Point in the earth's orbit where the earth and sun are the farthest apart
what is perihelion
Point in the earth's orbit where the earth and sun are the closest
what causes the different seasons?
the tilting of the earth's axis and its orbit around the sun
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 two dates do the equinoxes occur
March 21st and Sept 21st
what is used to classify planets
by location lnner vs outer by composition Terrestrial planets vs Gas planets vs Ice Giants
what is used to classify asteroids
composition and location
wha is used to classify comets
composition and origin- Kuiper Belt (short period) or Oort Cloud (long period)
In the origin of the solar system (Nebular Theory)starts with?
nebula made of dust and gas
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
what is waxing (lunar phase)
if the left side of the moon is dark then the light part is glowing
what is the waning(lunar phase)
the portion of the moon you can see
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 causes the various lunar phases?
the oons revolution around the Earth
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.
eclipses: what is umbral shadow
the darkest portion of the moon's shadow
eclipes: what is penumbral shadow
the lighest shadow on earth's surface
Lunar eclipses: light source
lunar eclipses: light blocker
lunar eclipses: shadow receiver
lunar eclipes: lunar phase
what is total lunar eclipses
the moon is completely within theearth's umbral shadow, reddish color
what is partial lunar eclipses
the moon is partly in the umbral shadow and partly in the penumbral shadow
what is penumbral eclipses
the moon is partly in or completely in tepenumbral shadow only
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 partial solar eclipse
the moon partly covers the sun. you are in the penumbral 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 tidal range
It is the difference between sea level at high tide and at low tide
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 apparent magnitude (brightness)
the brightness of a star as it appears from earth
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 ther relationship between color and surface temperature
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
what is the relationship between magnitude and size (diameter)
larger diameter=brighter magnitude
stellar evolution all main sequence stars begin their lives how?
in the same wa
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 low tides
low tidesoccur between the two high tides.water flows away
What are the two tides in tide cycle
spring tides and neap tides
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
right angle pull is associated with neap tide or spring tides?
the gravity of the sun and the moon pulling in the same direction is neap or spring?
whtat is the approx difference int ime beteen hgh and low tides
6hrs . the complete cylce is about 12 hrs. 6-high 6-low
who was the person who therorized the continental drift
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:
Pangaea Laurasia(NA,Europe, Asia) 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
where are plate boundries located
along very active earthquake fault zones and volcanic regions
what happens to the crust in divergent boundary
where two plated diverge from one another
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
the pocket beneath a volcano where magma collects
Volcanoes are classified according to three things?
frequency eruptive force composition
name the 3 frequencies of a volcanoe
extinct dormant active
name the 3 eruptive forcesof volcanoes
quiet active explosive
name the 3 composition of volcanoes
shield volcano\ composite cone cinder cone
what is extinct volcanoe
a volcanoe that is dead and that is unlikely to erupt again
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
when will radiactive decay stop
when a new lighter stable atom is produced
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)
in the geocentric model of the solar system, what planet is in the middle
the earth is in the middle of what model
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
subduction zones divergent boundaries hot spots 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
the milky way galaxy is what shape
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
stellar death is the death of what
stellar death of a star undergoes is directly related to its?
low mass stars (<0.7 s.m)
unknown, not enough time has passed for one to die
low mass stars (0.8-1.3 sm)
main sequence...red giant>planetary nebula>white dwarf>black dwarf
medium mass stars(1.4-<4 sm)
main swquence>red supergiant>suernova>neutron star or pulsar
high mass stars(>5 s.m)
blue giant or spergiant>red supergiant>suernova>black hole
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.