Updated: Jan 28, 2022
By Rosalyn Brady
[Source: New Atlas]
In the grand scheme of things, humans are a microscopic speck in the incomprehensible vastness of space. To us, even our planet and solar system seem immense. However, the Earth’s equatorial circumference of 40,075 kilometre distance and the Solar System’s diameter of 287.46 billion kilometres are merely short distances in the universal scale. This is because our own Sun is one of an estimated a hundred billion stars in the Milky Way galaxy, a small portion of the observable universe with an estimate of two hundred billion galaxies within it. With these estimates, we are able to calculate the ratio between the Sun and the observable universe: 1 to anywhere between ten sextillion and one septillion stars. Hence, these estimates and calculations, highlight the immensity of the observable universe.
Furthermore, the sextillions of stars and billions of galaxies within the observable universe are dispersed over large expanses of underdense regions, also known as cosmic voids. Making up the vast majority of our universe, these cosmic voids result in millions of kilometres between planets, trillions of kilometres between stars, and quintillions of kilometres between galaxies. These voids are made up of 71.4% dark energy, a hypothetical repulsive force that accelerates the universe’s expansion, 24% dark matter, another hypothetical and little-known force does not absorb, reflect, or emit light, and 4.6% common atoms that form things like stars and galaxies. Ultimately, these cosmic voids span 45 billion light years, or 400 sextillion kilometres - and that’s only the part humans have the chance to see. Beyond 45 billion light years, the stars and galaxies are so far from Earth that the light emitted by their formation has not reached us yet, and beyond 16 billion light years, light that the stars and galaxies there emit today will never reach us.
Our universe is an incomprehensible thing. There are far-away stars and galaxies that our species will never get the chance to see, and we will likely never even be able to visit many of the stars in our own galaxy, let alone the rest of the galaxies in the universe. Moreover, the universe is mostly made out of voids, containing particles such as dark energy, that we might never come to understand.
As humans, we have a long way to go before we can truly comprehend the vast emptiness that is the universe, but perhaps, figuring it all out could solidify our place in it.
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