TOPS June 21, 2001 - Origins?

Where did all this stuff come from?

(What astronomy has to say about it?)

Jeff Kuhn, IfA

kuhn@ifa.hawaii.edu

Substance?

• Molecules, compounds

• Atoms, elements

• Fundamental atomic constituents

Forces for change

• Thermodynamics

• Chemistry

• Life

Building blocks

Electrons

Elements

Nuclear building blocks and “patterns”

Cosmic abundances

Solar system abundances

Very local abundances

CNO

PbFe

Most common compound: Water!

Most common elementary particle: Neutron, almost same as protons, IDENTICAL number of electrons

Element origins

• Where does it start (Big Bang?)

• Did it all come from the first 3 minutes?– Can stars play a role?

A brief history

Epochs

BB works for light elements

• Even oldest generations of stars have a lot of Helium…

• “Hot soup” model works

Making He in the sun...

Heavy Stars

Evidence of heavy element production

Heavy elements require more...

• Higher densities and temperatures…

• Above Iron need something special to happen…

Heaviest elements from cosmic explosions (Supernovae)

• SN1987A was the first Supernovae in hundreds of years that was visible by eye

Molecule problems...

• Collisions aren’t frequent enough to get atoms to stick…Need a way to collect atoms so they can combine…

• Cosmic dust is the answer...

Molecules and solids?

We see dust/molecules around giant stars

Dust and gas are always foundtogether! ISO image of HD97300

Where did we come from then?

Summary

• Light elements formed in the first 3 minutes

• Heavies formed in stars later and now

• Dust (grains) formed in cool parts of giant stars

• Molecules formed on dust grains

• Planets condensed from stellar environment

• Biological processes differentiated elements

Web resources– www.pbs.org/deepspace/timeline/index.html

• Big Bang, classroom activities, screen savers– howstuffworks.lycos.com/atom.htm

• activities, atoms, general science, *links*– micro.magnet.fsu.edu

• higher level science, movies, Electricity/Mag– www.lbl.gov/abc/wallchart/index.html

• Nuclear science intro

– www.iso.vilspa.esa.es/science/– btc.montana.edu/ceres/html/stars1.html#lessonplans– helios.gsfc.nasa.gov/nucleo.html#nucactys– www.ncsa.uiuc.edu/Cyberia/Bima/SolSys.html– www.eng.rpi.edu/~napolj/Origins

– this power point presentation at hubble.ifa.hawaii.edu, anonymous ftp on directory INCOMING named topsorigins.ppt

Activities

• Concepts– Atoms as product of matter subdivision– Atoms mostly space, nucleus+electrons– Fission requires high density and temperature– “Cross-section” concept

• protons and neutrons different cross-sections

– Molecules built from atoms– Local constituents result from “fractionation”

Activities

• Making atoms, 10cm paper strip cut 31 times…

• Make cardboard atom target. Rice grain nucleus, 3’ diameter circle

• Proton and neutron target practice, making He

• Atomic differentiation, rice and bb’s for H and Fe