Eat My Waste

Toronto is really dirty at the moment. (Well, so it the whole world but Toronto is special now). The city workers have gone on strike and everywhere you look, you either see garbage or you see green stinky lines swirling out to your nose and causing you disgust. As much disgust as it caused me as well, I was thinking about recycling and how ineffective it is. There must be a way to get rid of all our garbage fast and give back to Earth like all grateful organisms should.

The solution lies with those awesome bacteria. Research has gone in to find that bacteria can indeed eat away our garbage and create gases that are useful to us. It's a prospect, but as the "really smart and visionary" businessmen aren't really all jumpy about letting their money making machines go, its developing slowly. But how does it actually work?

It works by accelerating the process of decomposition. Municipals store their garbage and waste in dry "tombs" and let the waste die away. The acceleration occurs by balancing the air-liquid quantities of the containers knows as bioreactors. Three types of bioreactors can be configured:
Aerobic- In an aerobic bioreactor, moisture is removed from one layer and piped to liquidsstorage tanks, and re-circulated into the landfill in a controlled manner. Air is injected into the waste mass, using vertical or horizontal wells, to promote aerobic activity and accelerate waste stabilization.
Anaerobic- In anaerobic bioreactors, moisture is re-circulated to obtain optimal moisture levels. Biodegradation here occurs in the absence of oxygen (anaerobically) and produces mostly methane which can be captured to minimize greenhouse gas emissions and for energy projects.
Hybrid (Aerobic-Anaerobic)- The hybrid bioreactor accelerates waste degradation by employing a sequentially alternating aerobic-anaerobic treatment to rapidly degrade organics in the container and collect gas. This sets off much rapid release of gases as well resulting in better efficiency.

Reference

Even though the technology exists and readily available, municipals are not ready to implement this. Maybe some conspiracy working behind it, as with everything else. So much so, liquids are prohibited in landfills of Ohio (read about it here).

So, the smell in Toronto is not going away any time soon. Nor is the world going to get rid of its waste the smart way. One can only hope municipals see that scientists actually know things better than those with fat bellies and as long as they don't, the can eat their waste themselves, and mine too.
----
By Kowsheek Mahmood
Ryerson University, Toronto
----
The Aftermath Publications, Issue 4
----

OLBERS’ PARADOX!

As theories of the universe evolved from that of Aristotle to that of Galileo, philosophers and scientists continued coming up with ever accurate theories until Isaac Newton (detail identification not necessary for obvious reasons!), came up with his most exact and mathematically sound theory of gravitation that could and can still explain the behaviour of celestial objects with amazing correctness. Newton formulated his theory of the universe according to which the universe was:

1. Static
2. Centre less
3. Infinite
4. Based on mathematical laws of motion and gravitation
5. Infinitely aged

The Newtonian universe is infinite in size and contains an infinite number of stars.




At the first instant, the Newtonian model of the universe seems to provide satisfactory explanations of almost all the celestial phenomena but if closely inspected, the Newtonian model offers some serious flaws!!

One of the consequences of the Newtonian model is that the night sky should have never been dark! According to our observation, the night sky is dark; atleast the spaces between the stars are dark. This is not surprising at the first thought. At night we are on the side of the earth that points away from the sun, it is bound to be dark, isn’t it? Actually it is not as obvious as that. Infact it is very difficult to explain why the sky at night is dark on the basis of the Newtonian model.

If, as par the Newtonian model, we consider that the universe is infinitely sized with infinite stars that maintain a certain distribution pattern, we can easily assign a number, say N, to the number of stars per unit volume of space. The volume of a spherical shell of space centred on the earth is ∆R*4πR2 where R is the distance of a shell of thickness ∆R which is at a distance R from the centre of the earth. If the stars are uniformly distributed, the number of stars in each shell is proportional to R2. The light emitted from a shell is thus proportional to R2. But light obeys inverse square law getting weaker with distance, in proportion to (1/R2). So each shell produces the same intensity of light at the earth. If there are infinite numbers of shells, i.e. if the universe is infinitely large, then the night sky should be infinitely bright!

This seemingly possible yet unobserved phenomenon is often named the OLBERS’ PARADOX.


The resolution to the paradox can be brought about very simply. First of all, it is very difficult to ascertain whether the universe is finite or infinite. Let’s keep this as a query to the best of the minds and proceed with the fact that the universe is infinitely large. Still we can solve the paradox! Until very recently, scientists like Edwin Hubble formulated laws like the Hubble’s law and made it sure that there is a particular age of the universe and thus it is not of infinite age. At any moment we are only receiving light from a finite number of stars. Light from others is still on its way to us (because they are very far from us and since the universe is not infinitely aged, the light from these stars did not get enough time to reach us). The overall effect is that we are continuously seeing light from the equivalent of a spherical shell of stars that is not wide enough to cover the entire sky. This explains why gaps between stars are dark.

More to be found in Hubble’s law is that distant stars recede from the earth at very high speeds than the less distant ones. This causes the energy from these stars to be red shifted sufficiently that by the time they reach the earth, they are no more in the visible range. Hence light from those stars can never be seen. If however, it becomes clear that the universe is finitely sized, it would rather reinforce the arguments put above to prove why the night sky is dark.


These inferences have serious consequences other than resolving Olbers’ paradox. The presence of visually undetected radiations in the universe suggests that there might be radiations reaching the earth’s surface now, that were emitted by stars and galaxies that once existed right after the birth of the universe. These radiations might hold important and intriguing information about the elemental compositions of celestial bodies right after the big bang and might often lead us into knowing why the big bang occurred in the first place!


----
By Mahmud Hasan
The Aftermath Publications.
----
The Aftermath Publications, Issue 4
----

Dance of the Spirits

For many years “Dance of the Spirits" has been mesmerizing millions of people. Yes, I am talking about the famous Aurora borealis, which is more frequently known as “Northern lights”. It is a very common phenomenon for Northern Hemisphere region as the chance of visibility increasing with proximity to the North Magnetic Pole, which is currently in the arctic islands of northern Canada.
But what exactly are northern lights? Or more precisely why does it occur?
Fusion reactions in the sun and the other solar lead to the production of charged particles (mostly electrons and sometimes protons). These charged particles usually have kinetic energy of the order of 100s of keV. This energy originates entirely from the fusion energy inside the sun and provides the particle with sufficient energy to overcome the magnetic field of the sun. When these particles come in vicinity of the earth, they become subjected to the earth’s magnetic field. The intrinsic magnetic field with the particles and the earth’s magnetic filed combine to produce an unbalance force on the particle, causing them to move from one pole to the other with high velocities. In the process they collide with atoms present in the earth’s atmosphere, raising them to higher energy levels. The high energy atoms in turn give out electromagnetic radiation in the visible range which is manifested in the form of the northern lights.

A magnificent view of the aurora

The aurora--a woodcut by Fridtjof Nansen

What does it look like? Most often, you see greenish white ribbons stretching across the sky, roughly from east to west, usually with waves in them. In Fairbanks they could be overhead, in northern Norway or Sweden too, sometimes even in Winnipeg. Further south those ribbons tend to be near the northern horizon. And if you look closely at them, you will note that they contain many parallel rays, running across their width (see picture beside).
Anyone who has ever used a compass knows that the Earth is a giant magnet. The needle of the compass usually points towards one of two points, the magnetic poles of the Earth, located near the geographic poles. But because the compass needle is mounted horizontally, it does not show everything. Actually, the magnetic force points not just northward but also slants down into the Earth. Compass needles carefully balanced on a horizontal axis ("dip needles") point in that slanting direction, when allowed to swing in a north-south vertical plane. In fact, the angle gets steeper the closer one gets to the magnetic pole. At the pole the force is vertical. The rays of the aurora faithfully follow that slanting direction.

What connects the pattern of the aurora to the region of the Earth's magnetic forces--the "magnetic field" of the Earth, as that region is known? For such a region, extending far into space, a convenient method is needed to describe it there. Such a method is provided by magnetic field lines, or as they were once called, "magnetic lines of force."
Chances are you have seen a drawing of the fieldlines of a bar magnet. They fan out from one pole, bend around in big curves, and then converge on the other pole. The magnetic pattern near Earth is like that, too--it is as if the Earth had a small (but oh so powerful!) bar magnet in its center: the lines fan out from the region near the south magnetic pole, reach their greatest distances above the equator, then converge again near the north magnetic pole.
To define field lines more exactly, imagine you had a compass needle hanging in space, able to tell us the exact direction of the magnetic force, in 3 dimensions. Such a needle will always point in the direction of the magnetic field line at its location. North of the equator such lines converge towards the region near the north magnetic pole, just like those of a bar magnet.

Back to the aurora. Between 1895 and 1907 the Norwegian physicist Kristian Birkeland tried to study its behavior in a lab. Inside a glass vacuum chamber he mounted a sphere with a magnet inside--he called it "terrella," Latin for "little Earth"-- and directed towards it a beam of electrons. To his surprise and gratification, the magnet steered the beam right to a patch around the magnetic poles of his small sphere, producing there, as it hit, a visible glow. He probably thought-- aha, so that is how it is done!
It turned out that negative electrons and positive ions alike are guided in space by magnetic field lines. They tend spiral around them, meanwhile sliding along them, like beads on a wire. Because Birkeland's field lines reached the terrella near its magnetic poles, that is where his electrons came down. Similarly magnetic field lines of the Earth guide electrons of the aurora to come down in the auroral zone. No wonder the rays of the aurora pointed along such lines! Each was produced by a ray of electrons, riding its own field line down to the atmosphere.
Understanding northern lights is a very small purchase, where the huge parlor of beauty and charisma is still to be discovered. Nature is still playing its own game of wonder. There is no ending of learning. Isn’t it? As the great man said “Learn to be unlearned” – Richard Feynman

----
By Mohammad Atif Bin Shafi
East West Univesity, Dhaka, Bangladesh.
----
The Aftermath Publications, Issue 4
----

Dark matter : science or fiction

As scientists began to unravel more information about our galaxies they were intrigued by more questions than answers. One of the many questions was that of the eluding Dark matter. It so happens that as scientists began studying about the rotation of galaxies and their temperature distribution they were able to predict the amount of material present in particular parts of space and that is what they exactly did. But Scientists were stunned with what they had found. Amazingly it turned out that there was 5 times more material in clusters of galaxies than they had expected by observing the hot gases. Thus it led scientists to believe that most of the stuff in clusters of galaxies is invisible and, since these are the largest structures in the Universe held together by gravity, scientists then concluded that most of the matter in the entire Universe is invisible. This invisible stuff is aptly called 'dark matter’. Scientist use the term to describe any matter that is not detectable by our usual x-ray, optical or even satellite telescopes.Dark matter does not reveal its presence by emitting any type of electromagnetic radiation. It emits no infrared radiation, nor does it give off radio waves, ultraviolet radiation, X-rays or gamma rays. It is truly "dark." leading Cosmologists to believe that we can only see about 10 percent of the matter in the universe.Until they can accurately determine the mass of the universe, they will not know for sure whether it is expanding infinitely or will stop expanding at some point and collapse. So, how in the world do scientists know that dark matter really exists?

Well we have to hand it to our scientists they have found a way to detect dark matter too. The key to detect dark matter lies in the ever so reliable gravitational forces. The most obvious of these gravitational effects has to be the rotation of galaxies. This begs us to ask the question of how that is to be done. No worries to study galactic rotation, astronomers look at the emission line spectra of stars in each part of the galaxy. When the light from a star is observed using a diffraction grating or a prism, the starlight is separated into its true colors, in much the same way ordinary sunlight is separated by rain drops during the formation of a rainbow.The true colors constituting starlight separate into a series of light and dark lines in the visible spectrum, with each colored line corresponding to a specific wavelength of light. The specific wavelengths at which these lines occur are characteristic of the elements the stars Thus, they can be used as an elemental "fingerprint" to identify a star's composition.When a star emitting these line spectra is moving away from us, all of the wavelengths of the spectral lines are shifted to higher values than they would have been were the star stationary or moving side to side (neither towards nor away from us). All of the spectral lines are thus shifted towards the long wavelength part of the spectrum, or to the red end of the spectrum.

Similarly if the galaxies are moving towards us they spectral lines would shift to the short wavelength part of the spectrum, or to the blue end. These phenomenons are respectively called the ‘red shift’ and the ‘blue shift’. By measuring the shift in wavelength, researchers can calculate the precise speed of a star, either towards us or away from us.

When a galaxy is rotating, the starlight from stars on the side of the galaxy that is moving towards are blueshifted, while the starlight from the stars on the other side of the galaxy are redshifted. Thus, we can tell how fast and in what direction each individual star in the galaxy is orbiting about the center of the galaxy.
When stars orbit the center of a galaxy, their orbital speed is determined by the distribution of the mass contained within the galaxy. A graph showing the orbital speeds of the stars versus their distances from the center of the galaxy is known as the "rotation curve" for the stars in the galaxy. If one takes all the luminous matter that can be seen in the galaxy (stars, gas and dust) and predicts the rotation curve using the well-known laws of gravitational physics discovered by Newton, the speed of stars should decrease in a predictable manner the father away they are from the center of the galaxy. Scientists however noticed some hair raising data from the curves. They saw that the rotational speed didn’t fall off with distance as expected. Instead, the curves level off, and star far away from the center of the galaxy move faster than expected. The only way to account for this observation is that a large quantity of matter which cannot be seen--dark matter--exists in the galaxies. To explain the astronomical observations, this dark matter must surround the spherical distribution known as a galactic halo.Theoretical candidates for dark matter have been divided into two groups, dubbed MACHOs and WIMPs. The existence of MACHOs (Massive Astrophysical Compact Halo Objects) has been confirmed experimentally--recently in our own Milky Way galaxy. The nature and origin of MACHOs are currently a matter of great speculation and debate, but their masses and distributions have been measured by their gravitational effects. Proposals for candidate MACHOs include primordial black holes, as well as some types of new, exotic astrophysical objects whose properties have yet to be properly described.WIMPs (Weakly Interacting Massive Particles) are exotic, massive elementary particles that do not interact strongly with matter. (Hence they have not been interacting with our detectors so we have not detected them yet). Because WIMPs do have mass, and there would be great numbers of them, their individually weak but collectively strong gravitational effects account for part of the impact that dark matter has on the rotation curves of galaxies.Dark matter is known to exist through the gravitational effect it exerts on visible matter in the universe. Scientists have made discoveries that point very strongly to their presence. But even than a lot more work still needs to be done if we truly are to understand more about dark matter and how it behaves.
----
By Tahsin Uddin Mullick
North South University, Dhaka, Bangladesh.
----
The Aftermath Publications, Issue 4
----