6.25.2012

On international travel

Friends,

Whenever I'm going to have an especially long absence from this site, I like to let you know about it.  The warning might save you a few seconds of visiting a non-updated Tangent Space(s), and at any rate it makes me feel like you might miss my blogging, and that thusly this whole enterprise is a valuable use of my time.

My raging neediness aside, it's time for one of those warnings.  I will not be updating this site until, say, mid-August.  You're probably wondering what could possibly tear me away from my beloved blog for so long, and you're right to wonder that.  It would take a lot.

Well, I will be spending the next 6 weeks in Melbourne, Australia!

I (and the team going with me) will be keeping a blog specifically to give updates about our mission trip-- stories, photos, prayer requests, etc.  Feel free to check that regularly if you want to hear about my ministry experiences and lessons learned in the land down under.

I thought I would leave you with one final (mini-)tangent.  And the tangent that's been on my mind lately, of course, is international travel.



The Best and Worst of Going Overseas
For general air travel woes, here's an old post on the subject


The Worst

1. Jet lag
I'm not necessarily a seasoned world traveler, but this ain't my first rodeo (somehow I need you to puzzle out that rodeo = flight across the Pacific).  If you've never been jet lagged, basically it's as terrifying as you'd expect-- your internal clock just being totally wrong.  Like, 12 hours wrong.  There's nothing fun about that.

2. Missing your checked bags
Flying domestically with one or more layovers, your checked bags have an okay chance of arriving when you do at your final destination (by no means 100%, but okay).  Going international, well... you're not getting that luggage when you get there.  Just accept it.  I hope you can fit 2-3 days of survival items in your carry-on.  You're going to need it.

The Best

1. The beauty of other cultures
It's so easy to think of America as the world.  I mean, I know there are other countries out there, but in the back of my mind, they function like Alaska or Hawaii.  Just more distant extensions of what I know.  Going to those countries helps to shatter this false picture of our world.  The mystery, unfamiliarity, strangeness (and yet relatability) of other cultures are fascinating.

2. A better understanding of humankind
Once you're in another place, meeting people and learning about their lives, it's so much easier to understand what things are universal to people everywhere and what things are specific to specific cultures.  Sure, we might learn in a classroom that America is "individualistic" while Mexico is "collectivistic", but what does that look like?  In what ways does a Mexican family function differently from an American one?  What would still look the same?


This isn't goodbye, it's... yeah, it's goodbye
But just for a month or two

Have you traveled overseas?  What was your favorite thing about it?

Jon

6.18.2012

Musings on the Speed of Light

Friends,
There's a really good chance that you're not as nerdy as I am.  I'm neither bemoaning the fact nor bragging (is nerdiness even braggable; is braggable even a word?).  I'm just stating a probabilistic [Exhibit A] fact.  Two nights ago I played a strategy game that featured cards called "King's Court", "Duchy", "Nobles", and "Steward" [Exhibit B].  Yesterday as I watched Moneyball, some of my favorite moments were the glimpses of the equations used to evaluate players' values [Exhibit C]. 

And now I'm blogging about thoughts I've picked up while reading Einstein and science fiction [Exhibit D].


The speed of light is finite, but faster than you
The former isn't obvious; the latter is routinely discarded in sci-fi

Since you're probably less nerdy than I [see Exhibits A-D above], you may not have ever thought about the speed of light.  No one would blame you for this, unless you studied physics.  But it's time to start thinking about it. 

Because I don't know enough about relativity to actually explain it to you, I'm just going to give you a few cool things to think about.  At least, I think they're cool.  And as we've determined, that might not mean anything.

1. The basis of every cool sci-fi thing: the speed of light is constant
Everything else I'll say hinges on this-- light travels at a fixed, finite speed.  This doesn't quite line up with our experience.  It travels so fast that we sort of assume it's instantaneously everywhere.  But no, when you turn on a flashlight, that light actually has to travel to the far end of the room. 

2. No events are truly simultaneous
To say that two things happen at exactly the same time, what do we mean?  We might imagine syncing up wristwatches or something, but the actual meaning of this must mean that an observer would 'see' (i.e. receive the light particles of) Event A and Event B without any passage of time in between.  But because light has a finite, constant speed-- it matters where the observer is standing!

Consider this example from baseball: a runner tags up from third on an attempted sacrifice fly to left field.  Now, suppose there are two observers: the centerfielder next to the left fielder, and the umpire next to third base.  When the ball hits the glove, the light has only a tiny distance to travel to reach the CF's eyes; but when the runner's foot leaves the bag, there is a much longer distance for the light to traverse.  So he sees the catch with virtually no delay, but a slight lag occurs before he sees the runner leave the bag.  Thus, if he sees the two events as truly 'simultaneous', then the umpire-- with the opposite vantage point-- would fairly call out the runner for leaving early!

[Two points: I realize there would be "virtually no delay" for all events in a baseball park, but over incredibly large distances, this sort of delay for light would be extremely relevant.  You might think there could still be simultaneity if you just plopped the observer at a place equidistant from the two events; but if you just altered the speed the observer is moving, the whole concept would fall apart again.]

3. Looking into the past
If you read the bracketed note above-- and I totally understand if you didn't-- you know that this only creates interesting scenarios if we have super long distances for light to travel across.  And nowhere on our planet do we have a distance long enough for this fact to really play out.  But if you've looked up lately, you might have noticed this thing we call "outer space".

Over the vast reaches of space, light's finite speed becomes incredibly interesting (to me).  The most interesting thing, maybe, is that when we look up at the night sky, we're looking into the past.

In our baseball example, the point was that the umpire might see the runner leaving third just after it happens, but (if the baseball field were enormous) he might not see the ball hit the left fielder's glove until a few seconds after it happens.  This is because the light takes a little time to travel the distance to where he's standing.

Well, space actually is enormous, so we don't have to imagine a pretend baseball game anymore.  We can consider actual facts!  The brightest star in our sky is Sirius.  Its distance from Earth is 8.6 lightyears.  What this means is that it takes light 8.6 years to travel from Sirius to us (or vice versa).  So, if something crazy happens to Sirius (e.g. it explodes), we will see the event eight and a half years later!  To put it another way, when you spot Sirius in the night sky, you are seeing Sirius from 8.6 years ago!  What's up, Past-Sirius?


That's all my brain can handle right now
Kudos to you if you made it this far through my nerdy ramblings

There are so many other cool (to me) consequences of relativity.  If objects were to travel at speeds close to the speed of light, so many crazy things would happen, including a slowing down of the passage of time for that object!  Maybe I can ramble about these things another time.  Now I need to go stare at a TV for a while.

What's your nerdiest pastime?

Any, um, cool physics thoughts?

Jon