All Life Starts with Light

All Life Starts with Light

It’s always a little startling when the pastor turns to you in the middle of the sermon and asks a question. When 500 people are attending the service, it gains even more of an edge.

That’s what I get for coming late and sitting in the front row today.

So, when Richard turned to me from the pulpit, in the middle of his discourse on the book of Ephesians, and said, “Ben, isn’t that right?,” at least I was paying attention. I tried to respond with a gesture that conveyed the nuance of the situation, nodding mostly yes, shaking a little no, but overall confirming that it’s the right idea, with a stately and contained mien. My wife says I quivered and grimaced, but I know what I meant.

Everyone else moved on at that point, but since I have a blog, I have unlimited verbal bandwidth to expand my expression with too many words. Here it is.

Before fixing me with his gaze, Richard had said that “All life starts with light.” He’s completely right, then he’s a little wrong, then where it matters most he’s right again. I’ll explain in three parts:

1.)    Yes, every thing started with light: When the universe was created, everything was packed into the space smaller than the size of a city block. And here, “everything” means each and every thing, atoms and energy, from neutrinos to neutron stars. Packed into such a small space, it was so hot that nothing held together and matter itself was melted. Instead, everything was photons and neutrino radiation. Only after space itself expanded could these waves of light cool down and condense into particles. Every bit of matter in you and around you right now was originally light.

That was the first event in the universe, when light was allowed to be light.*

2.)    But at first life got by without light: All this matter took an unimaginably long time to form anything that we could call “life.” Once it was created, life spread through the ancient waters and skies as tiny microbes that Moses never named. The oldest forms of life we can find didn’t live off sunlight, but squeezed energy out of various chemicals lying around the planet. They ate the earth, not the sun. These chemicals only gave energy for a meager existence, but it was all the microbes needed. But without an external source of energy, the earth would slowly run out of juice. Photosynthesis changed all this. Once life started to pull down energy from sunlight, it flourished in new ways and began to change the world (or at least its chemistry).

Even today, whole ecosystems can survive without light. Deep-sea vents give food and energy to weird red and white worms, crabs, and fish far from the reach of the sun. Near these vents, the creatures that are big enough for us to see must have drifted down from above and taken up residence by the dark, bubbling waters, eventually transforming from ordinary creatures into sub-oceanic bottom-dwellers, like Gollum wasting away under the mountains until even the memory of the sun is forgotten. Still, they have their own hidden glory and can eat and make chemicals beyond any human skill. They are so wonderfully weird that they would fit in well to a modern retelling of Job 38-42.

3.)    Complex life starts with light: It took a billion years for the gift of photosynthesis to be fully realized, and another two and a half billion years for it to have its full effect. The net effect of photosynthesis is a trick verging on alchemy: it turns sunlight, water, and exhaust (CO₂) into fresh air (oxygen) and sugar. From our human perspective, oxygen and sugar are definitely part of the good life. Our bodies and brains require huge amounts of each in order to think these thoughts and speak these words. Nothing else on the periodic table can do what oxygen does for us each day. Every breath you take and each bite you eat, something good in it comes from the sunlight pouring over our planet. This torrent of free light energy has persisted day in and day out for an unimaginable length of years. All of this is grace.

So, yes, Richard, the energy of life starts with the energy of light. Now we can even build small devices that, at the far extent of our effort and knowledge, might mimic the light-catching and energy-giving life of the everyday leaf. When we do this we’re still depending on the live-giving gift of light.

 When Paul says to live in the light, and when John says that light was the life of men, those connections are the same as before. Jesus is the light of the world. He made the sunlight and plants to give sugar and life to our bodies. He gave words of life that give sweetness and growth to our souls. There is not a firm line of distinction between the two modes of grace, and each reinforces the other.

Therefore, when the pastor asks you to confirm in front of everyone that all life starts with light, you can nod your head with confidence. Each muscle movement, however awkward, is fueled by the light.

(*By the way, don’t take this too far. This doesn’t mean that if you read the Bible carefully enough that you would come up with the Big Bang model for the creation of the universe. Rather, this means that we can work out each account on its own terms and then juxtapose them. When I set the Big Bang next to the Biblical account, the accounts make sense together and clash in interesting ways. It’s like playing two chords together on a piano to make an unresolved harmony pushing forward through time.)

The Sun of Many Colors

This video combines the different colors we can see in the sun. One of them is yellow (surprise). Several of the others are colors that we can't see and sit beyond human eyesight, but reveal features like particular helium energy emissions and things like that. Each of these wavelengths was assigned a different color that we can see in the video. It's kind of mesmerizingly beautiful, like peeling layers off of the sun to see the dynamics inside.

For more information see this blog post at Discover.

The Middle Earth Weather Report

A few years back there was a writer from Eastern Europe or Russia who wrote a version of the Lord of the Rings from Sauron's perspective, I think it was. That "Wicked"-esque stunt didn't attract my attention as much as that writer's claim that the geography of Middle Earth doesn't fit with its climate at all. I think that last comment would have rankled Tolkien (although he almost certainly didn't actually have climate in mind when drawing the maps, so he'd be right to concede the point!). It did sort of rankle me, because if you're going to make such claims you should back it up.

Yet here is a real climatologist analyzing the climate of Middle Earth and coming up with detailed weather maps of it. Lo and behold, it all fits together with Tolkien's description. The Shire's like some parts of England, and Mordor's like the Sahara and/or Los Angeles. Yeah, that works.

What initally caught my eye are two things: high CO2 levels from Mount Doom (which fits nicely with Tolkien's anti-industrial and even anti-auto bent) and how the global map of the planet looks suspiciously like our planet, if drawn by someone with the accuracy and perspective of the sea voyagers of the 16th century. Tolkien always claimed that Middle Earth was supposed to be part of our history, and that global similarity just confirms it to me.

So there you have it. Not only did Sauron cause the enslavement of peoples and the pseudo-eugenic experimental abominations of the Uruk-Hai (along with Saruman, yes, yes), he also caused global warming in Middle Earth. I knew it.

Everything You Need to Know about Radiation

When I was in tenth-grade US history, the teacher allowed us to take one sheet of paper along for the test as a crib sheet. Anything could be hand-written on that sheet of paper. I was the sort who'd cram in basically all possible text onto every inch of space so that from a distance it looked like one big blue ink-spot covering both sides of the paper. (I didn't notice at the time that in the process of creating the crib sheet I learned everything twice, so I rarely used it on the test!) If I had those same parameters for physics tests on radiation, it would have looked something like the picture below, but it wouldn't have been half as nice. Also, the fundamental physics is the same so all the information is as relevant today as it used to be when the chart was made. Enjoy! (Here is where I found it and a link to a bigger version.)

Book Review: Chemistry, Quantum Mechanics, and Reductionism by Hans Primas

Well, with a title like that, how can you go wrong? In this book, Hans Primas walks the line between physics-chemistry-mathematics and philosophy. Sections involving advanced mechanics algebra are outside of my field and it's not my field to critique those, but I found this fascinating. Two quotes by Goethe in a physical chemistry text is two more than what I've seen before, and there are other parallels I could make to Owen Barfield's arguments at times. Also, frequently Polanyi comes to mind. This book is as much philosophy as it is physical chemistry. Natural philosophy, of course.

Primas argues that it is not a trivial thing to cross from the quantum physical world to the classical physical world, and that some of the ways we "bridge the gap" mathematically don't work. To do it right, he starts from the ground up with a non-Boolean quantum logic that allows for superposition of states and also for the influence of the environment/measurement on the experiment. The biggest experimental indication that we need to do this seems to be the EPR correlations, which Primas argues shows that experiments are not as separable as we assume. I think I agree but am not enitrely convinced that EPR correlations affect classical outcomes.

Primas argues that we cannot so easily separate the experiment from the experimenter, and that we cannot build a classical physics from quantum mechanics alone. The extra ingredient we need to do so is context or observation on a classical level. Classical properties like chirality and molecular structure constrain the quantum mechanics. The world cannot be added up from quantum mechanics alone with a big enough computer, in other words.

What impressed me was the depth of philosophical thought. Primas is searching for a quantum ontology (if that's the right way to say it), and is not content with the standard "it's just what we measure, let's not think about what it means" Copenhagen interpretation. He digs back to Greek philosophy and makes the connections between his ideas and history as well as experiment and theory. He put his thoughts in the proper context, just like he argues we should do with our experiments.

It's strange to be reading a typed set of lectures from the 80's, but it worked for me, just like reading Polanyi's seminal article on similar topics still works. I found Primas by talking to Robert Bishop (philosophy of science, Wheaton) and reading his article "Whence Chemistry?" published in 2010, so people are still thinking about it, and it's not clear that Primas's objections have been adequately answered in the two decades since publication.

I'd like to list here for reference the six limits Robert mentioned to me that Primas lists, which must be crossed when moving from quantum to classical physics (p. 332ff). These are where the rubber meets the road for Primas's ideas, so they are particularly important:
1.) Shadow edges
2.) The van Hove limit
3.) The Boltzmann-Grad limit
4.) The Brownian-motion limit
5.) The Hartree limit
6.) Molecular structure (e.g., chirality)

I did not expect to get as involved in this book as I did, but it was a fascinating if somewhat vertiginous trip. Still processing and probably will be for quite some time.

PS: One useful tidbit: I did not know, or I knew but then forgot, that the Uncertainty Principle is not only found in Quantum Mechanics, but instead originated in the classical world. It's a consequence of limits on data transmittal, and in fact Heisenberg may have gotten the idea from a classical origin! So one of the prime examples of quantum weirdness actually doesn't require quanta.

PPS: As I was reading this a philosopher of science ran a pair of articles on the NYT philsophy blog about how he's frustrated at people who abuse quantum mechanics to make weird philosophical statements. I agree with him on many points but find his argument ultimately a lot less convincing on what really matters than the arguments of Primas. In fact, Primas argues forcefully against some of the statements made on that blog. Mostly, I'm frustrated with the attitude that if some people do the philosophy wrong, then EVERYONE must be doing the philosophy wrong and we all should just bite the bullet of the Copenhagen interpretation (or worse yet the Everett Many-Worlds interpretation). This is not a subject that can be resolved on a blog. Therefore ... I will shut up now!

Book Review: Weird Life by David Toomey

Books are fascinating windows into people. Take Weird Life, for example. The author is interested in the biology and physics, and in presenting a bunch of ideas, not tearing them down. On the Myers-Briggs J vs. P metric this book is clearly a Perceiving "P" not a Judging "J."  This has an important place in the ecosystem of scientific information, and it was a very entertaining book in its sheer diversity of ideas.

In this book, David Toomey describes all forms of life in the weirdest settings possible. He essentially starts with the tube worms at hydrothermal vents, which seem as weird as it gets, but wait, it gets weirder from there. At the same time, the book ventures out away from biology and toward physics, when usually you start with the physics. It becomes more and more speculative and (to this biochemist) less and less relevant as it goes on. Toomey deserves a lot of credit for describing some weird physics very well, like certain aspects of multiverse theory, better than any other book I've read. The biochemistry, on the other hand, is something I'd want much more of, but is not part of this book, reasonably so. Pretty much, this book starts with fascinating biological observations and then jumps to multiverse physics without much of the chemistry inbetween, at least at the level I would like. So I am happy to provide the chemist's perspective on this some day, I'm sure!

Weird Life does a nice job of cataloguing the biology and physics. I think I could be a lot more critical of some of the weird ideas here, and I found a few inaccuracies, but that's not really the point of a book like this. This book is a list of possibilities, and who knows, maybe some of them work. I hold out more hope for the first half of the book "working" than the second half, which gets into infinity paradoxes that, as a chemist, I think are closer to sophistry than to convincing arguments. But that's just one chapter at the end. This book is worth a read just for the discussion of Titan, that too is done better than any other treatment I've seen. Makes me want to go there, right now, where's the bus?

This was a fun book and enjoyable. Let's hope there's more material for another Weird Life book in a decade or two.

Barns Are Painted Red Because of the Physics of Dying Stars

Barns Are Painted Red Because of the Physics of Dying Stars | Smart News

The upshot of this link? Because of nuclear physics, iron has the most stable nucleus of all the elements. It just does. All else follows from this: Because iron is the most stable nucleus available, when stars smash atoms together, they will make more and make stable atoms till they get to iron, and then they will stop. Therefore there's a lot of iron, therefore iron is cheap. It's red when it combines with oxygen, so it's the most cost-effective paint pigment around, and it was used on all the barns.

I'd turn it around and say that barns and Mars are red for the same reason. Mars is pigmented like a barn.

It's interesting to think about this ... even more interesting to think about what it leaves out from the equation. But it works for a nice little blog post.

2013 Color Lecture

Every Spring when it's my turn to teach Natural Sciences Seminar I present a lecture about color, and I try to make it a unique combination of biology, chemistry, and physics. This year, lots of new information about these berries, which are the shiniest berries in the world. They can maintain bright color and shine without any pigments whatsoever. Here's the link if you're interested, the lecture itself starts about 18 minutes in.

A Map of Physics-Land, Circa 1939

Three-quarters of a century ago, this map of physics was published, its "rivers" leading from ancient Greek philosophers through to nineteenth- and twentieth-century scientists. You can find Faraday where the Electricity river joins with the Magnetism river to become Electomagnetic, because he's the prime figure in realizing those two forces are actually one and the same. Maxwell is at the junction of Light, Electromagnetic, and Mechanical into a sound labeled "Energy." Out there at the edge, Einstein and Dirac gaze out into the past future of physics.

Standing now this much farther down the river, we can see that the "Weak Force" river must have joined with "Electromagnetic" in the 70's to form the "Electroweak" river, with Salam, Glashow and Weinberg nearby.

Past that it's hard to plot history on the map. Grand unification of strong with electroweak, and of gravity with the other three, is somewhere out there, if theories check out. But they haven't, not yet.

How do we tell when we've passed from a river into a directionless swamp? Is that what String Theory is? All we have is a very nice map, but I haven't heard of any experiments yet that would confirm the reality of String Theory's extreme elegance. Multiverse theory seems to have broadened into more of a sea without direction than a river.

Apparently we found the Higgs, right where it should be. Because it was where it should be it looks like our maps have no problems with them. I can see why many physicists seem slightly disappointed with this. Where do we go next? Onward and upward to higher energies. What do we do with ourselves if our theories are perfectly right?

It's fascinating how different the physics world looks in 2013 as opposed to 1939. The first half of the twentieth century may end up being a time of discovery like no other, with a discoverer (Einstein) like no other.

Intro to Quantum Mechanics (Using Light Bulbs)

Did you know: The colors of fire are a big shining clue that light is made of discrete packets, or quanta? At least historically, the color of light emitted by a hot item led to the conclusion that light must be like a particle as well as like a wave. Via a few brains, including Einstein's. Now we can look at a star's color and tell its temperature. If you'd like to know how it all fits together (with stick figures to illustrate), here's a video of it, which you can be sure will find its way into my next physical chemistry course:

The Higgs Apocalypse (And I Feel Fine)

I thought this article was about the search for the Higgs boson, when in fact it's about the apocalypse. Funny how that happens. The connection between the two seemingly disparate things is that the currently measured mass of the Higgs boson implies that the universe is metastable. Lest this sound like a good thing it's important to remember that, since scientists think of energy the same way they think of gravity, becoming more stable = going "down" in energy, so that being "meta"/above the most stable level is a recipe for potential collapse.

If the Higgs field drops to a lower value, then everything that has mass is affected, and the delicate balance of forces that sustains matter itself reorganizes. No wonder they call the universe's current state a "critical" state!

My favorite quote from the end:

It’s a puzzle, he said, why the universe exists in such a critical state. In an e-mail, Dr. Giudice wrote, “Why do we happen to live at the edge of collapse?”
       

He went on, “In my view, the message about near-criticality of the universe is the most important thing we have learned from the discovery of the Higgs boson so far.”

      

Guido Tonelli of CERN and the University of Pisa, said, “If true, it is somehow magic.” We wouldn’t be having this discussion, he said, if there hadn’t been enough time already for this universe to produce galaxies, stars, planets and “human beings who are attempting to produce a vision of the world,” he said.

      

“So, in some sense, we are here, because we have been lucky, because for this particular universe the lottery produced a certain set of numbers, which allow the universe to have an evolution, which is very long.”

 

So the 13.7 billion years of constant physical constants (including Higgs boson mass not collpsing from its metastable state) is something to be grateful for. We're sitting on a bubble.

A couple of connections to be made here: First, this is reminiscent of Bill Bryson's A Short History of Nearly Everything in which he describes how the Yellowstone caldera is a gigantic volcano that could erupt and take this whole corner of the continential US with it. The metastable Higgs boson is the same kind of thing at a universal level. History had a beginning, and we're told it has an ending. The end is near.

Second, I realized over this weekend that two of my favorite movies (not objectively best but subjectively favorite, mind you) are Terry Gilliam's 12 Monkeys and Disney's animated Hunchback of Notre Dame. Both came out within about a year of each other and both are apocalyptic in several senses of the word. The idea of feeling on the verge of collapse is a familiar one and it makes for worthy art that resonates with, say, a college senior in 1995-1996.

But what should we do with this feeling? The answer is not to a personal collapse, or a bunker mentality. The answer is to realize that, one way or another, the kingdom of God is truly "at hand." It's sometime to wait for and anticipate, constructively. In the meantime, read Jeremiah 29, plant roots and work for the good of all around -- but don't worship the form of things that are, even now, passing away.

And be grateful for 13.7 billion years of constant,dependable physical laws. We may not get another 13.7 billion.

Book Review: Why Does the World Exist?

Spoiler alert: Why Does the World Exist? doesn't really answer its title question. Rather, the point is the journey, as you might expect from an author with a philosophy background interviewing various intellectuals and putting it together at a "magazine" level of detail. Most of the arguments I had heard before, but Holt allows the physicists and philosophers to use their own words and engages them like a student in one of their classes would. He also lets you know what he thinks about their arguments and why he finds many of them unsatisfying. I learned two things about myself from this book: 1.) My own impression that the anthropic principle is pretty powerful is indeed backed up by a large number of the intellectuals in this book, in their own ways. Although I don't think Holt is hard enough on the multiverse claims. 2.) I naturally resonated with the only two intellectuals with a theistic leaning: Richard Swinburne and John Updike. Probably confirmation bias, which shows why this is such a hard topic to explore semi-objectively, but I appreciated their inclusion in this book, and would have liked to have a few more chapters from those like them. There's a couple of simplistic swipes at theology but not too many.

I really do think theism is dismissed too readily by the modern mind because we assume that personality must be complex. The idea that a universe came from a personality rather than a mechanism is the key dividing line for me. I just don't have a problem with that. I think the irreducible part of the universe is more about personality than mechanism, and lo and behold, the theists make sense to me.  Holt is clearly on the other side of this. Is it that I tend toward stoicism and Holt toward epicureanism?

This book succeeds not because it is completely balanced, but because it is unbalanced, from Holt's point of view and with his questions and his life driving him on. The interplay of life and work is what makes this book succinct. It's not really a detective story, but it's more of a memoir at heart. That makes it work.

Have iPhone, Will Take Spectra

I've seen apps for scientific communication and even for microscopy. It was only a matter of time until someone wrote an app for an iPhone's camera to be able to separate light into its components: the iPhone spectrometer. The great thing about this is you just need some black construction paper and a diffraction grating ... and an iPhone or iPad. Then you can go around separating the light around you into rainbows that reveal how the light is made. I'm feeling a home science project coming on right now ...

Check it out here.

Is It Networks All the Way Down?

Quick: What do the brain, the Internet, and the universe have in common?

The chemist in me wants to say that electrons are very important to each, just at different scales, but that's not really a unique relationship. Rather, there may be a deep commonality among them, in that they can all be described with the same laws of network structure. This is the conclusion of a paper titled "Network Cosmology" out of the Cooperative Association for Internet Data Analysis (CAIDA), based at the San Diego Supercomputer Center (SDSC) at the University of California, San Diego.

It's almost funny to see how much science bloggers have to bend over backwards to point out that THIS DOES NOT MEAN THAT THE UNIVERSE IS A BRAIN. Please, please don't think that. It's not, nor is it a computer -- at least, if it is, I doubt we would be able to understand that it is anyway.

What it does mean is that when you graph out how these three complex networks are organized, that there are structural similarities at a surprisingly deep level. The physical forces organize the universe; the demands of life organize the brain; the demands of information flow organize the Internet. There must be structures and laws that work well for network organization, and it's very possible we haven't found the deepest, best formulations of those laws yet.

I'm fascinated by a quick observation near the end of the paper that this may have something to do with dark energy, which structures the universe. Does that mean that dark energy is a manifestion of this organization in some way? But I'm way over my head here so I'll leave that to the physicists.

One of the most beautiful things in science is the ability to see the same ordered patterns (fractals?) at multiple levels, such that the patterns fit together simply and satisfyingly. This "Network Cosmology" fits the brain, the Internet, and the universe together just so, like a major chord of three notes, and this paper feels like a major chord to me at first glance.

Now let's let wide peer review continue to do its job and see if it lasts the test of time, or if it's just a one-hit wonder.

Singing Sand: The Rocks Cry Out

Several dunes around the world "sing" when the sand is disturbed, and no one knows quite why. But now we seem to be closing in on what it is: not the shape of the dune but the type of sand in it. In other words, not so much the topography as the geochemistry and the geophysics.

The two different-sounding dunes in the video above still sound different when the sand is put in a shallow pan in the lab, and sifting the sand will change the sound. I find this all very cool. What kind of musical instruments could result from this? Something like the theremin at the very least.

More on the data, and another video, can be found here.

Beautiful, Breaking Bat

(Here I go making a pun reference to a  TV show I haven't seen but really want to start, some day ...)

I didn't see this happen but heard about it second-hand: the hit that broke open Game 7 of the NLCS last night shattered the hitter's bat and actually hit the bat two or three times. Just look at this:

Something about that is just beautiful, the way the bat bends and the ball just rolls along the line of the wavering wood of the bat, more scooped than struck. It's like one of those slo-mo water droplet pictures, and it basically meant the Giants return to the World Series and the Cardinals don't. So, more Angel Pagan!

Nice analysis of whether this was a legal hit or not, and why it faked out the shortstop, here at Fangraphs.

How to Advertise Science: Gold, Cat Pee, and Einstein's Happy Thoughts

Yes, that's really 2 oz. of gold.

This series of billboards (and other outdoor advertisements) put around Vancouver by the Vancouver Science Center shows that a clever marketing campaign is a lot like good teaching.

My favorite's either the Cat Pee one or the Gold one. I guess the gold one's classier but the cat pee one cracks me up. It's also the biochemistry one and a reason to carry around a UV light on your keychain (well, I do, in fact, why do you ask?).

Hopefully in my biochem lectures I can capture this spirit sometimes. This is what science teaching is about.

Oh, and thanks to my fellow physics prof that I co-teach a science seminar with, I now know that this particular advertisement ...

... has a unique place in science history, because it is this thought in 1907 led Einstein to the theory of relativity (his "happiest thought" of his life). It's an amazing world if a scale in an elevator can lead, through the right train of thoughts, to predictions of black holes and gravity warping space itself.

[reflink]

LEGO to Teach Color Inversion?

So there's a use for all those pink pieces after all! If you build something like this:

And then invert the colors of the picture, it suddenly looks like this:

Something tells me someone could make a pretty cool color physics learning exercise out of something like this ... let the students build structures and invert the colors to see what happens.

[backlink]

Video Games, for Science!

If my childhood was any example then I spent many hours developing the dexterity of my thumbs and the ability to plan any number of jumps across moving platforms floating in mid-air while collecting golden coins. But for some reason none of that got on my resume. Is there any way to make video games actually educational?

Today's New York Times has a profile of Valve, makers of the video games Half-Life and Portal. Portal I can vouch for as a video game good enough that it's worth playing even with my first-person-perspective motion sickness. ("Portal: Worth the Headache").  Portal has such a detailed physics engine behind it, and such simple controls, that you can use it to teach physics. This article links to lots more articles about how that can be done, for instance, turning Portal's cube into a harmonic oscillator. Maybe someday one of the required texts for physics will be a copy of Portal?

Video games can be used to teach immunology, too, although the case of Immune Attack is different because gameplay follows education, and it's clear that results in a different kind of game.

I didn't know just how unusual (that is, absent) Valve's corporate structure is. It's fascinating that they can get that to work to make these great games.

The Van Gogh Painting Hidden in the Sun's Corona

Quick question: Is the sun solid, liquid, or gas? I know, trick question ... it's none of the above, mostly being composed of plasma, a fourth state of matter beyond the typical three terrestrial states. Being its own unique state of matter, scientists are going to study it, and even something as simple as watching it heat up and cool down can yield unusual beauty.

Here's a picture of how the temperature of the sun's plasma changes:

Here's a video of how they did it:

And here's links to previous entries on the blog about how an island, the ocean and dominoes can look like Van Goghs, with various degrees of intentionality. Apparently since this is the fourth post on this kind of things, I need to create a category for "Van Gogh" in my labels section.