If you are just like me, wandering endlessly in search of answers to big questions, then I am glad I’m not alone. And you probably do not like wasting time on boring, windy intros to blog posts, so let’s jump straight into:
- What is time?
- Time vs Spacetime
- When did time begin?
- Is time infinite?
- Can we go backwards in time?
- Where does time not exist?
“A mystery is only a mystery as long as it remains uninvestigated, sir.“
Data on Star Trek: Next Generation
What is time?
In everyday life here on Earth, time can be seen as an invisible straight arrow on which we can track when events in our lives occurred. Our clocks measure how long an event lasted using units like seconds, minutes, hours and others.
Time vs Spacetime
It is important to understand that time can be seen differently in science. In physics, space is three dimensional and spacetime is four dimensional- if we are to treat time as a dimension. To understand the term “spacetime” I found a powerful explanation from Brian Cox and Jeff Forshaw’s book, “Why Does E=mc²?“:
“What we have to do is treat time as an additional dimension. Space has three dimensions: left-right, up-down and forward-backward. When we try to add time into space, we create four coordinates and a four dimensional space.”
OK, so why do we want to treat time as a dimension in space? Back in the 19th century a brilliant mathematician and physicist, Hermann Minkowski argued that space and time were not independent, but in unity. In 1905, he replaced the three dimensional space and one dimension time with a four dimensional unified entity. Additionally to Minkowski’s approach of treating time as a dimension, the four dimensional spacetime does also support Einstein’s theory of General Relativity. We will have a separate article on Einstein so stay tuned.
When did time begin?
No one knows exactly when time began. We, as humans, did not get a manual on how to handle time and that is unfortunate. Because if I had a copy of the time, I’d be able to go back in time to whenever I wanted and predict Manchester United wins. I know, right?
Before the invention of clocks and telescopes, however, people tracked the cycles of seasons, birth, death and often rebirth. As centuries went by, Christian religion became dominant in Europe and, as time itself went by, so did the proposals of connecting biblical events to the world at large. In fact, in 1620, Irish Archbishop James Ussher proposed the precise date of the Creation of the world to be 4004 BC by counting backward from the time of Jesus all the way to Adam himself using biblical genealogies and historical records.
As time continued to travel forward, so too, did the belief that the world began in 4004 BC, as scientists had no basis on which to make a different proposal.
But what about the fossilized species found in rocks? How did the remains of diverse species get fossilized in the first place, and, can someone explain how these fossils are found high above the sea levels, like the mountains? Clearly there was a need for a longer timeline, and we are talking a much longer timeline.
Centuries went by, and with them more theories on the age of the universe. Until one moment, in 1770s, a French mathematician and cosmologist Comte de Buffon proposed that the origin of our planet formed from a ball of molten material and estimated that it would take around 36,000 to 75,000 years to cool down into a solid state it is today. Theologians back then did not like this proposed number.
The eighteenth and nineteenth centuries too, had some of the finest scientists calculating and brainstorming about how we could find out the exact date of the Universe, and thus, time itself. Some famous names like pop up in those centuries, such as Edwin Hubble and his proposal of the age of the universe to be around 2 billion years.
Fast forward to our century and what we know about the age of time is through an event called the Big Bang. One possibility is that time started at the Big Bang event and simply did not exist before. Scientists have roughly narrowed down the Big Bang event to have occurred around 13.8 billion years ago thanks to powerful telescopes such as the Hubble Space Telescope which tracks the expansion of the universe using redshift — the stretching of light toward the red end of the spectrum.
Is time infinite?
There is no precise answer to that, but if I were to quote John Gribbin in “xxxx”: “The most important thing that the thermodynamics teaches us, is that nothing lasts forever. All things must pass, and everything wears out.”
On the other hand, a British astronomer named Fred Hoyle believed that the Universe may be infinite in time and space (a theory he proposed in 1948 called the “Steady State Theory”), whereas in 1957, an American physicist Hugh Everett suggested that there is an infinite variety of worlds across the Universe (a theory known as the “Many-Worlds Interpretation”)
Can we go backward in time?
In theory yes. If we were to consider time as a dimension, then Special Relativity theory by Einstein would allow time to flow differently for different observers. With a curved spacetime in mind, we can hypothesize a wormhole, which could hypothetically take me away from my desk and back to 20 years ago, when my existential crisis was non-existent. But for now, we do not have such wormholes.
Where does time not exist?
To quote Stephen Hawking from his book Brief Answers to Big Questions: “Inside a black hole time does not exist. Gravity can warp space and time.” We do not know what is going on inside a black hole in full detail but Hawking’s idea is thought-provoking.
Resources
The topic was inspired by various books:
- The Quantum Labyrinth by Paul Halpern
- Why Does E=mc²? by Brian Cox & Jeff Forshaw
- Black Holes and Baby Universes and other essays by Stephen Hawking
Thank you, I hope you enoyed the article. Please note, I carefully research the topic before publishing, however some facts could have changed since publishing this article, so I appreciate your understanding. All articles published are thoroughly researched and inspired by published books. The list of resources are published in every article. Please be kind, and have a nice day.
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