Why Travel? Because Science! A Scientific Case for Travel
So, I’ve been expounding the virtues of traveling for some time now; it gives you insight into other cultures, helps you to become conscious of others’ plights, and so on. These reasons are all elementary, by now, and it is easy for us to understand why even a small weekend getaway is beneficial.
However, I’ve been recently glued to physicists and astrophysicists, like Neil deGrasse Tyson and Brian Greene, and how could I not? Their energy and enthusiasm are quite palpable through any form of media I choose to catch them in.
Catching a quick intro lesson on relativity through Brian Greene’s World Science U, it slowly dawned on me that perhaps this relatively complicated idea (pun couldn’t be helped, sorry) of the warp in space and time caused by nearing the speed of light might also affect us travelers.
Relativity & Time Dilation
Let me explain as quickly – and as accurately, I hope – as possible the theory of relativity, specifically the “Special Theory of Relativity” and its sub-concept of time dilation. Special relativity posits that the laws of physics remain the same for two things traveling at the same speed and that the speed of light in a vacuum is also invariant for all observers. You may have heard of the anomalous nature of clocks in space: a clock orbiting on the International Space Station (ISS), say, perfectly functioning, would in mere months be some time behind the same, perfectly-functioning clock here on Earth (see Note 1 at bottom of page). This is because the faster one thing travels relative to another thing causes time to pass at different rates, more slowly for the faster-moving object; the ISS orbits around Earth at a speed of about 27,600 km/hour (17,150 mph), which is about 7.7 kilometers per second! This speed is enough to negate the opposite effect that gravity plays on time, but more on that some other time. This is time dilation, the way that time elapses differently in relation to motion.
So, how does this affect us travelers? Well, the way I understand the theory of relativity, the faster something moves in relation to Earth (let’s use our planet as a frame of reference), the slower time moves for the traveling item. This theory of relativity surmises that we can make things travel up to the speed of light, but no more; if one were to travel faster than the speed of light, they would be in a time that doesn’t exist yet, or perhaps start going back in time (this is quite trippy to think about) – I don’t know, ask Dr. Greene.
Anyway, so I was thinking, since time ticks ever “slower” for faster moving objects, flying in a plane must mean something, no? Well, let’s see.
The Lorentz Factor
There’s a formula called the Lorentz Factor (denoted by the symbol γ, Greek lowercase gamma), shown in the photo, that mathematically calculates the effect of speed on time. “V” is the velocity relative between inertial reference frames, and “C” is the speed of light traveling in a vacuum. To show you how exponentially speed affects time (and space), here are some pre-calculated figures obtaining the Lorentz factor from various speeds relative to “still” or us here on Earth, basically:
» At a speed of “0,” time equals a Lorentz factor of 1.000 (no change).
» At a speed of one-tenth of the speed of light (~30,000 km/sec), the Lorentz factor barely ticks up, to 1.005 (negligible amount).
» At a speed of nine-tenths the speed of light (~270,000 km/sec), things start to get interesting; the Lorentz factor is now 2.294.
» At a speed of 0.990 of the speed of light, the Lorentz factor is 7.089.
» At a speed of 0.999 of the speed of light, the Lorentz factor becomes a whopping 22.366!
What the hell does all that mean? The Lorentz factor number makes it easy. Take the last quote, for example. Going 0.999 the speed of light is essentially going about 299,700 km/second (185,814 mi/sec), a mere 300 km shy of the distance light would travel in the same time. And the Lorentz factor? That’s the multiple by which things would start to change: if we traveled at this speed, time would basically move about 1 year for us for every 22.366 years that passed back on Earth! That’s already insane to think about, but also our mass would increase by a factor of 22.366 while our size would “shrink” by the same factor – a 72.5 kg male (160 lbs) would now weigh 1621.5 kg (3578.5 lbs) and a 168 cm (5 ft 6 in) person would be about 7.5 cm (3 in) tall!!! (This is all correlative to what someone back on Earth would observe.)
So Why Travel? Some Scenarios to Consider
Naturally, we’re nowhere close to traveling at such a speed, and the speed in which we do travel falls far below even that “negligible” amount. Nonetheless, it is all still calculable! Let’s use some common scenarios for “us travelers,” disregarding the effect of gravity:
Scenario #1: Taking the Bus
Let’s take a cross-country bus into consideration. Say, on a highway, the bus coasts at around 100 km/h (62 mph). This gives us a Lorentz factor of 1.0000000000000044. At 1,000 hours (or 42 days) of bus travel at this speed, you stand a chance of gaining 0.00000001584 of a second. Not quite worth it.
Scenario #2: High-Speed Train
For this example, I’m gonna use Japan’s new maglev trains, which can go up to around 500 km/h (310 mph). This gives us a Lorentz factor of 1.000000000000107. At 1,000 hours (42 days, or two segments with Paul Theroux) of train travel at this speed, you stand a chance of gaining 0.000000385 of a second. Now we’re getting somewhere; in case you didn’t notice, that’s one whole “zero” less than the last!
Scenario #3: Flying On A Typical Airplane
A typical international flight travels at about 885 km/h (550 mph) at cruising altitude. Calculating that into the Lorentz formula, if becomes a Lorentz factor of 1.0000000000003364. At 1,000 hours (or 42 days) of train travel at this speed, you can gain an entire 0.00000121 of a second!
Scenario #4: Cruising Aboard the International Space Station
Let’s say we’re able to travel to the International Space Station. As with all the other examples, disregarding the effect of gravity, we’d be traveling at the aforementioned 27,600 km/hour (17,150 mph), which gives us a Lorentz factor of 1.0000000003270015. Let’s also stay up there for a year this time, which gives us a very palpable 0.0103123 of a second! Nine and a half years up there and we’d have essentially earned ourselves another second of life, and all we’d have to do is give up our earthly creature comforts for a decade, which are overrated, anyway.
One thousand hours seems like a lot, but think of how many thousands of hours you’ll travel within your entire life. These infinitesimally small amounts are just one more (also infinitesimal) reason to get out there and travel the world. So go out there; travel!
What will you do with all this extra free time? ;)
Note 1: Thanks to my friend and colleague, Illya Nayshevsky, for his assistance in making sure these ridiculous numbers were accurate. Illya is just about the smartest person I know, so I assure you that any faults or inaccuracies in this article are my own.
Note 2: Atomic clocks are used to track time in this case, they use spin of nuclei or radioactive decay to measure the time because that is stable (although nuclear spin could be affected by earth’s magnetic field). Also this time difference plays a big role in GPS, since it heavily relies on time it takes for radio signal to travel from satellites to GPS receiver on the ground. – Illya