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  • Jash Kikani

The Vast Cosmos

THE TRUE LIMIT OF HUMANITY

The Earth. We all live somewhere on this planet. Everyone we have ever known is on it. However, have you ever wondered how small the Earth is compared to the entire universe?


How about we start with our nearest cosmic neighbour, the moon. You may believe that it is quite close to the Earth for it is distinctly visible at night. Except in reality, the distance from the earth to the moon is almost 30 times larger than the diameter of the earth. If a car travelling at a constant speed of 100 kilometres per hour, moved towards the moon, from the earth, then it would take almost 160 days to reach it. Only 12 humans have touched the surface of the moon, representing the farthest limit that any human has ever been from the earth. This was achievable because communication took place at the speed of light, which only takes 1.25 seconds to travel from the moon to the earth.


The Voyager One space probe is the furthest away man-made object from the earth. It is currently 138 AU’s away from our planet. AU is the short form for “Astronomical Unit” and its value is 1.496 x 1011 metres. This is the average distance of the Sun from the earth. This means that the Voyager One space probe is 138 times further than the Sun is from the earth. It moves at a speed of 17 kilometres per second. Even at this pace, it will fail to pass the boundaries of our solar system for another 30,000 years!


We now move outside our solar system and into our intergalactic colony. Proxima Centauri is the closest star to earth, besides the Sun. It is 4.25 lightyears away from us. To put that into perspective, if Voyager One travelled in the correct direction, it would still take 70,000 years for it to reach the star!


THE OBSERVABLE UNIVERSE

The Milkyway Galaxy is our next stopping point. From one end to another, it spans over 100,000 Light Years and houses over 150 billion stars and planets. Yet our massive galaxy is nothing compared to the rest of what is in our universe. Zooming out even further allows us to see the Virgo supercluster of which our local group is a minuscule segment. It spans a distance of a mind-numbing 110 Million Light Years. Shockingly, even this is just a small part of a larger supercluster known as the Laniakea Supercluster, an enormous structure that is home to 100,000 galaxies, including our very own. The distance from one end to the other of this enormous cosmic structure is a whopping 520 Million Light Years.


We finally move to the universal scale. Even the Laniakea Supercluster is infinitesimal to the observable universe. The Observable Universe is home to at least 2 trillion galaxies. The distance from the earth to any side of the Observable Universe is roughly 46.5 Billion Light Years.


Now one may wonder, “How is the observable universe this large? To view just one end of the observable universe we would need 46.5 billion years of light to reach us. This would be impossible because The Big Bang was only 13.8 billion years ago, right?” Although they would be right about the age of the universe, they would be wrong with this assumption.


Nothing can achieve the speed of light. Light travelling through space is at the fastest speed attainable by matter, but what about space itself? Space cannot be called ‘matter’. It is the medium through which light travels. No matter in the medium can move faster than light, but the medium itself can expand. This expansion takes place at a speed greater than that of light. This is also why many galaxies seem to be moving away from earth at a rapid pace. Whereas in reality, the galaxies are stationary in space but the fabric of space between the earth and the galaxy is expanding.


THE THEORY OF COSMIC INFLATION

What is more intriguing, however, is what lies beyond the Observable Universe. The Observable Universe is only what we can currently see. This is because the light coming from other incredibly distant places that are beyond this point has not had enough time in the universe’s history to reach us. The rest of the universe outside of the Observable Universe may be much larger and more incredible than we can ever imagine.


According to the Theory of Cosmic Inflation which was proposed by Dr. Alan Guth, at the present day, the Universe is 150 sextillion (150,000,000,000,000,000,000,000) times bigger than the observable universe. This almost infinite scale is very hard for our finite minds to grasp because it is similar to us thinking that the Observable Universe was the size of a golf ball, but in reality, the actual Universe is the size of India.


This truly makes one realise how insignificant we are in comparison to the rest of the Universe. It humbles us and makes us realise that almost anything that we do will be inconsequential to the Universe. It will continue to expand and grow larger, leaving behind millions of things for us to discover, hidden somewhere in its massive self, shrouded in mystery. Nonetheless, another way to look at all this is, that we have the opportunity to find so many new parts of the mystery that is our Universe, together.


Bibliography:


  1. Guth, Alan. “The Inflationary Universe.” 250 W 57th St Fl 15 New York, NY: Perseus Books, 1997.

  2. Nasa. “Galaxies | Science Mission Directorate.” Nasa.gov, n.d.3 Apr. 2022. <science.nasa.gov/astrophysics/focus-areas/what-are-galaxies>.

  3. Seeker. “How Big Is the Universe?” YouTube, 13 Jan. 2014 3 Apr. 2022. <https://www.youtube.com/watch?v=hz0KGVwGwXQ/>.

  4. N.a. “The Voyager 1 Space Probe Is the Furthest Man-Made Object from Earth.” Letsques.net, 5 May 2021, 4 Apr. 2022. <www.letsques.net/the-voyager-1-space-probe-is-the-furthest-man-madeobject-from-earth-like-the-video-explained-it-is-138-au-away/>.

  5. “How the Universe Is Way Bigger Than You Think.” YouTube, n.d. 4 Apr. 2022. <www.youtube.com/watch?v=Iy7NzjCmUf0&t=0s>.


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