Saturday, September 15, 2012


Some of you may recall an article I wrote the other day (linked in the "Further Reading" section below) about a theory that was purposed that says time isn't an absolute part of the spacetime continuum and that the natural world can be described better by removing that part of the equation and thinking of time as a numerical order of change. We received a lot of interesting responses to the article. Some of which, were very thought provoking and I wanted to follow up with another radical idea I recently read about. This one postulates that time really is the fourth dimension. Not only is its existence real, but it may be disappearing from the universe entirely! 

If you've been a follower of any number of physics related pages or websites, you've probably heard about dark energy -- the mysterious "anti-gravitational" force that's accelerating the expansion of the universe and driving the galaxies apart from each other. Well, what if we're looking at it backwards? What if the universe itself isn't actually expanding an at ever increasing speed, but time is actually slowing down?

Of course, the changes in our everyday life would be minuscule and unnoticeable from the human perspective, but much more visible (and easily measured) in the vastness of the cosmic arena. That's exactly what the scientists involved (including ;Professor José Senovilla, Marc Mars and Raül Vera of the University of the Basque Country, Bilbao, and University of Salamanca in Spain) are proposing. Not only is dark energy dismissed as preposterous, but the very observation of the 'accelerated' expansion of the universe is nothing more than an illusion. The expansion itself isn't the illusion, but the accelerating expansion part is. The appearance of the acceleration is due to time gradually slowing much the same way as a clock behaves when equipped with a dying battery.

"If time gradually slows, but we naively kept using our equations to derive the changes of the expansion with respect of 'a standard flow of time', then the simple models that we have constructed in our paper shows that an "effective accelerated rate of the expansion" takes place," says those involved in publishing the paper. 

Physicists have been tracking the movement of supernovae explosions in the observable universe to confirm the accelerated expansion of the universe is happening. Using the Doppler effect to see the red-shift of objects that are traveling away from us, astronomers are able to pinpoint and discern how quickly the universe is expanding. All objects shifted towards the red, longer-wavelength are steadily moving away, while objects shifted towards the bluer part of the spectrum are. moving towards us. There's one problem though -- the accuracy of these measurements work under the assumption that time is invariable through all portions of the universe. 

So, what does this mean?

Basically, this theory suggests that the fourth dimension of the universe; time -- is slowly degrading into a new spatial dimension. If this were the case, the distant stars we perceive as moving away from us at an ever increasing speed are merely giving off that impression that they are accelerating. 

"Our calculations show that we would think that the expansion of the universe is accelerating," says Prof Senovilla. The theory bases it’s idea on one particular variant of superstring theory, in which our universe is confined to the surface of a membrane, or brane, floating in a higher-dimensional space, known as the "bulk". In billions of years, time would cease to be time altogether.

"Then everything will be frozen, like a snapshot of one instant, forever," Senovilla told New Scientist magazine. "Our planet will be long gone by then." 

Interestingly enough, the idea isn't entirely hogwash. According to our current big bang theory models, time along with the other dimensions that compromise space/time were created at the inception of the universe. Therefore, it can also disappear -- which is just the reverse effect. No need to worry about it happening anytime soon in the event that there actually is something to this hypothesis as the scientists involved think there are still billions of years before the clock ticks for the final time - leaving everything in the universe frozen in the vastness of space forever.

source: https://www.facebook.com/photo.php?fbid=352237194862696&set=a.313338668752549.73826.313312622088487&type=1&relevant_count=1&ref=nf

Dark Geology


Look and See


Glass beach


Wow, what a beautiful beach! All the different colours, it almost looks unnatural doesn’t it? – That’s because it is.


This is “Glass Beach” in Fort Bragg, California. The beach resides at the end of the cliff, and although, today it is part of a state park, that was not always the case.


In 1949, the site was a unregulated dumping ground, where people threw glass, appliances and even the odd car. This went on for 18 years until 1967 when the North Coast Water Quality Board and city leaders closed the area and removed some of the larger articles dumped there.


Over the course of a decade or two, the sea worked its magic by cleaning the beach and by sculpting the remaining glass into smooth, coloured trinkets which we can see today.


It is amazing to see and a true testimony to both the wastefulness of humans and the resilience of nature.



Supernova explosions provide us with spectacular displays, but have they done more for us other than some stellar fireworks?


Well the answer is yes! Life on Earth, and presumably life elsewhere in the Universe, does not remain the same over time - instead it evolves new forms, and supernovae are involved. Evolution occurs because within a particular species different organisms have different rates of success in producing offspring. The struggle for reproductive success promotes the characteristics of the more successful organisms. As a result, the characteristics of the organisms successful at reproduction will eventually become those of the species as a whole, which we may call a new species if those characteristics differ significantly from the original ones.


But what makes one organism within a species different from others? The answer lies with random genetic mutations of an organism. Most mutations are far from being helpful to an organism’s success at survival and reproduction, and so are generally harmful to a species so these ‘bad’ mutants quickly vanish from the scene. However, some mutations provide characteristics that help the organism to survive and reproduce. If these are inheritable, the ‘mutant’ will have many offspring, and so will their descendants until the ‘mutant’ becomes representative of a new species.


So what causes these random mutations? Well, no one knows for certain, but the answer includes such causes as genetic predisposition, trauma or chemical reactions. But it seems likely to be ‘cosmic rays' which is actually a misnomer because they are electrons protons and other nuclei that travel through space at nearly the speed of light. These fast moving nuclei continuously bombard the Earth and the rest of the Universe. Most of them pass through an organism when they encounter it, but it appears likely that some of the cosmic ray particles may sometimes strike the genetic material and alter it slightly, and so producing a mutation. If this is so, cosmic ray particles are a driving force behind evolution on Earth and everywhere else in the Universe.


And what produces cosmic rays? The solution appears to be supernova explosions, although some particles may be accelerated to near light velocities in interstellar space. The outermost layers of a supernova, blown into space at the highest velocities, may become cosmic ray particles, travelling through interstellar space. The bulk of the supernova explosion emerges at far more modest velocities, and eventually merges with other interstellar gas, enriching it in elements heavier than helium. But the fastest moving particles speed on their random ways until they encounter something to stop them, perhaps an interstellar atom, perhaps a star, perhaps one of us. Thus the relationship of supernovae and the evolution of life on Earth appears to be straight forward - supernovae make cosmic rays ray particles; cosmic ray particle impacts produce mutations; mutations drive evolution!



A Sunshine Holiday

Introduction:


Our Sun, burning brightly for currently about 4.5 billion years and will continue to do so for another 7 or so billion years. A photon from the surface of the Sun takes about 8 minutes and 20 seconds for it to reach the Earth, 500 seconds to travel about 150 million km. Inside the Sun however it takes many thousands of years for a photon to get from the core to the surface of the Sun. As the Sun is only about 700,000 km in diameter it should only take a photon traveling at the speed of light about 2.3 seconds to travel that distance, so why does it take so long? To find out, studying the inner anatomy of the Sun, itʼs density and processes the only way to come to understand why it takes as long as it does for a particle traveling at light speed to travel a short distance.


The Structure of the Sun:


When studying the Sun, only the very surface is actually visible leaving everything below the surface invisible and thus theoretical. Although studying below the surface of the Sun may be difficult there is decades of data to draw from and through the use of different simulations of theoretical models have been able to make what is referred to as the Standard Stellar Model allowing the Stellar Structure to be understood.


The Core of the Sun is where the Nuclear Fusion takes place and where the energy output comes from that keeps the Sun from collapsing under the influence of gravity. Although the core takes up the inner 25% of the radius it only contains 1.5% of the overall volume but because of the very high density it contains 40% of the Suns mass!
The next step out is the Radiative Zone. All of the energy generated in the Core of the Sun has to work itʼs way through the Radiative Zone by photons being absorbed and re-emitted over and over again as they make their “Random Walk” towards the Convective Zone. As there is no Fusion in the Radiative Zone the average temperature is only about 4 million Kelvin. This zone extends from the Core (25% radius) out to the Convective Zone (70% radius) where the temperatures range from 8 million Kelvin near nearer to the Core and as low as 2 million Kelvin around the Convection Zone. The Radiative Zone is the largest part of the Sun with 45% of the radius, 32% of the volume and 48% of itʼs mass.


The last of the main shells is the Convective Zone and this takes up the last 30% of the radius or approximately 200,000 km. Over those 200,000 km the temperatures ranges from 2 million Kelvin near the Radiative Zone and gets to a cool 5,700 K on the solar surface. As the Convective Zone is far cooler than the rest of the Sun, especially nearer to the Suns surface, some of the heavier elements such as Nitrogen, Carbon, Calcium, Iron and Oxygen are no longer fully ionized which makes the outer layer more opaque. This is how the convection occurs, pockets of heat stored up and then rise to the surface like water boiling on a stove.


The Core, Radiative Zone and Random Walk:


A photon begins itʼs life in the Core of the Sun as a Gamma-Ray through the P-P Chain. Without going into too much detain the P-P Chain is the process that the Sun uses to produce energy and a lot of it! This is Nuclear Fusion where Hydrogen is fused together to create Helium and a lot of energy.


Suppose a Gamma-Ray photon and a Neutrino are created at the very heart of the Sun, a Neutrino has about 700,000 km (distance from centre of Sun to surface) to travel as it is very weakly interactive with the physical matter within the Sun, moving at the speed of light itʼll take the Neutrino about 2.3 seconds to escape. The Gamma-Ray on the other hand has a much longer journey, as a photon not only strongly interacts with physical matter but there is a lot of physical matter densely packed together, the photon has to undergo what is known as a Random Walk.


Within the Core of the Sun, due to the density, a photon is not able to move very far before it makes an interaction with another atom. When a photon hits an atom it is absorbed and re-emitted in a random direction, hence the name for a Random Walk. This Random Walk also goes by the name of the Drunken Walk because a drunkard stumbling around a street in an attempt to not stumble over will make turns in random directions.
Although I've left all of the messy mathematics out I calculated that while traveling at the speed of light that photon would take about 264 years for a photon to travel from the Core of the Sun to the Convection Zone. This calculation is based on the average distance (that is displayed in most text books) that a photon will move before being absorbed and re-emitted.


Here lies a dilemma however, most text books put the time anywhere between 100,000 years all the way up to 50 million years so if from the results above it takes about a quarter of a millenium to get through the densest and largest portion of the Sun, it doesn't make a whole lot of sense. Obviously then, the Mean Free Path (average distance a photon will travel) must be far shorter than 1 cm (1 cm being what is generally quoted in text books). The reason for this according to Issue #50: Ancient Sunlight “Because textbook authors and editors do not bother to actually make the correct calculation themselves, and rely on older published answers from similar textbooks." [http://sunearthday.nasa.gov/2007/locations/ttt_sunlight.php]


Convective Zone, Photosphere and Earth bound:


The final main zone of the Sun is the Convective Zone composing of only 30% of the radius but 66% of the Suns volume. As the name suggests, photons in this part of the Sun no longer move through radiation part particle to particle but through convection. Within the Sun convection is able to occur because of the great decrease in both temperature and density.


The best illustration to describe this is a boiling pot of water. As the bottom of the pot is heated eventually there are cells of hot water that rise to the surface, these are the observed bubbles.


This is the basis upon how the Convection Zone operates, plasma from the inner part of the Convection Zone heats up which makes it more energetic and then rises towards the solar surface carrying that energy. Energy is gradually deposited along the way to the surface at which point it will have cooled dramatically. It is well reported that it can potentially take upwards of a million years from a photon to take a Random Walk through the Core and Radiative Zone but how long in the Convection Zone?


One source states that it may only take about 10 days to travel the 200,000 km journey. Comparing this means that almost the entire lifetime of a photon is spent in the inner part of the Sun bouncing around and barely moving.
The last section of the Sun that a photon spends time in before commencing an eight minute journey to the Earth is in the Photosphere. The Photosphere is only 500 km thick so compared to the rest of the Sun it is very thin. The temperature range of the Photosphere also doesn't have very large numbers, ranging from 6400 Kelvin at the bottom to only 4400 Kelvin at the top. Most of the light that is visible from the Earth is emitted nearer to the bottom of the Photosphere which is why the Sun has a said temperature of 5780 Kelvin and that would be the temperature nearer to the bottom of the Photosphere rather than near the top.


The last leg of a photons journey is the actual trip to the Earth. This is by far the furthest part of a photons trip but also ironically the quickest. As there is nothing so slow down the photon on the journey between the Sun and the Earth, just relatively empty void, a photon is finally able to move at the speed of light.This works out to 500 seconds and that is 8 minutes and 20 seconds.


Conclusion:


It can be hard to imagine the time scale that it eventually takes for a photon to travel such a relatively short distance, that the longest distance takes the shortest time to travel. What this goes to show is that density is the main determining factor as to the distance of the Mean Free Path of a photon within the Sun. Most web sites and text books put the Average Mean Free Path of the Sun as being 1 cm but as shown above, it take far less than the estimated 100,000 - over a million years to make the journey. The reason for this is simple that itʼs not high on the importance list to try to discover exactly. With all the time dedicated to more important studies, trying to calculate the exact time it takes a photon to make itʼs Random Walk through the Sun is not high on the priority list.


The transfer of energy within stars - why aren’t we ‘zapped’ by harmful radiation?


In the core of every star the energy motion made from energy mass via nuclear fusion appears in the form of additional velocity acquired by each of the particles that energy from the nuclear fusion. Before the fusion, the particles had energy of motion since each of them was in motion. After the fusion the particles have more energy of motion, which they gained from the energy of mass that vanished during the fusion process.


What happens to the energy of motion of the particles that emerge from the fusion? The particles collide with particles immediately around them, which in turn collide with other particles, and they in turn collide with others still, until the newly fused particles share the energy of motion made at the star’s centre with the entire star. 

Likewise, high-energy photons made during the nuclear fusion collide with other particles and increase the particles’ velocities. Eventually, like a mob animated by demagogue at its centre, all the particles within the star dance in a frenzy induced by the nuclear fusion at the stellar core. The particles dance most furiously at the star’s centre, progressively less so in the outer regions. 

Thus, from nuclear fusion at its core the entire star grows hot from the centre to surface. The star’s centre typically has a temperature of 15 - 60 million degrees Fahrenheit, while the surface falls to a mere 2,000 - 25,000 degrees.
Because a star is hot it produces electromagnetic waves, in fact any object not at a temperature of 0 Kelvin (the coldest temperature possible) produces electromagnetic radiation, and these levels increase the hotter an object gets. Furthermore, as an object grows hotter the chief type of electromagnetic wave it radiates will chance. Human beings and other objects near room temperature produce mostly infrared waves. Hence, the sizable military industry that has sprung up to detect the infrared waves that humans emit in order to see the enemy simply by the waves that they cannot avoid radiating. At temperatures of a few thousand degrees, an object will emit mostly visible light. Stars, with surface temperatures measured in thousands of degrees therefore radiate mostly visible light, along with sizable amounts of ultraviolet from the hotter stars. Not accidently, our eyes have evolved to detect mostly visible light, the sun’s primary output. 


In the core of a star such as the sun, where the temperature rises to millions of degrees, the hot gas radiates mostly X-rays and gamma rays. If the outer layers of the sun were transparent to this radiation we would be instantaneously zapped by these high energy photons from the solar interior. However, the matter in the sun effectively traps all this harmful radiation, each of the rays encountering a nucleus or an electron which blocks its path and deflects it in another direction. The high-energy photons therefore cannot escape from the sun; instead, their energy is constantly passed to other particles within the sun, heating them still further. The immense number of collision slowly lessens the energy of each photon, and if we could pass outward in the sun from its centre to its surface we would find mostly gamma rays and X rays near the core, mostly X rays and ultraviolet in its middle regions, and mostly ultraviolet and visible light near the surface. Finally from the regions close to the sun’s surface photons can escape, but because these regions have temperatures of only about 10,000 degrees Fahrenheit, the photons that do escape are ultraviolet and visible light photons, the kind that matter at this temperature produces.




Did you know that Earth - with its oceans, rivers and snow covered caps – actually has a water deficiency according to the standard model of the Sun’s proto-planetary disk?

 
Astronomers studying how the Earth formed out of the dust and debris of the early solar system - based on the current model of the sun’s proto-planetary disk - have been stuck trying to explain why the Earth lacks so much of this (seemly) abundant substance. It should have formed in a region plentiful in icy material. In other words Earth should be a water world, similar to that of Neptune or Uranus. These theories are based around the snow line, which is the distance from the Sun to which its rays can no longer melt ice; this line currently lies within the asteroid belt. The conventional model says that the disk was fully ionized and so material would have been funnelled onto the star. 

This line was said to have started out at least one billion miles from the sun, but as it cooled down it retreated inwards past Earth’s orbit BEFORE the planet had time to form. But if this line had moved before Earth was formed it should have been constructed into an icy planet, rich in water.


The latest study by Martin and Livio, says that the disk couldn’t have been fully ionized because normal stars don’t have the ‘energetic punch’ to do it. This means that the normal mechanisms going on can’t function as previously thought, so matter can’t move in towards the star and instead it sits in orbit. 

This leaves a ‘dead zone’ about 0.1 AU out, which acts like a wall that prevents material moving beyond it, however this build up in turn heats the region (stretching for a few AU) due to gravitational compression. Ice would have been evaporated leaving Earth to form out the dry material left over, and so this new version of the proto-planetary disk (featured below against the old one) now accurately explains why its composition lacks so much water. This isn’t a design to base every star system on as each one is different. Livio said brilliantly, ‘’chance, as much as anything else, determined the precise end results for our Earth.’’





The production of large nuclei – where did Earth’s elements come from?


Before a star goes into supernova it would have made elements up to and including iron, but the violence of the explosion itself makes nuclei with more protons per nucleus than iron. Between the two ways to fuse heavier nuclei from lighter ones, supernova explosions have made essentially all the nuclei other than hydrogen and helium (though much of the iron stays behind in the collapse core). We have seen that evolving stars can fuse nuclei up to iron, number 26 in the list of elements that starts with hydrogen and helium. If this were the full story we would have no explanation of sixty-six naturally occurring additional elements – those whose nuclei contain anywhere from twenty-seven protons per nucleus (cobalt) through to ninety-two protons per nucleus (uranium). The list of these sixty-six elements includes such important nuclei as copper, silver, iridium, gold, mercury, and lead - as well as rare elements such as dysprosium, ytterbium and hafnium. We now know where the elements with a large number of protons came from; the first fraction of a second of a supernova explosion!


When we look at the Universe as a whole, we find that all of the ‘high number’ elements are extremely rare – hydrogen and helium account for at least 99% of all the mass in the cosmos. The elements with three to twenty-six protons per nucleus (including carbon, nitrogen, oxygen, silicon, magnesium, aluminium, titanium, chromium, and iron) have a total abundance of less than 1% of the mass in hydrogen and helium nuclei. But the total abundance of all the high number nuclei (those with atomic numbers exceeding twenty-six) does not reach one-thousandth of the mass of elements three through to twenty-six! When you look for these high number elements (e.g. silver, mercury, uranium) you are looking for products of rare moments in the Universe, the moments after the explosion of a star.


When the Earth formed, close to our parent star, the warmth of the sun evaporated almost all the hydrogen and helium in our vicinity. As a result of the sun’s warmth, the Earth contains almost none of the two most abundant elements in the Universe. But the remaining elements were sufficiently heavy to avoid evaporation, and their abundances are much the same as we find in stars; oxygen, carbon and nitrogen predominately; silicon, magnesium, aluminium, sulphur, calcium, and iron and nickel appears only in trace amounts. This isn’t the case with everything, as lead, which we don’t think of as very rare, has an abundance of iron’s by a factor of half a million, gold only one tenth of this, and uranium has one tenth the abundance of gold (so very rare!)


When we seek to mine any of the elements heavier than iron (nickel is typically made in small amounts with the fusion of nuclei into iron - but we will exclude this to avoid confusion) we are searching for the remnants of rare moments, the sudden shocks that begun the explosion of supernovae. From these brief outbursts we must pry loose the elements we depend on for their special physical and chemical properties. The properties arise from the nuclear structure of elements that were assembled during tiny fractions of a second, close to a newly collapse neutron star, and then blasted into space through the same furious process that made them, a supernova explosion.


Some of these elements happened to occupy the regions of an interstellar cloud that later become the sun and its planets. And of the elements that made our planet, tiny fractions have temporarily become parts of our bodies. Every atom of oxygen, carbon, iron and the calcium in your bones was created in the core of a star. These nuclei not only connect with the stars and their history; they offer living proof that we would not be here without the stars that exploded to make the elements, which in turn, make us!


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Night life


See!! how the stars work.. so at night please close all your lights so that the star will show and for you to see them... and you will find how beautiful the world is.. how beautiful stars can be..  

Kabit

So much fun today!!!...
hahaha.. off to SANTA and to met the "KABIT" in vigan plaza..
and, YUCK!!! hahahaha