Nowadays we can often hear the term 'Greenhouse effect'. Global warming seminars and conferences are being conducted everywhere. Each and everyday we hear debates about these issues in News reports and other media channels. So, actually what is global warming (or Greenhouse effect)?? And why there is a growing concern about these issues??
Greenhouse effect and Global warning are related to each other. Actually, Greenhouse effect is a phenomenon that leads to Global warming. The trapping of infrared solar radiations by earth's atmosphere is known as greenhouse effect. Earth's atmosphere acts as a greenhouse. Actually it’s the atmospheric gases, mainly carbon dioxide, which traps the infrared radiations. This phenomenon keeps our earth warm and prevents it from cooling excessively during nights. It works in the same way as a Green house.
Earth's atmosphere allows small wavelength (high frequency) infrared radiations that are coming from sun, to pass through it. These infrared rays pass through the atmosphere and heats up the earth. When earth gets heated it also starts emitting infrared radiations. Since earth is less hot than sun (many many times), the radiations emitted by it are of large wavelength. The atmosphere does not allow the larger wavelength radiations to pass through it and reflects it back to earth. These again cause heating of earth surface. This whole process is known as Greenhouse effect. Carbon dioxide is a greenhouse gas. More concentration of CO2 in atmosphere will lead to higher rate of infrared ray trapping, which in turn will increase the temperature of earth. This will lead to Global warming. Hence due to Greenhouse Effect the temperature of earth is constantly increasing (Global Warming).
Monday, June 29, 2009
Thursday, June 25, 2009
Steady State Theory
In this post I will try to explain about Steady state theory. It is the less popular one. Although it has many flaws and discrepancies, still it is the main competitor for Big Bang.
As the name suggests, according to Steady state theory universe is constant it never changes. This theory states that even if Universe is expanding the relative density of the universe remain constant. The steady state theory asserts that although the universe is expanding, it does not change its look over time or in other words it has no beginning and no end. So, this theory requires that new matter must be continuously created so as to keep the overall density constant. Matter is mostly created in the form of hydrogen.
Flaws:
1) Steady state predicted that objects like quasars and radio galaxies are found everywhere. But observations and calculations suggest that this is not the case. In fact these objects are found only at large distances.
2) Another flaw in the theory is related to cosmic microwave background radiation. Steady state theory states that these radiations are from ancient stars. However, cosmologists found this explanation unconvincing, as the cosmic microwave background is very smooth, making it difficult to explain how it arose from point sources.
As the name suggests, according to Steady state theory universe is constant it never changes. This theory states that even if Universe is expanding the relative density of the universe remain constant. The steady state theory asserts that although the universe is expanding, it does not change its look over time or in other words it has no beginning and no end. So, this theory requires that new matter must be continuously created so as to keep the overall density constant. Matter is mostly created in the form of hydrogen.
Flaws:
1) Steady state predicted that objects like quasars and radio galaxies are found everywhere. But observations and calculations suggest that this is not the case. In fact these objects are found only at large distances.
2) Another flaw in the theory is related to cosmic microwave background radiation. Steady state theory states that these radiations are from ancient stars. However, cosmologists found this explanation unconvincing, as the cosmic microwave background is very smooth, making it difficult to explain how it arose from point sources.
Tuesday, June 23, 2009
Birth of Universe-The Big-Bang
Let us start with our first (and most probable) hypothesis-Big Bang. Actually Georges Lemaitre proposed this theory. This theory is mainly based on three laws, namely: -
1) General relativity
2) Homogeneity
3) Isotropy
According to Big Bang theory, the universe is expanding or we can also say that the galaxies are moving away from each other. Law of Doppler shift proves this. So, if the universe is continuously expanding it suggest that the evident expansion in forward time required that the universe contracted backwards in time, and would continue to do so until it could contract no further, bringing all the mass of the universe into a single point, a "primeval atom", at a point in time before which time and space did not exist. As such, at this point, the fabric of time and space had not yet come into existence. If we try to extrapolate this view we will reach a point when it is not possible to contract the universe any more and we will get a primeval atom with super high density and energy.
We will try to understand this concept using the example of football. We will try to correlate both the cases. Consider a football, think it as the primeval atom (starting point of whole universe). Now suppose we are pumping air in this football and we go on pumping till the football explodes. This point of explosion is known as Big Bang. Now as the football explodes the fragmented parts start flying away from each other. These fragmented parts correspond to the galaxies and they go on moving away from each other.
This is the basis of Big- Bang theory. I will try to explain this theory in more detailed manner (theoretically and mathematically) in my further posts.
1) General relativity
2) Homogeneity
3) Isotropy
According to Big Bang theory, the universe is expanding or we can also say that the galaxies are moving away from each other. Law of Doppler shift proves this. So, if the universe is continuously expanding it suggest that the evident expansion in forward time required that the universe contracted backwards in time, and would continue to do so until it could contract no further, bringing all the mass of the universe into a single point, a "primeval atom", at a point in time before which time and space did not exist. As such, at this point, the fabric of time and space had not yet come into existence. If we try to extrapolate this view we will reach a point when it is not possible to contract the universe any more and we will get a primeval atom with super high density and energy.
We will try to understand this concept using the example of football. We will try to correlate both the cases. Consider a football, think it as the primeval atom (starting point of whole universe). Now suppose we are pumping air in this football and we go on pumping till the football explodes. This point of explosion is known as Big Bang. Now as the football explodes the fragmented parts start flying away from each other. These fragmented parts correspond to the galaxies and they go on moving away from each other.
This is the basis of Big- Bang theory. I will try to explain this theory in more detailed manner (theoretically and mathematically) in my further posts.
Monday, June 22, 2009
Birth of Universe
Universe consists of many galaxies, millions- billions of stars and planets. Our own planet earth is like a grain of sand in the vast ocean (universe) floor. Many of us often think that how our planet was born or how our solar system was born. This is indeed a very interesting and fascinating question. Just think how much energy is required to produce this huge amount of masses (planets and sun) or vice versa how much mass is required to produce such enormous amount of energy (imagine the amount of energy produced by sun everyday). If you are not such a science geek then let me remind you that there is a very popular theory proposed by Albert Einstein known as mass energy relationship (E=mc^2).
If this is not enough then let us think of something more bigger(or the biggest!)-How the whole universe came to existence??
Still, we do not have a definitive answer for this. But indeed we have few hypothesis. Among these the most famous (or most probable) are:
1) Big Bang Theory
2) Steady State Theory
But before indulging into these topics more deeply let us try to identify the constituents of our universe (only brief description!). Our universe mainly consist of:
a) Stars- these are the shining members of our universe. Actually, the stars emit their own light. That means they produce their own energy(Basically heat and light energy). And how they produce it?? The answer is Nuclear Fusion.
E.g.- our own Sun.
b) Planets- The best example is our own planet earth. Planets are heavenly bodies that revolve around stars (due to gravity).
c) Natural Satellites- Like our moon. These natural satellites revolve around planets but they do not have their own energy.( Moon appears to glow only because it reflects sunlight).
Apart from these their are other heavenly bodies also like asteroids, comets, meteors, etc. We will discuss about them later, because as of now we are talking only about birth of universe.
So, let us go back to our hypothesis, namely Big Bang and Steady state.
Among these two, Big- Bang is more popular and is accepted by most physicists and cosmologists. It is supported by most comprehensive and accurate scientific observations and evidence.
On the other hand, Steady State theory is a model developed in 1948 by Fred Hoyle, Thomas Gold, Hermann Bondi and others as an alternative to the Big Bang theory. But this theory has very less number of supporters as compared to Big-Bang theory.
As the name suggests, Big-Bang is about one big explosion whereas steady state refers to one static universe(it has no beginning and no end). We will discuss these two topics in more detail in my subsequent posts.
If this is not enough then let us think of something more bigger(or the biggest!)-How the whole universe came to existence??
Still, we do not have a definitive answer for this. But indeed we have few hypothesis. Among these the most famous (or most probable) are:
1) Big Bang Theory
2) Steady State Theory
But before indulging into these topics more deeply let us try to identify the constituents of our universe (only brief description!). Our universe mainly consist of:
a) Stars- these are the shining members of our universe. Actually, the stars emit their own light. That means they produce their own energy(Basically heat and light energy). And how they produce it?? The answer is Nuclear Fusion.
E.g.- our own Sun.
b) Planets- The best example is our own planet earth. Planets are heavenly bodies that revolve around stars (due to gravity).
c) Natural Satellites- Like our moon. These natural satellites revolve around planets but they do not have their own energy.( Moon appears to glow only because it reflects sunlight).
Apart from these their are other heavenly bodies also like asteroids, comets, meteors, etc. We will discuss about them later, because as of now we are talking only about birth of universe.
So, let us go back to our hypothesis, namely Big Bang and Steady state.
Among these two, Big- Bang is more popular and is accepted by most physicists and cosmologists. It is supported by most comprehensive and accurate scientific observations and evidence.
On the other hand, Steady State theory is a model developed in 1948 by Fred Hoyle, Thomas Gold, Hermann Bondi and others as an alternative to the Big Bang theory. But this theory has very less number of supporters as compared to Big-Bang theory.
As the name suggests, Big-Bang is about one big explosion whereas steady state refers to one static universe(it has no beginning and no end). We will discuss these two topics in more detail in my subsequent posts.
Thursday, June 18, 2009
Robots and Humanoids
There is no doubt about it; human evolution and performance are limited. Our intelligence and physical abilities are restricted and we cannot survive without vital nutrients, air and other elements, necessary for our frail human nature. Therefore it is vitally important we improve and protect our abilities, and what better way to do so, then with mechanically engineered devices. The development of robots has helped us in our endeavors, be it for national defense purposes, on an industrial level where they are part of many manufacturing processes, or on a personal level at home where all kinds of gadgets help us in mastering our chores. But where is the world of robotics leading us? Will the world soon be overrun by androids, cyborgs and other automatons?
People already rely on artificial intelligence in many aspects of their daily routine and even if most of them do not have humanlike features, they may surround us as cleaning tools, who know when to return to their docking station after their cleaning cycle is done, or when their battery runs low, or they may act as toys mimicking and behaving like favorite domesticated pets, to name just a few. If science fiction gets it right, soon a multi-tasking robotic butler, complete with arms, legs and speech will become a common household feature. Many breakthroughs in the development of artificial interaction, locomotion, navigation, manipulation and intelligence have already been made, and various scientists are working equally hard on finalizing muscle-like, spring-based motors that will upgrade the limps of their mechanical life forms and increase their humanoid efficiency and reaction time. Progress in skin development has enabled more lifelike robotic hands to sense objects and their movement. This means that if a bottle would be slipping through the robot hand, the speed bump sensors embedded in the skin would record the pressure change, react to it, and stop the bottle from falling.Robotic Science has come a long way and many laboratories have the structures to prove it.
Domo is a robot like no other. Born and built at the Massachusetts Institute for Technology, Domo is the first robot able to give a hug. With less rigid elastic actuators in his fingers, wrists, arms and neck, and joints that are more flexible than those used in other humanoids, this robot feels not only the object, but also its pressure and touch flexibility. This allows Domo to fine-tune its grip, make handshakes less ferocious and hugs more temperate.
People already rely on artificial intelligence in many aspects of their daily routine and even if most of them do not have humanlike features, they may surround us as cleaning tools, who know when to return to their docking station after their cleaning cycle is done, or when their battery runs low, or they may act as toys mimicking and behaving like favorite domesticated pets, to name just a few. If science fiction gets it right, soon a multi-tasking robotic butler, complete with arms, legs and speech will become a common household feature. Many breakthroughs in the development of artificial interaction, locomotion, navigation, manipulation and intelligence have already been made, and various scientists are working equally hard on finalizing muscle-like, spring-based motors that will upgrade the limps of their mechanical life forms and increase their humanoid efficiency and reaction time. Progress in skin development has enabled more lifelike robotic hands to sense objects and their movement. This means that if a bottle would be slipping through the robot hand, the speed bump sensors embedded in the skin would record the pressure change, react to it, and stop the bottle from falling.Robotic Science has come a long way and many laboratories have the structures to prove it.
Domo is a robot like no other. Born and built at the Massachusetts Institute for Technology, Domo is the first robot able to give a hug. With less rigid elastic actuators in his fingers, wrists, arms and neck, and joints that are more flexible than those used in other humanoids, this robot feels not only the object, but also its pressure and touch flexibility. This allows Domo to fine-tune its grip, make handshakes less ferocious and hugs more temperate.
Monday, June 15, 2009
Huygens-Mathematical Genius and Astronomer
Christiaan Huygens was born in Holland in 1629 and he was a mathematical genius who invented several important mechanical devices including the pendulum clock. He had a deep understanding of astronomy, optics, mathematics, and mechanical devices. And he built some of the largest telescopes of the 17th century. Being a contemporary of Galileo he heard about Galileo’s telescope and he set out to improve on the design. One of the liabilities of refracting telescopes like the one that Galileo built was that because of optical problems they caused distortion in how things looked. The colors of objects were separated and things were not sharp. This was a phenomenon called chromatic aberration. Huygens discovered, after much experimentation, that this problem could be lessened by building lenses with much longer focal lengths. This type of lens with a longer focal length was easier to make accurately. And using this discovery he built telescopes that were as long as 120 feet. He called his style of telescope “tubeless” because it was an open air frame without a tube; and while he did build a monster that was 120 feet long it was cumbersome and difficult to use. Most of his observations and discoveries were made with smaller telescopes around forty feet in length.
He wasn’t just a lens and telescope maker though. He was also an avid astronomer and he used his telescopes to make some discoveries under the night sky. One of his most important discoveries was of the rings of Saturn. He wasn’t the first one to actually see them. Galileo did that. But because of chromatic aberration Galileo’s telescope wasn’t good enough to resolve the rings into what they truly were. All Galileo saw was what he described as a tri-form planet which was composed of a large center section that had a section attached to each side. He described these side sections as being much like the handles of a vase. Huygens, with his better telescopes, could resolve the image of Saturn better and see what was really there and in 1656 he published his findings. He described Saturn as being composed of a central globe much like Jupiter but girdled by a thin flat ring that did not touch it.
He wasn’t just a lens and telescope maker though. He was also an avid astronomer and he used his telescopes to make some discoveries under the night sky. One of his most important discoveries was of the rings of Saturn. He wasn’t the first one to actually see them. Galileo did that. But because of chromatic aberration Galileo’s telescope wasn’t good enough to resolve the rings into what they truly were. All Galileo saw was what he described as a tri-form planet which was composed of a large center section that had a section attached to each side. He described these side sections as being much like the handles of a vase. Huygens, with his better telescopes, could resolve the image of Saturn better and see what was really there and in 1656 he published his findings. He described Saturn as being composed of a central globe much like Jupiter but girdled by a thin flat ring that did not touch it.
Saturday, June 13, 2009
Digital and Film Photography
Photography is a way of life for some and at least a part of life for everyone else. In this day and age, technological advances await us at every turn, and the field of photography is no exception. Cameras have gone digital, and the potential is astounding. The following will take a look at some of the differences in the old and new ways, and weigh them out as either pros or cons of digital photography.Scientifically speaking, the differences between the two are enormous. With film photography, light traveling through the camera’s lens is actually burning the images onto the film. With digital photography, the light of the images is being encoded as binary data and stored in memory as with a computer. These differences, while huge, can be unimportant to some though. No one is actually interested in the technical aspect of how the cameras work. The photographer is more interested in what it means to him in regard to the pictures he can take and what he can do with them.One of the primary advantages of digital photography is versatility. Digital cameras can record not only the still images of film cameras, but also motion pictures and audio in some cases. While a film camera can be a specialized piece of equipment for taking still pictures, digital cameras can offer you an entire range of different equipment, all in the palm of your hand.
Digital cameras are also commonly found on other pieces of equipment. As technology advances, cellular telephones and MP3 music players now often have built-in cameras, which are always digital. This may offer some extra convenience to digital camera users, considering that they can decrease the overall number of devices that they must carry with them and use.Printing your pictures is also very different from digital to film photography. In both cases, though, you have many options. Professional film photographers may develop their prints on their own, in their very own dark room. Amateur or casual film photographers may simply drop their film off at a one-hour photo place. With digital, your pictures are recorded as electronic data, so you can use your computer to print them. Or, if you prefer, you can still drop them off at a photo shop and have it done for you. So as far as printing goes, it seems it is up to you how deeply you want to dive in. Both film and digital offer you a range of options, from the hands-on to letting others do it for you.So in the end, choosing between digital and film may mean considering the application. Hobbyists may stick to film, while technology buffs and burgeoning photographers will choose the brave new world of digital. Either way, it looks like both styles of photography are going to be around for awhile to come.
Digital cameras are also commonly found on other pieces of equipment. As technology advances, cellular telephones and MP3 music players now often have built-in cameras, which are always digital. This may offer some extra convenience to digital camera users, considering that they can decrease the overall number of devices that they must carry with them and use.Printing your pictures is also very different from digital to film photography. In both cases, though, you have many options. Professional film photographers may develop their prints on their own, in their very own dark room. Amateur or casual film photographers may simply drop their film off at a one-hour photo place. With digital, your pictures are recorded as electronic data, so you can use your computer to print them. Or, if you prefer, you can still drop them off at a photo shop and have it done for you. So as far as printing goes, it seems it is up to you how deeply you want to dive in. Both film and digital offer you a range of options, from the hands-on to letting others do it for you.So in the end, choosing between digital and film may mean considering the application. Hobbyists may stick to film, while technology buffs and burgeoning photographers will choose the brave new world of digital. Either way, it looks like both styles of photography are going to be around for awhile to come.
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