Time Travel will almost certainly kill you
Time travel theories discuss time but don’t discuss an equally important aspect—space. This post does.
The earth goes around the sun. Let’s start there. One way to see it is as depicted by the below animated GIF I found on Wikipedia.¹
Of course, the animation above isn’t accurate because our sun is at one of the foci of an ellipse around which the earth revolves but for the purposes of this post it doesn’t matter. Also, none of the images in this post are to scale etc.
Suppose now the following:
- I have a functioning time machine and
- It can instantly take me backwards or forwards in time.
(We require that time travel take zero time because otherwise one could make the simple and accurate argument that we’re already time traveling at a rate of one second per second.)
Let us further suppose that at this time when I’m considering time travel, the earth is at position of its orbit shown below and I wish to travel 6 months into the future.
The position of the earth 6 months into the future is as follows:
To further illustrate my point, I’ve annotated the images to include me (not to scale).
Position when I start the time machine:
If I travel six months into the future, I end up as follows:
While the earth has moved I’m still exactly where the earth was. This, as we all know, does not end well for me.
On the plus side, no more blog posts such as these.
Addendum
Things are actually worse. Remember, the earth goes around the sun; the sun goes around the black hole at the center of the Milky Way — our galaxy; and the Milky Way is itself moving away from other galaxies. This constant motion does not bode well for time-travel. It also makes the mathematical calculations that much harder. (Possibly impossible but I’m not sure.)
[I]f, some time-interval having been assigned, [a] body moves with the same speed in the last as in the first instant of that time-interval,… it could… continue in uniform motion forever. — Galileo Galilei, Dialogues Concerning Two New Sciences ²
Footnotes
¹ The animation is available at https://commons.wikimedia.org/wiki/File:Earth_tilt_animation.gif, available under the license: Creative Commons Attribution-Share Alike 3.0 Unported.
² “Dialogues Concerning Two New Sciences” by Galileo Galilei. Translated from the Italian and Latin into English by Henry Crew and Alfonso de Salvio. With an Introduction by Antonio Favaro (New York: Macmillan, 1914). Available at http://files.libertyfund.org/files/753/Galileo_0416_EBk_v6.0.pdf. Public Domain.
