INNER PLANETS

OUTER PLANETS

105

ly

IRpicture

Scorpiusconstellation

Galacticcenter

THE LOCAL GROUP

ANDROMEDA2x106 LY from us

106 ly

GALACTIC STRUCTURES

SPIRAL ELLIPTICAL -majority

LENTICULAR IRREGULAR

30%

ACTIVE GALAXIESRF JETS AND BLACK HOLE – NGC4261

GALAXY CLUSTERS

VIRGO COMA

FORMAX

RED SHIFT SURVEYS TO 150 Mpc, ~2% to edge

Filamentsand

Sheet-likeStructures

AndBubble-like

voids

EPICYCLES - COPERNICUS

KEPLER’S LAWS

The orbits of the planets are ellipses, with the Sun at one focus of the ellipse.

The line joining the planet to the Sun sweeps out equal areas in equal times as the planet travels around the ellipse.

Galileo’sdrawing

Huyghen’sdrawing

Hubbleimage

KEY QUESTIONS:• WHY SIX PLANETS ? • WHAT CONTROLS THE SIZE OF THEIR ORBITS

KEPLER MYSTERIUM COSMOGRAHICUM

A precursor to cosmographical dissertations, containing the cosmic mystery of the admirable proportions of the Celestial Spheres, and of the True and Proper Causes of their Numbers, Sizes, andPeriodic Motions of the Heavens, Demonstrated by the Five Regular Geometric Solids

Numbers …… …. Golden ratio, Golden number, Golden Section

A BCAB/AC=AC/CB

Bode’ Law

Distances of planets from SunM .39, V .72, E 1.0, Mars 1.5, J 5.2, SAT 9.5, UR 19, N 30, PL 39

Start with 0,3,6,12,24,48,96,192,384Add 4 and divide by 10

.4,.7,1.0,1.6,2.8,5.2,10,19.6,38.8

Missed Neptune and no planet at 2.8

Asteroid belt -> rocks (40000) few km size

Newton’s laws• Newton’s laws of motion

• Frames of reference

• Newton’s law of Gravitation

I: NEWTON’S LAWS OF MOTION

Begin by stating Newton’s laws:

Newton’s first law (N1) – If a body is not acted upon by any forces, then its velocity, v, remains constant

Note:– N1 sweeps away the idea of “being at rest” as a natural

state.

Newton’s 2nd law (N2) – If a body of mass M is acted upon by a force F, then its acceleration a is given by F=Ma

Note– N2 defines “inertial mass” as the degree by which a

body resists being accelerated by a force.– Another way of saying this is that force = rate of

change of momentum (rate of change of mv).

Newton’s 3rd law (N3) - If body A exerts force F on body B, the body B exerts a force –F on body A.