Not everything published on Jumpseatnews should revolve around trip trading, flight schedules, AFA, United, service flow, etc...etc...etc...  This section was designed for a little mind expansion and a little break from the normal routine of United Airlines.  It's a big, strange world out there, and high time that this website dives into something completely different.

For now, let's start at the beginning...

Guess what?  Time slows down while you're onboard an aircraft.

No, I don't mean your perception of time (like wondering when that boring when-the-hell-will-this-ever-end overnight flight to Newark finishes!), but the very nature of time itself?  Do you know that your body gets more massive as you fly faster?  So does your car while you are driving.  And so does a a dinner roll thrown at you by a Premier Executive.

We are going to discuss Einstein's Theory of Special Relativity and how time, space, and distance are affected by objects in motion.  If the subject of physics and Relativity seem daunting, don't worry---like everything else here at Jumpseatnews, we'll take it one concept at a time.  If you get too lost, go visit Better PA Announcements or something like that for lighter fare.

Please prepare now to have your mind blown wide open. I'm not kidding. The discoveries discussed in this article have forever changed the view of time and space. By the time you're finished reading, you will have a good knowledge of one of the greatest discoveries of reality.  You will never look at space or time quite the same way again.

A Little Background

During the mid-1800s, there were a series of scientific experiments conducted on what is referred to as the electromagnetic field.  If you have ever rubbed your feet on a carpet and then touched something metal, you've already experienced the electromagnetic field firsthand. Scientists at the time had concluded that these electromagnetic waves travel at a fixed and never-changing speed. Since light (as from, say, a light bulb) is also an electromagnetic wave, the scientists concluded that light travels at a fixed speed.

When we say that light travels at a fixed speed, we mean a very fast one.  The speed of light is 186,000 miles per second, or about 670 million miles per hour.  It's so fast that it's beyond our comprehension.  Yet, countless experiments prove that light does indeed travel at this exact speed and it does so at a fixed rate; it never goes any slower or faster, ever.  If you aim a flashlight at the wall and then turn it on, the beam of light will travel from the flashlight to the wall at exactly 186,000 miles per second.

Why is this so important?  You'll see in a few minutes.

The Premier Exec and the Dinner Roll

Around 1905, a young Albert Einstein (you may know the name) was very disturbed by this discovery of the never changing speed of light.  This is because it flies in the face of Classical Newtonian Physics.  Here's why: Suppose that on your flight to Chicago a Premier Exec in First Class is upset because he didn't get his first meal choice.  He's so angry that he picks up his dinner roll and throws it toward you.  Classical Newtonian Physics (the beliefs held in place for hundreds of years before Einstein) would dictate that in order to slow the roll down and avoid getting hit by it, you would have to run away (in the opposite direction) from the roll.

The speed of light is 186,000 miles per second, or about 670 million miles per hour.  It's so fast that it's beyond our comprehension. 

Thus, if the roll is traveling through the air toward you at 10 miles per hour and you turned and ran away from it at 12 miles per hour (now being chased by the roll), you could easily outrun it.  Even if you ran away at 8 miles per hour, the speed of the roll approaching you would appear to slow down (since you are moving faster away from it) and now the roll would only be approaching you at 2 miles per hour (10 miles per hour - 8 miles per hour = 2 miles per hour).  The roll in this case would eventually bonk your backside at a mere 2 miles per hour.

Ever play Frisbee?  If someone throws a Frisbee at you that is going to fly too high above your head, you would automatically turn around and run after it, hoping to 'catch up' to it before it hits the ground.  Again, this instinct is classical Newtonian Physics and is firmly rooted in our logical view of the world.

What bothered Einstein, however, was the following dilemma: What would happen if you chase after a light beam and try to 'catch up' to it?  Remember we mentioned before that the speed of light is exactly 186,000 miles per second, no more and no less.  Let's go back to our previous example: Suppose if instead of a dinner roll, the Premier Exec aims a flashlight at you and switches it on.  If you turn and run the other direction at say, 200,000 miles per second, would you then be able to outrun the light beam?  Suppose you travel at 186,000 miles per second exactly.  Wouldn't you then be traveling at exactly the same speed at the flashlight beam and therefore the light wave would appear stationary to your point of view?

The answer to both questions is no.  Experiment after experiment has confirmed that this is not true---you can never catch up to a beam of light.  The fact of the matter is that if someone aims a flashlight at you and turns it on, you're going to get hit by the light. If you turn and try to run away from it, you'll be in for big surprise: the light will still be approaching you at 186,000 miles per second no matter how fast you run away from it.  Your attempt to run faster than the light beam in order to get away from it makes absolutely no difference in the speed with which the beam approaches you.  The same is true if you try and run toward it, as the light won't approach you any faster.  Unlike the dinner roll example described above, running away or toward a light beam doesn't change the speed in which it retreats or approaches you.  This goes completely against our common sense.  Movie stuntmen, for example, have long known that to jump on to a moving train, you need to be going the same rate of speed as the moving train.  If you and the train are traveling at exactly the same speed in the same direction, the train will not be moving from your perspective, and you can easily jump on to it.  However, from the movie camera's (and thus the audience's) perspective, it looks like the film character is daring to jump on to a train moving at a high rate of speed.

To say that this light beam paradox puzzled and bothered scientists at the time is an understatement.  It disturbed them because it tore everyone's view of the physical nature of the world into shreds.  But it's a true and scientific fact that gave rise to a new perception of reality.  So to quickly review:

1. The speed of light is 186,000 miles per second.
2. The speed of light never, ever slows down or speeds up---it remains constant.
3. No matter how fast you travel toward or away from a beam of light, the speed of the light still retreats from or approaches toward you at 186,000 miles per second.

Einstein's Theory of Special Relativity

Einstein wrote his Theory of Special Relativity to explain what was going on with all of this.  The most important thing to remember about Einstein's Theory of Special Relativity is that perceptions of space and time are relative to the observer.  Here's an example: you and some friends are backpacking throughout Europe.  You happen to be in Germany during Oktoberfest and consume mass quantities of beer well into the evening.  You then walk straight from the beer garden to the train station where you board the early morning train to Prague.  Fatigue and a nasty hangover catches up with you and you soon fall asleep in the train car while still parked at the station.

When you wake up, you open your eyes and look out the window.  Another train is right next to yours and starts moving.  Or is it yours?  Because of your tired state, for a brief second you don't know which train is moving, yours or theirs.  You then feel a jolting and realize it's your train.

Have you ever been up in the cockpit and happened to see an airplane flying below or above yours in the opposite direction?  You watch it steak across the sky past you, but it's an eerie feeling because you really have no way to tell that it's moving at all.  It could be stationary and you are simply rushing by it.  Or you are stationary and it's rushing past you.  The people sitting in the cockpit on that plane would experience the same observation.

So far I've been discussing observations---dinner rolls, trains, planes flying past…etc…  Those objects all move differently relative to the person doing the observing.  However, we're going to move past observing and now discuss measuring.  What happens when you try and measure the physical events happening (relative to the person doing the observing) like the passage of time?

Relativity dictates that there is no such thing as an 'absolute' constant-velocity motion.  You cannot determine anything about your state of motion unless you make a direct or indirect comparison with 'outside' objects.  If you are sitting on an airplane and happen to glance out the window to see houses and roads moving below, you could reasonably determine that your plane is in motion.  However, if you had the window shades all pulled down and felt no turbulence, it would be much more difficult to know if you were in fact moving at all.  You would have to resort to other clues like engine noise or hearing the captain say, "Folks, we're leveling off at 35,000 feet."

Consider this: if you sit in your jumpseat and look down the length of the cabin, you would see seats, passengers, carpeting, overhead bins, etc…  Those items would appear to be stationary from your point of view, with the exception of the few passengers moving about the cabin while the seat belt sign is on!  However, to a person standing on the ground looking up at your plane with a telescope, he/she would see all those items moving by very quickly.  Likewise, if you looked down from the plane at that same person on the ground you would see that they are also moving by very quickly.

Einstein proposed in his Theory of Special Relativity that the laws of physics must be absolutely identical for all observers undergoing constant-velocity motion.  Constant-velocity motion is just that: motion at an unchanging rate of speed.  However observers in relative motion will not agree on events happening at the same time.  As I mentioned before, not agreeing on speed is one thing, but wait until you see what happens when they cannot agree on time itself...

Feeling adventurous? Continue to Part II...

Part II

Blowing Up FLT-LINE

Before we dive deeper into Special Relativity, we're going to discuss an example that will illustrate why this discovery was so groundbreaking.  Imagine that next year, United Airlines decides to do away with FLT-LINE and get a decent telephone system for their flight attendants.  When they make this announcement to the flight attendant population, they get such an overwhelming positive response that the management at WHQ decides to make a huge event out of it.

The WHQ management team decides that they will choose the flight attendant with the best sick leave record and allow him or her to press a button that will blow up (in a giant spectacle of fireworks) the FLT-LINE computer system.  The only problem is that there are two flight attendants that have exactly the same exceptional sick leave record.  Therefore, the WHQ management team decides to allow both flight attendants to blow up the FLT-LINE computer at exactly the same instant.

To make the ceremony completely fair, they seat both flight attendants at opposite ends of a long table.  In front of each flight attendant is a button that, when pressed, will instantly destruct the FLT-LINE computer.  A light bulb is placed on the table exactly in the middle, halfway between the two flight attendants.

The two flight attendants are then each given simple instructions: "As soon as you see the light, press the button in front of you.  Whichever one of you sees the light first will be the first to press your button, thus getting the honor of doing away with FLT-LINE. " (NOTE: For this example, we'll assume that both flight attendants have the same fast reflexes and that the buttons work properly) The light is then switched on and both flight attendants press the buttons at exactly the same time to blow up FLT-LINE.  Boom!  A cheer is heard from the crowd watching the ceremony and a new era of telephone professionalism is ushered in amongst fireworks, food and good wine.

Now…………let's take this same example and put it onboard a train traveling at a constant velocity past a crowd of spectators who can see the ceremony as the train rushes past.

Again, you have both flight attendants seated at the table, however one of them (Mary Mainliner) is facing forward toward the direction the train is traveling, and the other flight attendant (Joe Steward) is facing backward away from the direction the train is traveling.

Again the light bulb is switched on, both the flight attendants see the light at exactly the same instant, and both press their buttons to blow up FLT-LINE at exactly the same time---just like in the previous example.  All is well…according to those observers inside the train, that is.

However, the crowd outside the train begins to chant, "Not fair! Not fair! Not fair!"  When questioned why they are so upset, they reply that Mary Mainliner pressed her button before Joe Steward and blew up FLT-LINE first.  "That's impossible!" shouts Mary Mainliner back at them.  "We both pressed the button at the same time!"  Everyone, absolutely everyone, who was inside the train agrees with Mary that both buttons were pressed at exactly the same time.  However, everyone outside the train still continues to chant, "Not fair!" as they all firmly believe Mary went first.  Soon a large meeting is held to discuss the problem.  A WHQ task team is created at considerable budget to figure out what's going on.

Just then, one of the spectators who had observed the button pressing ceremony from outside the train comes forward with a film he'd taken of the train at the moment of the button pressing.  Everyone plays the film back and sure enough, the film clearly shows that Mary Mainliner pressed the button first.  All the people who were actually on the train at the time, including Mary herself, simply cannot believe their eyes as they watch the film.

How can this be possible?  Remember that the speed of light is a constant 186,000 miles per hour.  Since the pressing of the buttons depended on who saw the light first, and since the light bulb was placed exactly in the middle of the two flight attendants, the both of them (and everyone else inside the train compartment) would have seen the light on both sides of the table at exactly the same time.  The light would have traveled at exactly the same distance at exactly the same rate of speed to reach them.

So who really blew up FLT-LINE?  Whose observation is correct? The answer is that they both are correct.

Now picture yourself standing outside the train and observing the ceremony as it's rushing past.  The light is switched on and instantaneously travels at exactly 186,000 miles per second to opposite ends of the table.  However, since Mary was sitting facing forward in the same direction that the train was traveling, she was observed by the crowd outside to have moved forward toward the light beam.  The light beam therefore had less distance to travel before it reached her.  The opposite situation occurred for Joe Steward.  He was facing backward (with his back to the front of the train) and moving away as the light beam approached.  Therefore, the light had more distance to travel before it reached him.  Keep in mind that the light beam still traveled at 186,000 miles per hour---that never changed.  Rather, the light beam had a shorter distance to travel (and thus got to Mary first) according to the observers standing outside the train.

So who really blew up FLT-LINE?  Whose observation is correct?  Is it the people that were inside the moving train watching the ceremony or the people that were standing outside watching the ceremony?  The answer is that they both are correct.  As nutty as this may seem, the only conclusion that can be drawn is that according to the people inside the train, the flight attendants blew up FLT-LINE at exactly the same time; while according to the people outside the train, Mary blew up FLT-LINE first.

This is no joke.  These disturbing discoveries by Einstein into the nature of light completely changed how we view our perception of space, and as you'll see in the next section, the vary nature of time itself.  Events that happen simultaneously for one group of observers will not happen to another group of observers if the two groups are in relative motion.

The Passage of Time

Einstein also discovered that time will pass more slowly for an individual in motion than for an individual at rest.  Experiments with light clocks (photon-emitting clocks that measure time based on the number of round trips a light photon makes during a measured time period) in motion prove this discovery beyond all doubt.  The same holds true for normal clocks as well; time does indeed slow down as you speed up.

Suppose you synchronize your wristwatch with your friend and then work a flight to Sydney while your friend stays behind on the ground in San Francisco.  During your flight, all time as you experience it will slow down for you (and also for everyone else and everything onboard the aircraft).  You won't notice this as everything will appear normal in your perspective.  Once you arrive in Sydney, you then check your watch against your friend's.  Guess what?  Your watch will be a billionth of a billionth of a second behind your friend's watch.  This isn't because your wristwatch it got banged around in the galley or that the disinsection spraying gummed up your watch gears.  It's running slow because time actually slowed down for you.

The example illustrated above is a scientific fact, proven many times in laboratory experiments.  Keep in mind however that the differences in the passage of time are very, very small.  The human perception cannot possibility notice it.  This is because the current speed a 747-400 can achieve is nowhere near the speed of light, and thus the difference in time goes unnoticed by our senses.  But it's there all the same.  If a 747 could fly at close to the speed of light, you would notice your wristwatch would fall hours, days, perhaps even years behind that your friend's---all depending on how long you were traveling at this rate of speed.

Does this mean, then, that if you spend your entire career working onboard airplanes you would live longer than comparable people on the ground?  Would your aging process actually slow down as well?  The answer is yes.  Assuming the airline food, nasty passengers, germs, cosmic radiation, turbulence, and labor woes didn't shorten your life---then yes, you would indeed live longer as time would be moving much slower for you.  Of course, we're talking a fraction of a fraction of a fraction of a second, but longer nevertheless.

The answer is yes.  Assuming the airline food, nasty passengers, germs, cosmic radiation, turbulence, and labor woes didn't shorten your life---then yes, you would indeed live longer as time would be moving much slower for you.

Einstein thus made it clear that each observer has his or her own 'time'.  Identical clocks carried by different observers would not necessarily agree depending on the observers state of motion.  It's easier if you think of this in terms of distance, location, and time.  Suppose the crew desk makes the following PA announcement through the O'Hare airport, "Flight Attendant Lee please report to gate B6 at 2:00 pm"  You can calculate distance, speed, and time to figure out if Lee will get a DNF or not: if F/A Lee is standing at gate C20, the local time is currently 1:00 pm, and the distance through the terminal between gate C20 and B6 is six miles, than in order to make the assignment Lee must travel at least 6 miles per hour.

Suppose you change the location Lee is standing by assuming that he is standing at gate B7.  You would then calculate that the shorter distance he'd have to travel would change the amount of time necessary to get there, given that Lee travels at the same rate of speed.  Or suppose Lee had a fractured leg and could only walk at 3 miles per hour---you would then calculate that the slower travel speed would therefore alter the length of time necessary to get to the plane, given the same 2:00 pm deadline.

You can see how time, distance, and speed are used to measure and calculate an observer's perception of reality.  However, since the speed of light is shown to never change, regardless of who is doing the measuring, you must therefore conclude that Special Relativity does away with the concept of absolute time.  Time must change, i.e., slow down, the more you increase your velocity.  And time is relative to the observer.

The Price You Pay

It sounds pretty good doesn't it?  If you travel at a faster rate of speed, time will slow down, and you can get more stuff done than the slower-moving people on Earth, right?  Wrong.  Everything slows down...as it is time itself that's being affected.  It works like this: suppose you and Mary Mainliner can both take meal orders for an entire First Class cabin in 10 minutes.  Suppose that Mary's plane is parked at the gate while your plane is traveling at near the speed of light.  Time for you (and everyone else in your cabin) will slow down, including the time it takes to go through the motions of taking the meal orders.  From your perspective on the plane, it takes the normal 10 minutes to complete the meal orders.  But if Mary were to watch you from the ground, she would have great-grandchildren in high school before you would even have gotten out of your jumpseat.  You would appear in incredible slow motion to her.  For your perspective, everything is normal and fine and the meal orders only took 10 minutes. 

By the time you finish your meal orders (taking only 10 minutes for you), years will have passed on the ground and Mary will be long dead, having completed the meal orders decades ago. 

So the price you pay is that you don't get any 'more' stuff accomplished within your lifetime traveling near the speed of light, than would a comparable person at rest.  I sometimes think about this when I see a iPhone-texting idiot honking and racing his car all over the road in a never-ending hurry.

The Effect of Motion on Space

Time isn't the only nature of reality that is affected by motion.  Motion affects space also.  The faster you travel, the more you will be observed as shortened along the direction of your motion.  If a 747-400 could fly from LAX to SYD at near light speed, the plane would appear to be several feet shorter to someone observing it from the ground.

Einstein proposed that concept of time as being another dimension in the universe that is part of space.  Far from being a Twilight Zone episode, the idea of sharing space-time is the exact reason why it's impossible to travel faster than the speed of light.

Think about it this way.  When you check into a layover hotel, sometimes the captain (if he/she's a really nice one) will say, "Let's all meet here in the lobby near the elevator at 5:00 pm tonight for dinner."  You now have a 3-dimensional location: lobby (ground level) near elevator.  You also have a time dimension: 5:00 pm.  So 'lobby near elevator at 5:00 pm' gives you the four dimensions necessary to meet up for dinner.

Einstein did a lot of thinking about space-time.  He concluded with something very incredible: All objects in the universe are always traveling through space-time at a fixed speed which is the speed of light (186,000 miles per second).  So if someone is sitting still still next to you, all of their motion is being used to move through the time dimension.  In other words, all objects that are at rest (motionless) relative to you will move through time (and thus age) at exactly the same rate of speed.

The minute an object starts to move, it starts to divert some of its motion through time over to motion through space.  It now has less motion left over to travel through time with, and will thus move more slowly through the time dimension.  So a 747-400 going from LAX-SYD at near the speed of light will have very little motion left over for passage through time.  All of its motion is being used up on passage through space.  Time onboard that flight will pass very, very slowly from the observation of an individual motionless on the ground (for whom almost all of his motion is being used to move through time).

Einstein also demonstrated that the faster an object moves, the more energy and mass it will obtain.  As an object approaches the speed of light (186,000 miles per second), it continues to divert more and more of its motion into velocity (and thus mass) and less and less through time.  This will also have the effect on increasing the object's mass.  Since it requires more and more energy to 'push' that mass forward, you cannot have your cake and eat it too.  In other words, an object will forever get more massive into infinity as it approaches near light speed.  This would require an infinite amount of energy to move beyond 186,000 miles per second, and is therefore impossible.

Conclusion

This is very complicated stuff and I've only touched upon a few highlights.  The single most important thing you can remember about Special Relativity is that all events are relative to the observer, including time itself.  The old belief of time as a fixed concept that tick-tock-tick-tocks the same for everyone doesn't exist.  To notice the effects of motion on space and time you would have to be traveling at close to the speed of light.  In our normal everyday experiences of walking, driving, flying, etc… we will never ever notice these effects.  But they are there nevertheless.

So the next time you're on a flight, consider that from the perspective of those on Earth, you are moving slower and increasing your mass!  Distance is relative, size is relative, and you should now know that time is also relative.  It all, as they say, depends on your point of view.

Further Reading

If you are interested in this subject and wish further reading, I would recommend two references that expand on the subject further:

1. The Elegant Universe by Brian Green, W.W. Norton & Company, Inc., 1999 - this is an excellent piece of work that attempts to tie together Relativity with Quantum Mechanics into one theory.  Green's example of the moving train and the light bulb was so well thought out that we used it here for one of our examples.
2. A Brief History of Time by Stephen Hawking, Bantam Books, 1988 - an enormously successful guide into many of the principles of physics and the nature of reality.