The Universe

No one knows the size of the Universe. No one can tell how big is the Universe. The Universe has no center. So we can’t measure it. According to Astronomers, the universe is still expanding from the time of the big bank. So Universe cannot be measured, and it is continually expanding.

To measure the size of Universe we would need to calculate the decaying rate of expansion, the distance at which stars move away from each other, and the decaying speed, the speed at which starts travel over the decaying distances. An unknown factor would the volume of matter, as this would also be a determining factor on the speed and distance matter could travel and therefore final size. There may also be something to the spherical space theory. However, this itself begs the question as to what is outside the sphere of space?

The Universe is a large space that contains everything i.e. all matters and energy, from the smallest particles to the largest particles, whatever in the space is universe. It contains all the planets, stars, asteroids, meteors and all the galaxies. No one knows the size of the Universe. The astronomers believe that the universe is still growing outwards in every direction. Astronomers continue to investigate about it. One way they do this is by “using a spectroscope”. A spectroscope measures the color of light coming from an object. Changes in the color indicate whether an object is moving away from or towards the Earth. After the readings of spectroscope scientists believe that the universe is still growing outwards in every direction.

How Universe formed

According to the astronomers first everything was an incredibly solid, heavy ball of a matter. This heavy ball exploded billion of years ago and as a result the Universe was formed. The moment of the explosion of this ball is known as “Big-Bang”. After this explosion the early universe was very small and too hot but later it got cooled and it exploded and spread out into the small pieces. Small pieces formed the basic elements called hydrogen and helium. Then the pieces join together which results object formed. Over billion of years the object becomes Galaxies, Stars and Planets. How the universe was formed is still only an idea.

What are planets

Planets are defined as the asteroids which are revolving around any star like in our solar system there are nine asteroids Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto which are revolving around a star that is the Sun. So we call those asteroids as planets. The Earth on which we live is one of nine planets that move round and round the sun.

Why do all the planets look different

There are nine planets in our solar system and all the planets look different from each other. The reason of each planet to be looking different is that each one seems to be made up of different substances. Even though the all are planets revolving around the sun and part of the solar system, their composition varies. We actually know very little about what the planets are made of, and this is one of the questions man hopes to answer with the space explorations that have taken place and those that are being planned for the future. Let’s take a brief look at each of the other planets and see what is known of their make-up. Mercury is a small, rocky world. It has some dark areas and many craters on its surface, but has no atmosphere or water of any kind. Venus is a white globe with some hazy markings. It is completely covered by a layer of white clouds, which are not made of water vapor but of concentrated sulphuric acid. Underneath its clouds, Venus’s atmosphere is made largely of unbeatable carbon-dioxide gas. This traps heat from the sun like a blanket, so temperatures at the planets surface reach nearly 500 degree Celsius and there is scarcely any water on Venus. Mars is known as the red planet because of the color of its deserts. It is half the size of the earth and has thin atmosphere of carbon-dioxide in which clouds form. No definite signs of life have been found on Mars, perhaps because it is very cold there. Jupiter appears as yellowish globes with colorful bands of clouds swirling around it and a giant red spot clearly visible in the clouds. It is a giant ball of liquid, mostly hydrogen and helium, becoming denser and denser towards the planet’s centre. Saturn is mostly liquid hydrogen with a set of brilliant rings around it. These are made of countless particles all moving in orbits around the planet like miniature moons. Uranus has rings around it too, though these are much darker than Saturn’s. Neptune is a dim greenish object and Pluto is the smallest planet in the solar system, smaller even than our own moon. It has an eccentric orbit that sometimes brings it closer to the sun than Neptune. Exploration of space by satellites and probes is helping scientists learn more about the other members of the solar system.

A planet is very different from a star. A star is a huge ball of hot gases that gives off heat and light. A planet is a much smaller body that shines by reflected light. Now let’s take a brief look at the sizes of all the planets of our solar system. Let’s start with the planet nearest to the sun and then move outward. The first planet of our solar system is Mercury. Diameter of Mercury is 2,900 miles which is the width of the Atlantic Ocean. So it’s only a fraction of the earth’s size. The next planet we meet is Venus. It is very nearly the same size as the earth. The diameter of Venus is 7, 600 miles, while that of the earth is 7, 913 miles. By the way, an odd fact about Venus is that it rotates backward; that is, from east to west. The next planet we meet is earth. The diameter of earth is 7, 900 miles. The axis of earth tilted over at an angle of 23.5 degrees. The next planet is Mars. Mars shines in the sky with a reddish color. It has a diameter of 4, 200 miles, a little more than half that of the earth. Parts of its surface look like the moon, with large craters apparently formed by meteorites but there are also giant volcanoes and valley which prove there could be geological activity on the planet. After Mars we meet the Jupiter, the next planet, is far away from the sun. It takes near about 11.9 years to complete one orbit. Jupiter is the largest of all the planets of our solar system. The diameter of the Jupiter is 88, 700 miles which is 11 times the diameter of our earth. The next planet we meet is Saturn. Saturn is another giant. The diameter of Saturn is 75, 100 miles, nearly 9 times the diameter of earth. An unusual thing about Saturn is the group of flat rings which are made up of billions of tiny particles. After Saturn we meet Uranus, the next planet which is also larger than the earth. The diameter of Uranus is 32, 000 miles. It is titled over on its side. The axis of Uranus is tilted over at an angle of 98 degrees. After Uranus we meet our next planet which is Neptune. The diameter of this planet is 30,000 miles. Then we meet last planet of our solar system which is Pluto. The diameter of Pluto is 1, 865 miles. The Pluto is so far from the sun that the sun appears it as only a bright star in the sky.