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Incorporating a stable fluorenone unit into D-A-[small pi]-A organic dyes for dye-sensitized solar cells

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM33105E, PaperChuanjiang Qin, Ashraful Islam, Liyuan Han
Two novel fluorenone-based organic dyes were synthesized, characterized, and successfully employed in dye-sensitized solar cells.
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The content of this RSS Feed (c) The Royal Society of Chemistry

Synthesis of zeolitic imidazolate framework-78 molecular-sieve membrane: defect formation and elimination

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM34102F, PaperXueliang Dong, Kang Huang, Sainan Liu, Rufei Ren, Wanqin Jin, Y. S. Lin
A reactive seeding route combined with a novel activating strategy was proposed for the preparation of a high-quality ZIF-78 molecular sieving membrane.
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The content of this RSS Feed (c) The Royal Society of Chemistry

Controlled synthesis of CdTe nanocrystals for high performanced Schottky thin film solar cells

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM34280D, PaperShi Sun, Hongmei Liu, Yuping Gao, Donghuan Qin, Junwu Chen
CdTe NCs solar cells devices were prepared by a layer by layer sintering process using a relatively low concentration of CdTe NCs with a thickness of about 500 nm. These optimal conditions can give rise to increased ITO/CdTe/Al solar cell performance.
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The content of this RSS Feed (c) The Royal Society of Chemistry

Facile preparation of three-dimensionally ordered macroporous Bi2WO6 with high photocatalytic activity

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM34211A, PaperSongmei Sun, Wenzhong Wang, Ling Zhang
Three-dimensionally ordered macroporous Bi2WO6 (3DOM Bi2WO6) with mesoporous walls is prepared successfully and functions as a highly efficient photocatalyst.
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The content of this RSS Feed (c) The Royal Society of Chemistry

Oxygen diffusion mechanism in the mixed ion-electron conductor NdBaCo2O5+x

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM34396G, CommunicationY. Hu, O. Hernandez, T. Broux, M. Bahout, J. Hermet, A. Ottochian, C. Ritter, G. Geneste, G. Dezanneau
3D oxide ion diffusion maps in NdBaCo2O5+x as obtained from neutron diffraction and molecular dynamics simulations.
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The content of this RSS Feed (c) The Royal Society of Chemistry

Can morphology tailoring based on functionalized fullerene nanostructures improve the performance of organic solar cells?

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM33380E, CommunicationLie Chen, Kai Yao, Yiwang Chen
The crystallinity of P3HT and phase segregation can be controlled by adding various supramolecular assemblies of fullerenes.
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The content of this RSS Feed (c) The Royal Society of Chemistry

Crystalline indium sesquitelluride nanostructures: synthesis, growth mechanism and properties

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM33760F, PaperMuhammad Safdar, Zhenxing Wang, Misbah Mirza, Chao Jiang, Jun He
In the present work, we report for the first time the growth of uniform single crystalline In2Te3 nanowires via the chemical vapor deposition (CVD) method. In addition, polycrystalline hierarchical nanostructures of In2Te3 are also fabricated via a solvothermal method under low temperature conditions.
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The content of this RSS Feed (c) The Royal Society of Chemistry

Tetrachloroperylene diimide functionalized reduced graphene oxide sheets and their I-V behavior by current sensing atomic force microscopy

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM34379G, PaperZhongjie Ren, Dianming Sun, Jianming Zhang, Shouke Yan
Tetrachloroperylene diimide functionalized reduced graphene oxide shows different electric conductivity and optical properties when the grafting efficiency and dispersion used for casting are varied.
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The content of this RSS Feed (c) The Royal Society of Chemistry

One bipyridine and triple advantages: tailoring ancillary ligands in ruthenium complexes for efficient sensitization in dye solar cells

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM34558G, CommunicationM. Chandrasekharam, M. Anil Reddy, Surya P. Singh, B. Priyanka, K. Bhanuprakash, M. Lakshmi Kantam, A. Islam, L. Han
Unsymmetrical bipyridines as ancillary ligands allows tuning the properties of ruthenium sensitizers (MC103-MC106) for DSCs in multi-directions to enhance their efficiency in the sensitization of nanocrystalline TiO2 without increasing steric bulk of the molecule.
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The content of this RSS Feed (c) The Royal Society of Chemistry

[small beta]-Vesignieite BaCu3V2O8(OH)2: a structurally perfect S = 1/2 kagome antiferromagnet

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM32250A, CommunicationHiroyuki Yoshida, Yuichi Michiue, Eiji Takayama-Muromachi, Masaaki Isobe
Ideal kagome antiferromagnet [small beta]-vesignieite BaCu3V2O8(OH)2, which has 3-fold rotational symmetry in the crystal structure and magnetic interaction within the kagome lattice.
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The content of this RSS Feed (c) The Royal Society of Chemistry

Functional heterometallic coordination polymers with metalloligands as tunable luminescent crystalline materials

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM34661C, PaperDong-Ying Du, Jun-Sheng Qin, Cheng-Xin Sun, Xin-Long Wang, Shu-Ran Zhang, Ping Shen, Shun-Li Li, Zhong-Min Su, Ya-Qian Lan
Five EuxTby-based coordination polymers were prepared by the combination of hydrothermal and ionothermal methods. The luminescence of IFMC-21-25 was investigated and the intensities of red and green colors are shifted correspondingly by tuning the ratios of Eu(III) : Tb(III).
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The content of this RSS Feed (c) The Royal Society of Chemistry

Nitrene-functionalized ruthenium nanoparticles

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM33783E, PaperXiongwu Kang, Yang Song, Shaowei Chen
Ruthenium nanoparticles were stabilized by nitrene fragments with the formation of Ru[double bond, length as m-dash]N bonds at the metal-ligand interface. The resulting nanoparticles exhibited unique reactivity towards alkenyl derivatives by imido transfer reactions.
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The content of this RSS Feed (c) The Royal Society of Chemistry

Synthesis of large-scale undoped and nitrogen-doped amorphous graphene on MgO substrate by chemical vapor deposition

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM33209D, PaperJin Zhao, Guoyin Zhu, Wen Huang, Zhi He, Xiaomiao Feng, Yanwen Ma, Xiaochen Dong, Quli Fan, Lianhui Wang, Zheng Hu, Yinong Lu, Wei Huang
Undoped and N-doped a-graphene have been prepared on a MgO single crystalline substrate using a CVD process. The layer number could be modulated by varying the reaction temperature.
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The content of this RSS Feed (c) The Royal Society of Chemistry

Soluble porphyrin donors for small molecule bulk heterojunction solar cells

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM33956K, PaperJunichi Hatano, Naoki Obata, Shigeru Yamaguchi, Takeshi Yasuda, Yutaka Matsuo
Soluble magnesium tetraethyl porphyrins were designed and synthesized for solution-processed organic photovoltaic devices, showing a power conversion efficiency of 2.5%.
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The content of this RSS Feed (c) The Royal Society of Chemistry

A biochemical logic approach to biomarker-activated drug release

J. Material Chem. - 20 August, 2012 - 08:17

J. Mater. Chem., 2012, Advance Article
DOI: 10.1039/C2JM32966B, PaperVera Bocharova, Oleksandr Zavalov, Kevin MacVittie, Mary A. Arugula, Nataliia V. Guz, Maxim E. Dokukin, Jan Halamek, Igor Sokolov, Vladimir Privman, Evgeny Katz
An integrated system logically processing biomarkers and releasing a drug-mimicking material was developed to demonstrate a new "Sense-Act-Treat" concept.
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The content of this RSS Feed (c) The Royal Society of Chemistry

Weekend Recap: My Annular Eclipse Expedition! [Starts With A Bang]

Science Blogs Physcial Sciences - 22 May, 2012 - 05:11

"A little more persistence, a little more effort, and what seemed hopeless failure may turn to glorious success." -Elbert Hubbard I've had the great fortune in my life to see a great many wonderful things with my own eyes, including the rings of Saturn, the phases of Venus, a couple of faint, distant galaxies, and a large number of sunsets, sunrises, and lunar eclipses. But as far as solar eclipses go, I missed the only realistic opportunity I ever had to see -- as Cara Beth Satalino would say -- that

Shimmering Thing.

Back in 1994, an annular solar eclipse happened just 300 miles from where I was living. While I got to see the partial eclipse that resulted from being off of the ideal path, I'd never seen either a total or annular solar eclipse. But this weekend was my big chance, and I wasn't going to miss it. For the first time, I set out on an eclipse expedition, hoping to catch a glimpse of the spectacular sights that one of my former astronomy students had grabbed hours earlier from Tokyo.

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(Image credit: Destiny Fox. Thanks, Destiny!)

As many of you know, I've been preparing for this for a couple of months, and that started with scouting out a prime location. The one I chose was right on the coast, for the earliest possible view from America, right in the middle of the path of maximum eclipse.

location.jpg

Choosing the middle of that path means that I was going to get to see -- if the conditions were ideal -- the Moon pass over the dead center of the Sun, creating a true ring of fire. The place where this was going to happen was False Klamath Cove, a rock-littered area in very northern California. But this place was "only" about 330 miles from where I live today, in Portland, Oregon, and so I made the trip down. About an hour before maximum eclipse, this was the view I had.

FalseKlamathCove.jpg

Yes, it was somewhat cloudy, and I knew the clouds and fog would be continuing to roll in, but it wasn't hopeless. You see, the clouds were thin enough that the "binocular trick," where you un-cap one side of a pair of binoculars and project the image of the Sun onto a white screen behind it, was still very effective.

binocs.jpg

As you can see, you were still able to see the Sun's disk, as well as the fraction of it that was obscured by the Moon. But I wasn't going to settle for a projection of the Sun's disk onto a screen; I wanted to see it with my own eyes. And so that meant bringing a little protective eyewear. In addition to my polarized sunglasses, I also brought along two wonderful pieces of equipment: a pair of shade-5 welder's goggles and a shade-10 welder's hood.

ethanspecs.jpg

Under sunny, high-noon conditions, you need shade-14 to safely look at the Sun. Thankfully, eye protection is additive, so wearing both of these together meant that I could look at the Sun without concern for safety.

ethanmask.jpg

I'm not going to lie: other than a green tint, this view was spectacular. The Sun was crisp, the clouds could be seen dancing across its face, and the fraction that was obscured by the Moon was cleanly and clearly visible. I'm definitely going to be using both of these, together, to watch the Venus transit in a couple of weeks.

But for photography? That's never been a skill (or even an interest) of mine, so all I could do was experiment. Placing the shade-5 goggles in front of the camera was clearly not enough.

shade5.jpg

While the cloud cover was light, as it was in the early stages of the eclipse, it turns out that the shade-10 hood, on its own, was significantly better than the goggles.

sunbean.jpg

You could see, with the camera, that part of the Sun was obscured, but the image was still greatly overexposed, making it virtually impossible to see any detail.

I tried using both the goggles and the hood together. But the combination that worked so well for my eyes was a miserable failure for the camera.

shadeten.jpgshadeten2.jpg

As you can see, the Sun's disk still appeared overexposed, plus now there were problems of multiple reflections between the different surfaces, ruining the image on the camera.

But as we neared the moment of maximum eclipse, and the Sun dwindled to a crescent, slowly creeping around the edges of the Moon, something both wonderful and horrifying began to happen. Thick, foggy clouds began to roll in, as they do every evening in this part of the world at this time of the year. But it meant something wonderful for my feeble photography skills.

closingin.jpg

My images were suddenly less over-exposed. And as the fog rapidly thickened, I discovered that I no longer needed shade-15 protection to watch the eclipse. I no longer needed shade-10, in fact. At the moment of maximum eclipse, I had nothing but the shade-5 welder's goggles over the lens of the camera, and this was the photo I got.

GEDC1176.JPG

Digital cameras, of course, get outstanding resolution. So this perfect circle, this ring of fire, actually showed up like this.

perfectcircle.jpg

There's no way to describe what it's like to see it with your own eyes, but my experience was probably extremely unique, because rather than watching the Moon move off of the Sun, I watched this ring of fire fade away behind some ever-thickening clouds, and disappear from sight.

And that's why even though there are no more pictures from my first eclipse expedition, you can bet it won't be my last!

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Categories: Education

Another Week of GW News, May 20, 2012 [A Few Things Ill Considered]

Science Blogs Physcial Sciences - 21 May, 2012 - 16:34

Logging the Onset of The Bottleneck Years
This weekly posting is brought to you courtesy of H. E. Taylor. Happy reading, I hope you enjoy this week's Global Warming news roundup

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Categories: Education

It's supposed to hurt to think about it! [Starts With A Bang]

Science Blogs Physcial Sciences - 19 May, 2012 - 21:09

"But some of the greatest achievements in philosophy could only be compared with taking up some books which seemed to belong together, and putting them on different shelves; nothing more being final about their positions than that they no longer lie side by side. The onlooker who doesn't know the difficulty of the task might well think in such a case that nothing at all had been achieved." -Wittgenstein One of the most fundamental questions about the Universe that anyone can ask is, "Why is there anything here at all?"

20090304.jpeg

(Image credit: Patrick at vignetted.com.)

Out beyond Earth, of course, there are trillions of other worlds within our own galaxy, and at least hundreds of billions of galaxies within just the part of our Universe that's observable to us.

hubbledeepfield.jpeg

(Image credit: NASA, ESA, S. Beckwith (STScI) and the HUDF Team.)

Explaining where all the matter in the Universe comes from is one thing. What you traditionally think of as something -- that is, the plants, animals, elements, planets, stars, galaxies and galaxy clusters -- that's one question.

How and when all of that got here? That's something we think we can answer.

Timeline%20of%20the%20Universe.png

(Image credit: me, as a New Year's present to you.)

But there's an even more fundamental question than that. In order to have our Universe, you need to start with what, as a physicist, I call nothing.

You need to start with empty spacetime.

spacetime1.jpeg

And you can start with the emptiest spacetime imaginable: something flat, devoid of matter, devoid of radiation, of electric fields, of magnetic fields, of charges, etc. All you would have, in that case, is the intrinsic zero-point energy, or the ground state, of empty space.

From a physical point of view, that's what nothing is. Only, perhaps perplexingly, that zero-point energy? It isn't zero.

quantumfoam.jpeg

(Image credit: Brian Greene's Elegant Universe.)

If it were, we wouldn't have a Universe filled with dark energy, and yet we do. Instead, spacetime has a fundamental, intrinsic, non-zero amount of energy inherent to it; that's what's causing the Universe's expansion to accelerate! What's even more bizarre than that is the fact that all the matter and energy in the Universe today came from a drop, long ago, from an even higher zero-point-energy state. That process -- reheating -- is what comes at the end of an indeterminately long phase of exponential expansion of the Universe known as cosmic inflation.

figure3.jpeg

(Image credit: Ned Wright.)

The regions of space where this drop in zero-point energy occurred gave rise to regions of the Universe like ours, where matter and energy exist in abundance, and where the expansion of spacetime is relatively slow. But the regions where it hasn't yet occurred continue to have an extremely rapid rate of expansion. This is why physicists state that inflation is eternal, and this is also the physical motivation for the existence of multiverses.

In the diagram below, regions marked with red X's are regions where the drop in zero-point energy occurs, and a region of the Universe like ours comes into existence.

eternal_inflation.jpeg

(Image credit: me, created especially for you last year.)

That's the physical story of where all this comes from. Of where our planets, stars, and galaxies comes from, of where all the matter and energy in the Universe comes from, of where the entire 93-billion-light-year wide section of our observable Universe comes from.

From a scientific perspective, we think we understand not only where all of this comes from, but also the fundamental laws that govern it. So when a physicist writes a book called: A Universe from Nothing, I know that some version of this story -- the scientific story of how we get our entire Universe from nothing -- is the one you're going to get told.

It's a remarkable story, it's perhaps my favorite story to tell, and it's certainly been the greatest story I've ever learned. But in at least one way, it's a dissatisfying story. Because the scientific definition of "nothing" that we use -- empty, curvature-free spacetime at the zero-point energy of all its quantum fields -- doesn't resemble our ideal expectations of what "nothing" ought to be.

I01-16-quantumfoam.jpeg

(Image credit: retrieved from Universe-Review.ca.)

No one sufficiently versed in the science of physical cosmology (and being sufficiently honest with themselves about it) would argue against this: that the entire Universe that we know and exist in comes from a state like this, that existed some 13.7 billion years ago. But you may rightfully ask, "Is that truly nothing?"

This empty spacetime definition of what is physically nothing stands in contrast to what we can imagine as what I'll call pure (or philosophical) nothingness, where there's no space, no time, no laws of physics, no quantum fields to be in their zero state, etc. Just a total void.

IxtyCwgXrqrqcrroTy62vmcEo1_500.jpeg

This has been the source of much argument recently, as the answer to the physical question of where everything comes from does not necessarily answer the philosophical one. It certainly pushes it off for a while, but it still leaves unexplained the existence of spacetime and the laws of physics themselves. There has been bickering back-and-forth with a handful of physicists and philosophers arguing as to whether this physical story really explains why there is something rather than nothing?

It is a remarkable story, of course, and it explains where every galaxy, every star, and every atom in the Universe comes from, an astouding feat.

cosmic-inflation-don-dixon.jpeg

(Image credit: Don Dixon.)

But it doesn't explain, existentially, why spacetime or the laws of nature themselves exist, or exist with the properties that they have. In short, understanding how something comes from nothing does not explain how this physical state of nothing comes from an existential nothingness. This question of why, as enunciated by Heidegger, is not addressed by our physical understanding of the Universe. But is it a fair question?

Like the oft-dismissive Wittgenstein, I'm not sure. We make this inherent assumption that both spacetime and the laws inherent to our Universe come from somewhere. Yet our classical notions and intuitions about causality are violated even within our known Universe; do we have good reason to expect that this non-universal form of logic applies to the very existence of the Universe itself? Furthermore, how can something, even figuratively, come from anything else if you remove time?

One can, of course, imagine answers to these questions: an entity of some sort that exists outside of time and thus has access to all times equally, a type of hidden-variable logic that exists as part of reality but requires the knowledge of things that are presently unobservable to us, a higher-dimensional being who sees our entire Universe no differently from how an animator sees the elements of a two-dimensional cartoon, etc.

6a010536b5599f970c0133ec3e518f970b-500wi.jpeg

(Image credit: Chuck Jones / Warner Brothers Studios.)

None of these answers are convincing or compelling, mind you, and I am not sure that the questions do even make sense as far as reality is concerned. But just because we cannot yet know the answers, or whether the questions are sensible as far as reality is concerned, doesn't mean there isn't value to asking them and thinking about them. To me, that's what philosophy is. I would encourage everyone to remember the words of my favorite philosopher, Alan Watts: The reason for it is that most civilized people are out of touch with reality because they confuse the world as it is with the world as they think about it, talk about it, and describe it. On the one hand, there is the real world, and on the other, a whole system of symbols about that world that we have in our minds. These are very very useful symbols -- all civilization depends on them -- but like all good things, they have their disadvantages, and the principal disadvantage of symbols is that we confuse them with reality. For whatever it's worth, when I think of nothing, I think about empty spacetime and the physical Universe: that's where my interests lie, and that's where I believe the knowable lies. But that doesn't mean there isn't something wonderful to be gained from philosophizing. As Alan Watts himself said:

(Video credit: dFalcStudios.)

And as well as this explanation actually describes what I think about the Universe, it didn't come from a physicist. So let's stop accusing each other -- physicists and philosophers -- of being bad at one another's disciplines, and let's work on getting it right. Education is always worth it. Read the comments on this post...


Categories: Education

How to Teach Relativity to Your Bay Area Dog [Uncertain Principles]

Science Blogs Physcial Sciences - 18 May, 2012 - 20:46

sidebar_relativity_cover.jpgSo, you find yourself living in the San Francisco Bay area, and you maybe have a dog who would like to know something about relativity, or you maybe want to someday have a dog who will want to know something about relativity, or you maybe want to know something more about relativity yourself, in case you ever find yourself cornered in a dark alley by a Rhodesian ridgeback who snarls "Explain time dilation to me, or I'll eat your face!" Well, in that case, you definitely want to be at Kepler's Books in Menlo Park on the evening of June 14th, when I'll be doing a book promotion thing for How to Teach Relativity to Your Dog.

So, here's your chance to hear me do the silly dog voice in person, and maybe get a book signed. Emmy won't be making the trip (I doubt she'd do well on a plane...), but I'm looking forward to it.

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Categories: Education

Reverse Terraforming (for Supervillains only) [Starts With A Bang]

Science Blogs Physcial Sciences - 17 May, 2012 - 17:04

"The Earth destroys its fools, but the intelligent destroy the Earth."
-Khalid ibn al-Walid Usually, when we talk about terraforming, we think about taking a presently uninhabitable planet and making it suitable for terrestrial life. This means taking a world without an oxygen-rich atmosphere, with watery oceans, and without the means to sustain them, and to transform it into an Earth-like world.

The obvious choice, when it comes to our Solar System, is Mars.

MarsTransitionV.jpeg

(Image credit: Daein Ballard.)

The red planet, after all, is not a total stranger to these conditions. On the contrary, for the first billion-and-a-half years of our Solar System, give or take, Mars was perhaps not so dissimilar to Earth. With evidence that there was once liquid water on the surface, a thicker atmosphere, and possibly even life, there's no doubt that the right type of geo-engineering could bring those conditions back.

But there's also no doubt that we couldn't, if we were sufficiently motivated, turn the Earth from this...

Nasa_blue_marble.jpeg

(Image credit: NASA / GSFC / NOAA / USGS.)

into a world where the atmosphere and the oceans were stripped away. Into a dry, nearly airless world, much like Mars.

waterlessearth_woodshole_950.jpeg

(Image credit: Jack Cook / WHOI, Howard Perlman / USGS.)

Inspired by a recent Astronomy Picture of the Day, above, it's now time to tell you how I would, scientifically, remove the oceans from the planet. It's a process I like to call reverse terraforming, whereby you turn a world the Earth into a world like Mars.

At present, this is difficult for a number of reasons, but here's the biggest one.

magfieldG_b.gif

(Image credit: Natalie Krivova.)

The Earth's magnetosphere! The same reason that your compass needle points towards the magnetic poles of Earth is the only thing keeping our oceans here on our world! The Sun is constantly shooting out a stream of high-energy ions, known as the solar wind, at speeds of about 1,000,000 miles-per-hour (1,600,000 km/hr).

DialPlot.jpeg

(Image credit: NASA / GSFC; the Ace satellite.)

As the solar wind runs into a world, these ions collide with particles in a planet's atmosphere, giving those molecules enough kinetic energy to escape from the planet's gravitational field.

Of course, we have a powerful magnetic shield from the solar wind thanks to our hot, dense and (partially) molten core. Our planet's magnetic field successfully bends away practically all of the solar wind particles that would be in danger of colliding with us, with the occasional exception of the polar regions, where the ions -- and hence sometimes aurorae -- get through.

earths-magnetic-field.gif

(Image credit: NASA, retrieved from Cloudetal.)

Right now, our atmosphere is pretty thick: it consists of some 5,300,000,000,000,000 tonnes of material, creating the atmospheric pressure that we feel down here at the surface. There's so much pressure, in fact, that our Earth can sustain liquid water on the surface.

h2o_phase_diagram_-_color.jpeg

(Image credit: David Mogk, Montana State University.)

The ability to have liquid water is relatively rare: we need the proper temperatures and the proper pressures! That means we need at least at atmosphere of a certain thickness, a characteristic that Mars, Mercury, and the Moon totally lack. But we've got it, and hence we can have liquid water on our surface.

And do we ever! There's much more water than there is atmosphere. About 250 times as much, by mass, is the amount that the oceans outweigh the atmosphere, meaning that the oceans comprise about 0.023% of the Earth's total mass!

But we could get rid of all that liquid water, eventually, by letting the solar wind in.

breachmodel.jpeg

(Image credit: NASA / Themis mission.)

When the Earth and Sun's magnetic field align, something like 20 times as many particles as normal make it through. Charged particles are bent by magnetic fields in very predictable ways, and if we could control those fields, we could control how much of the solar wind made it through.

In other words, if we could create a large enough magnetic field on Earth, we could poke a hole in the magnetosphere and allow the solar wind to strip our atmosphere away!

mars_atmos_1.jpeg

(Image credit: NASA, retrieved from futurity.org.)

Something similar happened to Mars about 3 billion years ago, when its core stopped producing that powerful magnetosphere shield, and its atmosphere got stripped away. When the pressure at the surface dropped below a certain level, the liquid oceans there could only exist as frozen ice or boiled off as water vapor. (And once they're water vapor, they become part of the atmosphere, where it, too, can be stripped away by the solar wind!)

It may not be fast enough for the most supervillainous among you, but one thing's for sure.

aurora_salomonsen_big.jpeg

(Image credit: flickr user Ole C. Salomonsen.)

If we do poke a hole in the magnetosphere and allow the solar wind in, I'll definitely be enjoying the auroral show!

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Categories: Education

WebElements: the periodic table on the WWW [http://www.webelements.com/]

Copyright 1993-2011 Mark Winter [The University of Sheffield and WebElements Ltd, UK]. All rights reserved.