WAXING AND WANING MOON

The moon appears to grow and decay. What really happens? It is just an interplay of light and shadow.

Like earth, half of the moon's surface is illuminated by sun light always. The moon circles the earth every 28 days. when it shows fully illuminated face, we say it is full moon day. When it shows night side(dark side), it is new moon day. If it shows partly night side and day side, it must be either in waxing or waning phase. The figure illustrate the concept beautifully.

When we see exactly half moon, the earth, the sun and the moon must form a right angled triangle as shown in the diagram. The angle suspended at the earth is 89.85 degrees.
The trigonometry says :

COS(89.85) = distance between the moon and the earth / distance between sun and the earth = .002617
Reversing both sides,
distance between sun and the earth / distance between the moon and the earth = 1/0.002617 = 382

Hence sun's distance is 382 times the moon's distance from the earth. The moon is roughly at 400000 km from the earth. So the sun is at 382 x 400000 km from the earth. The trigonometry always plays the important role in astronomical calculations.

Moon's cycle is used as measurement of time till date (a month). Moon's phases gave us romance; threatened us; made us quiet and artist. There are many beliefs that surrounds the moon's phases.

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