THE UNIVERSE

In beginning there was nothing no galaxies no stars no planets

There was no matter at all, not even tiny particles existed. So how was something as huge and complex as the Universe created out of nothing?

According to it, at one stage the Universe must have come from a single point The Big Bang theory tells us how the Universe began and how it is evolving. Astronomers are now fairly sure that it happe- ned 15 billion years ago.

Just one second after the birth of the Universe spa- ce was flooded with parti- cles. Over the next 300 million years stars and galaxies began to evolve into the kind of cosmic landscape that we recognise today.

Our solar system is just a tiny part of the universe

There are eight planets in our solar system

Mercury is the smallest and fastest moving planet in our Solar System. It is also the closest planet to our Sun. If you were on the surface of Mercury, the Sun would look almost 3 times as big as it does from Earth! The planet has a huge range in temperatures. Its surface ranges from -270°F to 800°F (-168°C to 427°C), and it means about 600°C. It has no seasons.

Venus is the second planet from the sun in our solar system and the hottest one. Venus is almost as big as planet Earth but it rotates very slowly. As a conequence, each day on Venus takes 243 Earth days. Venus rotates in the opposite direction of the other pla- nets and no one knows why it has this unusual rotation. Venus is also known as the "morning star" or the "evening star".

The Earth is the third planet from the Sun in our Solar System. The Earth revolves around the Sun at a speed of about 30 km/sec, but its rotation is slowing down very slightly over time, about one second every 10 years. The temperature on Earth ranges from between -127°F to 136°F (-88°C to 58°C; 185 K to 311 K). It is the only planet in our Solar System that is known to support life.

Mars is the fourth planet from the Sun in our Solar System. Recent photos from Mars indicate that there might be so- me liquid water near the surface. Mars is much colder than the Earth. Mars' surface tempe- rature averages -81 °F (-63 °C). The ground is frozen and, occasionally, there are clouds in its atmosphere. The surface of Mars is dry and rocky, and it has 2 tiny moons.

Jupiter has four large moons and dozen of small ones. It also has faint, dark rings. Jupiter has no seasons. A day in Jupiter takes 9.8 Earth hours and a year, Earth years. Jupiter is the fifth and largest planet in our Solar System. Jupiter is made up of gases and liquids the gravity on it is 254% of the gravity on Earth.

Saturn is the only planet in our Solar System less den- se than water. It could float in water! Jupiter is the 6th planet from the Sun in our Solar System. Saturn is made mostly of hy- drogen and helium gas and it has lots of rings. Each day on Saturn takes 10.2 Earth hours. A year on Saturn takes Earth years

A space craft could never land on Uranus because the surface is made of gas and is not solid. Uranus is the 7th planet from the Sun in our Solar System. It is a blue icy planet covered with clouds and encircled by a belt of rings and moons. Uranus is a very bright planet that can be seen with the naked eye under dark sky conditions. It can be easily found with binoculars

Since Neptune was discovered in 1846, it has not yet completed a single revolution around the sun. Neptune is the 8th planet from the Sun in our Solar System. It is a giant, frigid planet with strong winds. Neptune cannot be seen using the eyes alone. Neptune was the first planet whose existence was predicted ma- thematically

All these planets evolve around the Sun.

Rival scientific theories try to predict whether the universe will be of finite or infinite duration. Other theories say that that the ex- pansion of the universe seems to be accelerating and will accelerate for eternity. According to the Big Bang theory, in the future the Universe will reco- llapse.

What do you you think about it ?