The universe is incredibly vast and mysterious. It is estimated that there are hundreds of billions of galaxies, each with sextillions of stars and planets, with Earth in the middle. However, the universe appears to be even bigger when we look closer. We can embark on a journey to explore this miniature realm, shrinking ourselves to the size of a grain of sand.
At this tiny size, a park that was only a thousand meters long before is now the size of France. Human-sized humans tower over us, four times the height of the Empire State Building, and a bee the size of a helicopter lands nearby. The air is so thick that it feels like we are moving through honey.
We can further shrink ourselves to the size of an E. coli bacteria. Now, the park is a million kilometers wide and it would take 25 years to cross it. We can see giant bees that tower like Mt. Everest and individual cells the size of a house. Drops of water the size of asteroids fall from blades of grass and we are pulled along by an invisible current in the microscopic lake. At the molecular level, viruses the size of tennis balls float around aimlessly, while others like the Euglena oxyuris cells pass by like freight trains. Most look like oily jellyfish the size of a car, with long tentacles that act like supercharged propellers. Despite the water holding onto them like glue, some move hundreds of body lengths per second, equivalent to a person shovelling through mud at over 600 km/h. Bacteria, however, weigh so little and water is so viscous that they have no inertia, resulting in a weird jerky motion.
When we go even deeper to the molecule realm, we become the size of a molecule, just under two nanometers wide. The droplet now seems as big as the Moon to a regular human, and the blade of grass it rests on could reach from the tip of Alaska to the end of Australia. The park is now almost the size of the Solar System, filled with innumerable amounts of molecules and atoms. The walls of the grass cells beneath us are vibrating, rippling with waves of energy. The water droplet contains nearly a sextillion water molecules that are all in motion, smashing into each other hundreds of trillions of times a second at speeds of around 2300 km/h. This is the source of the invisible current that was noticed when we were a thousand times larger.
At the subatomic realm, a human would be nearly 2 billion kilometers tall relative to us, so large they could stretch their arms from the Sun to Saturn. An atomic nucleus would be the size of a grain of sand we could hold on the tip of our finger and hold 99.97% of the atom’s mass. The rest is filled with an electron cloud, which is basically all the places where electrons might be at any given moment in time. Electrons are shapeshifters that morph around outside a nucleus, creating a vibrating mess of different shapes with every new moment.
When we take a breath, we breathe in mostly nothing with a few atoms. In fact, if we were to compress all the molecules and atoms buzzing around in the room, they would only fill about 0.1% of its volume. 99.9% of the space around us is a vacuum, which we just don’t notice. They hold back the same energy that powers nuclear bombs and it doesn’t let them sit still - they twist and vibrate sextillions of times a second. We have reached the bottom, the border between reality and unreality - the scale here is the Planck length, which is the distance light travels in a Planck Time. None of our models of the universe make sense at scales smaller than this, so for now, this is it. We think that down here, particles bubble into existence and then spontaneously disappear, creating a quantum foam of unimaginable energy.
It is time to return, and if you look up, the universe is large and strange - so incredibly large and strange. But if you look down, into the tiny and extremely tiny, the universe seems even larger, and even stranger. In the end, the perfect place might be where you are right now - not too big, not too small.
These hidden worlds are all part of our 12,023 Human Era Calendar - a true piece of kurzgesagt you can take home with you. Every calendar purchase directly supports what we do here at kurzgesagt - sparking curiosity all around the world. So because of you, we can spread knowledge and ignite an appreciation for space, nature and life in people everywhere. Thank you so much for making this possible! Have a wonderful 12,023! See you down in January!