The Big Bang Theory

Steady State Theory Steady State Theory: 1917 The universe is not expanding or contracting

Expanding Universe Theory The universe is continually moving outward

The Big Bang Theory The Big Bang Theory: 1927 13.8 billion years ago all the matter in the universe was very hot and dense. Since then, it has expanded and is still expanding https://www.youtube.com/watch?v=wNDGgL73ihY

Evidence for the big bang https://www.youtube.com/watch?v=aPStj2ZuXug

Evidence for the Big Bang The abundance of light elements The ratio of hydrogen to helium we see in the universe tells us how long ago the Big Bang happened Background Microwave Radiation There is microwave radiation left over from the energy released during the Big Bang

Evidence for the Big Bang 3. The evolution of stars Scientists calculate the age of the universe by observing the life cycle of stars 4. Hubble’s Red Shift of data Distant galaxies are showing a red shift in light because they are moving away from each other

Theories about the Future of the Universe The Big Rip Theory The universe is expanding so fast that someday it will be going so fast that matter will tear itself apart

Theories about the Future of the Universe The Big Crunch Theory Someday the universe will reach its maximum and matter will collapse back in on itself

Smallest to Largest Solar system Planet Comet Asteroid Meteor Universe Put in order from the smallest to the largest Solar system Planet Comet Asteroid Meteor Universe Galaxy Star Moon

Smallest to Largest Meteor Asteroid Moon Comet Planet Star Solar system Galaxy Universe

How big, how far, how fast https://www.youtube.com/watch?v=1g2IGCLrAio

Measuring the Solar System Astronomical Unit (AU):The distance from the Earth to the Sun How far is 1 AU? 149.6 million km (93 million miles)

Measuring the Universe Parsec: a measurement used to describe the distance to stars 1 parsec = 8 trillion miles (8,000,000,000) or 206,265 AUs

Speed of Light Speed of light 186,282 miles per second or 670,615,200 mph Light Year: (LY)the distance light can travel in one year 1 LY = 5.9 trillion miles

Nearest Star The nearest star: Proxima Centauri How far away is the nearest star? 4.2 light years away 24.78 trillion miles The Voyager 1 spacecraft is on an interstellar mission. It is traveling away from the Sun at a rate of 17.3 km/s. If Voyager were to travel to Proxima Centauri, at this rate, it would take over 73,000 years to arrive. If we could travel at the speed of light it would still take 4.22 years to arrive!

Nearest Star How big, how far, how fast? How long would it take our fastest space probe to get there? 79,000 years How long would it take us to get there if we could travel at the speed of light? 4.2 years

Age of the Earth, Solar System and Universe Universe: 13.8 billion years Solar System: 4.6 billion years old Earth: 4.5 billion years old

Evidence for the age of the universe Stellar evolution Background microwave radiation

Radioactive Decay Radioactive Decay: The decay of radioactive elements into other elements Mass and energy get released in the form of radiation

Radiometric Dating Radiometric Dating: Uses the rate of decay of elements to date objects

Evidence for the age of the Earth Date earth rocks Date meteorites Date moon/lunar rocks