Space and time are two concepts that define our reality.
But what exactly is space, what exactly is time?
Misty cliffs and snowgum forests, kunanyi. Hasselblad 500 cm, Cinestill 800. Sep 2022.
Although space and time are inseparable and neither would make sense without the other, space is perhaps the easier concept to comprehend. Space is the big emptiness that makes up most of our universe. And this big emptiness gives home to matter, objects with mass, like planets, stars, mountains, seas, rivers, animals, plants and pretty much everything we know and are familiar with. And while it is tempting to think of space as existing ‘out there’, between the planets and solar systems, between galaxies, there is also space within the atoms, the little building blocks that make up matter. Just how our Earth orbits the Sun, electrons orbit the nucleus, the centre of each atom. And between these particles, no matter how small or how big, there is space. Space has no character of its own, but without it, nothing could exist.
(Space also gives home to dark matter, which in fact makes up most of the universe and can be thought of as an imperceptible, thick soup in which we are constantly swimming without realising it. At least, that’s how I think of it. No one really knows much about dark matter, except that it exists and makes up most of the mass of the universe. There are some experiments underway to detect it, but detecting dark matter has so far proven very difficult indeed. )
Snowgum forest, Mt Field West, Hasselblad 500 cm, Cinestill 800. July 2022.
There are many ways to think of time. Some people consider it to be a straight line, allowing events to progress forward in a linear fashion. This makes sense in a lot of ways, as the linear view of time allows for the progression of events in our lives. Our recorded history and our time keeping customs are testament to this. Once something has happened, it’s done, we can’t go back. Time keeps moving forward, whether we like it or not. We are born, grow up, grow old and die. I’m yet to hear of a person who has managed to do this cycle in reverse.
But here comes the twist. Time could also be viewed in a circular fashion. Instead of thinking of time in a straight line, we could also consider it to be a circle. Events in our lives repeat, at regular intervals. Our Earth goes around the sun, and as it orbits, so the seasons change, and with each year that passes there is a chance for rebirth. Each day is a rebirth, in a way. When a tree is cut down, the growth rings embedded within the trunk stand testament to the cycle of the seasons. Empires rise and fall, and history has a way of repeating itself. What was once, will be again. Perhaps not exactly in the same way, but in a way that confirms the concept of time being circular. It goes around, then comes around. So on and so forth.
Looking west, from Mt Field West. Hasselblad 500 cm, Cinestill 800. July 2022.
And now to connect these two rather abstract ideas into a cohesive unit!
If we wish to travel through space, it will take time. The further we want to go, the longer it will take. When we start thinking about covering the distance between planets or stars, our basic unit of measurement takes the form of light years. This is because Einstein postulated that the speed of light in space is constant, regardless of your frame of reference. So a light year is the distance that light covers in one year and it’s a reliable measurement because the speed of light doesn’t change in space, regardless of whether the object that’s emitted it is moving towards you, or away from you. Given that light covers about three hundred thousand kilometres per second in space, a light year is a long way indeed!
In other words, we can get a scope for the scale of space by observing how long it takes light to cover certain sections of it. For example, we know light takes about 8 minutes from the Sun to reach us here on Earth. And this is the interesting bit. When we look at the sun, we are not seeing the sun how it is in this moment, we are seeing it as it was 8 minutes ago. And similarly, if we are looking at a star up in the night sky whose light has taken a million years to reach us, then we are seeing that star as it was a million years ago.
And so this shows that space and time are connected, inseparable. To overcome space, we need time. And to observe the passage of time, an event needs to occur in space.
Or something like that.
-A.S. 1/10/22, Lenah Valley