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what is a star
a large celestial body composed of gas and emits light
what is a galaxy
stars grouped together in a structure
what are galaxies made up of
large collection of stars, gas, and dust
list the 6 types of galaxies
barred spiral, irregular, spiral, peculiar, elliptical, lenticular
estimate amount of galaxies
100 billion
what does the universe contain
space and all the matter and energy
what is the ozone layer
layer in the atmosphere which absorbs harmful solar radiation + other gases (keeps the earth toasty)
what is a solar system
collection of stars and small bodies that orbits our sun
another name for bodies
planets
what is a planet
a spherical body which orbits the sun
name the terrestrial planets
mercury, venus, earth, and mars
qualities of the terrestrial planets
orbit nearest to the sun - rocky, dense, and relatively small
name the gas planets
jupiter, saturn, uranus, neptune
qualities of the gas planets
orbit farthest from the sun - thick, gaseous atmosphere; small, rocky cores; ring system of ice, rock, and dust
what are most stars made of
hydrogen and helium
life cycle of the star
RAHHHHHH
name the process which energy produced in the core of a star
nuclear fusion
what are galaxies
large collection of stars, gas and dust held together by gravity
how many stars do dwarf galaxies contain
few billion stars
how many stars do giant galaxies contain
hundreds of billions
where is our solar system located
Milky Way
why type of galaxy is the milky way
spiral galaxy
spiral galaxy
shaped like a pinwheel, central bulge which two or more spiral arms extend
elliptical galaxies
looks like spheres or ovals and do not have spiral arms
irregular galaxies
splotchy, irregularly shaped - blob
what is period of rotation
the amount of time taken for an object to rotate once (1 day)
what is period of revolution
the time taken for an object to revolve around the sun once (1 year)
what is gravity
a force that pulls all objects towards each other
what is inertia
the tendency of an object to stay either at rest or in motion along a straight path
what would happen if inertia was stronger than gravity
the objects would stay on their straight path and fly off into space
what would happen if gravity was stronger than inertia
the objects would crash into the earth
what do inertia and gravity do
work together to keep the moon orbiting the earth and to keep planets orbiting the sun
what is a comet
small body made out of dust, rock, gas, and ice
name parts of comets
nucleus, coma, ion tail, dust tail.
what are astroids
large pieces of space rock with irregular shapes
where do most asteroids orbit
sun in the asteroid belt located between mars and jupiter
what is a meteoroid
pieces of rock or dust that are smaller than asteroids
what is colour a clue about a star
the stars tempurature
what is a binary star
pairs of stars, pulled together by gravity, that orbits each other
what are binary star use to
determine the stars property
light year
units used to express stellar distance → distance light travels in one year
apparent magnitude
a stars brightness as it appears on earth
absolute magnitude
how bright a star actually is
what does the Hertzsprung-Russell diagram show
the relationship between the absolute magnitude and temperature of stars
what is Cepheid variable
a stars whose brightness varies periodically because it expands and contracts
list the ways a star can be classified
size, temperature, brightness and magnitude
size meaning (star)
how massive the star is
what colour do cooler stars have
red stars
what colour do warmer stars have
blue stars
what colour do medium stars have
yellow
what does a H-R diagram do
compares the temperature, colour and luminosity of a star on a graph
where is the temperature on the H-R diagram
horizontal (bottom axis) - hotter at left, cooler at right
where is the brightness on the H-R diagram
vertical axis (left side) - brightest near top, dimmer near bottom
name the two most common measurement for distance
astronomical unit - AU
light year
what does the astronomical unit measure
the average distance from the earth to the sun (used when discussing distance within our solar system)
who discovered redshift
Edwin Hubble
what did Hubble’s discovery tell us about the universe
almost all galaxies were moving away from each other
how does redshift work
shows how light moves towards longer or shorter wavelengths as galaxies and stars move closer or farther away
what does it mean if a star is moving closer to the red side of the spectrum
it is moving farther away from the earth
what does it mean if a star is moving closer to the blue side of the spectrum
it is moving closer to the earth
what is cosmic microwave background radiation
shows that when the universe was young it was very hot and as it expanded it grew cooler
who discovered the composition of the universe
Cecilia Helena Payne
what did Payne discover
stars were mostly made of hydrogen and helium
who discovered dark matter
Fritz Zwick
what are space technologies used for
to enter and retrieve objects or life forms from space
name the 3 present day space technologies
hubble space telescope
curiosity rover
kepler spacecraft
name the 3 future space technologies
antimatter-powered rockets
laser and microwave-powered rocket
sun powered rocket
what did Sir Isaac Newton discover
gravity, laws of motion, and the light spectrum
what is gravity
an invisible force that pulls everything towards the centre of earth
how is gravity measured
metres per second squared
how is mass measured
measured by how much matter is in an object
what is weight
weight is the force of a mass pushing down on the surface on which it is standingho
how is weight neasured
in newtons
