Monday, October 7, 2013

Gravity: How much of it is wrong, and why that's right

(Warning: Spoilers for "Gravity")

Alfonso Cuaron's magnificent film "Gravity" finally debuted last week.  I've been waiting for this event for years, having heard what he was attempting to do and having been totally blown away by his last film "Children of Men."  I was not disappointed.

Gravity is a masterpiece of film craft in every respect.  The effects are nothing short of breathtaking, the writing is crisp and compelling, and the performances are spot-on.  I did not realize what a brilliant actress Sandra Bullock was.  She really stands out, even though George Clooney is also performing at an extremely high level.

That said, the films physics (at least in terms of orbital mechanics) are completely wrong.  I think Cuaron knew this, chose to do it incorrectly, and that it was the right choice. 

Allow me to explain:

"Gravity" does not take place in zero-gravity, it takes place in free-fall.  Kowalsky and Stone are not in deep space, they are in orbit, where the gods of orbital mechanics make the rules.  They are extremely  odd rules.

In orbit, Earth's gravity is pulling you down constantly, but your forward momentum is pushing you away, at an angle.  The combination of this angular momentum with the gravity produces a balance that keeps you at a steady altitude above the earth and makes you feel and appear to be "weightless".  Even when the astronauts seem relatively motionless, they are hurtling around the earth at very high speed.  You cannot see this because they, and the shuttle, are moving together.

In orbit, your speed is your altitude, and your altitude is your speed.  If you increase your speed you move into a higher orbit, farther from the earth.  Decrease your speed, and the opposite happens, you drop into a lower orbit. The strange part comes from the fact that a higher orbit is a larger circle, and so you will take you longer to circle the earth.  In a lower orbit it takes you less time to complete that circle, because it is smaller.  So if you speed up, you don't increase your rate of orbit, you decrease it.

If you and I are in the same orbit, but you are 100km ahead of me and I want to catch up, I cannot do so by firing my thrusters forward.  If I do, I increase my speed and move myself into a higher orbit, farther from you.  Also, you will begin to creep away from me because you are in a lower orbit than I am.  No, to catch up with you I must fire my thrusters backwards, away from you, so I will slow down, drop into a lower, smaller obit, and then wait until I catch up with you and pass you a little.  Then, a bit ahead of you and below, I fire my thrusters again but this time to speed up, thus rising into your orbit for rendezvous.

This all assumes we are both in a standard equatorial orbit.  If one of us is orbiting at a different angle, then things get really complicated.

Rendezvous in orbit is really, really hard.  A major goal of the entire Gemini program was just to figure this out.  Buzz Aldrin (who landed on the moon with Neil Armstrong) got his PhD in just this problem, which is why many called him "Dr. Rendezvous".

I am sure Cuaron knows this, as he took years to prepare this film.  He also knew that if he filmed the real process of, say, Dr. Stone piloting her Soyuz to the Chinese space station by flying away from it, the visual result would make absolutely no sense to the audience.  Everything in orbit works backwards, and explaining this in a film would make for very dry, pointless exhibition.

This is a great example of the difference between verisimilitude on screen and "realism", which often does not work well as art.  It takes careful consideration to know when do to one versus the other.  All of the "three dimensional skating rink" maneuvers that Stone does while floating in the ISS, for example, are perfectly correct.  That works because the "floating astronaut" something we all understand now in terms of its visual language.

Again, I point this out not to criticize the film or the filmmakers, but to praise it and them.  The film gave me an absolutely real "feel" of being in space, even though I came to it knowing how the mechanics really work.  I was totally invested in the drama.  That's a master at work.

Friday, April 19, 2013

Whither Countries?

When Al Qaeda attacked us on 9/11, the immediate response was to mourn and attack.  The second response was to ask questions.  Why were we attacked, and what should we now do about it?

The "why", it was said, had to do with our military presence in places deemed sacred by Islamic extremists, like Saudi Arabia, and our strong alliance with Israel.  The "what to do" was pretty much a split between "we need to be stronger and fight back" and "we need to remove their motivation to attack us in the first place."

I was pretty much in the latter camp; not because I am overly dove-ish, but because it seemed to me that it would be difficult if not impossible to defeat an enemy that was diffuse, hidden, and motivated so strongly that its members are willing to die in order to harm us.  How, I thought, do you fight an enemy with tanks and bombs when that enemy is embedded in the civilian population?  If they are willing to die, then you can neither break their morale nor cause them to run in fear.  You would have to kill every single one of them, and they will be busy recruiting new members all the time.  In fact if you attack them where they are, in the midst of the innocent, then you will  simply create more hatred toward you, and inspire more terrorists.  You would be creating the enemy as you destroyed it, and you cannot win that way.

No, I thought, you have to remove their desire to act against you.

The recent bombings at the Boston Marathon have disturbed and sobered us all, but they have also called into question the notion that we can somehow become better actors in the world, and in so doing will remove the threat of terrorist attack.  Our best information is that these two terrorists came from Chechnya, and actually fled here due to religious and political persecution in their own country.

We have no bases in Chechnya.  As far as I know we have not done anything there, have not insulted any holy ground, nor buzzed them with drones, nor exploited their natural resources.  Their traditional beef is with Russia, and with forces within their own borders who are guilty of ethnic cleansing and other horrible atrocities.

I would not wish a terrorist attack on anyone, but why did these young men attack Boston?  Had they bombed Moscow or Grozny it would have been equally tragic, but it also would have a potentially logical link to the actions of the country whose citizens they attacked.  One could say "this is horrible."  One could also say "this is what motivated them."  Here, unless something we don't know about right now comes to light about the U.S.'s involvement in some kind of covert acts of oppression, we cannot say that.

I suspect they chose the Boston Marathon because it is very visible, very public, and a lot of people would be there in the open, and vulnerable.  I suspect they chose it because it was convenient; they were living there, had the resources to make the bombs locally, and did not have to infiltrate to plant them.

If this is true, then what does it mean?  We live in a world where you can tour Venice on your laptop in real time.  You can skype video chat with someone in the Sudan for free, as much and as long as you want.  You can enter a city you've never seen before, with no map, and be guided to anything with with your GPS at no charge.  The notion of "I am here and you are not" is gradually and inexorably fading away, and it may be that soon the notion of the country or nation state will be as antiquated as morse code.  Maybe it already is.

I suspect that writer Paddy Chaefsky was prescient when, in "Network", his character Arthur Jensen says:

"There are no nations. There are no peoples. There are no Russians.  There are no Arabs. There are no third worlds.  There is no West... There is no America.  There is no democracy.  There is only IBM and ITT and A T and T and Dupont, Dow, Union Carbide and Exxon.  Those are the nations of the world today."

Maybe this was already true in 1976 when that film was made.  It seems to me that it is increasingly true as history marches forward and soon we may realize that the ineffectual, paralyzed government that now fails us at almost every turn is simply the logical consequence of the fact that our country, that all countries are becoming irrelevant to our safety, prosperity, happiness, and freedom.

People who fight for their second amendment rights are patsies, as the whole argument, on both sides, is intended to sell guns and ammunition and make corporations rich.  Which it is doing.  People who want us in the middle east to secure our energy freedom are likewise patsies, as the price of oil causes gasoline prices to go up when it rises, and also when it falls, and the whole point is to enrich the Koch brothers with petro-dollars.  Which it does.  People who fight for immigration reform, or against it, are simply doing the work that the multinational corporations want, and whatever adds to their bottom line will be the eventual outcome of that legislation.

And the two young men who slaughtered the innocents in Boston?  We may never know the true details even if some seeming "motivation" arises, because the truth is it really does not matter where they came from, or what ills plagued them, and it would not matter what the country we call the United States of American did or did not do.  The chain of cause and effect that led them to the state of anger, or despair, or madness, or whatever their motivation was did not proceed from the plans of any government, be it eastern or western, because governments control those causes less and less every day.

If we ever hope to find an answer to international and domestic terrorism, I suspect it we be after we re-think how the people of this planet are arranged and organized, about what constitutes, as Roger Waters wrote, "Us and Them."  We may have to realize that we are citizens of an organizing system that we neither understand nor control, that we don't even really see.

Thursday, March 7, 2013


I love this movie:

I've watched it so many times I've lost track... which, oddly, fits neatly into the theme of the film itself.  My friend Max Guernsey recently watched it and asked some questions that got me thinking about the film all over again.  So, I thought to write a blog about it.

If you have not seen the film, please do not read this.  In fact, please do not read this unless you've seen it at least twice.  I would hate to rob you of a truly wonderful experience by spoiling it.

Shane Carruth says he did not really start out to make a film about time travel.  He wanted to make a film about trust, the sacrifices we make (or refuse to make) for friendship, and the human desire to "get things right" in our lives.  The device Abe and Aaron create is a vehicle (pun intended) through which the film explores these themes.

The plot is confounding, no doubt.  Here is my take at untangling it:

Alert! Spoilers below...

Abe is the first one to realize what they have.  He plans to prove this to himself and to Aaron by starting the box, sequestering himself in a hotel for a while, then entering the box to go back to just after he started it.  Once he does this he finds Aaron, and together they watch the original act of Abe starting the box and leaving for the hotel.  Aaron believes what he sees, but what he does not know is that Abe secretly created another box and turned it on earlier.  It is still running, and will continue to run until/unless he decides to use it  This is his "failsafe", which he can use if things go wrong; he can go back before he decided to tell Aaron about the discovery, and stop himself from doing so if need be.  He is not sure he'll need it, but there are so many unknowns that Abe, the good engineer, takes this precaution.

We do not see Aaron finding Abe's box, but he does as we find out later (in a sense).  He moves it to another location and replaces it with a box that he activates after Abe's original experiment.  Thus, he will be able to go back before this all began, but Abe will not be able to.  Aaron does not want Abe to be able to thwart him in what he intends to do.  Note that Abe's motivations are very different from Aaron's.

Abe is dating Rachel Granger.  Their efforts are funded by Rachel's father, Thomas Granger.  At some point, in a future we do not see, Granger finds a box running (we do not know which one, or how) and uses it to come back for reasons of his own.  He may, in fact, believe he will go back to the original failsafe point and take control of the technology from the boys.  He makes the mistake of exiting the box early, however (as Aaron did when they first traveled, only even moreso) and this damages him severely.

Abe is very disturbed by this, and also by a tragic event at a party involving Rachel's ex-boyfriend, and finally decides to use the failsafe to go back and prevent the entire series of events. He does not know that his failsafe is not the original, but the one Aaron replaced it with.  So, when he goes back he actually does not go all the way.  The Aaron that Abe now encounters is already a time-traveler.  The original Aaron?  Drugged and in the attic.

Aaron tells Abe the truth... he has been looping back over the events again and again, taking a machine with him (folded up) in the failsafe and, exiting, starting the new machine up so he can go back again.  He is trying to make the "perfect day" where the tragedy at the party, and the tragedy with Granger, never take place.  Now Aaron takes two folded-up machines back with him...

We do not know (cannot know) how many loops they go through (and how many drugged Abe/Aaron versions are in the attic) before he succeeds.  But he does.  They decide to do one more loop in which they do not set a failsafe again, and start a new time line that cannot loop.  Aaron decides to go off continent so he can never encounter another version of himself, and begins to build the room-sized machine.  What he intends is unclear.  Abe stays in the states and will prevent them from ever discovering time travel in the first place.  Their friendship is over.

We also are travelers, of course, as the film was made long ago but we can restart it and watch it whenever we wish.  We do do, of course, because we want to change our experience of the film by coming to understand it better until, I suppose, we create the "perfect run" of the film.

I'm sure I am missing things here.  I like that.  The whole thing just makes me smile.

Friday, January 18, 2013

The Second Amendment

Recent mass-shootings have once again stirred up public debate about the constitutional rights of American citizens to own weapons, whether there should be any limitations or regulations regarding this, if some weapons should be banned or if people who want to buy and own them should pass a background check, etc...

I grew up around guns.  I owned a .22 caliber rifle as a kid, and later a Schmitt-Reuben 7.62 Olympic match rifle and a 20 gauge shotgun.  I got my rifle and shotgun merit badge as a boy scout. I've been hunting with my father, and was a member of the NRA and an avid target shooter in my youth.  I understand the cultural aspects of gun ownership.

But what always seems to be missing in the argument, especially from the political right, is the actual second amendment itself.  They cite "The right of the people to keep and bear arms shall not be infringed."  That's only part of it.

Here is the whole thing:
A well regulated militia being necessary to the security of a free state, the right of the people to keep and bear arms shall not be infringed.
You'll note it is not terribly long.  Most of the constitution, especially the Bill of Rights, is not very wordy.  The founding fathers tended to craft these things without a lot of persiflage or extraneous language.  The NRA interprets the amendment as essentially saying "the rights of individual citizens to own weaponry shall not be limited" but that's not what the amendment says.  If that's what the founding fathers had wanted to say, I submit they would have said exactly that.

Let's look at the whole thing, piece by piece:

A well regulated militia

What is meant here?  Consider the context of the writing: this amendment was passed in 1791, not all that long after the revolutionary war.  A big part of that war, especially in the early days, was conducted by citizen soldiers (the minutemen, and others) who were very well organized and pretty darn effective.  I submit they were what the founders were thinking about; the value of our citizens being an organized militia when needed.  And why is this necessary?  They tell us why.

being necessary to the security of a free state

The purpose is the security of the state.  That is plainly stated.  It is not, as many have suggested, so that we can fight off the ATF or the FBI when they storm our mountain bunkers.  It is so we can defend the state from a foreign invasion.  At the time the amendment was written, this was no trivial concern.  We had been invaded, and would be again (the war of 1812).

the right of the people

Note "the people" is used here, not "individual persons."   In other places in the constitution, for example in the language that mandates the census (article 1, section 2, clause 3) they refer to "the whole Number of free Persons" when referring to individuals, not "the people".  What was meant by "the people" at that time?

Consider the declaration of independence... it begins "We the People."  This refers to the nation as a whole, not individuals.  Thomas Jefferson was not declaring his personal independence from England... we were, as a collective, declaring that independence.  Also, note that Abraham Lincoln referred to our government as being "of the people, by the people, and for the people."  "The people" means the country, all of us, including the government.

So, I submit that they are talking here about a people's militia, and how needed it is to keep the country safe from invasion.  The closest analog I can think of in the modern world is the National Guard.

to keep and bear arms shall not be infringed.

Note "arms."  At the time, "weapons" were considered to be arms and armaments.  Armaments would include cannon, mortar, and other large-scale military weapons that are used to attack large groups of people at once.  The founders did not include armaments in this right, only arms, which to them would mean side arms and along arms: pistols and muskets, and things like swords and muskatoons.

A key question to ask is this:  what would they consider an assault rifle, capable of rapid fire, and sporting a magazine that holds, say, 50 rounds, to be?  An arm?  Or an armament?  Or, had they known of such things, would they have created another category or term?  What would they think of VX gas and nuclear bombs?  We cannot know the answer to this, of course, but even the most staunch NRA booster would not, I hope, say that individual citizens should be allowed to posses nuclear weapons and nerve gas.  So everyone draws a line somewhere, it's only a question of where the line is drawn.

Given all of this, I submit that the constitution does not provide an unlimited right for each citizen to own any sort of weaponry they like, without any regulation whatsoever.

If you believe we should have such a right, then make your argument based on why you think this is the right thing for our country.  But don't distort the second amendment to suit you.  In my book, doing so simply means you don't feel you can make a strong enough argument based on the merits of your beliefs themselves.

I'll close with this:  Thomas Jefferson and John Adams made it clear that they did not consider the constitution to be holy writ.  Their expectation was that we would revisit it every ten years or so, because they were smart enough to know that the world would change, and that the constitution would have to be updated and modified regularly.  Practically the first thing they did to the constitution was to amend it. Would they have put in a literal right to privacy if there had been mass communication at the time?  What would they think of the internet?  Warrant-less wire taps?  Terrorists flying planes into buildings?  Torture?

Our country is ours.  We have to ask ourselves. regularly, what kind of country we want it to be, and take responsibility for what it is and what it does in the world.