We hope you’ve had your turbo charged coffee this morning, because we’re getting scientific on this blog today! We’ll wait while you get another cup of coffee. It’s OK. We have mornings too.
If you’ve ever spent more than 30 minutes on the Sci-Fi Channel, then you’ve heard the phrase “spacetime continuum“. What exactly does that mean?
Oh, now people want to get that second cup of coffee. We’ll wait. I’m starting the stopwatch now.
Everyone back and seated? Good. Moving on.
Notice that the word “spacetime” is one word. It’s not space time. It’s spacetime. The word intentionally merges space and time into one concept. To explain it, we’ll need to separate the two.
What is space?
Space is a word used to reference three dimensions of existence. We live in a three-dimension world. Things have a length, height, and depth. Even a vacuum has all three dimensions; it’s noting in three different ways. Space is where things are. On the globe we have latitude and longitude lines. These two lines show us where things are on maps. In the universe, on the world, and in our lives, two markers for space won’t cut it. We need all three. Space is the “where” of spacetime.
What is time?
Time is “resistant to simple definition” according to Carl Sagan. Time is time. It’s a fourth dimension all on its own and it’s the vibration of an atom. Until someone measures it and proves otherwise, time is believed to be constant. Oh wait! We did that. Experiments using atomic clocks have shown that time itself changes as astronauts accelerate. The length of a second changes in a measurable way as the object holding the clock approaches the speed of light. Thanks to Albert “there’s math in there” Einstein we have a theory that can help explain that. His Theory of Relativity helps us understand that time is relative to the person observing the time. Time is the “when” of spacetime.
Why do we need both?
If an event happened it had to happen at location and in a point in time. If an event is going to happen it must happen at a location and in a point in time. An event can’t exist in time, but not space. It also can’t exist in space, but not time.
The word “spacetime” is a fancy way of saying when and where something happened, is happening, or will be happening. It is the coalescence of all four dimensions (the three of space and the one of time).
Science fiction plays with this concept a lot. Space travel, inter-dimensional travel, and time travel remove or tweak one or more of the four dimensions. A little adjustment to the space part of spacetime and the members of SG-1 can “phase” into another aspect of this dimension. A subtle shift of the time aspect of spacetime and SG-1 enters into yet another time dilatation field. Why not play around with these concepts when it’s just fiction, right? There’s no such thing as a time dilatation field unless one wants to listen to Mr. Albert “not so fast” Einstein.
The Theory of Relativity led to what is known as the Twin Paradox. This concept is briefly explained in our blog post about time travel in the paragraph that talks about Einstein-Rosen Bridges, commonly called “wormholes”. That is a type of time dilatation. Another type of a time dilation field is a gravity time dilatation field. The field of quantum mechanics looks at physics on an atomic level. The work of Einstein and the work of another scientist named Lorentz has led to the understanding that the movement of atoms changes as an object passes through different gravity fields. The cesium in an atomic clock on Earth will mark the passage of time differently than the cesium of an atomic clock in a different gravitational field. Both gravity and acceleration influence time and create time dilatation fields.
Gravity takes us back to spacetime in a general sense. Gravity not only can create a time dilatation field, but it will actually change the fabric of spacetime. It warps and bends spacetime itself. The mere fact that something exists changes where and when it exists. This is similar to the idea that an observed event is changed simply because it is observed. The presence of an object changes the surroundings of that object.
If spacetime is where and when an event occurs, then it would seem that the word “location” would be an adequate substitute. At one time the word “space” was adequate. This was during the time of a Greek mathematician named Euclid. Euclidean space regards time as a constant. This concept is still used when physicists work with classical mechanics.
On the surface time seems like a very simple construct. It’s this abstract idea that tells us how long we have until we go to work, get up in the morning, or head out for a movie.
We can count down the time till a holiday or mark the passage of time with a stopwatch.
When we dive deeper into the concept of time we realize that our clocks only mark the passage of time.
Time, in and of itself, is a very complex subject and it’s connected with everything in our lives.
And, with that said, it’s time for us to end this blog post.
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