The concept of time is a fascinating concept that is hard for us to wrap our minds around. Dive in with me as we talk about what time is and how is shapes the universe.
The Invention of Time
Time is a crucial part of all of our lives. It defines what we do and how we do things. Our lives depend on it. Since the dawn of the human race we have perceived time as a constant aspect of the universe. We observe time move relentlessly forward into what we call the past. We gave hours to the day and minutes to the hour and seconds to those minutes. Yet even with us inventing the concept of time we still don’t have enough of it.
It is estimated that the first tool to keep time was the moon some 6,000 years ago. Lunar calendars consisted of 12 to 13 lunar months. This evolved even further to more complex ways of tracking time. Sun dials, water clocks, hour glasses, and even more devices were used to keep early time and allow early civilizations to have a sort of tempo of function.
The definition of the second and minute and hour and day and month and year has changed over the course of human history. But has it changed how we perceive time? From the moment humans evolved and began observing the universe or in the much narrower scope of the Earth their lives began taking shape and definition. Even now we can say how long ago early humans lived for we have defined the scale of time.
The universe doesn’t care about our definitions of time. The history of the universe would always be and always will be no matter what we define it as.
What is It?
Time is the never ending progress of events and existence. It doesn’t end. It continues forever. Surely time must be a construct of our minds? We perceive the universe using the very limited tools we have. Our sense of smell, our sense of sight, hearing, and taste are all limited. There is so much we don’t hear and see. We built tool to allow us to peak into the aspects of the universe in which we are oblivious to. We cannot see the cosmic microwave background radiation that is all around us. The static of your television is the ever lasting echo of the Big Bang.
Yet that was billions of years ago. Approximately 13.4 billion years ago the universe began and with it time. Before then time didn’t exist. There was nothing. From the start the universal clock began ticking. However we find that time is not universal.
It took human kind thousands of years to realize that time is not constant. On our level of experience we see time move consistently for everyone and everything here on Earth. However even here on Earth or at least near it we observe things behaving rather weirdly.
It was Isaac Newton who proposed that time was universal and constant throughout the universe. This idea is called absolute time also known as Newtonian Time. Newtonian time exists regardless of any one observing and progresses at a consistent pace throughout the universe.
Theory of Relativity
It wasn’t until Albert Einstein in 1905 published his paper on Theory of Relativity. Then later the General Theory of Relativity in 1916. In Special Relativity the observers speed relative to the event makes time variable. The faster one goes the slower time goes compared to other parts of the universe. The General Theory of Relativity tells us that the fabric of space time is both time and space woven together across the universe. Space and time are one.
These theories came together and gave us a new understanding of exactly what time is. It is a variable and changes depending on a couple of factors. One of the variables is of course the speed of something. The Milky Way Galaxy is roughly 100,000 light years across. It takes light 100,000 years to go across the galaxy. If we were to hop in a space ship that could go 99.99999% the speed of light and traveled across the galaxy. We would experience little to no time while the galaxy would have progressed about 100,000 years.
The idea of time dilation seems counter intuitive at first. But it something that has been observed. Time is also warped in the large gravity wells of stars, black holes and planets. Of course black holes have a much larger impact on both space and time. GPS satellites that orbit the Earth much faster relative to us on the ground experience time dilation. The time keeping devices have to constantly account for the drift of time. Time moves slower for the satellites then for us down on the planet.
The satellites in orbit loose about 38 microseconds every day from time dilation. If they were to be left to drift off the entirety of the GPS system would become annoyingly inaccurate.
Can We Go Back In Time?
While there are a couple theories of how time travel to the past could be possible it is hard to say if it is actually achievable. However we can look into the past per-say. Light we all know takes time to travel. In our narrow scope of things we see light here on Earth appear almost instantaneously. You flick on a light switch and the room is then bathed with light. However in the scales of the universe that isn’t the case. For example. The Sun is on average 93,000,000 miles away. It takes light approximately 8.5 minutes to get from the sun to the Earth.
This means that our view of the sun right now is what it looked like 8 and a half minutes ago. We are constantly looking into the past. We never have a “live” view of our humble little star. That is a pretty small amount of time in the grand scheme of things. A galaxy that is 13 billion light years away has been seen. This galaxy is so far away that it takes light 13 billion years for light just to reach us. This also means that the view we have of this galaxy is what the galaxy looked like when the first stars were forming in the universe. It would take another 13 billion years for us to know what the galaxy looks like at the time you are reading this.
Time is a fickle things. We don’t see to have enough of it. Maybe all we need to do is go a little faster and we would end up having all the time in the world. Time is not constant, it changes depending on quite a few variables. Take the time though and perhaps leave a comment about time and space and begin a discussion about how you think we could use time dilation to our advantage.
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