in what direction do opposing plates in plate boundaries move along a divergent boundary?
what is relative time measurement?
it measures time by stating whether an event is younger or older than another event
Describe the Law of Superposition
it states that if rock layers ae undisturbed, younger rocks lie above older rocks and the oldest rocks are at the bottom
The modern model of the solar system
sun-mercury-venus-earth-the moon-mars-asteroid belts-jupiter-saturn-uranus-neptune-kuiper belt-oort cloud
The equinoxes are when the Sun's rays directly hit the equator while crossing it. The Vernal Eqinox (March 21st) has the sun's rays moving north and the Autumnal Equinox (September 21st) has the sun's rays moving south across the equator.
what is used to classify planets
by location lnner vs outer
by composition Terrestrial planets vs Gas planets vs Ice Giants
wha is used to classify comets
composition and origin- Kuiper Belt (short period) or Oort Cloud (long period)
what is solstices
When the sun reaches its greatest distance north or south of the equator twice each year
what is lunar phase of the moon
the portion of the moon as seen by an observer, usually Earth. it is the differnt shapes of the moon you see from Earth. The pase ofthe moon you see depends on how much of the sunlit side of the moon faces Earth
when do an eclipse occur
when te moon's shawo hits Earth or Earth's shadow hits the moon, an eclipse occurs. when an object in space comes between the sun and a third objects, it casts a shadow on thatobject causing an eclipse.
what are the eight lunar phases as seen from Earth?
new moon-waxing crescent-waxing quarter-waxing gibbous-full moon-wanning gibbous-waning quarter-waning crescent.
what is partial lunar eclipses
the moon is partly in the umbral shadow and partly in the penumbral shadow
what is a lunar eclipse
When the earth is between the sun and the moon, and the earth casts a shadow on the moon
what is a solar eclipse
When the moon is between the earth and the sun, and the moon cast its shadow on the earth
what is a total solar eclipse
the moon completely covers the sun. the corona is visible. You are in the umbral shadow
what is a annular solar eclipse
the moon does not competely cover the sun. A ring of unblocked sun light is visible around a black moon disk
what is light year
the distance light travels in a year. the distance that light travels in a vacuum in a yr. (9.5 trin km)
what is absolute magnitude (brightness)
how bright a star really is ad does not depend on distance from earth
what is the relationship between gravity and energy
greater mass=greater gravity=greater energy output
what is the relationship between apparent magnitude and distance
farther away=dimmer appraent magnitude
what is the relationship between absolute magnitude and distance
absolute magnitude is done at distance of 10pc or 32.6 LY
stellar evolutiion all main sequence stars are?
condense from a nebula
begin theri life on the main sequence of the H-R diagram
stellar evolution some new stars will begin their lives as?
blue to white supergiants above the H-R diagram
what is a tide
the rise and fall of ocean water that occurs every 12.5hrs .the water rises for about 6hr then falls for about 6hr on a regular cycle
what causes the tide cycle
the force of the moon's gravity on Earth. the sun's gravity also pulls the Earths waters
what causes high tides
the foce of the moon's gravity pulls earth toward the moon, leaving the water behind. the moon's gravity causes high tide on the side closest to the moon
what is spring tide and how often does it occur
it occurs twice a month: new moon and full moon phases.
the sun, moon and earth are nearly in a line during a new moon. the gravity of the sun and the moon pull in the same direction. Their combined forces produce a tide with the greates difference between consecutive low and high tides. this is called spring tides
what is neap tides and how ofter does it occur
it occurs twice a month: 1st quarter lunar phase and 3rd quarter lunar phase. During the moon's first quarter and third quarter, the line between the earth and the sun is at right angles to the line between earth and the moon. the sun's pull is at the right angles to the moon's pull. this produces a neap tide. the neap tide is a tide with the least difference between consecutive low and high tides
whtat is the approx difference int ime beteen hgh and low tides
. the complete cylce is about 12 hrs. 6-high 6-low
what was alfred wegener's supporting evidence of the theory of continental drift
coastline fits the continents
geologic worik of other scientist(identical rocks in SA and Africa, folded mountain rages
fossils evdences found by scientist(glossopteris, mesosaurus)
what were problems with the continental drift therory
could not offer a reasonable explanation for continental movement through te earth's crust
THIS THEORY IS WRONG!
continental drifts structure:
Gondwanaland(SA, Africa, Antarctica, India, Australia)
what is the theory of plate tectonics
this theory combines the basic concepts of Wegener's Continenta Drift theory with Hess's Sea Floor Spreading Theory
what is plate
continents fit like puzzle pieces, fossil evidence, paleomagnetism, the earth crust and upper mantle are broken into sections called plates.
plates move around on top of the mantle like rafts.
what is lithosphere
A rigid layer of rock., outer layer of earths structure includes the crust and and upper mantle, major component in plate tectonic movement
what is divergent boundary
A divergent boundary is a plate boundary ion which the plates move apart.
what is a tsunami
a train of sea waves traveling of the oceans surface, triggered by an earthquake or other disturbance of the seafloor, Seismic sea waves
what is the moment magnitude scale
A rating system that estimates the total energy released by an earthquake.
what is the shadow zone of an earthquake
an area on earths surface where no direct seismic waves from a particular earthquake can be detected
what is the relationship between plate tectonics earthquakes and volcanism
most earthquakes occur along plate boundaries
most volcanism occurs along plate boundaries
what is radiometric dating
this method relies on the fact that the rate of radioactive dcay will remain constant for any particular radioactive isotope
what are the methods of measuring time: earth's history
relative time measurement(relative time can only be used to create a sequence of events(timeline) usually listed from oldest first to younges lat)
absolute time measurement (radioactive decay)
A representation of the universe in which starts and planets revolve around Earth. Ptolemy proposed the model., The idea that Earth is at the center of the solar system, Theory of the universe that states the earth is the center, and that the sun revolves around it.
A representation of the relationship between the Sun and planets in which the planets revolve around the Sun. Copernicus proposed the model., the accepted model of our solar system with the sun in the center, Theory of the universe that states the sun is the center, and that the earth revolves around it., the model where Earth and other planets orbit the sun
volcanic regions include
transform boundaries are NOT volcanic
(astronomy) a collection of star systems, large group of stars, dust, and gas held together by gravity; can be elliptical, spiral, or irregular, a collection of star systems
the galaxy containing the solar system, the name of our galaxy, the spiral galaxy containing the solar system
big bang theory
(cosmology) the theory that the universe originated 20 billion years ago from the cataclysmic explosion of a small mass of matter at extremely high density and temperature, States that all galaxies originated from one huge mass of densely packed matter., the theory that all matter and energy in the universe was compressed into an extremely small volume that 13 billion to 15 billion years ago exploded and began expanding in all directions
what is a black hole
region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull.
if a netron stare core continues to collapse so close nothing can escape;not even light
a galaxy whose arms curve outward in a pinwheel pattern, galaxy with arms that make it resemble a pinwheel spinning in space; Milky Way is one
barred spiral galaxy
A galaxy that is similar to a spiral galaxy, except that the spiral arm pattern originates from a bar of material that passes through the nucleus of the galaxy., Spiral galaxies that have a straight bar of stars cutting across their centers.