The Earth Story

Let there be Light: The Making and Death of Stars

Hubble has spent nearly 30 years sending us the most amazing and dazzling photos of our Universe. Hubble has literally expanded the frontiers of human knowledge. Using it to peer deep into space and back in cosmic time, astronomers learned that galaxies formed from smaller patches of ‘stuff’ in the early universe by capturing light from newborn galaxies as it looked 13 billion years ago. The creation of this light is made from the billions of stars out there, illuminating our universe for all to see. How is this light created? How are stars made and what happens once they have used up all their energy? Lets take a brief look at the making and death of stars. First of all, some basic facts about our Sun. Our Sun is a G2 V type main sequence dwarf star (medium sized), at the center of the solar system and contains nearly 99.8% of the solar systems mass. The colour is whitey green but appears yellowish due to the scattering of blue light in the atmosphere. It is a population I star, that being rich in heavy elements, (high metallicity). The Sun was probably formed from a high proportion of material from prior supernova events (death of super massive stars way bigger than our own). Its composition is about 74% Hydrogen, 24% Helium, 0.8% Oxygen, 0.3% Carbon and 0.2% Iron. Its gravity is about 28 x the Earth’s and is about 150 million km (93 205 678.8 miles) away from Earth, or just over 8 light minutes.

Each star is different, but starts life the same way in clouds and dust called Nebulas, stellar nurseries for stars such as Orion, Eagle and Horse head to name but a few. To make a star, all you need is gravity, hydrogen and time. Gravity pulls the hydrogen gas into a swirling vortex. Gravity brings matter together and when you 'squeeze' things together in smaller spaces, they heat up, basically when you compress something you drive the temperature up. Over 100's and 1000's of years the cloud gets thicker, a large spinning vortex as big as our solar system and at the centre a large dense spinning ball where the pressure builds until large jets of gas burst out at the sides. Eventually a star ignites, throwing off any remainder gas out. With a temperature of 15 million degrees at the core, atoms of gas fuse together. BOOM! A star is born.

So, we now know how a star is created, what about what drives stars energy then? Atoms of Hydrogen smash into each other, this process is called fusion. Hydrogen atoms naturally repel one another, chemistry 101, but if they travel fast enough, really fast, they crash into each other, fusing together to make helium, heat with a small amount of pure energy. The hydrogen gas weighs slightly more than helium, loosing mass during the collision in which this mass turns into energy. Stars are huge, and to drive this you need gravity to compress the star to create nuclear fusion at its core.

What happens when the fuel runs out? Well, eventually it will run out, bigger stars use their fuel more quickly so the bigger the star the shorter its life. Gravity is in a constant battle with the stars fusion process that they balance each other out, however gravity eventually wins the battle. Our Sun is no exception, every second it burns 600million tones of its hydrogen fuel. As hydrogen gets used up, the core slows down giving gravity the edge, with less fusion pushing outward, gravity pushes inward and as fusion fights back the star begins to expand. This is called the red giant stage that will consumes all the inner rocky planets, and most likely even the Earth. This is the end of our beautiful planet Earth (although some theorists think that this process may ‘push’ Earth further out). With no hydrogen left to fuel it, the star starts to burn helium and fuses it with carbon. Blasting energy from its core to the surface, these energy waves blow away the stars outer layer and slowly it disintegrates into a “white dwarf”. A white dwarf is so dense that if a sugar cube amount were placed on Earth, it would fall right through it. Astronomers believe that in the core of a white dwarf there is solid carbon, literally a diamond in the sky!

This is the outcome of our star, but what about bigger ones? Larger stars have a much more violent ending than our G type star. The gravity of these stars is so massive that they can smash together bigger and bigger atoms. The cores of these stars are like factories, manufacturing heavier and heavier elements, which lead to the stars destruction. Gold, Silver, Nickel and other elements are all created in these stars. The next time you wear your gold chain or ring, just think, it wasn't created here on Earth, but in the death of a super massive nova. Once the star starts to make iron, this is the end. Iron absorbs the energy in a 1000th of a second, robbing it of its remaining fuel until gravity wins and the star collapses. It creates a huge explosion, a supernova and the single most violent event in the universe, spewing everything out into space. Then, the whole process of star formation begins again. If it wasn't for these massive explosions, our Sun wouldn't be here, therefore so wouldn't we.

There is only so much hydrogen in the universe and astronomers believe that eventually, the entire universe will simply run out of the star forming gas and eventually the lights will all go out. Thankfully, we will not be around to see this, nor see the death of our own middle-aged star in about 4.57 billion years. We have a long time to appreciate it and be thankful for its life giving ingredients. To be thankful that its rises, sets and rises again, because without it, it’s goodnight sweetheart smile emoticon

Carbon, Oxygen, Iron in our blood, Everything around us came from the belly of a star. We are in a 'golden age' of the universe. A good time to be here, seeing the best of all stages of the universe, filling the darkness with light. For we are all made of stardust.

~ JM

Image Credit: http://bit.ly/1FnZ8dV

More Info:

Hubble: http://hubblesite.org/

Sun Facts: http://bit.ly/1xqjsaz

NASA Solar Dynamics Observatory:http://sdo.gsfc.nasa.gov/

Space Weather: http://www.spaceweather.com/

Encyclopaedia Britannica: http://bit.ly/1CiFOPI

Stellar Evolution: http://bit.ly/1BkXinG

NASA astronaut Reid Weisman snapped some shots of the captivating Northern Lights from the International Space Station. The northern lights, more appropriately the the aurora borealis, are caused by geomagnetic storms that occur when charged particles from the sun interact with the Earth's magnetic field, exciting oxygen and nitrogen in the Earth's upper atmosphere. The colour of the aurora depends on which atom is first struck and at what altitude. For example, the green colour in this image is the result of electrons interacting with oxygen molecules at an altitude up to 241Km (150 miles). Jean See more awesome images on Reid's personal twitter here: http://bit.ly/1naWxaX Image courtesy of Reid Weisman

Why are there so many colors of minerals?

We share a whole lot of mineral images on this page, many of which would qualify as gemstone if the stones are pristine enough. One great question for anyone who deals with minerals or gems is…where does the color come from?

Many minerals, when they are pure, are either completely colorless like quartz, or a single strong color, like hematite which will be dark black when found as a chunk. But on the other hand, there are minerals like corundum (aluminum oxide) which can be colorless, bright red as a ruby, blue as in a sapphire, or even pink and orange as in the rare padparadschah.

The scientific definition of a mineral is that it is a solid substance found in nature with an atomic structure that is consistent and repetitive over a distance. In other words, it is a crystal made up of atoms put together in a constant sequence.

The key to the color for many minerals, as explained in this chart, is found in that setup. A single crystal is made up of a huge number of atoms. Sometimes, when a crystal grows, it can substitute the wrong atom into a spot; iron going into quartz for the silicon atom or chromium going into corundum in place of aluminum.

These impurities can fit into spots in crystals some, but often not perfectly. They may vibrate around or they may bond incorrectly with the surrounding oxygen atoms, changing how the electrons in the structure join together.

Electrons are the keys to color. When electrons are able to move within the structure of minerals, they are able to absorb light and create colors that we are able to see.

This chart outlines how color forms in many common minerals and gemstones. Almost all of them follow a certain format; the wrong element goes into a crystal in a small amount, creating unpaired or mobile electrons that interact with light passing through the crystal structure.

-JBB

Image credit: Compound Chemistry (creative commons license): http://www.compoundchem.com/2014/06/29/what-causes-the-colour-of-gemstones/

Temperatures soared in China as glaciers retreated

One of the realities about “global climate change” is that the change seen by any specific location on the planet is very hard to predict. The temperature on the whole planet may change by a certain amount, but some places will change by much more and others not at all.

Right now, we’ve got a great example of this effect illustrated by the Earth’s poles. The climate is warming due to increased atmospheric CO2, but most places on Earth have warmed only slightly except for the poles. Close to the North Pole and in areas surrounding Antarctica, including the Antarctic Peninsula, temperatures have shot upwards at rates much faster than the rest of the globe.

Altogether, that means if we want to understand how the world will change due to the massive increase in atmospheric CO2 over the last century, we need not just to know how the average will change, we need records of what happened in individual places.

During the last glacial period, the wind currents coming across Central China built large deposits of wind-blown dust known as loess. The dust that built these piles was mostly sourced from the deserts in Northern and Western China and can be useful for scientists because it contains layers. Layering in loess can be related to seasons, years, and climate cycles, and thus can give information on time.

If we had a way to measure it, therefore, this section could be a great way of understanding how temperatures changed in a landlocked area far away from the glaciers. Using a new technique called “clumped isotope” measurements, researchers from UCLA this week reported exactly that data.

The clumped isotope measurement is a newly developed technique that allows for estimates of temperature to be created on all sorts of rocks, including things that weren’t formed from the ocean. Therefore, it’s the perfect tool to try to unlock the temperature history of a place like Central China, where carbonate shells that can be measured grew from lakes and rivers as the loess plateau was built.

The researchers collected carbonates from this section, measured the isotopes, converted them to temperatures, and found that the temperature change in this area between the last glacial maximum and now was 6-7 degrees Celsius (12-14 degrees Fahrenheit). The global temperature rise during this same period is about 3 degrees, so this part of China warmed twice as much as the average globe.

This temperature change probably tells us a lot about the atmosphere at the time. It probably tells us that at the last glacial maximum, this part of China was receiving most of its air from the north; it was receiving colder air and was part of the circulation pattern closer to the poles. When the atmosphere changed, this part of China started feeling the influence of the warmer climates to the south.

This research carries several messages for the modern era. First, it will help calibrate models for how climate can shift in local areas. Second, and probably more important, it is a reminder that unexpected areas could be vulnerable to climate shifts much larger than those happening on average globally, just due to the local conditions.

-JBB

Image credit: Wikipedia Commons, photographer Till Niermann http://commons.wikimedia.org/wiki/File:Loess_landscape_china.jpg

UCLA Newsroom report: http://newsroom.ucla.edu/portal/ucla/temperature-increases-in-central-245866.aspx

Research article (Subscription): http://www.pnas.org/content/early/2013/05/09/1213366110.abstract

BAUXITE: Will Climate Change Encourage Formation of New Aluminum Ores?

Climate change… Take another can of brew outta the fridge, and sit back, pull off the tab, hear that satisfactory sound of escaping bubbling CO2 and… let’s see about where that can came from.

Alumina is the 3rd most common element in the earth’s crust, but is always always always found bonded with oxygen, a hard atomic bond to break. Aluminum as an elemental metal wasn't even discovered until 1825, when Hans Christian Oersted first, with great difficulty and using a potassium-mercury amalgam, broke open that alumina-oxygen bond and reduced a lump of pure aluminum. Aluminum remained a rare curiosity of a metal, more valuable than gold, until an easier, less-expensive method of producing it from ore was developed in 1886, the Hall-Héroult process still used today. This “less-expensive” method utilizes electrolysis to remove Al from its oxide (Al2O3): in doing so, it uses 17.4 megawatt hours to produce a metric ton of metal, three times more than needed to make steel. Thus, aluminum is a recent addition in the inventory of metals commonly used by humankind.

Aluminum is produced from an ore called Bauxite: it is not a mineral, but a rock formation including aluminous oxide minerals like gibbsite, boehmite, and diaspore mixed with iron oxide minerals like hematite and goethite. It’s red, soft, heavy, generally a messy-looking rock. It can be formed from any kind of stone that is exposed to weathering on the earth’s surface. SERIOUS weathering. This kind of surficial weathering process is named “lateritic” and essentially requires a horrendous amount of rain water to percolate through a rock and leach out everything except those elements that are too difficult to leach away, leaving behind the “unleachables” including minerals with Al2O3 bonds, silica and nickel - iron oxides. It is estimated to take several hundreds of thousands of years to so totally destroy parent rocks via surficial weathering to the point that a lateritic deposit is produced.

But the kind of surficial weathering needs – a lateritic favorable environment. Which means – relatively high surface temperatures (annual average temperatures of 26 deg C) and ~10 – 11 months of constant rainfall to make 1.2 – 4 meters of rain a year! Even Brazil lags in these conditions (though lateritic soils abound there), but with increasing climate change… the conditions for laterite and bauxite formation could reach even Cretaceous conditions, once again.

Yep, take a sip from that ice cold can of beer and consider the climate that aluminum originally came from. Really makes one yearn for a cold beer…

Note: Recycling aluminum uses 5% of the electricity that is needed to produce aluminum from bauxite. Thus recycling could slow climate change, but not the consumption of beer.

Annie R

Graphic: by me using background within Vagonetto Mine of the Fokis Mine Park (Greece) and piece of bauxite (left) from near Delphi

Read more: http://www.episodes.co.in/www/backissues/22/ARTICLES--22.pdf http://www.chemicool.com/elements/aluminum.html http://www.vagonetto.gr/en/

Twinned pyrite cube

This metallic cube is the mineral pyrite, the most common iron-sulfide mineral on Earth. Pyrites atoms typically assemble in a cubic structure, with atoms repeating in all 3 perpendicular directions. However, sometimes when a crystal is growing atoms won’t quite fit in at exactly the spot they’re supposed to. The right atom will be there, but it won’t go in at quite the right spot – it’ll go in at an odd angle. Get enough atoms to go into the structure at an odd angle and suddenly the crystal has bent at that spot. The atoms on the other side can continue growing, forming in this case several different cubes that all seem to penetrate into each other. Somewhere in the structure there is actually a boundary between each of those cubes where the atoms are still stuck together but the chemical bonds kink. This structure of penetrating minerals of the same composition is called “penetration twinning”.

-JBB

Image credit: https://flic.kr/p/GvzKH4

Reference: http://www.minerals.net/mineral/pyrite.aspx http://www.tulane.edu/~sanelson/eens211/twinning.htm

Quantum tunnelling discovered in emeralds

A whole new state of the water molecule forbidden by classical physics (and not conforming to any of the standard phases of matter ie solid, liquid, gas or plasma) has been discovered using advanced techniques called neutron scattering combined with computer modelling at Oak Ridge National Laboratory. The water is tightly confined in tiny hexagonal channels a mere 5 angstroms wide (an atom is roughly one angstrom aka 1/10-billionth of a metre) tightly held in by the bonds of the crystal lattice of beryls (as you know, emerald is the green variety coloured by chromium and/or vanadium). Within the lattice a phenomenon known as delocalisation appeared, where the electrons and protons go 'fuzzy' as they tunnel, creating unexpected peaks in the spectra which were then revealed to be due to each atom being in multiple places simultaneously.

The experiments were run at low temperatures, and the water was seen to move through separating potential walls, which is not possible using classical physics as the model for the universe (remembering that in all scientific disciplines, the map that we make is not the territory). While hard to explain why in non mathematical language, the hydrogen and oxygen atoms were in six places at once (as induced by the hexagonal lattice of the beryl), proving some of the more bizarre assertions of quantum mechanics. This discovery may apply to other things under similar confinement, such as water in cells and cell wall channels and rocks (at grain junctions for example where odd recrystallisation phenomena occur in cooling lavas and metamorphic rocks), and may reveal something new and unexpected. Follow this space...

While we all know that the rules applicable to the very small are somewhat odd (to say the least), delocalisation involves Heisenberg's uncertainty principle, and whether one has chosen to observe the 'thing' in question as a particle or a wave. Basically you can tell where a particle is, or where it is moving, but you cannot measure (though perception might be possible) a gestalt of the particle/wave and its motion. The atoms making up the water were seen to be (paraphrasing the unspeakable) neither here nor there and simultaneously in six places at once... remember that when you look at a crystal, since it is likely that they're all thrumming multidimensionally before your very eyes.

The beauty in the photo comes from the edge of the Himalayas in China's Yunan province, and the two crystals are set in a quartz rich matrix. The specimen measures 7.5 x 6.0 x 5.1 cm.

Loz

Image credit: Rob Lavinsky/iRocks.com

http://bit.ly/1TtljVM Press release: http://1.usa.gov/1VOisuE Original paper, paywall access: http://bit.ly/231dWYl

Hydrogen

Perhaps because it makes up so much of everything we see or touch, scientists didn’t realise hydrogen was a distinct element until Henry Cavendish recognised it in 1776. Hydrogen, which contains one electron and one proton, is the simplest and most abundant of all the elements, making up of 90% of the visible universe. It is a clear, odourless gas and the lightest of all the elements in the periodic table.

Hydrogen is the fuel that stars burn in a process called fusion, a process that combines hydrogen atoms to form helium, releasing huge amounts of energy. Some scientists are working to replicate this process by colliding atomic nuclei at a very high speed to form a denser nucleus, a technique which emits photons (energy). While this is still being explored, hydrogen fuel cells are also used as a clean energy source in some vehicles. Not only is this element used to produce clean fuel, it’s also used in various other industries such as cryogenics, methanol production, metal ore reduction, and hydrogenating fats and oils (how margarine is made from vegetable oil).

The name is derived from the Latin hydro, meaning “water” and genes meaning “forming”. An apt name considering it’s found in the in almost all the molecules of living things, including us humans. This leads into one of my favorite quotes by the fantastic word-smith and cosmologist Carl Sagan.

“The cosmos is within us. We are made of star-stuff. We are a way for the universe to know itself.”

-GG

Sources: http://bit.ly/1ONqOOT http://bit.ly/1fgxLpC http://rsc.li/1kDHyH0 http://bit.ly/1SVGhd4

Image: http://bit.ly/1QiAqN6

Fluorite

This delightful cube is a crystal of fluorite, the mineral made of calcium and fluorine. The structure of this mineral is cubic and it commonly grows in settings with abundant fluids, allowing it to easily grow large, well-shaped crystals. Note how the purple color, the most common color in grains of fluorite, appears and disappears in certain bands that track conditions as the crystal grew. The purple color occurs when a fluorine atom is missing from the structure and an unbound electron takes its place. Unbound electrons would balance the charge in the grain, but they sit in open spaces and thus interact with light in the visible range.

These unbound electrons can be caused by radiation exposure, but it’s tough to expose a single layer in the middle of a grain to radiation. Instead, in this case it probably relates to the availability of calcium and fluorine as the crystal was growing. A layer that grows when extra calcium is available might leave missing fluorine spaces that can be filled by open electrons, creating this color pattern.

-JBB

Image credit: Macroscopic Solutions https://flic.kr/p/qm1VtJ

Reference: http://bit.ly/25DoCQM http://www.galleries.com/fluorite http://www.mindat.org/min-1576.html

Mica Window

These Russian windows are over 200 years old. Rather than being made of glass, they are instead lined with sheets of muscovite, a mica minera. Mica minerals form large, flat sheets due to their atomic structure. Strong silicon-oxygen bonds extend outwards in two directions while the third direction only has weak bonds with large, low charge atoms in the space.

These mica sheets can grow extremely wide, and can be peeled off with ease. Mineralogy labs are often covered with flakes of them gradually removed by students over the years. In this case, a big enough book of mica sheets was carefully peeled apart to create what would become windowpanes.

If thick enough, the mica would be as strong as glass, somewhat transparent (depending on the exact content of various elements), and even more heat resistant than the glasses we typically use today. Before the development of modern glass making techniques, peeling and carving sheets of mica could have been a perfectly normal way of getting the basic properties of windows today.

-JBB

Image credit: http://bit.ly/1SvwESh

Read more http://bit.ly/1qemdMy

Mole Madness

Since 1980, the twenty-third of October has assumed a special significance for chemistry students in the United States, Canada, Australia, and South Africa. The annual celebration of Mole Day traditionally begins at 6:02 am on 10/23 and ends at 6:02 pm. Over the years, between those two significant times, many, many bad jokes about moles have been told (Q: What did one mole say to the other? A: We make great chemistry together!). Food offerings have played a part as well. Snacks consistent with the celebration have included 6.02 molasses cookies per person, Avogadro’s dip (a.k.a. guaca-mole’), pie á la mole, a mole of molasses milk, and so on.

Besides culinary adventures, student-designed Mole Day flags have been designed and displayed and small stuffed moles were placed in extraordinary vignettes ranging from prehistoric cave dioramas, to riding on molarcoasters or stepping out of a time-traveling blue police box. Past years have also seen chemistry classes compete in games like whack-a-mole and Moleopoly. None of these observances sound like they have much of anything to do with chemistry, unless, of course, you noticed the subtle reference to the name of the dip.

Mole Day originally began with an article in “The Science Teacher” magazine as a way to encourage student interest in chemistry, and after a decade of observance led to the establishment of the National Mole Foundation. It has become part of the American Chemical Society-sponsored “National Chemistry Week” and a very popular way to encourage the interest of young people in the study of chemistry.

Mole Day began as a way to get students excited about chemistry and to acknowledge the accomplishments of an Italian scientist, Amedeo Avogadro. Son of an Italian count, Avogadro was formally educated in law and began his career as an ecclesiastical lawyer. However, he arranged for private tutoring in mathematics and the sciences and eventually became the chair of the physical chemistry department at the University of Turin. In 1811, Avogadro hypothesized that equal volumes of a gas, at the same temperature and pressure, would have equal numbers of molecules. His hypothesis, which is now taught in chemistry classes all over the world, was not published until nearly 50 years after its conception.

No one knows for sure who actually coined the term, but in 1909, nearly 100 years after Avogadro’s hypothesis was formulated, reference to “Avogadro’s Constant” first appears in a paper written by Jean Baptiste Jean Perrin. Perrin’s paper, “Brownian Movement and Molecular Reality”, stated: "The invariable number N is a universal constant, which may be appropriately designated ‘Avogadro's Constant’."

Over time, chemists worked out the atomic weights of chemical elements and decided that an amount in grams equal to the value of the atomic mass of an element would be designated as a “mole,” derived from the word “molecule”. Using the number of atoms in 12 g of carbon-12, the amount of atoms in a mole was calculated to be 6.02 X 10 to the 23rd power. Today, chemists use Avogadro’s constant in reference to one mole of atoms, a mole of molecules, of ions, or really, of anything. It is the basis for an entire area of chemical calculations known as stoichiometry.

So, given the importance of Avogadro’s constant to chemistry and the difficulty in getting the average student to pay attention, Mole Day has taken its rightful place among other great science observance days like last week’s National Fossil Day and Pi Day, held on March 14th (3/14). Of course, if your interest in science falls more in the line of fiction, May the 4th be with you!

CW

Images

http://bit.ly/1NQpQBx (safety goggles added)

Sources

goo.gl/sSEL8C

http://bit.ly/1z8d1It

http://bit.ly/1OOvQJR

http://bit.ly/1Kk5Y22

http://bit.ly/1grVNRG

https://iweb.tntech.edu/chem281-tf/avogadro.htm

http://www.chemistry.co.nz/mole.htm

NEW FIFTH FORCE OF NATURE?

We’ve always understood there to be four fundamental forces of nature; gravity, weak and strong nuclear forces and electromagnetic, but a new breakthrough in particle physics means we may be on the path to discovering a fifth “force of nature”.

So what is this fifth force? The fifth force is based upon “long-range spin-spin interactions” of atoms, which have only ever been theorized but never proven. If this force is indeed proven to exist, it would make a connection between the interaction of atoms of the deep mantle and those at Earth’s surface. Essentially, it suggests that the particles can “sense” each others presence, and are affected by this interaction. The information we could gather from this would open new doors into understanding the make up of Earth’s mantle, which has generally been too inaccessible for us to fully understand.

To appreciate the idea of what “long-range spin-spin interactions” are, we need to consider the interaction between the spinning of electrons, neutrons and protons in the lab and the spinning of the electrons within the Earth. The spinning and polarization of these electrons is influenced by the Earth’s geomagnetic field. To observe this, researchers, led by Larry Hunter, professor of physics at Amherst College, created the first comprehensive map of electron polarization within Earth that details the magnitude and electron spins throughout Earth.

But what is spin? Well, every atomic particle has the property of “spin”; a vector, or an arrow, pointing it in a particular direction. That includes all of the protons, neutrons and electrons that make up all of our Earth; the mantle, the crust and the core. The mantle in particular, lying between the crust and core, has a dense make up of iron-bearing minerals. These atoms are influenced slightly by Earth’s magnetic field, which causes some of the particles to become “spin-polarized”. Instead of random spin points, there is now some net orientation of the spinning particles.

The pictured artist's impression depicts long-range spin-spin interaction (blue wavy lines) in which the spin-sensitive detector on Earth’s surface interacts with geoelectrons (red dots) deep in Earth’s mantle. The arrows on the geoelectrons indicate their spin orientations, opposite that of Earth’s magnetic field lines (white arcs).

Now here is the weird part; when experiments remove the influence of the magnetic fields, there is still some factor influencing the spin-polarization of these particles! It is this mystery factor that scientists have been attempting to isolate and theorize to be “long-range spin-spin interactions”. The idea behind this is that there is a long-range interaction, aligned by the geomagnetic field, between the spins in the experimental device and the electron spins within the Earth; that it is not merely electromagnetism influencing the particles, but that the particles can “sense” each other.

Whilst no experiments have provided conclusive findings to confirm this “fifth force”, this new research has been a breakthrough in supporting the theory. The findings of this research have helped to infer that any interactions, if they exist, are incredibly weak and, thus, more sensitive equipment must be used to search for this elusive fifth force. The possibility of future experiments discovering this fifth force has exciting potential for both particle physics and geoscience.

-LCA

Picture Credit: Illustration, Marc Airhart (University of Texas at Austin) and Steve Jacobsen (Northwestern University)

References and further reading...

http://phys.org/news/2013-02-probe-earth-deep-interior-particle.html#jCp

http://www.sciencemag.org/content/339/6122/928.short

http://www.researchgate.net/publication/227276586_-Electron_Long-Range_SpinSpin_Coupling_in_the_Full_Configuration_Interaction_Method

The backbone of a rock

When you walk outside and pick up a rock, what are you actually holding? When you lean against a brick wall, what are you leaning up against?

The chemistry answer to this question is “mostly empty space” – most of the volume of every atom is empty space occupied by moving electrons, so from a chemistry perspective that answer is correct and adequate. Geologists, however, tend to look at bigger systems. We consider lots of atoms and how they behave in bulk, so the geologist would probably give a different answer. For a most solids on Earth, it turns out the geologist’s answer is “oxygen”.

Oxygen is the backbone of virtually every rock we see at Earth’s surface (with the exception of things like metals or native elements such as coal). It doesn’t matter whether you’re picking up a scoop of dirt or holding a rock; whatever you’ve got is extremely likely to be held together by oxygen.

The most common exposure most of us have to oxygen is in the air, where oxygen is neutrally charged and covalently bonded to another oxygen atom (you just took a breath didn't you?). However, that’s not what oxygen usually does – it takes energy to turn oxygen into a neutrally charged atom. Instead, oxygen really likes having a negative charge and bonding with whatever positively charged atoms it can find.

When bonds with atoms as an ion it can build a variety of structures. The most common setup in the earth is a silicate – a silicon ion surrounded by 4 oxygen atoms that make a tetrahedron around it. In this structure, oxygen can serve as a bridge – with single oxygen atoms shared between multiple silicon atoms, allowing the mineral structure to repeat and forming larger crystals.

The example you see here is a pyroxene structure – a particularly common mineral, one that makes up between 20-40% of the Earth’s upper mantle. The oxygen atoms are the larger spheres that surround the smaller silicon atoms at the center. In that structure, oxygen atoms form long chains and other atoms, like calcium, iron, or magnesium, are stuck in smaller spaces in-between the chains to balance the charges.

This is just one possible arrangement of oxygen atoms; the universe gets a little creative with all the varieties. Oxygen atoms can be not shared at all, shared with up to 4 different silicon atoms, or anything in-between. There can be no silicon at all like in carbonates, and all sorts of other elements can be stuck in spaces in-between, from heavy as uranium to the lowest-mass element, hydrogen.

This one, useful element makes up about ½ of the atoms in Earth’s Mantle. The bonds oxygen makes absorb your weight and keep you from falling downward under the force of gravity. Oxygen: the air we breathe and the backbone of the ground we stand on. Is there anything it can’t do?

-JBB

Image credit: http://bit.ly/1LXTfoC Read more: https://books.google.com/books?isbn=1429255196 http://bit.ly/1oKcSEH

WHAT MAKES ARGYLE DIAMONDS PINK?

Australia’s Argyle diamonds are naturally pink in colour, though why has been a mystery to scientists for quite some time. New research into the photochromic behaviour of Argyle diamonds (the way diamonds change colour upon exposure to light) led by Keal Byrne, a PhD student at the University of Western Australia in Perth, has taken a step towards determining what creates this colouration. Byrne and his team used a suite of lights with narrow frequencies to bleach the colour from the pink diamonds, which allowed them to understand their photochromic behaviour.

Diamonds are carbon atoms bonded together in a crystalline lattice that doesn’t absorb light, resulting in a colourless appearance. Coloured diamonds contain a defect centre, where one or more of the carbon atoms in the diamond lattice may be missing, or may have been replaced with a different element. If there are enough defect centres the diamond can take on different properties, like absorbing light in a way that gives it a visible colour difference. Yellow diamonds are the result of a certain amount of nitrogen atoms in a diamond, while blue diamonds result from a certain amount of boron impurities. Black diamonds (carbonado) are not the result of impurities; they have a polycrystalline structure, which means they do absorb light.

The defect centres that cause pink, purple and red colours in diamonds are still unknown; however Byrne and his colleagues did provide new constraints on the colour centre responsible. The photochromic behaviour seen in natural pink diamonds is explained in the research as a competition between electron photoionization and trapping processes at several distinct species of defect centres. Only one of these defect centres shows the characteristic absorption bands of pink diamond.

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http://www.australiangeographic.com.au/journal/why-are-some-diamonds-pink.htm http://www.sciencedirect.com/science/article/pii/S0925963512001975 Image: http://www.oneworldpublications.com/assets/images/pinkdiamonds%20courtesy%20Arglye%20Mining..jpg

DATING TECHNIQUES: COSMOGENIC EXPOSURE DATING Cosmogenic exposure dating, also known as surface exposure dating, is used to estimate the amount of time a rock has been exposed at the surface. It is useful for dating many different geological events such as, fault scarps (which is a displacement of the surface of the land because of fault movement), rock slides, meteorite collisions, lava flows, erosion areas, and glacial advances and retreats. Cosmogenic exposure is most useful for dating rocks that have been exposed to the surface for 10 thousand years to 30 million years but can be used for dating younger time periods as well. The primary dating technique used in Cosmogenic exposure dating is Cosmogenic radionulide dating, but Lichenometry (dating rocks using lichens) can also be used in surface exposure dating as well. Earth is assaulted with high energy particles every day, (ex: protons and alpha particles). These are known as primary cosmic rays. When the primary cosmic rays interact with atoms in gasses from the atmosphere, there are secondary particles that are produced and provide energy for many different reactions in the atmosphere. These rays reach the earth’s surface are mostly composed of neutrons When the particle rays strike an atom on the earth’s surface, they can dislodge protons from an atom or add/dislodge neutrons in a process called spallation. Spallation is a process in which a heavy nucleus emits a large number of nucleons as a result of being hit by a high-energy particle, thus greatly reducing its atomic weight This will produce a different isotope of the atom or producing a completely different element all together. These new isotopes are called cosmogenic nuclides With rocks, usually only the first meter of the material is affected. Using this technique, scientists can find out information about geologic events such as how long a surface was exposed, how long a piece has been buried, even how quickly a certain area is eroding. The Radionuclides are produced at a known rate and the decay rate is also known. Variables: The results can be affected by fluxuation in cosmic rays. These are variables such as: elevation, latitude, intensity of the magnetic field, solar winds, and air pressure variations. Aluminum-26 and Beryllium-10 are the two most common and measureable isotopes produced by Cosmogenic exposure. They are produced from silicon-28 and oxygen-16 respectively. The two parent isotopes are commonly seen in materials at the earth’s crust and surface and therefore are present in most measureable Cosmogenic exposure situations. Cosmogenic exposure dating can be used in conjunction with other dating methods to get more precise information about ages and exposures. In this picture here you can see that 4 different types of dating methods are used. Cosmogenic exposure dating, radiocarbon dating, optically stimulated luminescence dating, and uranium –series dating. -CS More info: http://www.landforms.eu/cairngorms/cosmo.htm http://quaternary-science.publiss.net/issues/57/articles/782