WHY ARE THE ECLIPSES SO RARE?

WHY ARE THE ECLIPSES SO RARE?

When the moon in its journey around the earth passes directly between the earth and the sun, it casts its shadow on the surface of the earth, and an eclipse of the sun takes place.
An eclipse of the sun occurs only when the moon is new, for then the moon is on that side of the facing toward the sun. Then why isn't there an eclipse of the sun every time there's a new moon? The reason is that the path of the moon around the earth does not lie directly in line with the orbit of the earth about the sun. In its 29-days trip around the earth,the moon passes sometimes above and sometimes below the path of the earth.
An eclipse of the sun can be total, annular, or partial. If the moon hides the sun completely, the eclipse is total. But the moon is not always the same distance from the earth. Often, it is too far from the earth to hide the sun completely. Then, when an eclipse takes place,the moon is seen as a dark disk which covers the whole sun except a narrow ring around its edge. This thin circle of light is called "the annulus" meaning "ring".This is an annular eclipse.An eclipse is partial whenever only part of the disk of the moon comes between the sun and the earth.
An eclipse of the moon occurs only when the moon is full, for then it is at the opppsite side of the earth from the sun. When the moon comes directly behind the earth as seen from the sun. when the moon comes directly behind the earth, as seen from the sun,it passes gradually into the great shadow-cone cast by the earth and disappers from view. A total eclipse of the moon then occurs. A partial eclipse takes place when the moon enters only partly into the shadow.

In some years, no eclipses of the moon occur. In other years, there are from one to three. Every year, there must be at least two solar eclipses, and there may be as many as five. At any one place on the earth'h suface,a total solar eclipse will be visible only once in about 360 years.

WHY IS THE SOLAR SYSTEM THE WAY IT IS?

WHY IS THE SOLAR SYSTEM THE WAY IT IS?

As far as we know, there is no reason why the solar system is arranged exactly as it is. It might have been arranged differently. This has to do with the way it originated. But man has discovered certain laws of nature that seem to keep the solar system in its present pattern.
Earth, like the solar planets, follows its path, or orbit, around the sun.
The period of time that the earth takes to go around the sun is called a year.
The other planets have orbits larger or smaller than the earth's.
How this solar system came to be and how the planets came to have the size,location,and orbits they have, astronomers cannot fully explain. But they have teo main types of thories. one type of theory suggests that the formation of the planets was a part of the gradual change of the sun from a whirling mass of hot gas to its present size and brilliance. The planets formed as small whirling masses in the giant gas and dust cloud as it turned.
Another group of theories is based on the idea that at some time here was a near-collision between the sun and another star passing nearby. Large pieces of the sun were pulled away and began to resolve around the sun at different distances. These are now planets.
No matter which theory is right, the solar system caem to be as it now is more or less by chance. Why does it stay this way? Kepler's Laws of Planetary Motion state that all planets travel about the sun in an elliptical ( oval ) path; that a planet moves faster in its orbit as it nears the sun; and that there is a relation between its distance from the sun and the time it takes to make an orbit. Newton's law of Gravitation, of which kepler's three laws were an indispensable part, explained how two objects attract each other.
So the solar system remains as it is because certain laws of nature maintain the relationship of the sun and the planets.

WHY DO SUNSETS LOOK RED?

WHY DO SUNSETS LOOK RED?

A beautiful red  sunset, the colors warm and glowing, is one of the loveliest sights we can imagine. And sometimes, when we look at it we might say, "see how red the sun is!"
But, of course, we know that the sun itself hasn't become red or changed in any way. It merely looks that way to us at that particular time of day. In fact, at that very moment people are looking at that same sun thousands of miles to the west and it doesn't look red to them at all.
What produces the colors of a sunset is the distance that the sunlight must travel through our atmosphere. the lower it is, the more of our earth's atmosphere does that light travel through.
But first, let's remind ourselves that sunlight is a mixture of light of all colors. Normally, this mixture of light appears as white to our eyes. But the atmosphere has molecules of air, dust, water vapor, and other impurities present in it. As the light passes through them, different colors are scattered by these particles. Now, it so happens our atmoshere scatters out violet, blue, and green light more than it does the reds and yellows. So when the sun is low, this scattering leaves more reds and yellows for us to see and we have a reddish sunset.
By the way, this scattering of light also explanis why the sky liiks blue, Violet and blue light have short waves and are scattered about 10 times more than red light waves by our atmoshere. This means that the red rays go straight through our atmosphere, while the blue waves don't come through directly but are scattered by the air, water, and dust particles. It is this scattered light that we see as the blue sky when we look up.

how big is the universe?

HOW BIG IS THE UNIVERSE 

It is impossible for the human mind to conceive a true picture of the size of the universe.We not only don't know how big it is,but it is hard for us even to imagine how big it might be.
If we start from the earth and move out, we'll see why this is so. The earth is part of the solar system,but a very tiny part of it.The solar system consists of the sun, the planets that revolve around it , the asteroid, which are tiny planets, and the meteors.
Now, this whole solar system of ours is only a tiny part of another, much bigger system called " a galaxy". A galaxy is made up of many millions of stars,many of which may be much larger than our sun, and they may have solar systems of their own.
So the stars we see in our galaxy, which we call "the  Milky Way". are all suns . They are all so far away that distances are measured in light years instead of in miles. Light travels about 6,000,000,000,000 miles in a year. The bright star nearest to the earth is Alpha Centauri. Do you know how far away it is ? 25,000,000,000,000 miles!
But we're still talking only ablut our own galaxy. This is believed to be about 100,000 light years in width. This means 100,000 times 6,000,000,000,000 miles! And our galaxy is only a tiny part of a still larger system.
There are probably millions of galaxies out beyond the Milky Way.
And perhaps all these galaxies put together are still only a part of some larger system!
So you see why it is impossible for us to have an idea of the size of the universe. Incidentally, it is believed by scientists that the universe is expanding. This means that every few billion years two galaxies will find themselves twice as far apart as they were before!

Asia Satellite Image and Map - Satellite Photos - GEOLOGY.COM

Asia Satellite Image and Map - Satellite Photos - GEOLOGY.COM

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