Astronomy Unit Flashcards
star
ball of gases that gives of energy
what are starts defined by
size, temp, luminosity, an color
what do colors of stars tell us about temp
blue stars are hotter
red stars are cooler
why do stars appear to move in the sky
because Earth is moving
what is a red-shift & blue shift
colors in the spectrum of a star moving towards earth shows a blue shift. and moving away shows a red shift
what is a light year
the distance light travels in a year
about 5.88 trillion miles
apparent magnitude
the brightness of a star as it appears from earth
absolute magnitude
the true brightness of a star; the brightness that a star would have at a distance of 32.6 light-years from Earth.
when/how does a protostar turn into a star
when temp rises 10,000,000C and nuclear fusion begins
giant
a large, bright star whose core has used most of its hydrogen
white dwarf
extremely dense core left after a star collapses
it is a small,hot, and dim star
galaxy
a collection of stars, dust, and gas bound together by gravity
what are the types of galaxy shapes
spiral, elliptical, and irregular
what shape is our galaxy
spiral; the milky way
what color is our star
yellow (the sun)
what are the 2 most common elements in a star
hydrogen and helium
what is the seasonal movement and circular motion due to?
seasonal movement- revolution of the Earth around the sun
circular motion-rotation of the Earth on its axis around the Polaris
what are circumpolar constellations? give examples…
stars that rotate around the Polaris
such as: Ursa Minor, Little Bear
Cosmic background radiation
radiation uniformly detected from every direction in space; considered a remnant of the big bang.
Big Bang Theory
the theory that all matter and energy in the universe was compressed into and extremely small volume that 13 to 15 billion years ago exploded and began expanding in all directions.
Quasar
a very luminous object that produces energy at a high rate; very bright, distant galaxies that are thought to have enormous black holes in their centers.
Black Hole
an object so massive and dense that even light cannot escape its gravity; a star that collapsed into itself
Pulsar
a rapidly spinning neutron star that emits pulses of radio and optical energy.
Neutron star
a star that has collapsed under gravity to the point that the electrons and protons have smashed together to form neutrons.
Nova
a star that suddenly becomes brighter.
Nebula
a large cloud of gas and dust in interstellar space; a region in space where stars are born.
Parallax
an apparent shift in the position of an object when viewed from 2 different locations.
Doppler Effect
an observed change in the frequency of a wave when the source or observer is moving.
Evidence for the big bang theory includes…
red shifts, cosmic background radiation, and ripples in space.
what can constellations be used for
they can be used to locate celestial objects.
What do Main-sequence stars generate energy through
hydrogen fusion
what are galaxies movement to a central point
they are moving away
energy in stars is produced by…
the fusion of hydrogen into helium
The seasons are caused by
the tilt of Earth’s axis
perihelion
aphelion
p: point closest to the sun in the orbit of a planet
a: point farthest from the sun in the orbit of a planet
what provides evidence that the Earth is rotating
the Foucault pendulum and the Coriolis effect and the change in location of constellations depending on season
one revolution of Earth around the sun is eqaul to..
1 year
one rotation on earths axis is equal to..
1 day
how did planets form?
from collisions of smaller bodies called planetesimals
in what part of a planets orbit does it move the fastest
when closest to the sun it moves faster
what are the inner planets
mercury, venus,earth, mars
what are some differences between terrestrial/inner planets and outer/gas planets
they are much closer together, much smaller, and denser
what inner planets have moons? notable atmospheres?
moons: earth and mars
notable atmosphere: all but Mercury
How was Earths moon tought to have been made?
a giant impact between Earth and a Mars-Sized body caused part of Earths mantel to be ejected. As the molten cooled it formed 3 layers of the moon
when do Eclipses occur
when one planetary body passes through the shadow of another
starting from full moon what are the phases of the moon
new, waxing crescent, 1st quarter, waxing gibbous, full, waning gibbous, 3rd quarter, waining crescent
how does the moon affect tides
the closer the moon is to earth the higher the gravitational pull and tides
astroids and comets
a: large rock bodies
c: smaller made of rock dust and ice
sunspot
spots on the sun that are darker because they are much cooler and have stronger magnetic fields than their surrounding.
it is cooler because it does not get as much energy from the core
cycle of a star…
> sun like star>r giant>planetary nebula>w dwarf
nebual»_space; prostar
> massive star>red supergiant> supernova> Neutron stars, pulsars, or black holes.
what does the big band theory tell us about early universe?
at one point in time all matter in the universe would have been close together and then the “big bang” sent all the matter fling outward and all directions causing them to start moving away from eachother
