In this lecture we take a first look at the universe from the perspective of different sizes. The universe has been observed by humans with very cleverly constructed instruments. Information is available from 10^-17 meters to 10⁺²⁶ meters. The following video and internet link provide a peek at what is known.

Video: Powers of Ten. (The films of Charles & Ray Eames, vol.1. Pyramid Film & Video)
Internet link: similar info available at CERN's Microcosm: Travel accross the Universe, powers of ten

What is a power of 10, discuss and understand. Compare sizes of ordinary objects in proportion to each other, what powers of 10 do you find? Examples: compute ratio of sizes USC/dime, (LA county)/dime, Earth/dime, how do these compare to atom/nucleus, (Moon's orbit)/Earth, (Earth's orbit)/sun, dime/atom. See approximate sizes at the bottom of this page.

Scientific notation : see back cover of book. Mega, kilo, centi, milli, micro

SI units: MKS,cgs systems - see Appendix-A in book, pp.685-688
                internet link with much more information on SI units, and unit conversions to other systems.

Successive levels of structure in matter

Laws of physics and forces that play a role at different scales.

• Gravity : everyday scales to sizes of planets, stars, galaxies, universe
• Electro-magnetism: atomic sizes (and smaller) to macroscopic sizes, including electric storms in atmosphere, Earth's magnetic fields, Light from the sun and stars.
• Weak and Strong forces: sizes of nucleus, elementary particles, quarks, the Early Universe and Big Bang.

Approximating them as if they are circles or spheres, the following are some average radii:
dime =0.85 cm, USC =250 m, LA =50 km, Moon = 1.74 10⁺⁶ m, Earth =6.37 10⁺⁶ m, Sun =6.96 10⁺⁸, Moon's orbit =3.84 10⁺⁸ m, Earth's orbit =1.5 10⁺¹¹ m,  atom = 0.5 10^-10 m, nucleus (Hydrogen) = 10^-15 m.

Reading assignment
    Hewitt, Ch. 1
    Think about "next time questions" for Ch. 2,3

Homework