16-4 Elements from Stardust

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

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

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

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

Hydrogen all the way to Oxygen As “He” builds up in the sun, bigger and bigger nuclei can form. 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

Supernova With time, large stars have enough energy to produce heavier elements (from oxygen thru iron) 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 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 The huge explosion produces the heaviest elements

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. The matter that makes up Earth was probably formed in a gigantic supernova that occurred billions of years ago.