They say, perspective is everything. Here on Earth, our perspective is quite narrow, as far as distances are concerned. One of the reasons for that is, we don’t get to deal in large distances in our day to day life.
From hundreds of kilometres to probably thousands of kilometres (if travelling outside country), our range of distances that we traverse is quite low. But once you shift your perspective to what lies outside our planet, you will realise the stark contrast.
That’s why many people are not able to fathom the distances involved in space and have to be given specific perspectives to realise the same. For example, did you know that you could fit all the planets in the solar system between the Earth and the moon? That’s how far moon actually is.
Distances in space between objects are so huge, that we use a completely different way of measuring them. We use what is called a light year, which is the distance travelled by light in a year. And if the distances weren’t already large, they are getting ever so larger.
An Expanding Universe
You might already know that the universe is expanding at an accelerating rate and therefore the galaxies are getting further and further away from each other. The universe is about 13.7 billion years old and already the observable universe is about 93 billion light years in diameter.
And that is just the universe that we can observe i.e. light has had time to reach us from those parts of the universe. Who knows how much larger the universe is beyond that point.
You might think that if the universe is just 13.7 billion years old how could the observable universe is 93 billion light years wide if nothing can travel faster than light. Short answer: The very fabric of spacetime seems to be stretching faster than light.
That means all the galaxies that are travelling away from us faster and faster every moment are not actually travelling faster than light but it’s just that the space between them and us is expanding at faster than light speeds and it is exactly this phenomenon that will one day make the universe a very lonely place.
A Lonely Universe
So, there are possibly trillions of galaxies in the universe with huge distances involved between them already. If interstellar space travel seems like such a sci-fi thing to do, you could only imagine what intergalactic travel would be like!
Add to the fact that those distances are increasing and that too at unimaginable speeds and even that is increasing!! We are literally being driven apart from the rest of the cosmos.
Well, not just us, every thing in the universe seems to be getting driven apart from the rest as space expands between them, the main culprit of which is suspected to be the mysterious dark energy, which is still not really understood.
In a far future, perhaps billions of years from now, every galaxy will be so far away from the next, that to an observer, it would seem like there’s is the only galaxy in the whole universe, floating around in a vast nothingness.
Such a lonely place it would be. In a way, we are lucky to be alive right now where we can observe so much of the universe and have been able to look back in time to the first moments of the big bang.
The universe has so much beauty to offer in terms of stars and galaxies which invite so many questions about existence and gives purpose to an intelligent species to pursue these questions and expand out into space as space faring civilisations and look for other potential intelligent beings.
Imagine a universe where your’s is the only galaxy there is and you just can’t figure out the true nature of the universe. The most you would be able to do is travel within your own galaxy which seems quite an impossible feat right now but for a species that would have been around for quite a while, it would be as boring as just swiping apps to the left and right on your smartphone!
There are theories that state that the universe will come at a point where it will stop expanding and start contracting in which case things might get less bleak, but who’s to say this will happen and the time that it would take, would render anything irrelevant.