What does NASA say about time travel?

Time Travel: Fact, Fiction, and the GPS in Your Pocket – According to NASA

The allure of time travel, fueled by countless books, movies, and TV shows, continues to captivate the human imagination. From H.G. Wells’ “The Time Machine” to modern-day blockbusters, the idea of hurtling through the centuries, whether to witness historical events or alter the course of the future, holds a powerful grip on our collective consciousness. But what does NASA, the scientific vanguard of space exploration, have to say about this tantalizing concept?

The short answer, according to NASA, is that a time machine capable of transporting us centuries forward or backward remains firmly rooted in the realm of science fiction. Sadly, despite our yearning to visit the dinosaurs or peek into the 31st century, constructing a device to achieve this is currently beyond our reach.

However, that’s not the whole story. While NASA considers time travel as depicted in popular culture to be purely speculative, they also emphasize that the mathematical principles underpinning the theoretical possibility of time travel have very real and practical applications in our everyday lives.

This might seem counterintuitive. How can something so seemingly fantastical be connected to our daily routines? The key lies in Einstein’s theory of relativity, particularly the concepts of special and general relativity.

Relativity and the Subtle Dance of Time:

Einstein’s theories revolutionized our understanding of space and time, demonstrating that time isn’t absolute but is relative to the observer’s motion and the gravitational field they experience. This means that time can, in theory, be affected.

• Special Relativity: Imagine a spacecraft traveling at a significant fraction of the speed of light. According to special relativity, time would pass slower for the astronauts on board compared to someone on Earth. This phenomenon, known as time dilation, is not just theoretical; it’s been experimentally verified with atomic clocks flown on high-speed aircraft.
• General Relativity: Similarly, gravity can also warp time. The stronger the gravitational field, the slower time passes. A clock at sea level, closer to the Earth’s center and experiencing a stronger gravitational pull, will tick slightly slower than a clock on top of a mountain.

From Theoretical Physics to Your GPS:

These mind-bending concepts might seem far removed from everyday life, but they are absolutely crucial for technologies we take for granted, most notably the Global Positioning System (GPS).

GPS satellites orbit the Earth at a high altitude, experiencing both a weaker gravitational field and traveling at a considerable speed relative to observers on the ground. Consequently, time passes slightly faster for the atomic clocks on board these satellites compared to clocks on Earth.

If engineers didn’t account for these relativistic effects – both from special and general relativity – the GPS system would quickly become inaccurate, drifting by several kilometers per day! This correction, based on the same principles that underpin theoretical discussions about time travel, ensures that your GPS can accurately pinpoint your location.

So, while a “Back to the Future” DeLorean remains a dream, the science underpinning the theoretical possibility of time travel is actively shaping the technology that guides us, helping us navigate the present with unprecedented precision. NASA’s perspective reminds us that even the most far-fetched scientific concepts can have profound and practical implications for our lives.

In conclusion, NASA’s stance on time travel is nuanced. They acknowledge the current impossibility of building a time machine for macroscopic journeys, but they also highlight the crucial role that the very same theories allowing for the consideration of time travel play in vital technologies like GPS. It’s a fascinating example of how theoretical physics, even in its most fantastical forms, can have a tangible impact on the world around us.