Physical Science Test 2 Flashcards
Draw the life cycle of a star
drawing
nebula
gravity begins to pull gases and dust together, temperature remains fairly cold, no fusion yet.
a large cloud of gas and dust spread out over a large volume of space
Ex. Eagle Nevula pillars of creation
protostar
some heat produced, no fusion, gases and dust become more dense especially at center
a contracting cloud of gas and dust with enough mass to form a star
main sequence star
fusion force outward matches gravity inward(equilibrium), sizes and colors of stars vary, 90% of stars are in this stage
red giant and giant
gravity overcomes fusion and compresses the star, to relieve the heat and pressure, the star expands and star cools, light produced is now more dim
supernova
fusion slows down gravity is winning, star collapses, heat build up causes explosion
planetary nebula
gravity continues to win but outer gases leave, core remains, fusion can cause other elements
white dwarf
may have companion star. Can steal hydrogen from companion but takes in too fast causing supernova
black dwarf
all fusion has ended
neutron star
mostly neutrons remain after an explosion, some fusion with helium wich causes pulsating light
black hole
remaining core is so dense that supergravity doesn’t let light escape
what percent of stars are white dwarfs
10%
what percent of stars are giants or supergiants
1%
when is a star formed?
when a contracting cloud of gas and dust becomes so dense and hot that nuclear fusion begins
how is a main sequence star in equilibrium
when it’s outward thermal pressure from fusion and gravity’s inward pull are equal or balancing itself out
list 3 characteristics of a large, young star
- large core
- huge amount of energy
- strong gravity
- bluelish color
why do large stars not last as long as small stars
they use their energy more quickly because they’re so bright, causing them to run out fuel more quickly.
what causes a star to begin dying
it runs out of fuel
how is iron made in high mass stars
when it evolves from hydrogen fusion to fusion of other elements
How did Giovanni Baptista Riccioli discover about Mizar and Alcor
he discovered that they are a binary star system
what is a binary star
a star system with two stars
if one star of a binary star system is dim how do we know its there
by the motion of the other star
what is an eclipsing binary
one star passes in front of the other
what are two differences between an open cluster and a globular cluster
open- disorganized
globular- large group of older star
galaxy
a huge group of individual stars, star systems, star clusters, dust, and gas bound by gravity
what is a spiral galaxy
bulge of stars at center, with arms
barred spiral galaxy
bulge of stars with arms extended from a bar
elliptical galaxy
spherical or oval with no arms
irregular galaxy
disorganized appearance
how many stars are estimated to be in the milky way galaxy
200 to 400 billion star
how long does it take the sun to rotate around our galaxies center
220 million years
Read over highlighted terms in “Two Exiled Stars are Leaving Our Galaxy Forever”
read
photosphere
the thin, intermost layer of the sun’s atmosphere
corona
the outermost layer of the sun’s atmosphere
prominences
huge loops of gas that erupt from sunspot regions and extend upward from the phtotsphere into the chromosphere and sometimes to the corona
solar flares
a dramatic eruption on the sun’s surface
light year
the distance that light travels in a vaccum in a year
apparent brightness
the brightness of a star as it appears from Earth
absolute brightness
a description of how bright a star really is
hypervelocity stars
zoom around the center of the Milky Way
Magnetar
type of neutron star with powerful magnetic field
galaxy mergers
occur when 2 galaxies collide
Georges Lemaitre
Roman Catholic Priest, Father of the Big Bang Theory
Fred Hoyle
Goes against the Big Bang Theory, believes in Steady State universe- doesn’t expand or contract. Aliens came to Earth and seeded life
Stephen Hawking
Doesn’t believe in a god. Studied black holes, they burp and shoot out Hawking radiation. Has disease AOS.
whats uniformitarianism
the belief that all the laws and rules of nature have been the same from the beginning of time and will stay the same to the end of time
Draw out the Nebular theory
drawing
Describe the nebular theory
- the solar nebula is formed from material expelled from pervious stars
- A shock wave caused the nebula to collapse
- As it rotated faster, it flattened out, creating a protoplanetary disk.
- the majority of the mass became focused at the center. The temp. increased
- Nuclear reactions began to fuse hydrogen and helium
- Dust collected into planetestimals by accention
- They grew and began to exert a gravitational pull
- They grew until they created moon sized protoplanets
- The planets joined to form our curret planets by colliding
