Astronomy Exam 1

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Introduced "Objective Reality"

Thales

First to picture an infinite universe

Anaximander

Originated the 7-day week and the roots of the 24-hour day and 60 minute hour

Summerians

Perpetuated the calendar choices of the Sumerians, developed algebra

Babylonians

Used a 10-day week. Developed geometry

Egyptians

Atomic Theory and the Vacuum

Democritus and Leucipus

Separated science and philosophy

The Pythagoreans

Suggested the Earth rotated on its axis, and possibly was not the center of the universe

The Pythagoreans

One of the Athenian Philosophers

Socretes

deepest thinker of the Athenian philosophers. founded the first "University" - Empirical Philosophy

Plato

Founded the current scientific disciplines - founded his own university. big contributions in biology. Argued the Earth was a sphere. Argued against a heliocentric theory because of the lack of an observable stellar parallax. Also an Athenian Philosopher

Aristotle

A contemporary of Plato and Aristotle. Early developments of Mechanics in physics

Eudoxus

First serious proponent of the Heliocentric theory

Aristarchus

The greatest observational astronomer in antiquity. Developed the Stellar Magnitude scale. Produced a star catalog. Measured the distances to the sun and moon. discovered the 26000 year precession of the Earth's axis of rotation. Argued against the helioc

Hipparchus

Passed down to us much of what we know about the earlier contributions. Set down the principals of celestial navigation and Astrology

Ptolemy

Re-introduced the Heliocentric theory. Described the Solar System with the correct Sidereal periods

Copernicus

Compiled large volumes of observational data

Tycho

Used Tycho's data to discern his 3 laws of planetary motion.

Kepler

The father of modern science. Used telescope to discover the 4 brightest moons of Jupiter, the crescent phases of Venus, stars too dim to be seen with the naked eye

Galileo

Discovered the Law of Inertia and introduced the scientific method

Galileo

The father of modern physics

Newton

Three laws of motion: *The law of inertia (An object in motion...) *F = ma *Conservation of Momentum - mv (Action - Reaction)

Newton

The Law of Universal Gravitation - F = G m1m2/r^2

Newton

General form of Kepler's 3rd law (M1 + M2)p^2 = a^3

Newton

The reflecting telescope and the spectrum of light

Newton

Electric charges (q/r^2) and changing magnetic fields (delta B / delta t)

Electric Field Sources

Causes a force in the direction of the field on all charges

Electric Field Effects

Moving charges (Right-Hand-Rule) and changing electric fields

Magnetic Field Sources

Causes a force on moving charges (qvB) perpendicular to the field and the direction of motion of the charge (Right-Hand-Rule)

Magnetic Field Effects

Light is composed of

Electromagnetic Waves

Accelerating charges create

Electromagnetic Waves

nucleus with negatively charged electrons orbiting around them

atoms

positively charged protons and neutral neutrons

Nuclei

number of protons

atomic number

determines the chemical element properties

atomic number

total number of neutrons and protons

atomic weight

number of neutrons determins the

isotope

when atoms gain or lose electrons

ions

same number of electrons as protons

neutral atoms

losing electrons

ionized

when electrons drop from a higher level to a vacancy in a lower level they emit

photons

quanta of light. they have momentum and energy given by their frequency times Planck's Constant. they also behave like waves

photons

Spectra - when all wavelengths are present

continuous

when hot solid objects or high pressure gasses radiate

Black Body Radiation

Spectra - when light is present at all wavelengths EXCEPT at certain wavelengths

absorption

when light passes through a diffuse gas and certain wavelengths are absorbed out of the light that continues on

absorption

when light is present ONLY at certain wavelengths

emission

when light passes through a diffuse gas and is absorbed, raising electrons to higher levels, when those electrons drop back down they emit light

emission

due to fundamental quantum effects

natural width

due to doppler shift from the motion of the emitting molecules at any temperature above absolute zero

thermal broadening

due to frequent collisions of the emitting atoms in a high pressure gas

collisional broadening

due to the splitting of levels in strong magnetic fields

zeeman effect

due to emission from a rapidly rotating star where the doppler shifts mix from emissions on different sides of the star

rotational broadening

the positioins of the lines are a characteristic function of the individual emitting elements. this allow identification of the relative composition of the source

spectral line positions

these characteristic positions are shifted by the doppler effect when the entire source is moving with respect to the observers on the earth

spectral line positions

a difference of 5 magnitudes means a factor of <blank> in brightness

100, (2.5)^difference in magnitude

the smaller the algebraic value of the magnitude the <blank> the source

brighter

<blank> magnitudes are the magnitude a star would have if it were at a distance of 10 parasecs

absolute

<blank> magnitude is the magnitude that an object appears to have

apparent

if you know both the apparent and absolute magnitudes, you can calculate the <blank>