The Big Bang Theory Part I The Big

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 • 1 st 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.