Astronomy
0 > F = GM1/GM2 > 0
0 = mass, F = force, r = gravity The bigger the mass, more gravity. The further the distance, less gravity.
Newton's Law of Motion
1. An object at rest will stay at rest. 2. When a force is exerted on an object, its acceleration is universally proportional to its mass. F = M/A 3. When object A exerts a force on object B, object B exerts an equal and opposite force to object A (gravity).
Kepler's Three Laws of Planetary Motion (1) ellipses (2) focus (3) semimajor axis
1. Planetary orbits are ellipses having the sun as one focus. 2. A planet moves faster as its orbit takes it closer to the Sun. 3. The orbital semimajor axis is simply related to the planet's orbital period.
List the two modifications made by Newton to Kepler's laws.
1. That a planet does not orbit the precise center of the Sun but instead that both the planet and the Sun orbit the common center of mass of the two bodies. 2. That gravity binds the planetary motion together.
Ellipses
A mathematical shape (oval)
The Atmosphere
About 50 miles from the ground. Most of the atmosphere is within the first mile from the surface of the Earth. Has particles and molecules moving around. Makes it harder to get a clear picture or image.
Electricity and Magnetism
Always go together.
Electron
An electrically charged particle.
White Light
Carries all the colors in the spectrum. Each color has its own wavelength.
Electromagnetism
Constitute an electromagnetic wave that carries energy from one part of the universe to another.
Active Optics
Control mirrors by bending them slightly to correct for atmospheric distortion.
Absorption Spectrum
Created when atoms absorb protons of right energy for acceleration.
Epicycle
Each planet was taken to move uniformly around a small circle
Geocentric
Earth lay at the center of the universe and all other bodies moved around it.
Gravitational Force
Every object having any mass exerts a gravitational force on all other objects, and the strength of this force decreases with distance.
The Kelvin Temperature Scale
Fahrenheit...motion stops: -459, water freezes: 32, water boils: 212 Celsius...motion stops: 273, water freezes: 0, water boils: 100 Kelvin...motion stops: 0, water freezes: 273, water boils: 373
Aristotle proposed that all planets revolve around the Sun.
False
Copernicus's theories gained widespread scientific acceptance during his lifetime.
False
During retrograde motion, planets actually stop and move backward in space.
False
Galileo's observations of the sky were made with the naked eye.
False
Kepler's laws hold only for the six planets known in his time.
False
The heliocentric model of the universe holds that Earth is at the center and everything else moves around it.
False
The speed of a planet orbiting the Sun is independent of the planet's position in its orbit.
False
Why is Galileo often thought of as the first experimental scientist?
First person to use a telescope to look at the heavens.
Proton
Fundamental components of matter.
Emitting
Giving in
Omitting
Giving out
Refractor Telescope
Has a lens, not a mirror. Lenses are clear, the light goes through.
Ptolemaic Model
Have the Sun, Moon, and planets all orbiting Earth.
How did Tycho Brahe contribute to Kepler's laws?
He made accurate naked-eye observations of the positions of stars and planets in the sky. He had positional data for Mars spanning more than 20 years.
Comets
Icy with some rocky parts
The Doppler Effect
If one is moving towards the source of radiation, the wavelength seems shorter. If moving away, it seems longer. Depends only on the relative motion of source and observer. Red Shift: lower frequency, it goes away from you Blue Shift: higher frequency, traveling towards you
Interferena
If the sum of two waves maybe larger or smaller, then the original wave.
How did the heliocentric model explain planetary motions and brightness variations?
It can have different positions relative to the Sun and the Earth, depending on where the two planets are in their orbits. It looks brightest when it is closest to the Earth.
What is the basic flaw of the Ptolemaic model of the universe?
It is geocentric.
The Jovian Planets
Jupiter, Saturn, Uranus, Neptune Large and gas
The Terrestrial Planets
Mercury, Venus, Earth, Mars Small and dense
Molecular Spectra
More complete than atomic spectrum, even for hydrogen.
Magnetic Field
Must accompany every changing electric field.
Heated Hydrogen Gas
Only emits at certain wavelength.
Venus
Orbits opposite all the other planets.
Electromagnetic Waves
Oscillating electric and magnetic fields: changing electric field creates magnetic fields and vice versa. Needs no medium. Water waves and sound waves travel in a medium.
Retrograde Motion
Planets' normal backward (westward) loops; as a real backward motion of a planet as it moves along the epicyclic path.
ROYGBIV
Red, Orange, Yellow, Green, Blue, Indigo, Violet
Reflector Telescope
Reflect light with mirrors. Mirrors reflect (and bend the light).
Types of Telescopes
Refractors and reflectors Image acquisition: charged-coupled devices
Asteroids
Rocky
Emission Lines
Single frequency emitted by particular atoms.
Spectroscope
Splits light into component color like a supermarket barcode.
Strengths and Weaknesses of the Geocentric Model of the Universe
Strength: It has the accepted model of the Solar System for centuries. Weakness: Geocentric model places the Earth as its center.
What would happen to the Earth if the Sun's gravity were suddenly "turned off"?
The Earth would go flying off course.
Astronomical Unit
The average distance from Earth to the Sun.
Diffraction
The bending of a wave around an obstacle.
Gravity
The force of attraction by which terrestrial bodies tend to fall toward the center of the Earth. It attracts the planets to the Sun.
According to Newton, why does Earth orbit the Sun?
The gravitational pull of the Sun keeps the planets moving in their orbit.
Acceleration
The rate of change of the velocity of an object.
The Copernican Revolution
The realization that the solar system is Sun centered, not Earth centered
What does it mean to say Kepler's laws are empirical?
They are only descriptive; an observation or experimentation.
Wave Motion
Transmission of energy without the physical transport of material.
You throw a baseball to someone; before the ball is caught, it is temporarily in orbit around Earth's center.
True
Heliocentric
View of the solar system, due to Aristarchus and later Copernicus, holds that Earth, like all the other planets, orbits the Sun.
Velocity
Wavelength
All types of electromagnetic radiation travel through space in the form of what?
Waves
Deferent
Whose center moved uniformly around Earth on a second and larger circle.
