Where did Elements come from?

1. Where did Elements come from?

2. A Conundrum…. • Elements make up all matter. • The Law of Conservation of Matter states that matter can be neither created nor destroyed. • So where did it come from?

3. The Big Bang • One theory suggests that the universe started with a big bang…. • Made by a proton. • What do we know about protons? • Positive-charge • Found inside the nucleus of atoms • So tiny that 500,000,000,000 will fit into a dot of an ‘i’

4. Recipe for a Universe • Take one proton. • Shrink it down until it’s one-billionth times smaller than normal. • Now shove about 1 ounce of stuff into it. • Run away. Fast!

6. In less time than it takes you to blink, the four fundamental forces appeared: • Gravity- attracts large objects to each other • Electromagnetism – light, electricity, magnetism • Weak nuclear force – radioactive decay • Strong nuclear force – holds protons in the nucleus together over tiny distances.

7. In less than one minute… the universe got really big – about a million billion miles across and was growing fast. It was also got really hot – about ten billion degrees.

8. It was so hot that atoms were formed from this energy. • Think about that – matter came from energy. • That’s what String Theory assumes, anyway. • But I digress. The universe was so hot that nuclear reactions took place. • What is a nuclear reaction? It’s a reaction that affects the nucleus. In nuclearfusion, two nuclei are fused together to create a new element. • These reactions gave birth to the lightest elements: Hydrogen – one proton Helium – two protons Lithium – three protons

9. The lightest elements:

10. In less time than it takes to make a sandwich…. • 98 percent of all matter was created. • BUT not one of the heavier elements that makes us (carbon, nitrogen, oxygen, etc.) was formed by the Big Bang. • To make elements, you need the heat and energy of a Big Bang, but there was only one Big Bang, and it didn’t make ‘em!

11. Millions of years passed…. • Still no carbon…. • We’re carbon-based life forms…. • The light elements got together and made some stars. • Clock’s ticking…. • Finally, 10 billion years ago, carbon and a few of the heavier elements appeared.

12. So where did the heavier stuff come from? • For a long time, no one could even guess….

13. Neutrons • Then, along came an odd man named Fritz Zwicky. • He liked to show off by doing one-armed pushups in the dining hall. • None of the other scientists at CalTech liked him.

14. BUT every now and then he had an amazing insight…. • The neutron had just been discovered by James Chadwick in England. • So everybody who was anybody was talking about it. • Zwicky wondered what would happen if a star collapsed until it was as dense as the core of an atom. • The star would be really squished.

15. The star would be so tightly squished that the atoms making up the star would be crushed together. Their electrons (-) would be forced into the nucleus (+), forming neutrons. You would have a neutron star! Neutron Stars

16. Think about that…. • Their electrons would be squished into the nucleus, where they would hook up with the positive protons. http://www.uwosh.edu/faculty_staff/mihalick/history/sciencehistory.html

17. A Neutron Star Artists Impression of Supernova 1986J N. Bartel & M. Bietenholz; artist: G. Arguner

18. This would make a neutron star • The collapsing star creates a black hole in the middle and… • It shoots out a huge amount of energy, creating a supernova. • A mid-sized star can create enough heat to form carbon, oxygen and nitrogen. • But a supernova, 10 times bigger than our sun, can make the heavy metals – iron, uranium, plutonium - in gigantic cataclysmic waves. • Those heavy elements are then spewed all over the universe.

19. Cassiopeia A • 9400 years ago: Cassiopeia A, a supernova, blew apart. • In the mid-1600’s the light from that explosion finally reached us. • We can still see it.

20. Too faint to view without a telescope, but it's easy to see where the remnant is in the northern summer sky. Simply go outside just after sunset and look 45 degrees above the NNE horizon between Cepheus and Cassiopeia. Cassiopeia A (nicknamed ‘Cas A’)

21. And Cas A is still spewing out stuff! • NASA has a tool that can tell what kind of elements are shooting out of the supernova. • They took pictures of silicon, calcium and iron being blasted in high-speed jets into space.

22. CassiopeiaA

23. Where is this stuff going? • Heavy elements might be nothing more than cosmic pollution, but they’re really important to us. Without them, solid, rocky planets would be impossible. • The iron we see now in Cas A might one day flow as hemoglobin in the blood of some future alien species. • The calcium could support living organisms, as coral reefs and skeletons. • Those fast moving jets of silicon could one day become sand on otherworldly shores, where crashing waves of H2O send thunderous sound waves through a nitrogen-rich atmosphere – like ours.

24. Elements don’t go away…. • Nuclear fusion occurring in stars may be creating new elements out of the lighter-weighted ones, • But those elements are still around from billions and billions of years ago.

25. When? • The Big Bang was almost 14 billion years ago. • Those elements are the same ones here now. • They don’t go away. • They made you, your DNA, the air you breathe, the food you eat, the water you drink…. • Yes, you are made of stardust.

26. Actually, recycled stardust • Every atom in you has probably passed through several stars. • Every atom in you has probably been part of millions of organisms (plants, bacteria, Shakespeare) before becoming you. • Every atom probably lives about 1035 years.

27. After another 10 billion years… • DNA, the amazing self-replicating molecule, appeared on Earth.

28. In the immortal words of Carl Sagan, “We are star stuff.”