As Time Goes By

So you’ve decided to visit the grandchildren. They won’t be born for 50 years, but you’ve borrowed a DeLorean from the scientist next door, and you’re armed with enough Plutonium to get you to 2062 and back, with enough leftover to make your own low-grade, dirty bomb.

But is travelling to the future even possible?  Willie Nelson does it all the time on his tour bus, but what about the rest of us? Can we really travel into the future?

The majority of physicists say it’s possible. In fact, it’s going on right now.

The GPS satellites that are orbiting the Earth are actually travelling in the future!

Because of time dilation, each day, the GPS satellites are actually 38,640 nanoseconds ahead of the clocks on Earth. While this sounds like a very small amount, at the end of the day, it’s enough to alter the GPS accuracy by almost 2 miles! Imagine having to vomit on a city street at 2 AM because Siri can’t find you a Taco Bell parking lot.

So why are the GPS satellites travelling through time? According to Einstein, there are two reasons for this odd behavior, and surprisingly, neither involves bacon.

Einstein’s theory of general relativity tells us that a clock close to a strong source of gravity, like the Earth, will run slower than a clock further from the Earth. So the clocks on Earth actually tick more slowly than the clocks on the GPS satellites which are orbiting 2.5 miles above the Earth and its gravitational field.

At the same time, Einstein’s special theory of relativity states that the faster an object moves in relation to another object, the slower it experiences time. On Earth, we spin around at 1,000 miles per hour, while the GPS satellites are whipping through space at 9,000 miles per hour -which causes their internal clocks to run slower than the clocks on the Earth.

The net effect of both interactions on the GPS clocks is that they are actually AHEAD of our clocks on Earth. Scientists use complex formulas and lots of bacon to continuously compensate for the time disparity. Without this compensation, much of our technology and communication would be useless. But thanks to modern physics, Google Earth can continue to look through your bathroom window from space.

Great Scott!

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