Stars are formed from clouds of dust and gas that collapse under gravity. Most stars spend around 90% of their life fusing hydrogen into helium through nuclear reactions. When stars run out of fuel, their cores collapse and they expel their outer layers, forming planetary nebulae. This leaves behind dense, hot cores known as white dwarfs. More massive stars may explode as supernovae when nuclear fusion can no longer counter gravity, or collapse entirely into black holes.

1. The life and death of stars
By Megan Soh and Dominique Lux

2. The formation of all stars
• All stars began as clouds of dust
• Collapses and turns into a heated core

3. Chemistry Behind Stars
-Stars spend about 90% of their life time fusing
hydrogen to produce helium
-Chemical Formula:
Hydrogen +Heat Helium
-The bigger the star the
shorter its life

5. Formation of the White Dwarf
• Formed when all energy is released through
the Red Giant and the Planetary Nebula
phases
http://chandra.harvard.edu/xray_sources/white_dwarfs.html

6. Chemistry Behind White Dwarfs
 White dwarfs are formed as the outer layers of a star
are emitted from the core
 The white dwarfs are able to remain stable because
of the pressure of the fast moving electrons in the
core

7. … Or a Supernova

8.  Pressure inside a star can no longer counter its
own gravity
 Counter pressure builds up, result is an explosion

9.  In a supernova, a stars core collapses and
explodes
 Nuclear reactions lead to the formation of iron
 An enormous amount of energy is released

11.  The final phase of a star with too big of a mass
 Leads to the star crushing under its own gravity
 Thus forming a black hole that devours
everything in its sight

12.  A black hole has a gravity so strong that
nothing can escape its immediate proximity
 A black hole can only be spotted indirectly
 Studied by gamma and x ray emission

13. • http://www.youtube.com/watch?v=YU6X3SPZAJo