Your time-traveling adventures have caused a few issues with the space-time continuum. For instance, your old high school bully, Riff, is now ruling the future with an iron fist. You and the professor have driven your hovering DeLorean back to the past to undo your own meddling. However, shortly after you fix your mistakes, another DeLorean appears and crashes into yours. Out step older versions of you and the professor, who apparently had the same idea from somewhere else in the timeline.
The professors panic and explain that the universe could collapse now that you’re both in the same time and place. The only hope is to merge the time streams by having each version of you simultaneously time travel home. You both have plenty of fuel, but the crash broke your chrono-stabilizing gyroscopes and your cars can only time travel under very specific circumstances.
Each of you will need to drive a mile south, then a mile east, and then a mile north to get the gyroscopes into temporal alignment. That would be easy, except each calibration requires placing a portable time gate at your starting point and then driving into it at the precise end of your three-mile drive without it moving. Not only that but your two time gates must be placed at least 100 miles apart so their signals don’t interfere.
In other words, you need to find two different locations where you can drive a mile south, a mile east, and then a mile north and end up exactly where you started. The professors are about to show you where you can do this when they vanish, becoming victims of the collapsing timeline. It’s up to you now: where can you place the time gates?
If the earth were flat, there would be no way to solve this riddle. What you need is some way to use the sphericalness of the planet, some of its notable features, and the fact that lines of latitude aren’t really lines— they’re circles. The equator is the biggest of these circles, but it doesn’t do much for you, and you can’t even go south from the South Pole.
But let’s try the North Pole. When you go a mile south, you’ll be on a circle that runs east-west. After a mile east, you’re still on that same circle, so the final mile north brings you back to your starting point. Perfect. That’s one gate down, but where should you place the second?
Well, the nice thing about circles is that if you travel on them far enough, you come back to where you started. If there were a circle that had a circumference of one mile, that would work marvelously. You could drive south a mile to reach it, make the one-mile rotation east, and then go north a mile to return to where you started. Such a circle does exist just north of the South Pole.
To find your starting point, you can use the standard formula for the circumference of a circle. If you wanted to be absolutely precise, you could use an equation that takes into account the roughly spherical shape of the Earth. But an area this small is so close to being flat that the standard formula gives a solution within a fraction of an inch of the actual distance. A circle with a one-mile circumference has a radius of just under 0.16 miles, so any point on the circle one mile north of that will be suitable for your time gate.
In fact, there are other answers too: start a little further south, and you could travel east around the Earth twice, three times, or more! In theory, there are infinite possible starting points, but the circles get so tight that they aren’t actually practical to drive.
Everything’s getting a little weird by the time you reach your starting points. You drop the time gates, sync up with your doppelgänger, and slam down the pedal. You both reach 88mph just as you complete your three-mile circuits, merge the timelines, and save the universe.
Using a world map, plot the journey described in the article. Start at the North Pole and draw the path of traveling one mile south, one mile east, and one mile north. Then, find another starting point near the South Pole and repeat the process. Discuss how the spherical shape of the Earth affects these paths.
Design a simple board game or computer simulation where players must navigate a grid to simulate the time travel journey. Include obstacles and challenges that mimic the issues faced in the article, such as avoiding interference between time gates.
Calculate the exact starting points for the time gates using the formula for the circumference of a circle. Work through the math to understand how a circle with a one-mile circumference has a radius of just under 0.16 miles. Discuss how this calculation helps in placing the time gates.
Write a short story or comic strip that continues the adventure from the article. Imagine what happens next after the timelines are merged. Include elements of time travel, problem-solving, and the consequences of altering the past.
Hold a class debate on the potential paradoxes and ethical dilemmas of time travel. Discuss scenarios such as meeting your past self, changing historical events, and the implications of multiple timelines. Use examples from the article to support your arguments.
time travel – the concept or action of moving between different points in time – “In the movie, the protagonist invents a machine that allows for time travel.”
space-time continuum – a mathematical model that combines space and time into a single interwoven continuum – “According to Einstein’s theory of relativity, gravity is caused by the curvature of the space-time continuum.”
universe collapse – the hypothetical event in which the universe undergoes a complete and irreversible collapse – “Scientists are still uncertain about the fate of the universe and whether it will eventually experience a collapse.”
temporal alignment – the synchronization or arrangement of events or objects in relation to time – “The archaeologists used the alignment of ancient artifacts to determine the chronological order of the historical site.”
time gate placement – the strategic positioning or installation of a portal or device used for time travel – “The scientists carefully considered the optimal time gate placement to ensure safe passage through different eras.”
solution – a means of solving a problem or resolving a difficult situation – “After hours of brainstorming, they finally came up with a creative solution to the complex puzzle.”
second gate placement – the selection and positioning of a secondary time gate for additional access points – “To enhance their time travel capabilities, the team decided on a second gate placement in a remote location.”
calculating the starting point – determining the exact moment or time period from which the time travel journey will commence – “The scientists meticulously analyzed historical records to assist in calculating the starting point for their expedition.”
other possible starting points – alternative moments or time periods that could serve as the initial point for a time travel journey – “During their research, they discovered several other possible starting points that could provide unique experiences.”
time travel success – the achievement of a desired outcome or result in a time travel endeavor – “After numerous failed attempts, they finally celebrated their time travel success when they arrived at their intended destination.”
