Kepler's Laws and Motion in the Solar System

Speed

Rate of motion; distance per time.

Tycho's Universe

Planets orbit the Sun; Sun orbits Earth.

Parallax

Apparent shift of an object's position.

Irregular Motion of Mars

Mars exhibits the most elliptical orbit.

Kepler's First Law

Planets orbit in ellipses with the Sun at focus.

Kepler's Second Law

Equal areas are swept in equal times.

Kepler's Third Law

p² = a³ relates period and semi-major axis.

Conic Sections

Shapes formed by intersecting a cone.

Eccentricity

Measure of an ellipse's deviation from a circle.

Velocity

Speed with direction specified.

Acceleration

Change in velocity per time unit.

Momentum

Mass multiplied by velocity (p = mv).

Net Force

Total force acting on an object.

Newton's Second Law

F = ma; force equals mass times acceleration.

Gravity on Earth

Acceleration due to gravity is g = 10 m/s².

Weight

Force acting on an object due to gravity.

Free-Fall

State of weightlessness in a gravitational field.

Newton's First Law

Objects maintain velocity unless acted upon.

Newton's Third Law

Every action has an equal and opposite reaction.

Mass

Amount of matter in an object.

Isaac Newton

English mathematician and physicist; formulated laws of motion.

Maria Cunitz

Published simplified version of Kepler's laws.

Astronomia Nova

Kepler's treatise on planetary motion.

Weightlessness Misconception

Weightlessness is due to constant free-fall.

Voyager 1

Spacecraft traveling 17.2 km/s since 1977.

Friction

Force opposing motion between surfaces.

Acceleration of Gravity

All objects fall at 10 m/s² on Earth.

Newton's 2nd Law of Motion

Acceleration is proportional to net force and mass.

Newton's 3rd Law of Motion

Every action has an equal and opposite reaction.

Acceleration Formula

a = F/m; F = ma.

Force Unit

Measured in Newtons (N).

Mass Unit

Measured in kilograms (kg).

Acceleration Unit

Measured in meters per second squared (m/s²).

Rocket Acceleration Misconception

Rockets accelerate by expelling gas, not against surfaces.

Momentum in Rockets

Faster exhaust increases momentum imparted to rocket.

Weight vs. Mass

Weight changes with gravity; mass remains constant.

Gravity Everywhere

Gravity exists in all locations, not just Earth.

Orbiting Objects

Objects in orbit are in free fall towards Earth.

Center of Mass

Orbiting bodies revolve around their common center.

Inverse Square Law

Gravitational force decreases with the square of distance.

Universal Law of Gravitation

Every mass attracts every other mass.

Weight on Moon

Weight is 1/6th of weight on Earth.

Kinetic Energy

Energy of motion, dependent on mass and velocity.

Conservation of Energy

Total energy remains constant; forms can change.

Thermal Energy

Total kinetic energy of particles in a substance.

Gravitational Potential Energy

Depends on mass, gravity strength, and height.

Mass-Energy Relation

Mass can be converted to energy (E=mc²).

Light Absorption Lines

Indicate elements present in the Sun's composition.

Interactions of Light

Includes emission, absorption, transmission, and reflection.

Reflection vs. Scattering

Reflection directs light; scattering diffuses light.

Density and Temperature

Density affects thermal energy transfer efficiency.

Newton's Modification to Kepler's Laws

Relates orbital period to mass and distance.

Kepler's 3rd Law

Links orbital period and average distance of bodies.

Energy Measurement

Energy is measured in Joules (J).

Thermal Energy vs. Temperature

Temperature is average kinetic energy; thermal energy is total.

Free Fall

Condition of being in continuous gravitational pull.

Light

A form of energy perceived by the eyes.

Watt

Unit measuring energy flow; 1 watt = 1 joule/second.

White Light

Composed of all colors of the rainbow.

Newton's Particle Theory

Proposes light consists of small particles.

Visible Spectrum

Range of light visible to human eyes (350-750 nm).

Speed of Light

Constant speed in vacuum, denoted as c.

Speed of Light Value

c = 2.99792458 * 10^8 m/s.

Diffraction

Bending of light waves around obstacles.

Interference

When light waves overlap, creating patterns.

Young's Double Slit Experiment

Demonstrated light's wave-like behavior in 1801.

Photon

Particle of light, carries energy and momentum.

Wave

Pattern of motion carrying energy without matter.

Wavelength

Distance between consecutive wave peaks.

Frequency

Number of wave cycles per second (Hz).

Wave Speed Formula

Wave speed = wavelength * frequency.

Maxwell's Revolution

Oscillating charged particles create electric and magnetic fields.

Electromagnetic Spectrum

Range of all types of light, from radio to gamma.

Continuous Spectrum

Uninterrupted range of wavelengths emitted by hot objects.

Absorption Line Spectrum

Spectrum with dark lines from absorbed wavelengths.

Emission Line Spectrum

Spectrum with bright lines from emitted wavelengths.

Atomic Number

Number of protons in an atom's nucleus.

Atomic Mass Number

Total of protons and neutrons in an atom.

Bohr Model

Model depicting electrons in discrete energy levels.

Emission

Process of an electron releasing energy as a photon.

Absorption

Process of an electron gaining energy from a photon.

Wien's Law

Higher temperature results in shorter peak wavelength.

Thermal Radiation

Radiation emitted by objects due to their temperature.

Power of Spectroscopy

Analyzing light spectra to determine composition.

Mars

Planet identified through spectral analysis.

Higher Frequency

Corresponds to shorter wavelength and higher energy.

Major Planets

Eight planets with nearly circular orbits around the Sun.

Dwarf Planets

Smaller than major planets, often with elliptical orbits.

Orbital Direction

All planets orbit the Sun in the same direction.

Rotation

Most planets rotate similarly to their orbit direction.

Conservation of Momentum

Momentum is conserved in the same orbital direction.

Venus and Uranus

These planets rotate differently than they revolve.

Sun's Mass

Over 99.9% of the solar system's total mass.

Sun's Composition

Primarily composed of hydrogen and helium gases.

Energy Conversion

Converts 4 million tons of mass into energy per second.

Terrestrial Planets

Rocky planets: Mercury, Venus, Earth, Mars.

Gas Giants

Larger planets: Jupiter, Saturn, Uranus, Neptune.

Mercury

Small, cratered planet with extreme temperature variations.

Venus

Hottest planet, thick CO2 atmosphere, extreme greenhouse effect.

Earth

Home to life, has oceans, ice caps, and a large moon.