16-4 Elements from Stardust

1. 16-4 Elements from Stardust

3. Elements from Stars • Scientists study the stars and our sun to understand how elements (matter) were created and why. • The sun is mostly made of Hydrogen (H). H

4. PLASMA STATE • The temperature of the sun is very hot—15 M degrees Celsius. • At hot temperatures and high pressure, matter exists as plasma. • In the plasma state, nuclei are stripped of their electrons and packed tightly together, they don’t repel each other. P+ N NO ELECTRONS P+ N P+ N

5. NUCLEAR FUSION • With the high pressure and hot temperature in the sun, nuclei of atoms are squeezed together and they collide. • Nuclear fusion combines smaller nuclei into larger nuclei—making bigger and heavier atoms.

6. Hydrogen into Helium • When isotopes of hydrogen fuse, they produce nuclei of helium + HUGE amounts of energy for us!

7. Hydrogen all the way to Oxygen • As “He” builds up in the sun, bigger and bigger nuclei can form. H + H makes He (2p+) He + H makes Li (3p+) He + He makes Be (4p+) and so on, and so on, up to oxygen

8. Supernova • With time, large stars have enough energy to produce heavier elements (from oxygen thru iron) • A supernova is a huge explosion that breaks apart a massive star, because the star becomes too dense • The huge explosion produces the heaviest elements

9. Earth has abundant amounts of iron but also has many elements heavier than iron. How are these present? • The matter that makes up Earth was probably formed in a gigantic supernova that occurred billions of years ago.