AT THE SPEED OF LIGHT

Light takes 3+ seconds to travel from the moon. It takes 8 minutes and 17 seconds to travel from the sun. The nearest star alpha centauri is 4.37 light years away. So light propagation is not instantaneous as we experience every day. It has finite speed 300000000 met/sec in vacuum.

When light travels in denser medium like water or glass, it slows down. In glass, it travels at 2*10 ^8 met/sec speed. The ratio of speed in vacuum to the speed in glass is 1.5 and it is the refractive index of the glass.

Discovery of speed: Ole roamer observed Jupiter through telescope. He was able to see the shadow of its moon 'Io" on the face of Jupiter as a blackspot. When the Jupiter was close to earth, the spot appeared at one place; when the Jupiter was far away from the earth, the shadow appeared at another place. From these observations, he was able to calculate the speed of light.

Einstein said: "The velocity of the light is independent of light source speed and observer's speed". A car speed is relative to the earth surface or another car speed. But the light speed is absolute, not relative and a constant. This principle is the 'corner stone' of theory of relativity.

Einstein also said: "The light speed is maximum attainable speed in nature". That is, nothing can travel faster than light. Some scientists say this barrier will be broken in future and we will be able to travel faster than light in space.

Light speed plays an important role in Einstein's topmost formula E= mc^2.

So what is speedier than speed of light? One can answer philosophically, it is the speed of thought.

Comments

THE EARTH, A SUPER ORGANISM

JOIN MY COURSE: "Become a programmer in a day with python" A man called 'love lock' (what a name) proposed a theory called Gaia theory, named after Greek Goddess. It says, "Earth is a self-regulating organism like a human being. The organic life in it interacts with in-organic matter and maintains atmosphere, temperature and environment". Hence the earth is still suitable for the life to thrive. Imagine, in a particular place, there are lot of flowers. Some flowers are white and some are darkly coloured. We know, white reflects light and heat while dark absorbs the same. White flowers can thrive in hot climate. But dark flowers requires cold climate. The absorption and reflection balances and the environment reaches average, warm temperature at which both the flowers can co-exist. This is the essence of "Gaia" theory. On our earth, the oxygen constitute 20% of the atmosphere. The oxygen level is always mai

THE PARABOLA

A jet of water shooting from a hose pipe will follow a parabolic path. What is the so special about parabola. Y= x^2 Draw a graph for the above equation. It will result in a parabola. This parabola is also called unit parabola. Any equation involving square will yield a parabola. Example: Y = 2x^2 +3x+3 (also called quadratic equation) X= 2 and -2, both satisfies the equation 4 = X^2. Parabolic equations always have two solutions. Any motion taking place freely under gravity follows parabolic path. Examples: An object dropped from a moving train, A bomb dropped from flying plane, A ball kicked upwards. If a beam of light rays fall on the parabolic shaped mirror, they will be reflected and brought to focus on a point. This fact is made use of in Dish Antenna, Telescope mirrors, etc. Inverted parabola shape is used in the construction of buildings and bridges. Because the shape is able to bear more weight. A plane

DISORDER IS THE "ORDER OF THE DAY"

Imagine a balloon full of air. The air molecules are moving randomly inside the balloon. Let us pierce the balloon with a pin. The air rushes out. Why should not the air molecules stay inside the balloon safely and ignore the little hole? That is not the way the world works. The molecules always "want to occupy as many states as possible". Hence the air goes out in the open to occupy more volume. The things always goes into disorder (entropy) and the disorder increases with time. The above statement is what we call "second law of thermodynamics". Consider a cup of coffee on the table. Suppose the heat from entire room flows to your cup of coffee, the coffee will boil and the rest of the room will freeze. Freezing means bringing things to order and arrangement. It violates the second law. Hence it will never happen. Hence heat must flow from high temperature to low temperature and not the other way. The air molecules in y

sciencecapsules

Search This Blog