Cosmic Proportions
From a tiny grain of dust to entire galaxies, it is impossible to go anywhere in the universe without encountering space on an immense scale. We are surrounded and dwarfed by the immense and ever-changing cosmos. Our traditional idea of the cosmos has been dominated by images of nebulas, stars, galaxies, and strange celestial bodies beyond our wildest dreams or imagination. But what lies at the core of these seemingly limitless wonders? What is the true size of the cosmos?
The answer, as it turns out, is mind-bending. Our universe is so large, so layered and complex, that no living being can comprehend the magnitude of its true proportions. To put its size into perspective, here are a few astounding facts about our cosmic home.
The Universe
The universe is the grandest possible scale in cosmology. It comprises all the matter and energy in existence, and its size cannot be measured exactly due to its continually expanding nature. It is estimated that the universe has a diameter of at least 93 billion light-years, and could be as large as 250 billion light-years in any direction. By comparison, the Milky Way galaxy – our own home galaxy – measures about 100,000 light-years across. This means that the universe is roughly 931 million times larger than the Milky Way.
The Largest Galaxies
Galaxies make up some of the most obvious structures in the observable universe. Most galaxies are relatively small, but some reach truly massive proportions. The largest known galaxies are the so-called "super-clusters", with diameters of around 1 to 4 million light-years. They can contain hundreds of billions of stars and can reach masses of more than 10 million billion times the mass of the Sun.
The most extreme example is the Virgo Super Cluster, one of the largest known structures in the universe. It has a diameter of 110 million light-years and contains thousands of galaxies. By comparison, the Milky Way is relatively puny; its diameter is just 100,000 light-years.
Black Holes
Black holes are mysterious phenomena that represent some of the heaviest and densest objects in the universe. They have such an immense gravity pull that their mass is actually folded in on itself and can no longer escape; in some cases, even light cannot escape.
The size of a black hole varies significantly depending on its mass. Most of them are no bigger than a few miles across, but the largest ones can be up to 500 million kilometers across. By comparison, Earth's circumference is just 40,075 km.
The Largest Object
The single largest known object in the universe is the ZTZ-1 quasar, which is estimated to be around 26 million light-years in diameter. This is an astonishing find, given that the observable universe is only 93 billion light-years in diameter.
Even more impressive is the sheer amount of matter contained within the ZTZ-1 quasar. It is estimated that it contains over 100 quadrillion solar masses — about as much matter as would be required to make one galaxy for every person in the world.
Time
Finally, there is the grandest scale of them all: time. The age of the universe is estimated to be around 13.8 billion years, and its future remains unknown. We can only speculate as to what lies ahead — perhaps the universe will expand forever, or perhaps it will eventually collapse in on itself. One thing is certain, though: it will take an eternity to truly comprehend the incredible scale of the cosmos.