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How long would it take to travel a light year?

By Harriet Piercy

Nov 27, 2020

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Our universe has a speed limit, and this limit is set by the speed of light which travels at the mind boggling pace of 186,282 miles per second, or 299,792 kilometres per second. That’s 670.6 million miles per hour, or 1.1 billion kilometres per hour. Basically, if you had the ability to travel at the speed of light, you would be able to do a darting cycle around the Earth seven and a half times each second. Windburn will get ya, that’s for sure. So, when human hour’s turn to years, we’re talking light years in particular—how long would a light year take in human time?

How long would it take to travel a light year?

Thanks to Albert Einstein’s theory of relativity, which is based on two key concepts; special relativity and general relativity, we can figure this out. An overview of the thought that these theories trigger is that, well, everything is relative, but the speed of light is constant. To warp your thinking a bit: rulers and clocks, the tools that mark time and space, are not the same for different observers. However, if the speed of light is constant, as Einstein said, then time and space cannot be absolute or uniform, they must instead be subjective. Einstein read the relationship between space and time, and noticed that their consequences were intertwined. In fact, space and time can no longer be independent.

We as humans have many misconceptions of time and space, because time for one, feels like it’s relentlessly moving forward. Time to us flows, and has a direction that advances in an orderly fashion. Time has become like a backdrop in which all events take place in space, sequence and durations are measured. However, this smooth concept is challenged by Einstein’s theory of relativity whereby space and time convert into each other in such a way as to keep the speed and light constant for all observers, in other words, they depend on the motion of the observer who measures them, this is why moving objects appear to shrink. The theory is the infrastructure of our current understanding of the universe. What does this relate to in terms of calculating the speed of light then?

Keeping the perspective of a viewer in mind, and bringing in an object that travels (which is essentially what we are measuring here) let’s say, a human, that is travelling at the speed of light. To an observer, the size of the human would be miniature, but to the human travelling, they would remain their own size. Time also passes slower the faster one goes, and mass also depends on speed. The relationship between mass and speed (or energy) is calculated with the formula: E=mc^2, where E is energy, m is mass and c is the speed of light.

Now to get back to figuring out how long it would take us to travel a light year. If we were to measure distances in miles or kilometres, we would be working with enormous numbers, so we measure cosmic distances in light years according to how fast light can travel in a year. According to Futurism, there are just about 31,500,000 seconds in a year, and if you multiply this by 186,000 (the distance that light travels each second), you get 5.9 trillion miles (9.4 trillion kilometres) which is the distance that light travels in one year.

The time that it takes us humans to travel one light year is considerably longer than a year. To put it into context, it takes between six months and a year for us to reach Mars, which is in light year terms, 12.5 light minutes away. It took NASA’s New Horizons spacecraft almost ten human years to reach Pluto from Earth (which is ‘just around the corner’), only 4.6 light hours away.

Saying we were a space shuttle that travelled five miles per second, given that the speed of light travels at 186,282 miles per second, it would take about 37,200 human years to travel one light year. That’s a long time, and what would you see? Well, not much unfortunately. You’d be closer to the centre of our own galaxy, but with a further 26,000 light year distance still to travel. All I can really say after writing this piece is that i’m exceptionally relieved that I’m travelling at my own pace, which seems almost too fast even in relation to myself some days, but hey, it’s all relative.

How long would it take to travel a light year?


By Harriet Piercy

Nov 27, 2020

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How would language change if some of us moved into the interstellar?

By Harriet Piercy

Jul 13, 2020

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Imagine Noah’s ark, but floating in a sea of stars. If worse comes to worst and we really do have to abandon Earth, we’ll have to take our generation with us in order to save the next—the new generation would then become the ‘generation ship’. In order for us to save the human race,  a variation of ages would be sent to space. How could a potential move to space alter the way we speak?

First things first, we would need to take our environment with us. Everything will be on board—everything alive, that is. Maybe we’d be allowed to bring the odd memorabilia, but all packing has a priority order as we know, meaning that the heavy bits and pieces at the bottom of your shopping bag would usually go first. In this case, other than ourselves, the minuscule would take a predominant lead with bacteria, seeds and gases.

The long journey we would be embarking on also means that we would inevitably evolve over time. People will continue to be born, raised and, eventually, die. Interstellar travellers would probably have a lot less space to live their lives. Biologically, this could lead to all kinds of issues or mutations that cannot be foreseen. One other thing in particular will have to evolve too: language.

A team of linguistics professors, Andrew McKenzie and Jeffrey Punske, published an ongoing study based on Language Development during Interstellar Travel, in the April issue of Acta Futura, the journal of the European Space Agency’s Advanced Concepts Team.

In the study, they discuss how languages evolve over time as communities grow isolated from each other. In this case, our entire population couldn’t possibly fit on the ship—which sparks another discussion altogether—we would have to leave humans behind. If the ship were to come back to Earth, would the two groups still be able to understand each other, having evolved separately?

One would hope that Earth and the vessel would keep in contact with each other, but time warps in space, so communication of any kind will eventually lag. “If you’re on this vessel for 10 generations, new concepts will emerge, new social issues will come up, and people will create ways of talking about them and these will become the vocabulary particular to the ship. People on Earth might never know about these words unless there’s a reason to tell them. And the further away you get, the less you’re going to talk to people back home. Generations pass, and there’s no one really back home to talk to,” explains McKenzie.

The paper is concluded by the statement that on the generation ship “Eventually, the language or languages of the crew will diverge from those on Earth. If they start out with multiple languages, those will perhaps converge towards each other,” whereas on Earth, the opposite may happen. Language is formed by finding mutual understandings for the purpose of communication or translation. So, with a significant sum of our population subtracted and shipped away, the geography of our population would be dispersed further. The world as we know it would be, for a time, underpopulated—which may lead to more distinct language barriers and divergence.

We could argue that because of the internet, distance doesn’t control our differences in language as much as it would have in the past. Would the generation ship evolve technologically faster than Earth? It’s hard to decide without knowing exactly what resources they would discover out there  compared to our current rate of advancement.

Time on our beloved planet has proven thus far that most of the imaginable is possible. What’s stopping us from imagining a little more? Furthering our understanding is arguably humankind’s greatest trait, but it’s also the misunderstandings that push our drive to understand further. We’re aiming high to test this out, quite literally. Turns out science and fiction really are yin and yang, but their language is different.

How would language change if some of us moved into the interstellar?


By Harriet Piercy

Jul 13, 2020

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