In Search of The Origin – IV
The Universe in Perspective
Continuing on our deliberations on the subject of our Origin, and to have a better understanding of the nature of our own self, we are going to review and analyze the present ‘state of affairs’ of the Universe – It will help to put in perspective the ‘significance’ of our planet Earth, and, by relevance, the ‘importance’ of us – The Humans.
We use the word ‘universe’ quite loosely in our daily conversation. We have the names and terms like; ‘The digital universe’, ‘Universe of Opportunities‘, and, what not, ‘The Universe of Shoes‘ – We even have “Miss-Universe” pageants (courtesy of the sole surviving dinosaur on the planet Earth, Donald Trump) to crown one of the chosen damsel as ‘Miss-Universe‘!
What an insult to the smart, dedicated, hard working, intelligent, educated, dignified and contributing women of the human society – But, that is beside the point here.
In our discussions here, when we refer to ‘universe’, we mean ‘The Galactic Universe‘ that our solar system is a minuscule part of – The Universe that contains hundreds of billions of Galaxies like ‘our own’ Milky Way Galaxy.
There are still some of us who still insist in believing that the planet Earth is the center of ‘whatever’ is out there – The universe, or ‘whatever out there’, revolve around the Glorious Earth. It has to be – otherwise, why The God would send His ‘only‘ Son to Earth?
Well as ‘valid‘ the above argument may be, our perspective here is purely scientific and logical.
We acknowledge, our understanding and knowledge is not perfect, and we are still trying to seek answers to some very fundamental questions concerning the universe we live in: What is the nature and composition of this Universe? How it came into existence? Is this the only Universe, or are there more Universes in a ‘Multi-Dimensional Multi-Verse’ system?
We have a long array of questions on these same lines. We are still trying to seek answers. We have our theories that are based on the analysis of the observed data, and on our logical and deductive reasoning.
On the ‘qualitative’ side of the nature of this Universe, we don’t know much, but, on the quantitative side, we are pretty confident in our understanding of some basic facts. We have sufficient data available to give us a high degree of confidence in our estimates of the lower bounds of the counts and expanse of the Universal bodies – Latest data and its analysis suggests that the Universe may even be much larger and complex than what we have so far calculated.
Anyhow, the objective here is to present a comparative description of ‘our’ Galactic Universe in order to put our self and our Earth in proper perspective.
The Earth and the Solar System
We are ‘Earthlings’. Earth is our home. It is home to 6 billion plus human beings, and a plethora of other life forms sharing the planet along with us. It is a vast globe of land. Those of us who get a chance to venture out and away from the major the city centers know that most of the land in between the cities seems very thinly populated – it is mostly an open and vast land. Earth’s landmass is quite large, even for billions of us. Even the largest cities, containing millions of homes, offices and buildings, are just tiny dots on the surface of our Earth. Earth’s mean radius is 6,371 km – giving us a surface area of 510,072,000 sq km. The Earth’s land surface area is around 150,300,000 sq km (57,500,000 sq mi) – that provides around 270,000 sq ft (25,000 sq meter) land area per person – of course, that includes the uninhabitable areas, farm land, and provisions for the infrastructure. Still, it is a large area by any account.
Our Earth is one of the star Sun’s planets. As per our present observations and classifications, there are ten planets orbiting the Sun. Sun’s radius is 696,000 km (compare it with Earth’s radius- 6,3785 km). Moon is earth’s satellite. Some of the other planets of our solar system carry more than one moon as their satellite. The distance from Earth to moon is just 384,000 km. [Suns’ diameter is more than 3 1/2 times the distance between the Earth and Moon.] The median distance from Earth to Sun is 150,000,000 km (93 million miles). This is our ‘own’ solar system – the system of ‘our’ star, Sun.
When we speak of the distances between the stars, we are speaking of a scale that dwarfs the scale we are accustomed to dealing with on Earth. It will be a good idea to get acquainted with the astronomical units that are used to represent the interstellar and galactic distances. Our planetary units of the measurements, even with preceding billions and trillions, don’t carry us far enough. The sizes and distances in the galactic world are measured in the units of AU, Parsec and Light-Years.
The Astronomical Unit (AU)
The basic unit for representing the distances between the solar systems is the Astronomical Unit (AU). Roughly speaking, it is the average distance of Earth from the center of the Sun. One AU is 150,000,000 km. To put it in perspective, Earth’s equatorial radius is 0.00004 AU (4 hundred thousandth AU). But, if you are already awed by the AU, wait until you are introduced to the Light years and the Parsec!
The Light Years and The Parsecs
Even the AU becomes inconveniently small if we want to venture beyond the interstellar systems. To facilitate our journey into the intergalactic world, we have devised some other astronomical units that allow us to express measurements in decipherable numbers.
For all the practical purposes – in a down to earth manner, we can safely assume that light moves instantaneously. But, beyond the Earth, we cannot make such an assumption. Take the distance from Sun to Earth – That is one AU – light travels from Sun to Earth in just 8 minutes and 19 seconds. It means that light travels 1 AU – that is 150 million km – in 499 seconds. Now, to visualize the enormity of the size of our Milky Way Galaxy – It will take the light almost 120,000 years to cross the galactic disk of the Milky Way.
To put it in perspective; Sun is approximately 8 light minutes away from the Earth, while the Milky Way galactic disk is 120,000 light years across.
But when we start discussing the distances in inter-galactic terms (there are billions of galaxies in the Universe), even the units in light years are not large enough. So, we came up with even larger unit – The Parsec.
The unit of Parsec (pc) was devised using the trigonometric method to compute the parallax distance of far away stellar or galactic bodies with reference to Earth-Sun distance. Without going into the technical details of Parsec computation, 1 Parsec is equal to the distance covered by light in 3.26 years – that equals to 206,264 AU, or about 31 trillion kilometers.
When even the Parsec unit become too small for the scale, we start using the kpc (thousand Parsec) and mpc (million Parsecs).
Now that we have a handle on our astronomical units, we can proceed to investigate our intergalactic universe.
The Milky Way – Our Galaxy
Our Sun is one of the stars in the galaxy, that we call, the Milky Way. Milky Way is a type of galaxy that is known as the Spiral Galaxy – so called after the visible gas and stars in the galaxy that form arms that seems to be twisting around the center of the galaxy.
The Milky Way galaxy is composed of two types of matter; parts that are visible to us, and the sections that are invisible to us. The visible parts are a disk of stars and gas, the spiral arms, and a relatively smaller central bulge. The invisible part is a Halo that, most mainstream scientists believe, contains low-luminosity stars, and perhaps other types of gravitating material (?). Then, there is, we assume, a nucleus as the gravitational center of the galaxy – That, most probably, is centred within the ‘halo‘ of the galaxy.
The nature of the matter and its mass in the Halo and at the Gravitational Center are in a form unknown to us. Spiral arms are composed of very dense gas and stars. Highly dense gas in this region has been the incubator of new stars. The disk provides the orbital plane of the young stars in the Milky Way Galaxy. The disk is much thinner than its diameter. The orbits of stars are nearly circular around the center of the Galaxy. Regardless of how far a star is from the center of the Galaxy, it travels around the galaxy at a constant speed of about 250 km per second.
The stellar disk of the Milky Way Galaxy is approximately 120,000 light years – that is around 37,000 Parsec, in diameter. Our Sun is in the galactic disk, about halfway from the galactic center to the outer edge of the disk. At its distance from the galactic center, traveling at 250 km per second, the Sun orbits the Galaxy once every 200 million years. During its 4.5 billion years of existence, the Sun has orbited the Galaxy only about 22 times.
The Milky Way galaxy contains some 200-300 billion stars like our own Sun. The average distance between these stars is 31 Trillion kilometers. Which is 206,264 times the distance from the Earth to the Sun. All the stars that we see in the sky are in the section of the Milky Way galactic disk that is close to our star, The Sun.
The nearest known star to the Sun is Proxima Centuri, which is 4.23 light-years (41 trillion km, or 25.3 trillion mi) away. In terms of interstellar travel (Star Trek – USS Enterprise!), a spacecraft, moving at 60,000 kilometer (37,000 miles) per hour, would achieve the travel in several tens of thousands of years – to be more concise, a journey to Proxima Centauri would take around 80,000 years – Provided, of course, we could solves the problem of energy/fuel for the propulsion of the spaceship in the first place.
You may like to consider these facts next time you stumble upon a story about the “UFO” sightings!
A Universe of Billions of Galaxies
‘Our’ Milky Way is just one of the 100-200 billion of Galaxies in the Universe. These galaxies are of varied shapes and sizes and are positioned at distances from each other that correspond to their relative shapes, sizes and the collective cluster mass.
The nearest spiral galaxy to our Milky Way is the Andromeda Galaxy. It is roughly 2.54 million light-years away. As of the present date, the most distant observed galaxy is some 13.2 billion light-years away, which is 5000 times more distant than the distance to Andromeda Galaxy.
The vastness, the complexity, and the order of this universe is simply mind-boggling. Even though we put the word and figures to describe it, the reality of the enormity of this universe is beyond the grasp of our human mind – we cannot even come close to visualizing the magnitude of the dimensions of this Universe.
And, there are strong indicator to point to the existence of more universes beside ‘our own’ universe – In a multi-dimensional ‘Multi-Verse’ system!
The Case for The Intelligence:
Mathematical probability aside, extrapolation of significantly large data, compiled over the last couple of decades, indicate that there are billions of the star systems that carry planets that have the atmosphere and the essentials, very similar to Earth, to support the life – Is it too far fetched to acknowledge that millions of those planets may have an advanced form of life – With hundreds of thousands of them bursting with life form ‘way more advanced’ than us – And, ‘They’ may not be the warmongers and genocidal killers like the dwellers of the planet Earth!
And, The Faith
It has to be faithfully acknowledged that the faith is just a matter of Faith. But, would you still want to believe that this minuscule Earth is the only planet in this enormously vast Universe that is inhabited by the intelligent life? Would you still like to believe that the planet Earth is the Center of The Universe? Do you still believe that The Universe was created just to make it orbit around this Earth?