« Back to jordanbalagot.com
A Quick Note on Time Travel and Universal Coordinates

Posted on Wednesday 31 March 2010

Edit: This comic posted from Max below shows the same idea:

Science Fiction constantly imagines scenarios where a character time-travels on earth using a time machine. In most cases, the concept seems simple–a character uses a time machine and ends up in the same place on earth at a different time. The difficulty of time travel aside, how difficult would it be to end up at the same location on earth at a different time? And I’m even ignoring geological changes to the earth’s surface.
Let’s say you have a 3D coordinate system for the entire universe, and have compensated for universal expansion. At a given moment, you are on the surface of earth at a specific coordinate. But the earth is rotating every 24 hours. Its axis wobbles. It orbits the sun once a year. The sun is orbiting the center of the milky way galaxy. And our galaxy is hurtling through space at 630 km per second. Because of this, the earth travels 51.84 million km per day. (And we’re worried about an asteroid hitting *us*?)
Just by staying completely still on the surface of earth, you are traveling in a squiggly, rotating, wobbling, looping, swirling path hurtling through space generally pointed away from the center of the universe at a tremendous speed. Just once I would like to see a character finally invent a time machine, use it to go back just an hour, and end up thousands of miles from earth in space because they didn’t bother to compensate for that. As for people who accidentally time travel or cannot control the amount of time they travel…God help ’em.

3 Comments for 'A Quick Note on Time Travel and Universal Coordinates'

    Max F. Exter
    May 1, 2010 | 11:42 am

    So, what you’re wanting to see is this?


    I actually found your post while looking for some general information as to the “direction” that the earth and solar system are moving in, just to have a smarmy argument to throw at somebody the next time they talked about traveling back in time by some sort of small increment of time. I mean, the answer can vary for one second. Do they end up in the Earth’s mantel? Space? I suppose it would depend on the time of year and where you are on the planet. And even then, if you wanted to appear on land (as opposed to the ocean or above/below ground) there are probably only a small number of place on the planet where it would be feasible, mostly on the equator. This, of course, assumes that the equator lines up reasonably nicely with the direction that the milky way is traveling in. (And ignore other things we don’t know, like whether or not we are affected by the so-called “dark flow” or gravitational tug from an object / source of gravity outside of the known universe).

    Fourth descent into ADD indeed.

    May 1, 2010 | 11:09 pm

    Max: Yes!! That’s awesome. Where did that comic come from?

    May 8, 2010 | 5:38 pm

    Here’s another comic with the same idea.

Leave a comment



Information for comment users
Line and paragraph breaks are implemented automatically. Your e-mail address is never displayed. Please consider what you're posting.

Use the buttons below to customise your comment.

RSS feed for comments on this post | TrackBack URI