In the beginning…

The History of the World

The Big Bang

• A long, long, long time ago (14 billion years ago?) there was an explosion which created matter and anti-matter

• There was slightly more matter than anti-matter and the universe began

How do we know this?

• Scientists have studied what elements are made of

• However, it is still just a best guess

• Known as Theoretical Physics

• This is not what we are studying!!!

Stars are born

• matter grows in size until elements Hydrogen and Helium are born

• These elements group together and create stars

• Stars group together in clusters called galaxies

• Our galaxy, The Milky Way, was born 13.4 billion years ago

• The Sun was born 5 billion years ago

How do we know this?

• Huge telescopes are able to see back in time

• Light from distant stars is very old by the time it gets to our eyes

• Oldest observed stars are 13.4 billion years old

• We compare our star (The Sun) to other stars in the galaxy

Milky Way is 100,000 light years across

The Sun is 30,000 light years from the center

Our Solar System

• Nuclear reactions in stars create different elements

• When stars die and explode in a supernova, they release these elements into the universe

• These elements came back together to create the Sun and created planets, moons, asteroids, and comets

• The Earth is born 4.5 billion years ago• Collision creates The Moon and tilts Earth on

its axis, creating seasons

How do we know this?

• This evidence gathering is known as…

• Astronomy

• Also, study of these elements is known as….

• Chemistry

• This is not what we are studying!!!

Life Begins

• 4 billion years ago- simple cells born• 1.2 billion years ago- sexual reproduction

speeds up evolution, multi-cell organisms born

• Evolution is the process of genetic mutation and natural selection

• 600 million years ago- animals and plants born

• 500 million years ago- animals and plants live on land

How do we know this?

• We can study the rocks of Earth, Moon, and meteorites

• This is known as…• Geology- study of rocks • Study of fossils in the rocks• This is known as….• Paleontology- study of ancient life• This is not what we are studying!!!

Humans are born

• 5-7 million years ago- apes left the forests of Africa and began to walk on two feet

• These apes evolved into various species of humans

Modern Humans

• Our species is called Homo Sapiens• Modern humans first appeared in Africa

around 150,000 years ago• Every human’s ancestors came from

this small group• This group grew larger and spread

around the world

How long have we been around?

• Spread your arms wide - This represents the history of Earth

• From your left fingertips to your right fingertips represents about 4.5 billion years

• At your left elbow- single cells were born• At your right elbow- multicell organisms• Right wrist- animals and plants born• End of fingernail- apes left the trees• One thin layer of skin- homo sapiens

QuickTime™ and a decompressor

are needed to see this picture.

Human development

• From your toes to the top of your head represents 200,000 years

• Waist- humans left Africa• Belly button- Toba volcano erupted, perhaps

only 1000 humans left• Sternum- reach Asia• Shoulders- reach Europe & Australia• Mouth- reach Americas

How do we know this?

• We can study and compare ancient human remains

• This is known as paleoanthropology

• This is not what we are studying!!!

World History

• With the development of writing, we are able to transfer memories through time and increase human knowledge

• Middle of forehead• THIS IS WHERE WORLD HISTORY

BEGINS!!!• But not US History

US History

• Many people consider US History as beginning on July 4, 1776:

• The Declaration of Independence

• This is barely the thickness of the hair on your head

• THIS is what we are studying :)