Waves (2015-07-09) by NASA/JPL-CaltechNASA
1. Matter is solid
Diamonds are one of the hardest substances we know, but would it surprise you to learn that they – and everything else – aren’t as solid as they appear?
Blue Heart Diamond (1909/1964) by Atanik Eknayan, Harry Winston, Inc.Smithsonian National Museum of Natural History
Our understanding of quantum mechanics and particle physics has expanded exponentially over the last 100 years. We now understand that atoms – the fundamental building blocks of everything around us – are in fact anything but “blocks.”
Atoms are made up of protons, neutrons, and electrons, and some of these particles are made up of even smaller ones. As we've learned more, we have come to understand that the space between atomic particles is not occupied by matter at all. Most of an atom is empty space!
Antiproton annihilation with a Neon nucleus (1984/1984) by Patrice LoiezCERN
The Large Hadron Collider
Here at CERN in Switzerland, you can explore the Large Hadron Collider, the largest and highest-energy particle accelerator on the planet. Click to look around!
The Large Hadron Collider (2018-10-11) by CERNCERN
2. Earth is flat
It’s easy to observe our world and assume, as some of our early ancestors did, that because the Earth looks flat from our field of view, that it really must be flat. However, for millennia, we’ve understood that the surface of the Earth must be curved.
Psalter World Map from Westminster Abbey (1265)Original Source: British Library Add. MS 28681
It’s remarkably easy to prove that the Earth is a sphere. The experiment requires nothing more than shadows! Greek polymath Eratosthenes was able to prove we live on a globe, and measure its circumference, in approximately 240 BCE!
Eratosthenes’ technique was simple, and you can recreate it today. Place two poles of equal height in two different cities. Examine the shadows they cast when the sun is directly over just one of the poles. You’ll find that one casts a shadow while the other does not.
Pharos (The Lighthouse at Alexandria) (1572) by Philip Galle, after Maerten van HeemskerckNational Gallery of Art, Washington DC
If the Earth were flat, the poles would cast shadows of the same length. Today, we can simply look at the wealth of photos and videos captured from space to prove the world is a sphere!
View the Earth shot of the International Space Station. (NASA) (2016-04-19) by (NASA)Museu do Amanhã
3. Everything revolves around the Earth
As with many early observations, the assumption that the sun, stars, and planets revolve around the Earth is a logical one to make. From our perspective, the world seems motionless, and we see a predictable rotation of celestial bodies.
But this explanation does not stand up to scrutiny. Close observation revealed to astronomers that smaller celestial bodies orbit larger ones, and that retrograde motion – where some bodies appear to move backward – could be explained by the relative motion of our own planet.
Corporu(m) (C)oelestium MagnitudinesAdler Planetarium
Still, the geocentric model remained the predominant viewpoint until Copernicus’ On the Revolutions of the Heavenly Spheres began to shift the paradigm after its publication in 1543. Here we see an armillary sphere on display at the Museo Galileo in Florence. Click to explore!
Museo Galileo - Istituto e Museo di Storia della ScienzaMuseo Galileo - Istituto e Museo di Storia della Scienza
4. The sun is the center of the universe
As our understanding of the cosmos grew, the next logical observation was that the other planets and stars orbit the sun, which, according to Copernican theory, is a motionless body at the center of our universe.
This idea was superseded by the proof that our sun was simply one star among billions of stars, in a galaxy among billions of galaxies. The scale of our universe is truly staggering, but evidence shows the sun, and indeed everything in space, is in motion.
Harmonia macrocosmica : seu, Atlas universalis et novus...Adler Planetarium
Thanks to satellite imagery, our picture of the universe today is much clearer, although our understanding is still lightyears from being complete. This map of the universe shows the cosmic microwave background, radiation leftover from the earliest stages of the universe.
See what our satellites see in the video below!
Best Map Ever of the Universe (2013-03-21) by ESA and the Planck CollaborationNASA
Flight Through the Orion Nebula in Visible and Infrared Light (2018-01-11) by NASA/ESA/STScINASA
5. Outer Space is empty space
When you look to the night sky, do you think about the celestial bodies or do you consider the vast emptiness? For centuries, we’ve considered space to be, well, just that: space occupied by nothingness.
However, dark matter, dark energy, and other imperceptible things pervade the universe. While the term ‘dark matter’ may sound sinister, it simply means matter that does not interact with electromagnetic radiation, making it incredibly difficult to find.
How do we know dark matter is there?
Astrophysicists have calculated that the observed effects of gravity can’t be explained unless there is more matter in the universe than what we can perceive. In fact, scientists believe that up to 85% of the matter in the universe could be dark matter!
Hubble Spins a Web Into a Giant Red Spider Nebula (2017-12-08)NASA