The Universe

Hello! This week in class we have studied the Universe and we have learnt that: 


 The Universe is everything, without exceptions. Matter, energy, space and time, everything that exists is part of the Universe. It is very big, but not infinite. 

The Big Bang

  Most astronomers believe the Universe began in a Big Bang about 14 billion years ago. At that time, the entire Universe was inside a bubble that was thousands of times smaller than a pinhead. It was hotter and denser than anything we can imagine.

 Then it suddenly exploded. The Universe that we know was born. Time, space and matter all began with the Big Bang. In a fraction of a second, the Universe grew from smaller than a single atom to bigger than a galaxy. And it kept on growing at a fantastic rate. It is still expanding today.

 As the Universe expanded and cooled, energy changed into particles of matter and antimatter. These two opposite types of particles largely destroyed each other. But some matter survived. More stable particles called protons and neutrons started to form when the Universe was one second old.

 Over the next three minutes, the temperature dropped below 1 billion degrees Celsius. It was now cool enough for the protons and neutrons to come together, forming hydrogen and helium nuclei.

 After 300 000 years, the Universe had cooled to about 3000 degrees. Atomic nuclei could finally capture electrons to form atoms. The Universe filled with clouds of hydrogen and helium gas.

The Solar System and its planets

 The Solar System is made up of the Sun and all of the smaller objects that move around it. Apart from the Sun, the largest members of the Solar System are the eight major planets. Nearest the Sun are four fairly small, rocky planets - Mercury, Venus, Earth and Mars.

 Beyond Mars is the asteroid belt – a region populated by millions of rocky objects. These are left-overs from the formation of the planets, 4.5 billion years ago.

 On the far side of the asteroid belt are the four gas giants - Jupiter, Saturn, Uranus and Neptune. These planets are much bigger than Earth, but very lightweight for their size. They are mostly made of hydrogen and helium.

 Until recently, the furthest known planet was an icy world called Pluto. However, Pluto is dwarfed by Earth’s Moon and many astronomers think it is too small to be called a true planet.

 An object named Eris, which is at least as big as Pluto, was discovered very far from the Sun in 2005. More than 1,000 icy worlds such as Eris have been discovered beyond Pluto in recent years. These are called Kuiper Belt Objects. In 2006, the International Astronomical Union decided that Pluto and Eris must be classed as “dwarf planets”.

 Even further out are the comets of the Oort Cloud. These are so far away that they are invisible in even the largest telescopes. Every so often one of these comets is disturbed and heads towards the Sun. It then becomes visible in the night sky.

 Furthermore we have seen this video in class, and we think thtat it is interesting, so we want sharing with all of you!

Group 3