Exam 1
Weak force
causes radioactive decay Short range force
Velocity
change in position/ change in time
Acceleration
change in velocity/ time taken to change it in meters/second^2
Nucleus=
core of atom, surrounded by electrons (protons+ neutrons)
Vernal equinox where is the sun?
crosses celestial equator
1st quarter/ 3rd quarter
half lit moon
Solar eclipse
moon casts shadow on Earth (black w/ light)
Quarks
protons and neutrons are built of these elementary particles up quark (u) down quark (d)
Celestial equator
right above equator, extension of equator onto celestial sphere
Studying the universe allows us to
1. Identify chemicals found in distant galaxies 2. Explain how our sun and planet were created 3. Demonstrate how lifeforms can change planets
As you travel out the universe
1. Solar system 2. Milky way 3. Local group 4. Virgo cluster 5. Supercluster
Planet orbiting Proxima Centouri
1.3 x the size of Earth Orbits every 11.2 days May have liquid water, rocky like Earth
32.6 light years = how many parsecs?
10
1 light year?
10 Trillion KM 6 Trillion miles
Big bang
13.8 Billion years ago Galaxies are flying away from each other as a result of this explosion
1 AU=
150 Million Km, 93 Million Miles
Sun's distance from Earth
150,000,000 Km
Sidereal day
2 successive meridian crossings of a star 4 mins shorter than solar day
Protons (how many quarks)
2 up and 1 down
Angle tilt of rotation axis
23.5 degrees
Lunar phase length (moon cycle)
29.5 days
Light speed=
300,000 Km/ second
Sun- size
300,000 times the mass of Earth 100x the Diameter
How long is a actual year?
365.2 days
Moon's distance from Earth
400,000 Km away
Earth's Mass
5.972x10^24 Kg
Earth's radius
6371 Km
O with + in it
= International symbol of Earth
Vector
Acceleration, velocity and forces
Sun's mass
All of the solar system doesn't add up to even 1% of the sun's mass
Mass
Amount of inertia
Keplers 3rd Law
Amount of time a planet takes to orbit the sun p^2=a^3
Aristotle
Argued that the Earth is a sphere
Strong force
Associated with color change Binds protons and neutrons 100x electromagnetic force Powerful attraction between quarks
Radioactive decay
Atomic nucleus splits into 2 smaller nuclei, releases radiation
Gravitational force
Attraction between all masses Infinite range Attractive Associated with mass
Tycho Brahe
Measured the stars Invented large protractor like devices Model suggested that sun moves around Earth and other planets move around the sun
8 planets in order (MVEMJSUN)
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
Prime meridian
Middle line
Gibbous
More than half of the moon lit
Retrograde motion
Moving East to West
Elementary particles
Neutrino, electrons, quarks
Made of elementary particles
Neutrons &Protons
Law of Gravity
Newton Gravitational force between 2 bodies depends on their mass
Latitude
North to south, declination
How the sun produces energy
Nuclear reactions turn hydrogen into helium
Penumbra
Only see part of sun blocked by moon. Lighter shadow, partial eclipse
Keplers 2nd law
Orbital speed of a planet varies Planet moves fastest perihelion
Kepler's 1st Law
Planets move in elliptical orbits with the sun at one focus of the ellipse Perihelion- planet is closest to the sun Aphelion- planet is farthest from sun d= (1-e)a
Galileo Galilei
Presented convincing evidence for heliocentric model -Mountains on moon -Moons orbiting Jupiter -Spots on sun -Phases of venus Observed sky with one of the first telescopes
Hypothesis=
Proposed in scientific method, can be tested
Constellation
Recognized grouping of stars, 88
Common Era
Replacing AD, abbreviated as CE
Ptolemy
Retrograde motion Planets move around the earth on small circles called epicylces which move around another circle called deferent Equants were introduced, earth is a little off center
Stars rise and set
Rise in east and set in west (follow the sun)
Model=
Schematic representation of a physical system
Zenith
Straight above you
Nadir
Straight below you
Proxima Centouri
"Pale red dot" Closest star 4.243 Light Years away .12x size of sun 4.85 Billion years old
Atomic #=
# of protons
Atomic mass?=
# of protons +neutrons
Neutrons (how many quarks)
1 up and 2 down
Occam's Razor
Believed that entities must not be multiplied unnecessarily Preferred least complicated explanation of phenomenon
Eratosthenes
Calculated the size of Earth
Electromagnetic force
Carried by photons Infinite range Opposites attract Likes repel
Stellar Evolution
Changes of stars by gravity
Supercluster
Collection of galaxy clusters gravitationally bound to eachother in structures that span hundreds of millions of light years
Milky way galaxy
Collection of hundreds of billions of stars, billions of solar masses of gas and dust Part of the local group galaxy
New moon
Completely dark moon
Virgo cluster
Contains thousands of galaxies part of the local group
Umbra
Darker shadow, complete eclipse
Parallax
Displacement of a distant object along two different lines of sight
Lunar eclipse
Earth casts shadow on moon (red)
Longitude
East to west, right ascension
Earth-Moon System
Equal and opposite forces attract them Earth is more massive- acceleration much smaller
Aristarchus
Estimated size and distance of the sun and moon Studied the size of earth's shadow during lunar eclispes & compared them to sidereal month
Newtons
Measure of force
Weight
Measure of the force of gravity
Nicholas Copernicus
Heliocentric Model Modified Ptolemy's model
Angular size
How big an object looks
Theory=
Hypothesis tested and not yet disproven
O with . in it =
International symbol for the sun
Isaac Newton
Invented calculus Realized planets were held in motion by same force that causes things to fall to the ground on Earth (gravity)
Solstice- sun stands still
June 21 & December 21 Farthest point north or south on the celestial sphere Pauses north-south motion and changes direction
Newton's first law of motion
Law of inertia- a body continues in a state of rest uniform motion in a straight line with a constant speed unless acted on by another force
Photons
Make up light
Strength of a force=
Mass/ Distance between centers^2
Law=
Mathematical statement that encapsulates theory
Atomic mass=
Sum of protons+ neutrons
Inertia
Tendency for object to continue at a fixed speed Measured by mass
Newton's second law of motion
The force acting on an object equals the product of its acceleration and mass. F=m*a
Ecliptic
The path the sun traces across the celestial sphere tilted with respect to the equator 23.5 south in december 23.5 north in june
Why was geocentric model believed for so long?
There was no observation of parallax
Solar day
Time between two successive apparent noons (sun is at highest point)
Atoms, + how many?
Tiny particles that make up Earth, 92 kinds
Asterism
Unofficial grouping of stars (big dipper)
Equinox- equal day and night
Vernal- March 20 Autumnal- September 22
Johannes Kepler
Was Brahe's assitant, received his observations when Brahe died. Observed that Mars (and all planets) move on ellipses around the sun
Newton's third law of motion
When 2 bodies interact they create equal and opposite forces on each other
Phases of the moon
waxing crescent- 1st quarter- waxing gibbous- full- waning gibbous- 3rd quarter- waning crescent- new
