ANSWERS.
The Big Bang - Answers-The whole universe was born from this, theory states that
about 13.7 billion years ago all the matter in the Universe was concentrated into a single
incredibly tiny point. This began to enlarge rapidly in a hot explosion, and it is still
expanding today
Chemical composition of universe - Answers-roughly 74% hydrogen and 24% helium
with other elements in trace amounts
how many stars are in the universe? - Answers-there are about 10^22 stars in the
universe
physical structure of universe - Answers-93 billion light years across, more than 100
billion galaxies, 13.7 billion years old, full of new-expanding-and decaying stars
solar nebula - Answers-the solar system formed from this cloud of gas that collapsed
under its own gravity, as the nebula shrank the sun formed in the center
Circular orbits - Answers-large bodies in the solar system have orderly motions-all
planets have nearly circular orbits moving in the same direction
planet categories - Answers-1. small, rocky terrestrial planets
2. large, hydrogen rich jovian planets
asteroids/comets - Answers-rocky asteroids and icy comets are concentrated in the
asteroid belt, Kuiper belt, and Oort cloud
Exception to orbits - Answers-some planets have unusual axis tilt, unusually large
moons, or moons with unusual orbit or unusual rotation
astronomical unit - Answers-the average distance of the Earth from the sun, which is
about 150 million Km
cosmic address - Answers-a way to think of the Earth's place in the universe
Earth>solar system>milky way galaxy>local group>local supercluster>universe
stars - Answers-are born when gravity is able to contract a cloud of cold interstellar gas
to the point where it becomes so hot that nuclear fusion begins in its core
molecular clouds - Answers-the cold, dense clouds that form stars, tend to be massive
and generally give birth to many stars at a time (clusters)
,corona - Answers-the outermost layer of the star's atmosphere, has an astonishingly
high temp
chromosphere - Answers-middle layer of the solar atmosphere that radiates most of the
Sun's UV radiation around 10,000K
photosphere - Answers-the lowest layer of the Sun's atmosphere and is the visible
surface of the sun, sunspots are found on this layer
convection zone - Answers-the central region of the Sun where energy is transported
outward by convection
radiation zone energy - Answers-energy moves outward as photons of light, the temp
rises around 10 million K
core - Answers-is where nuclear fusion is taking place, transforming hydrogen into
helium, temp is around 15 million K
planets - Answers-moderately large objects that orbit around a star, large enough to
have gravity to make it round, orbit can't cross other's path
three requirements for a planet - Answers-1. orbits around the sun
2. has enough mass to generate a gravity strong enough to make it round
3. must clear its neighborhood as it orbits the sun
star color - Answers-come in different colors because they emit thermal radiation,
spectrum depends on the surface temp of the star, brightest/hottest= white/blue,
coolest/dim-red
star size - Answers-astronomers use Kepler's third law in order to measure a star weight
Kepler's third law - Answers-distant planets orbit the sun at slower average speeds,
need to know orbital period and separation of the star
luminosity - Answers-the total amount of power energy per second that a star emits into
space regardless of their distance
luminosity classes - Answers-1. supergiants
2. bright giants
3. giants
4. subgiants
5. main-sequence stars
star distance - Answers-measured by stellar parallax: the small annual shift in the star's
apparent position caused by Earth's motion around the sun, distant stars have smaller
parallax angles
, Fusion in stars - Answers-1. high temp=high speed nuclei
2. two nuclei collide, produce a heavier nucleus
3. four H nuclei combine to produce a helium nucleus is converted to energy
4. called the proton-proton chain
5. takes 100s of thousands of years to travel from the core to the photosphere
patterns of stars - Answers-constellations, stars appear to lie close to each other but
might be far apart, stars move gradually across the sky from east to west
moon phases - Answers-based on its position to the sun as it orbits the Earth, each
complete cycle takes 29.5 days
new moon> waxing crescent> first quarter> waxing gibbous> full moon> waning
gibbous> third quarter> waning crescent> back to new moon
telescope - Answers-allows scientists to analyze the light the telescopes collect, capture
images of different wavelengths
radio telescopes - Answers-studies wavelengths that are much longer than visible light
wavelengths, needed in order to achieve good angular resolution
infrared - Answers-studies objects that emit an infrared wavelength
visual - Answers-the two main features of a telescope are the light-collecting area and
its angular resolution
x-ray telescopes - Answers-measure x rays in space
gamma ray telescopes - Answers-used to detect very short, high energy wavelengths of
gamma rays
divergent boundaries - Answers-involves two plates (continental or oceanic), located
along oceanic ridges, where new oceanic crust is formed, hot magma rises and creates
a crust that cools over 80 million years
convergent boundaries - Answers-destructive plate boundaries, one plate is being
forced under the other, the plate that is more dense will be subducted
oceanic and continental convergence - Answers-the more dense oceanic crust will
descend beneath the less dense continental crust
oceanic and oceanic convergence - Answers-one descends beneath the other, this
initiates volcanic activity, water is squeezed out and triggers melting, can grow into a
chain of islands