As long as the human history continues, star gazing does too. Humans have been looking up to the sky and marveling at the beauty of stars since the beginning of times. Our ancestors, we can imagine must have looked up and thought about the vastness of the sky. Every civilization from the past has tried to mark their position in the universe, often having their attempts ending in futility.
Back Tracking to Ancient Times
The systems developed by Babylon and Egyptian civilizations to understand our universe, became the basis for Greek astronomy. Indians, Chinese, and people from the Americas came up with their own systems.
The reason we were able to get our hands on Greek literature is because their astronomical work was taken up by Arab academics during the Abbasid and Umayyad rules, predominantly during the 8th and 9th century. This was when the Arabic empires took control of many regions out west that were previously Hellenized areas e.g. Egypt and Levant (present day Syria, Lebanon, Jordan, Israel, and Palestine).
The progress on the Greek work continued it from Islamic Arab and Persian empires, and then this creeps into early modern European astronomy, which carried the work forward at exponentially faster pace. So, basically we owe it to Greeks today for the knowledge about cosmos.
Cosmos and Universe
Many times, people confuse between cosmos and universe. To define cosmos in simpler words we would just say that it sums up everything Milky Way, the galaxies, and even the universe.
Even the word ‘cosmos’ originates from Greek language, the Greek word ‘kosmos’ means ‘order’ and ‘world’ both. Cosmos is a system that is only governed by natural laws.
Now, one would naturally inquire what the meaning of the word ‘universe’ is. Well, pretty much the same!
Everything that exists, that we know existed, or is existing, or will exist in future is the universe. It includes literally everything from matter to planets to galaxies to energy and to the elements; time, space, and vacuum.
It is tricky and it messes up the mind. If universe and cosmos are the same things then why are they not used synonymically for each other? To be honest, they are used alternatively at most times. The only difference is that the universe refers to narrower scope whereas, cosmos is large and a complex system.
How Big Our Universe Is…
When you start to think about all this deeply, then the question naturally comes up that how big is the universe? How large are the cosmos?
Let us try to address some answers to these questions …
It is well-known now that human race is living in a very tiny segment of the universe. Our planet is part of the universe which is vast and gigantic. This is not the limit though, cosmos are even bigger. We need to understand one thing before we go berserk in calculating the vastness, depth, and all the other exciting stuff about our universe.
As we have mentioned earlier, humans have been intrigued about this throughout our history. Naturally, there have been numerous astronomers throughout times and still are, who have dedicated their lives to serve this purpose.
Luckily, today technology development has offered us many new tools and instruments for astronomers, to be able to look back and study how and when big bang occurred. Now, this creates a great misconception that it means astronomers are able to view or understand the entire universe these days.
The size of universe cannot be easily determined with any certainty, at least at the time of this writing, as it is dependent on several elements like the shape of the universe, its continuous expansion, and about the many mysterious constituents. The fact is; no one has ever been able to put a number definitely next to the size of universe. Now, the other mind boggling question that follows is; does it go on forever?
The light we see in the sky comes from the planets or stars which are tens of thousands of years away from our planet Earth. And these distant structures we are talking about, are actually the nearest ones. Now try to imagine the enormity of our universe.
Sarah Gallagher, who is an astrophysicist at University of Western Ontario, once replied on the question about how big is our universe, “That may be something that we actually never know.” read more
Although it may seem impossible to know but the remote possibility of unearthing these important facts, coupled with curious and inquisitive human nature, has meant that scientists and academics continue to keep trying.
Light and Distance
The closer an object is, the easier it is to measure it. Same applies to the objects in our universe. We know exactly how big the sun is, and humans already have measured the dimensions of the moon accurately enough. To tell you the truth, calculating the moon dimensions was much easier than the sun.
All scientists did was sent a beam of light upwards and calculated the time it took to bounce off the surface of the moon and coming back. Easy right? Not so much for other distant objects…
First of all we need a beam of light that has enough energy and strength. We mean really strong to travel to all the far-off planets, stars, and to whatever that is lurking in the unknown realms of our universe. Even if we are able to have such a strong light source, the second problem will still be there: Time.
Who has thousands of years to sit tight and wait for the light to travel back to our planet?
This is however not the end for our astronomer friends… they have some dope tricks rolled up in their sleeves. This is now a common knowledge that stars tend to change their color as they age. So, our dear scientists estimate the energy, and light of these stars based on the color. The father one appear dimmer than the ones which are near us.
How Far The Edge Is?
Now, the next question is; what is the absolute edge of universe and how can we figure that out? This is the mind baffling one. We know that the light from the far, far off stars take billions of years to reach us, what if some of them are so far from us that even after all these billion years of universe, light hasn’t reached the Earth?
According to a physicist at SUNY (State University of New York), Buffalo, Will Kinney, “we can only see a tiny, little bubble of [the universe]. And what’s outside of that? We don’t really know.” He also mentioned, “There’s no evidence that the universe is finite,” he said, “It might very well go on forever.” read more
There is still no way to tell if it’s finite or not. And sadly, we only know very little about it. Our universe is freaking huge but that is not all. Our observable universe is expanding and the edges are moving away from us faster than their light is able to reach back to us. It means we may never be able to observe more of our universe than we are currently capable of doing today.