We all know that absolutely everything that is visible and invisible in the universe is made up of atoms (dark matter does not count, because nobody really knows what it consists of). Each of these particles contains a nucleus and electrons that revolve around it and are bound to the nucleus because of electromagnetic interactions. However, the nucleus of an atom is so small that if you imagine an atom that stretches to the size of a soccer field, its core is as small as a poppy. Why does an atom need so much extra space and is it true that our universe is 99% empty?
Why can not we walk through walls?
Despite the fact that a large part of an atom is empty, its tiny components – electrons – play a very important role in "filling" this gap. Although an atom normally contains very few electrons, its behavior resembles that of a large flock of birds, in which there is no clear limit to synchronous movement. All we can see with such a movement is a chaotically changing indeterminate form. Electrons that constantly change their position in the atom are strictly following the equation first described by the famous scientist Erwin Schrödinger in the 20th century. Yes, the same scientist who loved doing quantum experiments on cats.
See also: The quantum experiment has shown that there is no objective reality
Electrons that dance within an atom can absorb and release energy coming from outside. Therefore, light can not penetrate the wall because the electrons of the atoms of the wall simply absorb the energy of the light and release it again after a short time. Thanks to this phenomenon of receiving and returning light, the wall next to you looks solid and opaque.
Can the universe be empty?
The universe is famous for objects that, with their colossal dimensions, can surprise any earthly skeptic. The largest object in the part of the Universe we studied is an object called the Great Wall of Hercules – the Northern Crown. The gigantic structure stretches over 10 billion light-years and is a huge number of galaxies, which are composed in different shapes and sizes.
Compared to the gigantic structure, our solar system seems to be a small point lost somewhere far on the edge of the Milky Way. Nevertheless, the gravitational field of our sun (and not just it, but other stars of the universe) is several thousand times larger than its own size. Thanks to this clever co-ordination, planets can revolve around the orbits of their stars, without fear of flying far into space.
A similar situation arises in the interior of the atom. The ratio of the sizes of the electrons, the atomic nucleus and the distances between them is strongly reminiscent of the ratio of the sizes of the cosmic bodies and their distances in the macrocosm. In other words, the great distances within the atom can shed light on the possible emptiness of the universe.
If so, then the universe is really 99% empty, while 1% of the matter visible to the eye is generated by the world around us. Despite this incredible fact, all this enormous "nothingness" contains many invisible and unexplored forces that we may one day be able to contain.
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