Monday, 17 October 2011

THEY SAW IT …



The 2011 Nobel prize winners in science (physics, medicine and chemistry)


There were those who sought to the stars and their eyes trying to catch hold of supernovae afar… there were those who sought within their own body, their eyes and mind trying to understand the workings of  the immunity system … and then there was one who changed the rulebooks of crystallography… And they are none other than  the Nobel prize winners of 2011... 



Looking out into the night sky, and trying to solve the mysteries of birth and death, of seeking the arrow of time and predicting our fate. Would we collapse into singularity or would we die out with universe expansion  into cold state, or would we continue to enjoy the pleasures of today, in the steady state of a flat universe ? We knew that the universe was growing, after Henrietta Swan Leavitt’s study on the redshift pattern. But what would be our fate was the question… Most cosmologists were happy to believe in the most simple and mathematically elegant Universe: a flat one, where the expansion is believed to decline, and we‘d reach an equilibrium to stay on for eternity. Saul Perlmutter, Brian P. Schmidt, and Adam G. Riess set out to confirm the same only to be startled by discovering that truth wasn’t what they thought, rather the universe was accelerating. Einstein’s concept of cosmological constant was now revived, a term which explained the concept of non-static accelerating universe, a term, which was in dark shadows of rejection in the past. But after the Nobel Laureates’ discovery, things took a 180 degree turn as to the understanding of the universe. They had proceeded to study the universe at cosmic scale, to look more into the past, and go a step beyond Henrietta’s work. And thus, they set out to study supernovae (massive star explosion) where they accounted  50 distant supernovae whose light turned out to be  weaker than expected, contrary to what they had envisioned. If cosmic expansion had been losing speed, the supernovae should’ve appeared brighter. But, the supernovae were fading as they were carried faster and faster away, embedded in their galaxies, which concluded that universe is not slowing down – quite to the contrary, it is accelerating. The reason for such a scenario is due to, the dark energy, which is estimated to be  71.3 % of the universe, that forces the expansion and it isn’t a constant quantity, as the universe is accelerating. But what is dark energy is a question, no physicist has an answer to, yet. And yes, we await those who can shed more light on this darkness…   


Moving on to the men of honour in medicine :: Bruce A. Beutler, Jules A. Hoffmann and Ralph M. Steinman, have changed the way we think so as to fight against pathogens, by discovering the workings of our own immune system.  Bruce Beutler and Jules Hoffmann discovered receptor proteins that can recognize such microorganisms and activate innate immunity (the first step in the body’s immune response). Ralph Steinman discovered the dendritic cells of the immune system and their unique capacity to activate and regulate adaptive immunity (the later stage of the immune response) during which microorganisms are cleared from the body. It is now known, what triggers the immune system response, and what steps we can take to fight against diseases such as cancer and inflammatory diseases.  The detailed study of Toll gene has lead to understanding as to why the immune system reacts the way it does, and what changes can be made while avoiding an attack on the body’s own endogenous molecules. Signals arising from the innate immune response and sensed by dendritic cells were shown to control T cell activation, thus the interlink between the innate and adaptive immune system, has opened new doorways of research into development of new vaccines and cures to fight pathogens. 


Now, coming to the man, who changed the rulebooks of crystallography, who was faced with complete opposition and even ridiculed for what he had discovered, and also asked to leave the research group by his boss for his claims. He is none other than Nobel Laureate (2011) Dan Shechtman. His article was rejected by Journal of Applied Physics. But tables turned, when he met Cahn, Gratias and his research work then got published in November, 1984, in Physical Review letters. Dan Shechtman and his discovery of quasicrystals changed the very basic concept of crystallography. According to the textbooks, five-fold symmetry wasn’t possible, as the atoms would lie at unequal distances and non-repetitive patterns, the same applies to seven fold or higher symmetries. But what Shechtman saw through his electron microscope was a ten-fold symmetry with atoms aligned in concentric circles, he then rapidly cooled the substance expecting the atoms to disarray, but again they arranged themselves in same fashion, representing the crystal pattern. He revised his observations and checked if they were twin crystals, but came up with the same observation. His experimental proof to Alan Mackay’s theoretical postulation (using Penrose mosaics ) explained the existence of quasicrystals. The discovery, opened the eyes of many crystallographers, who had dismissed their observations of higher fold symmetries as twin crystals. Today the applications of quasicrystals are found everywhere, from frying pans to LEDs and naturally occurring quasicrystals have also been reported. Had it not been Shechtman’s boldness to defy conventional wisdom, quasicrystals would never have been termed. 

To these men of honour, I bow, their research work and experimental proofs that led to understanding of reality have extended our vision, lighted pathways for new discoveries, and truly grasped the essence of understanding existence. 

For more information check out :: www.nobelprize.org 

                                               



Sunday, 4 September 2011

Curious Eyes


In the dark glistening expanse of the night sky, the stars sparkle just like the rhymes we’d learnt… only later do we understand why stars sparkle, and how stars are not as tiny as they appear to be… rather an alarming size, as one approaches it close, and the hot jets burst in flares every second, the very source of light, which from distant seemed so calm…

In Carl Sagan’s words, “We are stardust… “  …. and very literally, yes, we are… For you see, it is after birth of stars (be it via supernova explosion or collapsing of nebula) , does the formation of heavier elements take place over time, and cloud, gas and matter take form to form their respective solar systems, and collectively, formations of galaxies… 

Our seek to understand the origin of us, leads to discovering, our roots, and the birth of universe… and so we start looking at what’s in proximity :: our very own solar system in the milky way galaxy. If answers to the existence of solar systems and its formations could be defined, so would the larger questions be answered, like fitting in the little pieces of a large jigsaw puzzle… 

Today, our eyes aren’t just limited to the what we see with our retina, but eyes, that travel across the deep space of the universe due the technological advancements that provide lens to our eyes… 

The spacecrafts that wonder across the night sky : there are those that set out to uncover mysteries while orbiting the subject, and those who travel to the very surface of the planets we watch from afar… 

And of all the various missions, I shall elaborate on the recent space mission (JUNO) to orbit Jupiter for a year, so as to provide about the information that Jupiter holds, for it isn’t any other planet, but a planet if 80 times more than its present state could’ve been the sun, a planet with 50 moons, a planet that was formed just after the infant sun and helped shape up the solar system, a planet whose immense thunderstorm created the ever so prominent great red spot that is about the size of two earths, and the planet‘s immense magnetic field that creates the brightest auroras in the solar system ; Also, Jupiter's giant mass allowed it to hold onto its original composition, providing us with a way of tracing our solar system's history… 

Beneath its dense cloud covers, hiding the secrets of its workings, and Juno shall unveil what lies beneath the stormy atmosphere, and the core of Jupiter. Juno will determine the global structure and motions of the planet’s atmosphere below the cloud tops for the first time, mapping variations in the atmosphere’s composition, temperature, clouds and patterns of movement down to unprecedented depths. 

Deep in Jupiter's atmosphere, under great pressure, hydrogen gas is squeezed into a fluid known as metallic hydrogen. At these great depths, the hydrogen acts like an electrically conducting metal which is believed to be the source of the planet's intense magnetic field. This powerful magnetic environment creates the brightest auroras in our solar system, as charged particles precipitate down into the planet’s atmosphere. Juno will directly sample the charged particles and magnetic fields near Jupiter’s poles for the first time, while simultaneously observing the auroras in ultraviolet light produced by the extraordinary amounts of energy crashing into the polar regions. These investigations will greatly improve our understanding of this remarkable phenomenon, and also of similar magnetic objects, like young stars with their own planetary systems. By determining the water content in Jupiter’s atmosphere, it’ll help determine which planet theory is correct (or if new theories are needed). 

The understanding of the giant planet shall reveal the story of the solar system. And eventually the story about us… 

So next time, when you look out to the night sky, you aren’t just peeping into unknown distant lights, rather you are gazing at your own roots, and the silent detective spacecrafts that work through years, in order to explain the mysterious workings of the universe…. 

For more information and exploration you can check out :: www.nasa.gov about the various past, current and future missions. Also you can explore into the solar system with the software :: “eyes into the solar system” , a virtual reality built by JPL (Jet Propulsion Laboratory) and Caltech wherein you can just explore the universe by changing the space-time coordinates, and look at the orbits, the planets and the space shuttles. 


                                


Neutrinos

A neutrino is an elementary particle, which was first postulated by Wolfgang Pauli (1930) I order to explain the missing energy in radioactive decays. It was only later in 1965, that neutrino was first detected by Clyde Cowan and Fredrick Reines. 

A neutrino is an obscure particle, with zero electric charge and rarely interacts with matter, and according to recent studies has a small mass (which was earlier believed to be massless according to standard model of particle physics). About 100 billion neutrinos from sun, pass through your thumbnail every second, but you don’t feel them because they interact so rarely and weakly with matter. Because they interact so rarely, neutrinos can escape from solar interior and bring direct information about the solar fusion reactions to us on earth. The neutrinos from the fusion process in the sun can pass through several light years of solid lead before being absorbed by matter. 

There are 3 types of neutrinos: electron neutrino, muon neutrino and tau neutrino. Nuclear fusion in the sun produces neutrino related with electrons called electron-neutrino. Muon-neutrino and tau-neutrino are produced in lab accelerators and exploding stars along with heavier versions of the electron, the muon and tau. 

The neutrinos can be divided into two categories. The low energy neutrinos and the high energy neutrinos. The low energy neutrinos (about 10th MeV) are produced in nuclear processes such as fusion reactions of the sun or in the center of an exploding supernova. High energy neutrinos (more than 10th GeV) are produced due to high energy particle collisions which produce short-lived mesons decaying into neutrinos and other particles. 

Only low energy neutrinos have been detected so far: the solar neutrinos and the supernova neutrinos. Raymond Davis Jr., 2002 Nobel Laureate in Physics, managed to catch an average of half an electron neutrino (solar neutrino) interaction per day in his detector during his 20 years of research. While the Supernova Neutrinos were observed during 10 seconds in 1987 when a star in the Large Magellanic Cloud exploded as a supernova. The neutrinos from the inner part of the collapse reached the earth after a journey of 170,000 years, a few hours before the arrival of light from the supernova. The neutrinos were able to travel more or less directly from the central collapse in the inner part of the star. About 25 neutrino interactions were observed by the detectors at Kamiokande (Japan), Baksan (Sovjet union) and IMB (USA) during those 10 seconds. This observation of neutrinos from the sun and the supernova represented a new kind of astronomy since the neutrinos give us information from processes deep inside objects.

The unknown sources of high-energy cosmic rays produce high energy neutrinos called the GZK neutrinos when the accelerated high-energy protons (possible sources are gamman ray bursts, super heavy stars collapsing to black holes or two neutron stars falling into each other) collide with the photon gas around the sources, or with the microwave background (remnant of the Big Bang). These collisions will produce short-lived mesons, which decay to neutrinos and other particles. These neutrinos will travel, unaffected by the magnetic field in space and if detected on earth, will point back to the sources of the cosmic rays, which would help us identify the source, unlike cosmic rays which are electrically charged and get deflected due to the magnetic field in space. 

High energy neutrinos, might be produced in connection with another strange observation called "dark matter" in the universe. Galaxies and groups of galaxies rotate as if they contain more matter than what we can observe with our standard astronomical instruments. With only the observed visible matter, the galaxies should eject stars and matter out in the empty space due to the fast rotation. But this is not happening, which indicates that there is more matter than what we can observe. It is only the gravitational force, which feels the unknown hidden matter. This matter is called the "dark matter." One popular explanation of the dark matter is that the large part of this different kind of matter consists of weakly interacting massive particles (WIMPs) that were created in the Big Bang at the same time as our ordinary matter. Today, these WIMPs surround us, but can’t be felt as they weakly interact with matter. But when WIMPs pass through strong gravitational fields, they would tend to get gravitationally trapped within the core of the strong gravitational fields. When WIMPs interact they annihilate each other and produce high-energy neutrinos and other particles. Detection of these high energy neutrinos from the core would prove the existence of WIMPs and stand as an indirect proof of dark matter. 


The neutrino saga that started as a theoretical postulation to recent detection and experimental proof in the 20th century has much in store. It forces us to revise the standard model of particle physics that states neutrino as massless. It provides us an eye into the beginning of universe: the Big Bang and explore into the unsolved mysteries of the universe about dark matter. From particle physics to astrophysics, the neutrino holds the key to unravel the unexplained and unseen.