The Big Bang

The beginning of our universe as we know it

A few questions to ponder…

• What is the universe?• What is the Big Bang

Theory? • What is a theory?• How did it begin?• Who came up with

this idea?

http://startswithabang.com/wp-content/uploads/2008/05/bigbang.jpg

Video Introduction

http://www.youtube.com/watch?v=hSZqhqR5XKM

What is the universe?Dictionary: • the totality of known or supposed objects and

phenomena throughout space; the cosmos• a world or sphere in which something exists or prevails

In other words? Everything we as humans know exists

Background Photo: Hubble Telescope picture of the farthest known reaches of the universehttp://heasarc.gsfc.nasa.gov/docs/cosmic/gifs/cdfs_xray.jpg

(Colliding galaxies)http://www.thekeyboard.org.uk/Antennae%20galaxies.jpg

“Known Universe”

• When scientists talk about the size of the universe, they are talking about what we are able to observe. Based on their calculations, the visible universe is about 46.5 billion light years in any direction.

http://chandra.harvard.edu/blog/files/images/jelly.jpg

“Jelly Bean Universe”

What is this, “Big Bang”?

The beginning of our expanding universe, which is still expanding. The Big Bang is an explanation for how and why our universe is expanding.

http://www.wildwildweather.com/forecastblog/wp-content/uploads/2009/03/big_bang_wmap.jpg

Universe Expanding

• The Big Bang occurred about 13.7 billion years ago, when the universe was very small, dense, and hot

• Since then, it has been cooling and expanding

http://www.scienzagiovane.unibo.it/darkmatter/images/expanding-small.jpg

“The space we inhabit is itself expanding. There was no center to this explosion; it happened everywhere. The density andpressure were the same everywhere, so there was no pressure difference to drive a conventional explosion.”

Scientific American: Misconceptions about the Big Bang

http://www.astro.princeton.edu/~aes/AST105/Readings/misconceptionsBigBang.pdf

But it’s “just a theory…”• A scientific theory is not something that is just

plucked out of thin air. It is something that has been accepted by the scientific community as the best possible explanation for a phenomenon, after careful reasoning.

Toothpastefordinner.com

Where did this idea come from?

• The origin of the Big Bang theory can be credited to Edwin Hubble, who made the observation that the universe is always expanding. He observed that a galaxy’s velocity is proportional to its distance. Galaxies that are twice as far from us move twice as fast, and that the universe is expanding in every direction.

http://www.wwu.edu/depts/skywise/cosmo/hubble.jpg

Making our own Big Bang with balloons!

http://www.dark-cosmology.dk/~tamarad/images/balloons.jpg