Essential facts about the Hierarchy of the Cosmos

Are you an astronomy enthusiast? Or have you just began to wander through the mystic pathways of the cosmos? Do you really know the accurate structure of the universe? This article is a simple outlook about the hierarchy of the cosmos from our own earth to the multiverse.

Ever since I was a little boy I found it fascinating and mind soothing to gaze upon the different patterns of clouds, different colors of the sky, and most importantly the stars and the planets which surrounds us. I was so attached to the peacefulness, and it helped me numerous times to calm myself. That must be the way our ancestors began to observe outer space.

Earth —

Ever since the dawn of mankind we believed that the earth is the center of the universe & the sun revolved around the earth. But with the important work done by scientists like Nicolaus Copernicus (1473–1543), Giordano Bruno (1548-1600), Galileo Galilei (1564 - 1642), it was proved that the earth revolves around the sun & earth is not the center of the universe. Earth is the third out of eight planets in the solar system.

Oort cloud —

This oort cloud defines the cosmological boundary of our solar system. It is divided into two regions: a disc-shaped inner Oort cloud (or Hills cloud) and a spherical outer Oort cloud. Both regions lie beyond the heliosphere (the region of space, encompassing the solar system, in which the solar wind has a significant influence) and in interstellar space. Most people aren’t aware of the trans- neptunian region (Second region of the oort cloud) and that it is a part of the solar system. It contains a swarm of trillions of frozen comets and planetesimals. In other words they are the leftovers from the formation of the solar system. The suns gravity pulls all these matter into the vast space of the solar system. Each one of these comets are far from each other as earth is away from saturn. That gives a fine idea about how massive the oort cloud really is.

Voyager (i) —

Out of the point where Pluto resides there exists an interesting object, a man made object! Out of the thousands of space crafts put out in the space by mankind this is the spacecraft which traveled the farthest from home. She bears a message to the rest of the universe containing knowledge about humans & who we are, our pictures, languages, music, history etc. As of February 22, 2019 it was 21.7 billion km; 13.5 billion mi from Earth, making it the most distant from Earth of all known human-made objects. On August 25, 2012, Voyager 1 became the first spacecraft to enter the interstellar medium.

Milky way —

Out of this point what lies beyond is a mystery for the naked eye and ordinary telescopes. To observe even more we need infrared, UV, X-Ray telescopes. This is the galaxy where we live in. We live in the Orion arm(Orion Spur) about 30,000 light years away from the center of the galaxy.

Local Group —

Local group is the combination of the milky way and its nearest neighbors. It consists of other galaxies such as Andromeda, Triangulum, Sagittarius Dwarf Galaxy. The three largest galaxies in the local group are Triangulum Galaxy, Andromeda Galaxy and the Milky Way. All three are spiral galaxies. The total number of galaxies in the Local Group is unknown (due to its partial occlusion by the Milky Way) but known to exceed 54, most of them being dwarf galaxies.

Virgo Supercluster —

Superclusters are the set of galaxy groups like our own Local group. These are vast collections of galaxies. The supercluster we live in is known as the Virgo Supercluster. It’s an enormous collection of more than a million galaxies, stretching across a region of space 110 million light-years. Astronomers recognized that we were in a supercluster of galaxies in the 1950s, but it wasn’t until the 1970s that astronomers actually mapped out the Virgo Supercluster’s shape; it has a flattened disk, somewhat like our galaxy itself.

Scientists have mapped the Virgo Supercluster with the use of supercomputers

The Laniakea Supercluster

The red dot shows the milky way

This massive Supercluster contains our virgo supercluster and encompasses approximately 100,000 galaxies stretched out over 520 million light-years. It has the approximate mass of 1017 solar masses, or a hundred thousand times that of our galaxy. It consists of four sub parts, which were known previously as separate superclusters:

  1. Virgo Supercluster (Where Milky Way resides)
  2. Pavo-Indus Supercluster
  3. Southern Supercluster
  4. Hydra-Centaurus Supercluster (Contains two other small superclusters)
  • Antlia Wall (Hydra Supercluster)
  • Centaurus Supercluster

Superclusters are some of the universe’s largest structures and have boundaries that are difficult to define, especially from the inside. Yet these superclusters fill up only a tiny part if the universe.

Computer-generated image- Laniakea Supercluster

Observable Universe —

This is the cosmos on the grandest scale we know. It consists of a net of 100 billion galaxies. Imagine you have all the equipment needed with telescopes designed with mind blowing specifications, still you won’t be able to look in to all the dark corners of the universe. That’s because the universe is not old enough for the light or other electromagnetic waves to reach us from the most distant corners of the universe. The universe is only 13.7 billion years old, which means our cosmic horizon lies above 13.7 billion light years away! Beyond that horizon are the parts which will remain a mystery for a long time. If you have an adequate knowledge about physics, you must realize that this horizon is expanding with a “y=mx” pattern with time.

Multiverse —

An illustration

A significant portion of scientists believe that all these galaxies, groups, superclusters and our own universe is nothing but one tiny bubble in an infinite ocean of other parallel universes. This is called the multiverse! This is still a theory which not has been proved yet. But this theory sums up how large the space that we live could be!



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Isuru Pamuditha

Isuru Pamuditha

Ponder & Wander... That'll make you an interesting person || Engineering Undergraduate ||