The origins of the universe 

• This theory suggests that the universe as we know it started with a small singularity, then inflated over the next 13.8 billion years to the cosmos that we know today

• Scientists believe that the solar system formed about 4,500 million years ago in a huge cloud of gas and dust called a nebula.

Evidence 

- Mathematical formulas and models has formed much of our understanding of the Big Bang Theory so far. However evidence exists to support this theory. 

- One form of evidence is that Scientists believe we can see the "echo" of the expansion through a phenomenon known as the cosmic microwave background.

Evidence 1 - COSMIC MICROWAVE BACKGROUND 

If you were to point a satellite dish into empty space you would get static  

The universe has an underlying static - Cosmic microwave background  

Before the Bang

• Scientists believe that before the Big Bang space and time didn't exist and all that existed was energy

• The Big Bang occurred when all of this energy was concentrated into a single point called 'singlularity'

• Space began to expand quickly and the temperature was hot (an estimated 100 million trillion trillion degrees!)

Cosmic Microwave Background 

• Big Bang Theory suggests that the universe was a very hot place and that as it expands, the gas within it cools 

• As the universe began to cool, radiation began to fill the universe as a remnant of the heat left over - this is called 'Cosmic Microwave Background'

• The cosmic microwave radiation is like an 'afterglow' of radiation

Nucleosynthesis

Formation of elements in stars

Write down your answers and answer on the next slide.

Go here

https://public.nrao.edu/gallery/animation-of-stellar-nucleosynthesis-inside-a-red-giant/

Go here

https://public.nrao.edu/explore/milky-way-explorer/?location=astrochemistry

Atom: Nuclear Reactions

How are these 3 types of decay similar different from one another?

alpha decay / beta-minus / beta-plus

Nuclear reactions can be:

natural or artificial

The next question can somehow tell if you've worked on part 3 of the playlist, and how much you have understood the concept of nuclear reactions so far...

Why would an element spontaneously undergo decay?

The goal is to have a more stable nucleus.

NUCLEAR EQUATIONS

For a better analysis of nuclear reactions, EQUATIONS are used. So let's study/review how to write them!

Get ready for the next review question...

Beta-plus Decay

A proton transforms into a neutron (by ejecting a positron) decreasing the atomic number of the original element by one.