Today, let's delve into the fascinating mysteries of **special relativity**! This theory, crafted by the genius of Albert Einstein, opens the doors to a universe where time itself becomes a** dynamic player**.

**Time dilation**, an effect of special relativity, explains that when a clock is moving at a certain velocity relative to a stationary frame of reference, it appears to **tick more slowly** compared to a clock in that stationary frame.

Imagine yourself taking a flight from Paris to New York. At first glance, it seems like a simple crossing of the ocean, but according to special relativity, it's much more than that. This theory teaches us that our experience of **time is intimately linked to our speed of movement**. The faster we travel, **the more time appears to stretch, slow down**, as if it's playing with us in space.

Take this concrete example: by taking a transatlantic flight, you become a participant in a temporal play. It's as if you enter a temporal bubble, where each second counts differently depending on your speed. Simply **flying at high speeds induces a subtle effect of time dilation**. When you land, your watch may seem to have ticked a bit more slowly than someone who stayed on the ground. Strange, isn't it?

Now, imagine a fighter pilot soaring through the skies at dazzling speeds. Upon returning to Earth, not only can they boast breathtaking aerial maneuvers, but they can also boast of having traveled through time in a minuscule way. According to special relativity, their **personal clock would have advanced less rapidly than that of a comrade who stayed on the ground**, leaving them literally younger at the time of landing.

Certainly, this phenomenon becomes notable at remarkable speeds, **exceeding 10% of the speed of light**, which is a little over 100 million km/h (well beyond the cruising speed of a commercial airliner!). It reminds us that the fabric of space-time is anything but static; instead, it is a dynamic canvas on which our movements create subtle patterns.

So, when you take your next transatlantic flight, remember that not only are you exploring new geographical horizons, but you are also **challenging the boundaries of time itself**. Special relativity reminds us that the universe is a place where every movement, every journey, is a dance with the spacetime continuum.

Again, this phenomenon is only observable at speeds currently unattainable by humans. Nonetheless, after a fighter jet flight, considering the fatigue experienced during it and the stress on your body, you will have aged more than if you had stayed on the ground ;)

Absolutely! This phenomenon of time distortion is **also linked to gravity**! Similar to the movie Interstellar, where time passes "more slowly" when subjected to intense gravity (near a black hole), this alteration of the temporal rhythm extends to general relativity as well. **Clocks close to a massive object, like a planet, tick more slowly compared to those farther away.**

In summary, both speed and proximity to massive objects influence how clocks measure time. Time will pass more slowly than if you were in open space, devoid of any gravity and velocity.

**To conclude, here are some explanations:**

In terms of calculations, we talk about proper time and measured time, each belonging to a different reference frame. For a fighter jet, the proper time denoted as *T*0 belongs to the moving reference frame, that is, within the jet. Let's assume a clock placed in the cockpit.

The measured time, denoted as *T*, belongs to another reference frame, let's assume a terrestrial reference frame: a person remaining on the ground to measure the duration of the flight.

Special relativity states that** ***T***>***T***0 because time "dilates."**

As mentioned earlier, the measured flight time in the jet will thus be less than that measured by the person remaining on the ground.

We denote the ratio between these two measures as:

T=*γ*⋅*T*0

where *γ*** is the Lorentz factor**.

This *γ* factor allows for the calculation of **time dilation** with:

Where *v* is the speed of our object (in this case, the airplane) and *c* is the speed of light (3.00×10^8 m/s3.00×10^8 m/s).

Let's put into practice what we have seen:

Let's assume that our airplane reaches 0.1*c* (10% of *c*) and that the flight lasts 1 hour.

We have: *T*=*γ*⋅*T*0

*T*=1.005037815⋅*T*0 rounded to 9 decimal places

So:

T0 = T/1,005037815

T0 = 1/1,005037815

T0 = 0,9949874371

Therefore, the measured flight time in the airplane is approximately 0.9949874371 hours, or around 3582 seconds.

However, an hour is equivalent to 3600 seconds. The pilot would have gained 18 seconds compared to the Earth!

Photo credit:

alachassebordel - Dassault Rafale (+edit pocket watch)

Wix Galery and Unsplash

## Comments