Exam 1 Flashcards
(44 cards)
Cosmic Address
Earth, solar system, Milky Way, local group, supercluster, universe
Scientific Method
Is a way to falsify, not prove, ideas; thus all scientific knowledge is provisional. Observation idea - hypothesis - prediction - further observation/ test the prediction - tested theory
Theory
All theories have enough supporting evidence behind them that we can move forward under the assumption that they are correct unless a test proves otherwise.
law
A set of observations that can make predictions without explaining why. Give predicted value. What is going to happen but can’t tell why
hypothesis
Testable (predictive) explanation of the observation on its way to becoming a theory.
Occam’s Razor
Simple is better fewer assumptions
- Newton’s gravity vs Einstein’s gravity
- Scientific “aesthetic” values simplicity
Linear vs. Logarithmic scales
Linear- constant slop, Slope = change in y / change in x
Logarithmic (logs)- helps plot numbers with a large discrepancy between them or exponential growth (highlights detail)
Celestial Sphere
Objects that we see in the night sky and different distances. Projecting these objects onto an imaginary sphere yields the celestial sphere.
Zenith
Directly overhead
Horizon
the boundary of what we can see in the sky 90 degrees from the zenith
Celestial Poles
NCP/SCP north and south directly above Earth’s poles say fixed doesn’t change
Celestial equator
Align with longitude and latitude. Projection of Earth’s equator into space
Rotation direction of the Earth
Earth rotates counterclockwise
Axial Tilt, Equinox/Solstice why and how does this affect the seasons?
Earth’s axial tilt is 23.5 degrees
If the earth had an axial tilt of 0 degrees we would have no seasons at all 90 degrees makes seasons extreme.
Moon Phases
It is caused by the arrangement of the sun and moon relative to the Earth.
New - waxing - full - waning - new
Eclipses
When one body gets in front of the other and light is affected.
-Solar Eclipse
3 types:
total- whole disc of the sun is blocked
partial- only part of the sun is blocked
annular- only the interior of the sun is blocked, leaving a ring, the annulus.
Lunar Eclipse
the moon is in Earth’s shadow orbit and is not parallel why we don’t have as many solar eclipses.
-Line of Nodes
Intersections between the moon’s orbit and the Earth’s orbit
Eclipses only happen when a full/new moon is near the line of nodes
Geocentric vs. Heliocentric Model
Geocentric is the model that the earth is at the center. Problem with geocentric model spots on the moon, Jupiter’s moons, and phases of Venus.
Heliocentric is the sun at the center.
Newton’s Law of Gravity
-Mass vs. Weight
-Center of Mass
weight- A force between a planet’s gravity and a given mass (Fweight = MGplanet)
Orbits
-Escape Velocity, circular velocity, bound/unbound orbits
Escape velocity- velocity at which you leave the planet. Depends on both the radius and mass of the planet.
Circular Velocity- only leads to a circular orbit, distance from Earth isn’t changing.
Bound orbit- More circular velocity but less than escape velocity
Unbound orbit- escape velocity or more
