I learned: The earth is a giant battery, and it powers life

Twenty meters beneath the frosty surface of Antarctica lies Lake Vida, a thin pool of salty slush that, against all expectations, teems with life.

The presence of life under such extreme conditions is an assemblage of amazings. The temperature of the pool is -13°C.  The water is 19% salt, over five times the concentration of the ocean.

And most incredibly, an ice cap has sealed off the lake from the rest of the earth’s ecosystem for almost 3000 years.  All light is blocked by 20 meters of dirty snow.  Organic matter – otherwise known as “food” – can neither enter nor leave.

Without food or energy, how do its resident microbes survive? Continue reading

I learned – The million dollar dissident

Two weeks ago, an Arab human rights activist was targeted in a hack.  Clicking on a web link would have given hackers full access to his iPhone, and using this technology they could track his movements, see his chat messages, and even take pictures using his camera.  So this week, like hundreds of millions of other iPhone users, I protected myself by updating my iOS.

All of this seems like the standard inconveniences of life in a digital age.  Yet hidden inside this details is a potentially transformative story about the shifting social contract between governments, businesses, and the people. Continue reading

I learned – The origin of causality

We can only tell the difference between cause and effect because of the Big Bang.

The story starts with the laws of physics, with a spotlight on the 2nd Law of Thermodynamics: Disorder increases over time.

The driving force of the 2nd Law is easy to understand – there are many more ways for a thing to be disordered than to be ordered. Drop a lamp, and it will shatter and spread pieces in random directions. If you collect those pieces together and drop them again you are really, really unlikely to get a lamp back. Over time, in any closed system (meaning that no energy is coming in), disorder prevails.

In fact, when we talk about *caused* that lamp to break, we implicitly invoke the 2nd Law. The rest of the laws of physics actually have no way of distinguishing cause from effect, or “before” from “after”. Gravity and Newton’s laws and quantum mechanics all look the same whether you run time forward or backwards. It’s only the 2nd Law that actually has an arrow that points forward.

In fact, we know implicitly that the broken lamp came after the whole lamp in the same way we know that the sky is “up”. There is no “up” in the universe. The “up” we perceive is because we stand on the Earth, and its gravitational pull creates a reference frame that distinguishes up from down.

The arrow of time that we perceive is similar. We can tell what happens “after” from what happened “before” because “after” things are more disordered.

The only way we can distinguish future from past is because we live in the shadow of the Big Bang. Like the Earth serving as our point of reference for space, the Big Bang is our point of reference for time.

The universe was more ordered yesterday than it was today. And when you scroll back enough yesterdays, you get to the Big Bang, where all matter and energy existed in the same place. That’s as ordered as the universe can get. As time marches forward from there, things fall apart.

Cause and effect are as meaningless as “up” and “down” as far as the rest of physics is concerned. The Big Bang anchors history, and every event since then only makes sense in reference to it.

The talk linked here from Sean Carroll goes into this in more detail, starting at 25:00 or so. To me, though, the next most interesting thing is to ask if somehow this implies why the universe is this way. Note that this next bit is not solid physics – it is more pub physics – but it is (as Carroll says in the video) really fun just the same.

Start in *any universe* with the simple assumption that order has to increase as you go back in time. Turn back the clock a little and light is absorbed into stars instead of being emitted by them. Order increases when you return all the energy to one place.

The same is true for mass – there is more disorder in lots of small stars than there is in one big star. You get more order by pushing stars together. When you roll back the clock far enough, the only way to keep gaining more order is to push all matter and energy in the universe until it’s in one ginormous pile.

And when all the matter and energy is in a gigantic pile, gravity and other other laws of physics will collapse that pile into a singularity, where (amazingly) the laws of our universe actually fall apart.

You’ve reached the only plausible beginning. And you have used only the 2nd Law of Thermodynamics to get you there. The Big Bang had to have happened.

I find this weird bit of speculation oddly comforting. I can’t say that it’s right, but it’s somehow reassuring to think that, perhaps, the universe *has* to be this way.

Just for a moment, existence seems a little less arbitrary, and maybe a little less fragile because of it.

I learned – A universal theory of deliciousness

A few months ago I made an amazing salsa using strawberries and ginger. It was transcendent.

But why did it work so well?

It’s an oddly visceral experience, to prepare a food that is called one thing (salsa) that it clearly isn’t, and yet somehow is at the same time. And David Chang in his recent piece in Wired, “The Universal Theory of Deliciousness“, explained to me what I was experiencing.

Chang’s grand idea is that a truly great dish doesn’t just please the palate, but also evokes memories of dishes from our past. Our brains preserve memories as stories, so even memories of smell and taste get woven in to grander reminiscences of childhood and family. By retelling these food stories in new ways, a dish can be more than good – it can surpass the moment and capture something about our personal history in each bite. Food prepared with this kind of thought goes beyond nourishment, and speaks directly to who we are.

I totally buy this. Chef Watson, IBM’s recipe generator (www.ibmchefwatson.com) is what got me to that strawberry ginger salsa. Using a very similar-sounding process to Chang’s, it breaks ingredients into classes (spicy, fatty, sweet), and then randomly suggests replacements (such as swapping serranos for ginger and tomatoes for strawberries). It’s computer controlled, yet somehow has its own genius. And when it works, it delivers an emotional wallop.

Of course, Chang not only has a good theory of food, he’s exceptionally well practiced and thoughtful about details as well. So he probably wouldn’t have made my next attempt, a hot mushy mess of ginger bacon pumpkin chili that sparked a kitchen revolt by my family.

I haven’t played much with Watson since that particular disaster, but Chang has inspired me to go back. By overlaying some of his wisdom on top of the randomness of their algorithm, perhaps I can do better than my past luck would allow. And maybe I can plant some great memories with my kids as well, for them to rediscover while eating another dish, decades later.

I learned – PTSD

Since this weekend, I cannot stop thinking about the shootings in Dallas and Baton Rouge, where two ex-servicemen, pledged to protect our country, made a decision to become cop-killers. Is there a link between their service and their later, fateful decisions?

So I’ll ask what others are probably thinking: is it PTSD that caused these eruptions? And what, exactly, does that even mean? Should we think about this as a psychological disfunction, caused by bearing witness to horrors and pain, or is it something more?

A bomb blast creates a pressure wave that travels through the entire body. Simple physics dictates that at each interface between tissues some of that pressure is reflected, some is transmitted, and some is absorbed. Soldiers who have experienced a bomb blast have been found to exhibit a unique type of brain injury, where their white matter appears as though it has absorbed the energy and separated from their grey matter, scars forming at what used to be a smooth interface. These men (the data set is almost all men, so far) also have unique behavioral problems, including an inability to focus, depression, and loss of self-control. And lashing out, at themselves (in the form of suicide) or at those around them.

I do not know what trauma these men experienced in Iraq, yet I cannot help but wonder if the hell they chose to visit upon their fellow citizens this past week is a hell they brought back from war. A hell that deserves its own research, and the tolerance that comes from understanding that we, as a society, may have created it inside the citizens we respect most, as part of the job we asked them to do.

I don’t know any of the answers here. I do not want to stigmatize our veterans, or in any way distract from the great and good things they contribute on a daily basis, both here and abroad. But I implore us, as a society, to not dismiss this topic because it is uncomfortable. Reality is often uncomfortable, but the discomfort only grows if we do not recognize it for what it is.

I learned, 7/8/16

This is the story of a cat video that showed me something about how to do science.

I intended this week to tell a simple story about why we like fizzy drinks. Carbon dioxide bubbles are produced by bacteria and yeast as they spoil food, so you can imagine that the ability to detect this would be important for survival. And in fact, all mammals have receptors attached to their taste buds that are specific to identifying carbon dioxide. They clearly help us survive.

So why do we humans seek out fizz, when in principle we are evolved to avoid it?

That’s a question about motivation, a kind that’s harder for science to answer. In the articles I read, researchers speculated that humans may like fizz for the same reasons we like hot peppers, perhaps as a way to display fitness by showcasing our ability to tolerate discomfort. It’s the gastronomical equivalent of spreading our plumage to attract a mate.

The scientists support this speculation with experimental data: When animals are offered sparkling water in the lab, they refuse it. We also know that humans often have to be acculturated to soda or seltzer before they develop a taste for it. So perhaps cultural learning plays a role in overcoming our inherent aversion to the sour, slightly painful taste of carbonation.

It’s a lovely story. But is it true?

Not entirely convinced, I decided to take a slightly different tack: searched YouTube for videos of cats drinking seltzer. And while plenty of videos show animals freaked out by bubbly water, videos of cats, dogs and rabbits drinking soda water were actually quite easy to find.

The first thing that I find interesting here is that a bunch of cat videos on YouTube clearly show that the research scientists were wrong. Or, more precisely, that the scientists were making inferences about real behavior from a very small number of lab subjects, under a very unnatural set of conditions. Cat videos, in this case, serve as a useful check on the arrogance of researchers who believe that their work in the lab means they understand their world.

 

 

Yet, beyond the curiosity that a cat video can undercut a scientific hypothesis, they also present a fascinating opportunity: These cat videos potentially offer a better way of doing science.

What is the purpose of carefully controlled experiments that are so hard to generalize to the real world? What if, instead of doing their original lab experiments, scientists decided to learn about animal behavior by simply asking YouTubers to upload videos of their cats drinking seltzer?

The crowdsourcing approach to science would be cheaper than lab work. It would test the preferences of many, many more cats than are possible in a research lab. And even though scientists would complain that such videos create a “biased” sample (not representative of a random selection of cats), that doesn’t matter when testing the veracity of this particular hypothesis.

In fact, I would argue that any hypothesis that explores the limits of behavior, or the breadth of behavior, would benefit from studying these sorts of huge, hastily-organized groups.

Human behavior is magical in its diversity – just look at our variations in preferences for food, entertainment or sex. The traditional approach of science is to strip away as much of the variability as possible, to study the core of what is human by studying the “average”.

But what if there is another way? What if cat videos made by random people across the world give us the opportunity to explore behavior that could never be captured in a lab? What if asking the crowd to run experiments is more productive than running them ourselves?

It’s axiomatic in science that tight control is the first requirement for a good experiment. But that represents just one way of doing science, one that’s made oodles of sense in a world where communication and coordination is expensive. We’ve never had a tool with the reach of the internet before, and there is ample evidence from other disciplines that reams of low quality information can be much more valuable than a few, carefully selected data points.

To me, internet communication, as exemplified by cat videos, has the potential to not just improve the way that information is disseminated, but how knowledge is generated in the first place. Knowledge generated not just by scientists in lab, but by all of us working together.

Science could be made better by bringing in the non-scientists to participate. It’s enough to make me want to break out the bubbly.

I learned, 7/1/16

How on earth did the venus flytrap happen?

A venus fly trap closes its jaws in as little as 100 milliseconds. This is nuts, given that the plant has no muscle fibers or nervous system. So the plant is rightly famous, lauded both by Charles Darwin (“one of the most wonderful plants in the world”) and creationists (as proof of “evolutionary fantasy”).

So how does it work? And why?

The traps themselves are what mechanical engineers call a “bistable system” – they can exist happily in either the open or snapped condition, but not in between. Think of a snap bracelet, straight as a rod until you apply a little energy in the right place… it magically curls around your wrist.

An insect wiggling the inner hairs of a flytrap triggers a small but critical change in the plant that pushes the trap from its initial state to past its intermediate point, causing it to snap shut. Now, a bistable system isn’t that hard to design – snap bracelets are often made out of recycled tape measures, which aren’t all that complicated. But the speed is impressive.

To close, the venus flytrap has to send a signal from the hair, to a (still poorly understood) system that changes the mechanical properties of the trap, pushing it past its point of instability. And it has to do so before the insect leaves. So the flytrap has evolved the ability to send electrical signals an order of magnitude faster than most other plants. All plants move a little – think of how plants will turn its leaves to face the sun – but in terms of speed, the flytrap is a champ, closer in speed to an insect than a grass.

Optimizing both the mechanics and the electrical system seems like an awful lot of evolutionary trouble. Why bother? And why is the flytrap so unique?

Selective pressures push plants towards canivory when there aren’t micronutrients to sustain them. A flytrap can fix carbon through photosynthesis just like other plants. But the bogs it inhabits in North and South Carolina are covered with peat moss and almost completely lacking in available nitrogen and phosphorous. And plants need fertilizer to thrive. So evolution drove plants to capture from the air what they could not take from the soil.

There are other carnivorous plants in those bogs, ones that rely on passive techniques such stickiness to capture small insects, absorbing their nutrients after they die. The flytrap hit upon a system that could capture large insects like spiders and ants as well.

It’s not a great system – a trap can only close two or three times before it becomes jammed with the undigestible exoskeletons of its meals. Flossing may be an evolutionary bridge too far. But as snap traps evolved around 65 million years ago, it seems to be plenty good enough for survival.