Lecture 2 (cont’d): In the Beginning: Origins of the Elements 1.The Periodic Table: elements and isotopes 2.Synthesis of elements in the Early Universe 3.Stars: making the “elements of life” 4.We are made of star stuff.

2 Millenium Run, Springel et al. 2006

* LIFE & CULTURE * JANUARY 29, 2011 If You Don't Like This Universe… Brian Greene and David Gelernter discuss alternate realities, like a cosmos with a Jets-Bears Super Bowl

Electron Orbits in Atoms

The Periodic Table

Electron Orbits in Atoms

Plots of electron density shapes of 1s, 2p and 3d orbitals:

The Periodic Table … in terms of electron subshells:

The Periodic Table … the elements of Earth life:

Looking Back into the Past Hot Dense Smooth Cold Thin Clumpy

Looking Back into the Past NASA’s WMAP mission mapped the sky in microwaves

Looking Back into the Past False-color map of the temperature fluctuations seen by measured by WMAP. This pattern appears to be random, but it is the superposition of waves of different size. It is like a fingerprint. The pattern seen is consistent only if 75% of H and 25% of He constitute the gas.

Stars like our Sun expand and disperse their envelopes It takes 3 to 10 Ga for the the synthesis of light and heavy elements in these stars. Their envelopes are rich in heavy elements - yet, especially in C, N, and O. Eventually new stars are formed from this gas. How do we know that ? a)We see the signatures of these newly synthesized elements in their light.

The most massive stars end their thermonuclear cycles as Supernovae Supernova 1994D: the bright explosion of a star in the outskirts of a distant galaxy. During the explosion, in a matter of minutes, hours and days, large quantities of iron and other heavy elements are synthesized.

The most massive stars end their thermonuclear cycles as Supernovae During the explosion, in a matter of hours and days, large quantities of iron and other heavy elements are synthesized. How do we know that ? a)We see the signatures in the light from the explosion; b)Computer models reproduce measured isotopic ratios in Solar System objects and other stars.

We are made of star stuff By mass - Human body: H = 10%, He = 0%, C = 18%, N = 3%, O = 65%, Ca = 2%, Fe = 0.004%. Earth’s crust: H = 1 %, He = 0%, C = 2%, N = 0%, O = 47%, Si = 26%, Ca = 3%, Fe = 5% Sun & stars: H = 71%, He = 27%, all other elements = 2% (with O most abundant).

The Periodic Table … the elements of Earth life:

Main points to take home: 1) Elements: def. by protons in atom (90 stable); Isotopes: def. by neutrons in atom (266 stable); The Periodic Table of the Elements allows the analytical description of all species of mineral or biological origin. 2)There are 2 main sources of their origin: a) H, He, & Li were synthesized ~13.7 Ga ago in the Early Universe; b) stars transform H & He into all the rest. 3) Planets and life are here thanks to many past generations of stars.

The Periodic Table

We are made of star stuff By mass - Human body: H = 10%, He = 0%, C = 18%, N = 3%, O = 65%, Ca = 2%, Fe = 0.004%. Plants: H = 10%, He = 0%, C = 3%, N = 0.3%, O = 79%, Ca = 0.1%, Fe = 0.02%. Earth’s crust: H = 1 %, He = 0%, C = 2%, N = 0%, O = 47%, Si = 26%, Ca = 3%, Fe = 5% Sun & stars: H = 71%, He = 27%, all other elements = 2% (with O most abundant).