The Big Bang Theory Part I

The Big Bang theory The universe was created ~13.7 Billion years ago. The universe began as a massive explosion.

~ 3 minutes after big bang All the matter and energy were condensed into an tiny and extremely dense point.

~ Several hundred thousand years after Big Bang After the explosion the matter expanded. ATOMS formed (specifically Hydrogen and Helium.) The early Universe was about 75% Hydrogen and 25% Helium. It is still almost the same today.

~200 to 400 million years after Big Bang 1st stars and galaxies formed when the dust and the gas collapsed.

~ 4.6 billion years ago Our Solar system formed

Today Continuous expansion Galaxies are moving away from each other The BIG CRUNCH Theory which states that ,one day, the universe will STOP and begin to contract again.

Big Bang Timeline – Big Bang – energy Matter protons Neutrons electrons Atoms Hydrogen Helium Stars and galaxies Our solar system Sun and all planets Earth (present day)

what is a Galaxy? It´s an enormous group of stars, planets, gases and dust. It´s a gravitionally bound system.

Types of galaxies according to their shape: Elliptical galaxy Spiral galaxy Barred spiral galaxy Irregular galaxy

Our Galaxy: the Milky Way Almost everything we see in the night sky belongs to the Milky Way. We see the Milky Way as a faint band of light across the sky.

The Milky Way It’s part of the Local Group It’s part of the Virgo Supercluster It’s a barred spiral galaxy We are in the Orion Arm of the galaxy.