Monday, August 30, 2010

Animal Coolness: Score One for the 'Good Guys'!

aka:  Orca's hunt Great White Sharks

Blog post the Fourth  (when will I stop doing that?  Stay tuned and see).

Who are the 'Good Guys'?  Why us, of course.  If you don't think of your own tribe as the good guys... what's the point of any notion of 'good'?  But who are us?  is us?  We be who?  Whatever.  'Us' in this case does not refer to the U.S., nor to the 'Free World', nor even the 'Human Race'... but to 'Mammals'.  That's us, folks.  I mean really,  if one animal is gong to hunt and kill another animal, wouldn't you rather see a mongoose kill a snake(Go Rikki!) than a snake kill a guinea pig (do not dare follow that link if you are sensitive!  And if you do, then follow the link to cheer on Rikki, it will make you feel much better)? 

I know there a few humans out there, perhaps you are one, who have a genuine affection for reptiles.  Steve Irwin anyone?  Opps I mean this Steve Irwin).  But that is OK, because when it comes down to us against the aliens, 'us' becomes all life on the whole planet earth, and I'll be the first to kiss an alligator or a bacterium if it knocks off some nasty evil E.T. that wants to harvest my brain, or whatever it is that nasty evil E.T.'s do.

But as long as we're keeping things intramural, I'm casting my lot with my closest relatives, the mammals.  Which brings us to today's Animal Coolness™  Orcas who hunt Great White Sharks!

This may be old news to some, but it did not get so much press that everyone has heard about this yet.  Hopefully this is new to some of my readers.  If the video below doesn't work, follow the link to watch directly on Youtube.

Orcas are very smart, and they figure out and teach each other new hunting tricks.  The trick to killing a great white shark is to quickly turn it upside down.  Many sharks and rays become paralyzed or "go to sleep" if turned upside down, and they cannot pass water over their gills.  They suffocate.  You might imagine Orca vs. Great White to be some titanic battle.  But in reality, in the eyes of an Orca, a Great White Shark is just a...

Saturday, August 28, 2010

Racing the Wind!

Blog Entry the Third.  This time, rather than weighty matters, I'm going to tackle a light and airy science topic.  The question before us is this:

Is is possible for an object solely powered by the wind to move downwind faster than the wind itself?

Sounds preposterous right?  Turns out it is much easier than you might think, as proven by Rick Cavallaro and John Borton, as recounted in the Wired magazine article.

EDIT:  (Disclaimer) For the record, while I am qualified to talk about physics, I am not by any means an aerodynamics or sailing expert and not conversant with the jargon of either, so I have used some loose terminology below.  For example, where I say "real" or "actual" wind below, I mean "true wind".  I also may not be using the term "tacking" entirely correctly -- or at least it has multiple meanings only one of which is applicable here.  The cartoon vector diagrams do not account for every subtlety, but do describe the "jist" of what happens with the air flow and forces involved.

I just saw that article yesterday, and this is the first I have heard of a great controversy that has raged across the internet among profession and amateur sailors, aerodynamics engineers, and even, apparently Nobel Prize winning physicist advisors-to-the-president.  See the article to learn more.

Simply moving faster than the wind is nothing new to sailors, and is not controversial.  They do it with a technique called "tacking", which has to do with the angle of the boat and the angle of the sail relative to the direction of the prevailing wind.  A sail boat moving across the wind can easily move faster than the wind.

In the diagram above, you can see how it is possible to move faster than the wind.  To understand the basics of a force provided by a sail, wing, or propeller, you don't really have to understand fancy aerodynamics such as the "Bernoulli effect".  What it boils down to is the sail (or propeller, or wing) deflects the flow of air -- it pushes on the air which results in an equal and opposite force on the sail (or wing, or propeller).  Here we end up with a force at an angle to the direction in which we want the boat to go, but the keel of the boat prevents sideways motion.  As long as there is enough force in the forward direction to overcome the drag at a particular speed (the drag increases with speed), the boat can accelerate.  When the forward component of force equals the drag, the boat will move at constant speed.  If you have a big enough sail to generate lots of force, and your boat has a small enough drag coefficient, it can easily move across the wind faster than the wind itself is blowing.

To understand the rest of what I am about to explain, take note of the yellow and red arrows in the diagram.  They show the induced wind and apparent wind felt by the boat.  Induced wind is just the wind you feel because you are moving.  If the air is still and you run at 10 miles per hour, then you will feel a 10 mph wind blowing on you.  The apparent wind is the combination of the real wind and the induced wind.  If the wind is already blowing at 10 mph and you run 10 mph with the wind, then you won't feel any wind, because you are keeping pace with the actual wind -- or you can think of it as your induced wind exactly cancels out the real wind.  If you run at 10 mph, against a 10 mph wind, then you will feel a 20 mph headwind.  If the real wind is a crosswind, then your induced wind will combine with the real wind to change both the speed and angle of the apparent wind.  This is what we see in the above diagram.

Notice the position of the sail and the direction of the force in the diagram above.  This example already has the boat going quite fast, so the apparent wind is coming in at an angle getting somewhat close to a straight on headwind, even though the real wind is coming in from the side.  The angle of the sail is necessary to catch the wind at this angle.  Notice that the force is almost sideways to the boat, but still a little bit forward.  This means that most of the force is wasted against the keel (which prevents the sideways motion), but there is still some force pushing the boat forward against the drag.  It is the forward component of the force that matters -- as long as that is enough to overcome drag, the boat can go even faster.  But the faster you go, the more the induced wind looks like a full-on headwind.  To catch that wind with the sail,  you have to anlge the sail so that you end up with almost all the force going sideways.  This reduces your forward force and eventually the drag (which gets bigger as you get faster) will exactly cancel your forward force (which is getting smaller as you get faster).

Now you know the basics of how a sail boat can go faster than the wind, but this example was for a boat going across the wind.  You can't outrace the wind by gong sideways!  What if we want to go in the direction of the wind?  Intuition will tell you that once you match the speed of the wind, you won't feel any more wind at your back -- your force will have dropped to zero and that means the drag will actually start slowing you down.  In other words you won't even be able to match the wind speed -- you have to go a little slower so the sail catches just enough wind to give you a forward force that matches the drag, and then you coast along at your maximum downwind cruising speed.

Interesting, isn't it, that  you can go faster by crossing the wind than by going with the wind.

How can we outrace the wind if gong with the wind means we cannot go faster than the wind?  The answer lies in tacking.  The above diagram is for a boat going exactly perpendicular to the wind.  But what if we go at an angle, partially with the wind, and partially across it?  Take a look at the next diagram.

Now the boat is going partially with the wind and partially across the wind.  The black, yellow, red triangle in the bottom right shows how the real and induced winds combine to form the apparent wind.  Another thing to look at is the velocity.  Here the velocity is not only faster than the wind, but if you look at the upper left of the diagram, you see that the portion of the velocity in the direction of the wind is faster than the wind itself.  In other words this cartoon boat is moving downwind faster than the wind.  But can this be done in real life?  The answer is yes.  It is just a matter of having enough sail, and a sufficiently streamlined, low-drag ship, so that the forward part of the force in this configuration is greater than the drag.  Real sailors on real yachts do this sort of thing all the time.  It is not controversial, though it may be surprising to anyone who does not already know about it.

EDIT:  I have learned from someone with expertize in aerodynamics and sailing that, in fact, this is not quite common knowledge and not quite non-controversial, even though it has been proven in both theory and practice.  A lack of awareness of this basic fact no doubt contributes to the controversy.

But how can we race the wind directly?  Suppose there is a balloon or wisp of smoke and we want to beat it to a particular point directly downwind?  If we go at an angle, as in the diagram above, then we won't reach our destination.  The answer is to make a zig-zag pattern using the mirror image of the above diagram.  Then we can beat the wind at its own game:

Above we see our boat zig-zag its way to beat a wind-blown balloon across the finish line.  Maybe the balloon should be frowning.

The Controversy

Everything I have explained so far is well known to sailors and to experts in aerodynamics (Edit: or perhaps not so non-controversial).  But it gives you just enough knowledge to understand the "controversy".  If you followed the link to the article and read it, then you already get what the fuss was about.  What I have shown you is how a boat can tack or zig-zag to beat the wind.  The big controversy is whether you can beat the wind in a straight line.  An ordinary sailboat cannot do this for reasons explained a few paragraphs up.  Once you match the speed of the wind, you no longer have a wind to provide any force, so you cannot get any faster, right?

Certainly appears to make sense.  And this is central to the thinking of everyone including respected experts who scoff (or scoffed) at the idea of beating the wind at its own game.

The first way to think about it is to imagine using shorter and shorter zigs and zags (but a lot more of them).  If you make  your zig-zags small enough, you are for all practical purposes just going in the straight line downwind.  But of course a boat can only turn so sharply, and it loses speed on the turns, so this is not a practical approach.  But it is on the right track.

What if we somehow let the sail and the mast move laterally in the zig-zag pattern, while the boat moves staight?  This is in principle the solution.  But the forces involved make it effectively impossible to engineer.

The ultimate solution, then, is to let the sail rotate instead of moving side-to-side.  In other words the sail becomes a propeller blade -- and for balance we'll have at least two blades.  This is the solution used by Rick Cavallaro and John Borton.  But there still is a little more to it.

If the propeller is simply free to turn, it is like a ship without a keel.  Remember all that sideways force acting on the boat?  If there was no keel, the boat would rapidly lose speed and change direction (if it did not just tip over).  And for the propellers, that force would just end up slowing down the propeller and the ship (or wind-car) will slow down as well.

Borton & Cavallaro deal with this problem in their wind-car by connecting the propeller to the wheels with a transmission.  This locks their motion together in a way that is mathematically equivalent to the effect of a keel on the tacking ship.  The equivalent for a straight-downwind-sailing ship would be a kind of "rotating keel" (one for each blade on the propeller all on the same axle).  The rotating keels would need to to be angle to correspond to the equivalent angle of a tacking ship.  A keel is just large flat blade, and angled blades on a rotating axle is just a propeller.  Basically the "rotating keel" would be another propeller, this one underwater, linked to the "sail" propeller with a locked transmission so they rotate at the same rate.  The pitch angle of the "keel propeller" will have a steeper pitch than the "sail propeller".

Edit:  Technically, the rotating keel will act as a 'turbine' not a 'propeller' -- propellers push the medium (air or water) and provide thrust to whatever they are attached to.  Turbines are pushed by the medium, which cause the turbine to rotate.

One last thing.  Some will insist that Borton & Cavallaro's sail car worked by storing up energy in the rotating propeller like a flywheel, and then releasing that energy all at once for a burst of speed faster than the wind.  You can imagine that the transmission from propeller to wheel has a clutch, then they could let the wind spin up the propeller, pop the clutch and have the car rush forward realy fast for a short burst.  If this were the case it would obviously be cheating.  But the way the propeller is locked to the wheels, no appreciable energy is can be stored and released in this way.  If the tail wind stops, the car will slow and stop almost immediately.  The same would be true of my proposed "rotating keel" -- it would not be used to propel the ship forward.  The rotating keel serves the same purpose as the keel in the tacking ship -- it forces the sail-propeller to move in a specific helical pattern which is equivalent to the keel forcing the normal tacking sailboat to move in the desired straight line (at an angle to the wind direction).

Counter-intuitive though it may be, the Borton & Cavallaro car really does beat the wind at it's own game!

Thursday, August 26, 2010

Is it Righter to be Nicer than it's Nicer to be Right?

OK, so here is blog post the second.  Thought I'd explain the title of my blog.

There have been times during debates or arguments about things like politics or religion that I have been informed that it might be more important to be nice than to be right, and I want to address that sentiment here.

The choice of words for the title is inspired by a line from the musical, Pippin:

"It's smarter to be lucky than it's lucky to be smart."

I have always loved that line, comparing "luckiness" on a scale of smartness (as if it were a choice) to "smartness" on a scale of luckiness, and it suggests that if you had the choice, then the "smart" choice is to be "lucky" (rather than "smart"), because "lucky" means good results pretty much by definition.  Likewise it may not be so "lucky" to be "smart" because even the smartest plans of go astray. 

But what about "niceness" verses "rightness".  Is it more "right" to be "nice" than it is "nice" to be "right"?

The most correct answer is both obvious and cowardly:  "It depends on the circumstances."  But what about a general, though not absolute principle?  In that case, my answer (that partially evades the question) is:

It is not nice to be wrong.
What do I mean?  Certainly you can be wrong about innocuous things without doing much harm.  Making a mistake does not imply that you have intentionally done something mean.  However, being wrong, when it has consequences, can often do harm -- can often have results that are "not nice."

For example, suppose you believe the recent hysteria blaming vaccinations for autism.  Perhaps you refuse to have your children vaccinated, and you encourage others to do likewise, with some success.  The end result, is children dying of measles and other diseases that had previously been eradicated, and not one child saved from autism, because the claim of a causal connection is completely unfounded.

Another example.  What if you believe that homosexuality is a sin.  That it is a matter of choice or a sickness that can be "cured".  Children who grow up in your family or community, who happen to have same-sex attraction due to their genetics, and perhaps also have opposite-gender personality traits may hear your condemnation of what they are, thus destroying their sense of worth, making them believe that they are evil or defective.  Any wonder if among gays there is a higher suicide rate?

Another example.  What if you believe in the biblical apocalypse?  What if you believe that "signs and portents" mean it is imminent?  If you area voter or a elected official, this may seriously influence your priorities.  After all, if the earth is pre-destined in a matter of year to descend into chaos, then cleansed by fire (rather than flood), and then a kingdom of heaven on earth will be founded, do we really need to worry about global warming?  Do we really need to worry about nuclear disarmament?  Ah heck, maybe the nukes will be God's method of engulfing the world in flame. 

The preceding are "big" examples on "big questions".  But even in day-to-day life, being wrong can have very negative consequences for yourself and those around you. 

I'm not suggesting that we all need to feel guilty about our inevitable mistakes.  We cannot help but make mistakes.  None of us can be right all the time, and the requirements of just getting things done each day mean we cannot devote the time and energy to research and think as much as we would like on any particular topic.

But what I am calling for, and promoting, is a certain passion for not being wrong
In any disagreement, there is automatically the implication by the other person the you personally are wrong about something.  To be told you are wrong carries the potential implication that your mental faculties are not up to snuff, or perhaps that you are "ignorant".  In other words, mere disagreement has the potential to be insulting.  If the topic raises passionate emotions, the potential for perceived insult is even greater.  If  you find yourself uncomfortable or feeling insulted in the course of a discussion, disagreement, debate with anyone... if you find yourself offended by the opinions I express in my blog or anywhere else on the web, then I ask you to stop and think to yourself: 

"I could be wrong."
If a person passionately argues their point of view, even if they seem arrogant in the confidence with which they express themselves, please consider that perhaps rather than trying to prove you wrong and make you feel stupid, perhaps rather than attempting to just "win" the argument, they are in effect trying to save you from a mistake -- a mistake which might not affect your day-to-day life, but which might nonetheless have indirect consequences for your community or the entire world.  Then also tell yourself, "They could be wrong." -- after all, since you still disagree with them, you actually must think they probably are wrong.  And consider that defending your own viewpoint right back at them might help them correct a mistake.

I personally have a passion for not being wrong.  It has nothing to do with wanting to feel superior.  I cannot say exactly where that passion comes from.  it is a passion for science and critical thinking.  In my personal life, perhaps it borders on a paralyzing compulsion, where in some situations I end up "not acting" until I'm sure I know the "right" thing to do.  "He who hesitates is lost" as it is said.  But it is also said, "look before you leap."  So there you have it.

But the process of critically examining and re-examining any and all beliefs and assumptions is also what makes science work.  It is why science has the "peer-review" process, which is really just the second line of defense (the researcher own inner critical thinking is the first line of defense).  After results are published the 3rd, 4th, 5th... lines of defense are all the debate, experimental tests, attempts to reproduce results, more debate.  In this way theories are hammered on until we can confidently say "this theory describes what happens in the real world, and we know it because we can look for ourselves, and see."

I happen to think all beliefs, held by all people, about pretty much anything that is not a subjective aesthetic opinion, should be held to the same standard.  I'm not saying we should all publish our beliefs in peer-reviewed journals.  I'm saying that the spirit of allowing our beliefs to be scrutinized, criticized and tested by reason and evidence should be regarded as a high virtue in and of itself.  Not the only important virtue, by any stretch, but a virtue nonetheless.

Striving to be right can help make the world a nicer place.

Tuesday, August 24, 2010

In the long run, will even Solar Power be enough?

Hi folks.  This is my brand spankin’ new blog.  I’ve put off starting a blog for a long time, wanting to open in some appropriate way, summarizing my philosophy, reasons for the blog, etc.... and well I don’t think I’ll ever get started that way.  So, instead, I’m just going to write about something I'm thinking about at the moment... and other topics will come along in time.

Quite often in discussions about global warming, “green” energy and so forth, it is mentioned that the solar power reaching the earth is for all practical purposes unlimited.  More precisely, the number which is tossed around is that there is about 10,000 times as much solar power reaching the earth as our current power consumption.  We also tend to think of the total power produced by the sun (not just what hits the earth) as “infinite”.  Compared to what we use today, it might as well be infinite.

But here is some sobering math that might just wake you up, if it doesn't put you to sleep.  :)

First lets confirm that factor of 10,000.  Current global energy consumption (2008) is about 474 exajoules/year.  The total solar power reaching earth is 174 petawatts.  Doing the math:

(174 petawatts) / (474 exajoules/year) = 11584

So the 10,000 multiplier is about right.  10,000 is really big.  How could we ever use that much more energy than we do now?  (rather, how could we ever use that much power -- the rate at which we consume the energy and how fast the energy is supplied are what we are talking about, and the correct term for both of those is “power”).

It seems like a lot.  It seems like we could “never” need so much power.  Now for the sobering math.  Over the past century or so, we can estimate the growth rate of global energy consumption.  It is about .5% annual growth in energy consumption.  It has been close to 2% recently.  Lets take the smaller number.  Assuming we continue at that rate, how long before we would be using all the solar power reaching the earth?  Rounded off we have:  

#years .5% energy growth = log(11584)/log(1.005) = 1876 years
Now, almost two thousand years is still a long time... but it is far from an eternity... just 19 centuries is a time-span we can easily grasp.  It brings into perspective just how rapidly our energy use is increasing.  The solar supply is far far from unlimited, and nothing else we have comes close.  If our energy consumption grows at the 2% number, then here is that calculation again:

# years = log(11584) / log(1.02) = 473 years
Less than 500 years!  Given that 2/3rds of the worlds population are scrambling to get to the level of technology, industrialization, quality of life that we have in the U.S, and given the the U.S. by far uses the most energy per capita, we can be sure that the growth in global demand for energy is not going to level off any time soon.  The only thing that will slow down the growth in consumption is if the energy is simply not available.  High demand for a scarce resource means trouble.

Now here is something I think is even more sobering.  The total power output of the sun is 3.86x1026 watts.  At the above growth rates, how soon would we be using that much energy?

# years  at .5% growth = log(3.86x1026watts / 474 exajoules/year) / log(1.005)
= 4,805 years

# years at 2% growth = log(3.86x1026watts / 474 exajoules/year) / log(1.005)
= 1210 years
At our current rate of growth of energy consumption we will need the entire energy output of the sun to sustain our civilization within about 1000 to 5000 years!  All the power output of the sun.  Let that sink in.  All the power output of the Sun.  

No amount of earthbound energy, no amount of oil, no number of nuclear reactors, no amount of solar panels can so much as scratch the surface of the power output of the Sun.  The sun is a giant fusion reactor, about 300,000 times the mass of the earth.  Nuclear reactors (fusion or fission) on earth will never produce a significant amount of power as compared to the sun (This does not mean they won’t play an extremely important role in the near to mid-term).

It is also unrealistic to suppose we’ll be able to grab every drop of sunlight even with some crazy science-fiction technology.  We won’t be able to get all the solar power reaching the earth even if we blanket the planet with solar panels.  Getting all the power of the sun will require satellites in solar (not earth) orbit... it would take so many satellites we’d have to strip the earth of pretty much all useful material just to build them and launch them into space -- perhaps we could consume the entire moon for this purpose.  This means that the time estimates before we saturate the available energy are actually quite a bit shorter.

Now you might say “500 years, 1000 years, 5000 years... that’s too far in the future to worry about.”  What our descendents do when the energy from the Sun is not enough will be their problem, true.  But the point is that our demand for energy is increasing so fast, it is going to outstrip everything we can possibly get our hands on, unless we can research and develop new sources very quickly.  Competition for scarce energy resources is going to shape our near and long term future.  There are only three possibilities:

(1) War!  War that makes WWII look like a pillow fight folks.  Not an acceptable option, I should hope.
(2) Conservation.  This will be forced on us by simple reality.  But not without huge conflict -- see #1 above.  Remember half the world is impoverished and scrambling to reach our quality of life, unless we set an example by cutting back massively, they are not going to voluntarily sit in poverty.
(3) Research. Develop new sources of energy, especially solar power, as fast as we possibly can.  This means research research research.

What can you do?  Individual conservation (recycling and whatnot) is a good gesture, but cannot possibly fix the long term problem -- you won't convince enough of the rest of the world to do it with you, and there will always be others willing to consume what you do not.  We’re just not going to convince enough people to conserve before shortages force them to do without.  But you can do the following three things.

(3) Invest.  Seriously.  Invest spare cash into energy research.  Nowadays anyone can invest via simple internet sites like E-trade.  If you have a retirement account that lets you choose investments, make a heavy allocation specifically towards energy research and development.  Any company researching new energy or developing energy technologies.  There are plenty of mutual funds focusing on energy R&D.  It does not take an expert in energy or investment to do this.  Even invest in the dreaded “big oil” -- even at the risk of repeating the Gulf Coast disaster, the looming energy shortage means we’re stuck with “big oil” in the near term.  Investment in any research and development in products that make more efficient use of energy is also good -- electric cars and so forth.

(2) Talk.  Make people aware that the sheer magnitude of the problem of “not enough energy” trumps even “global warming”.  It trumps worries about supposedly “unsafe” nuclear power (which is arguably far safer in terms of long term health effect than oil or coal, and also does not cause global warming).  You are a participant in the global conversation.  You are one drop in the bucket of “public opinion” and “political will”.

(1) Vote. And contact your representatives.  Demand massive investment into energy research.  New energy of all kinds really does need to be today’s “Apollo Program”, but on an even more massive scale.  Demand a repeal of regulations blocking nuclear power.  And since we're stuck with oil for the time being, we must also research so-called geo-engineering methods to prevent or mitigate global effects such as climate change in the face of continued use of fossil fuels.


skg rightly points out that the exponential growth in power usage must slow down or even halt, so that my projections are not likely to come to pass, with which I completely agree.  If we are unable to collect that amount of solar power, we won't be consuming it either.  But that is precisely my point -- our insatiable demand for more energy is going to hit a brick wall of limited supply very very soon, unless we are able to science & engineer our way out of the dilemma.  There is simply no other way.