Stars life cycle pt2.
How do stars form?
Gravity pulls gas and dust into the center of the nebula
What are the names of the constellations based on?
Greek culture
What was Orion? Why did the Greeks say the constellaion disappeared for a year?
He was a hunter. he disappeared because they said he was bit by a scorpion and fell into the sea.
How and when did the object in space we now call the Crab Nebula form?
In 1054 C.E. Chinese astronomers spotted an explosion. It was so bright they could see it in daylights. And since the drawing of it looked like a crab they named it the crab nebula.
How does a black hole destroy space?
It pulls everything that's too close in and it's invisible.
How long does a star remain a main sequence star?
It remains as long as it is fusing hydrogen to form helium.
In terms of nuclear fusion, what happens once a main sequence star uses up all of its hydrogen?
It stars to use helium atoms into larger elements like carbon.
How big is our sun?
It's a medium sized star.
What are the characteristics of our Sun compared with other stars?
It's average. There is some that are bigger and some that are smaller.
What eventually happens to a white dwarf?
It's light eventually fades out because it cooled down.
How many black holes are in the Miliky Way Galaxy? Where are they?
Millions and millions. each galaxy has one big one and millions of smaller ones.
How are constellations consistent?
Move with seasons. Patterns never change.
What will happen to the sun once it is no longer on the main sequence?
Our sun will become an enourmous red star. It will grow so large that it may even engulf our Earth.
What are some ways in which constellations are, or have been, important to people?
The ancient greeks named the constellaions and told stories about them
Under what circumstances would the remains of a supernova explosion become a black hole?
The core being more than about 5 times the mass of the sun. The core would then collapse to become a black hole.
Where and what is a singualrity?
The heart of a black hole. Point of infinite density.
What is the relationship between the temperature and brightness of a main sequence star?
The hotter a main sequence star is, the brighter it is.
Describe a white dwarf
a hot, white, glowing object, about the size of the Earth
Describe a red giant.
a larger star that is cooler on the surface and red in color.
neutron
a neutral particle in the nucclus of an atom
What is now at the center of the Crab Nebula?
a neutron star
Describe the mass/size of a neutron star.
a neutron star has about 500,000 times Earth's mass. It is the size of Brooklyn, New York.
What is a constellation?
a pattern of stars
red dwarf
a relatively cool small star.
White dwarf
a small to mid-sized star that has collapsed
Main sequence star
a star that is fusing hydrogen atoms to helium; a star in the main portion of it's life.
Binary star system
a system of two stars that orbit a common center of mass
What is the mass range of main sequence stars compared to our Sun?
a tenth the mass of the sun to about a hundred times the mass of the sun.
Supernova
a tremendous explosion that occurs when the core of a star is mostly iron.
Why do some stars become red supergiants?
all of their hydrogen has been used up in fusion
supergiant
an enourmous star that is near the end of it's life.
Supergiants
an enourmous star that is near the end of its life
Large stars _______ _______ on the main sequence as long as small stars.
are not
white dwarfs are the ________________ core of stars.
burned out
Stars in a constellaion may be fairly ___________________________. More likely, though, they are extremely ______________.
close together. far apart.
In a red giant, the inner helium core _____________ while the outer layers of hydrogen ______________.
contracts. expand
What characteristic do all main sequence stars have?
converts hydrogen to helium
After a supernova explosion, the star's ______ is left.
core
How do astronomers study the life cycle of stars?
data gathered from visual, radio, and x-ray telescopes.
As matter falls into a black hole it creates a _________ around it.
disk
A nebula is a cloud of _________ and __________.
dust. gas.
Main sequence stars fuse hydrogen into helium for ______________.
energy
Chemical elements ______________________________ form in a supernova.
heavier than lithium
Large main sequence stars may be _____________ than small stars---- but not always.
hotter.
What is the mass of the object at the center of the Crab Nebula?
hundred billion tons
When the red giant exhaust all of it's ______________ fusion stops.
hydrogen
What are main sequence stars converting?
hydrogen to helium
What happens to the helium before a star becomes a white dwarf?
it burns it up in its core.
What happens to a star that gets too close to a black hole?
it will be pulled into it and swallowed up.
When stars fuse helium into _____________ atoms, they become red giants.
larger
What are the characteristics of small stars?
less massive, cooler, longer life span than the sun
If the core that is left after a supernova explosion is ___________ dense, it becomes a neutron star. A neutron star is made almost all of ________________.
less. neutrons.
Some energy that falls into a black hole can be turned into _______.
light
Stars spend most of their lives on the __________ ________.
main sequence
Whar are the characteristics of large stars?
more massive and hotter, and shorter life span than the sun
If the core is _________ dense, it becomes a blackhole. No___________ can escape a black hole.
more. light
Nebulae can be spotted with the ___________ ___________ or simple ______________.
naked eye. telescopes
Stars form in a ___________.
nebula
What did our sun and solar systems form out of?
nebula
when a massive star has _____________________________________, it explodes as a supernova.
no more elements left to fuse
How does a star generate energy?
nuclear fusion
Constellations are ____________ of stars seen from Earth. These stars are usually _________________ each other.
patterns. not near
How do most stars change during their lifetimes?
size, color, class
A supernova explosion __________________________ into nearby space. This is the ____________ fo most of our elements.
spreads the elements. source
red giant
stage in a star's development when the inner helium core contracts while the outer layers of hydrogen expand, producing a very large red star.
The points of light in the night sky are _______________ that are balls of _________. They are lit by ________________.
stars. gas. nuclear fusion.
The constellaitons ____________________ night after night.
stay the same
White dwarfs carry around the same mass of the _____.
sun
Describe what happens to the core and outer layers of a stary as it becomes a red giant.
the core collapses inward. The star's outer layers will spread out and cool.
What happebs when there are no more elements for a star to fuse?
the core succumbs to gravity and collapses.
Why do constellaions change position in the sky?
the earht spins on its axis so different constilations appear at night
What keeps the main sequence stars stable?
the principle of hydrostatic equilibrium
Neutron star
the remanant of a massive star after it explodes as a supernova.
black hole
the super dense core left after a supergiant explodes as a supernova.
when the helium is gone from a red giant, the stars become _______________.
white dwarfs.
What type of star is our sun classified as?
yellow dwarf
How long has our sun been a main sequence star?
5 billion years
How many constellations are there?
88
How long will the sun continue ot shine?
5 billion more years
What is a black hole in reality?
A black hole isn't a hole at all. It is the tremendously dense core of a supermassive star.
How does a neutron star's mass and diameter compare to that of the sun?
A neutron star has more mass than the sun; yet it is only a few kilometers in diameter.
What forms because of a supernova explosion?
Elements heavier thatn iron. ex. gold, silver, uranium
____________ continues the life of a Red giant.
Hydrogen
What is a neutron star?
Is made almost entriely of neutrons
Under what circumstance would the leftovers from a supernova explosion become a neutron star?
It depends on the core's mass. The core might be less than about four times the mass of the sun.
In terms of nuclear fusion, what happens that causes a star (such as our sun) to become a white dwarf?
It stops fusion and shrinks inot a white dwarf
Where are new stars born?
Nebula
Are black holes visible? Explain
No. Not even light can escape their gravity. This is why they are black.
What process releases energy in these stars?
Nuclear fusion process
Explain what scientists believe is happening in the Pillars of Creation.
Stars are forming. And the dark areas may be stars that are about to begin.
What does it mean if stars "live fast and die young?"
They burned though their suppy of hydrogen very quickly.
What types of stars become supergiants?
Very massive stars
How does fusion in a red supergiant compare/contrast to fusion in a red giant?
When all the helium in a red supergiant is gone fusion continues. This does not happen in a red giant.
What is a star?
giant ball of glowing gas is very hot.
What are the properties at the center of a black hole?
gravitys infinite
What does the word constellaion mean?
grouping of stars mapped out like a blue print
What type of star precedes a white dwarf?
red giant
What is created in a supernova?
Carbon and oxygen. elements likd gold and platinum.
How does a star become a supernova?
Core becomes heavy with iron. fusion stops. core explodes.
When does nuclear fusion begin in a star?
As the material becomes denser, the pressure and the temperature increase. When the temperature of the center becomes hot enough, nuclear fusion begins.
What is astrology? How is it different from astronomy?
Astrology is the explanation to how things are due to constilations. It's different from astronomy because Astrologers do not change or abandon their ideas when they fail like other scientists do.
Why do people say that everything is made of stardust?
Because everything has the elements that resulted from the supernova explosion.
Why do stars typically not form heavier elements?
Because it uses more energy than it produces.
How do scientists know that black holes exist?
Because the black hole affects the objects around it. It affects them with it's gravity. Some radiation amy leak out. around the edges of a black hole.
How is the life cycle of a str similar to the life cycle of people?
Because they are born, can grow, change over time, and eventually grow old and die.
Why do all stars (except for our sun) look like single points?
Because they are so far away
Describe the relationship between a star's surface temperature and it's size. Does the relationship always hold true? Explain.
Bigger stars produce more energy, so their surfaces are hotter. No, some very small stars are very hot. Some very big stars are cool.
Describe what is left over after a supernova explosion.
The star's core is left over. This material is extremely dense
What happens when there is nothing left to fuse in a supernova?
The star's iron core explodes violently.
How do constellations change?
They change during the seasons because of Earth's position
How do zodiac constellaions differ from other constellaions?
They cross the path of the eliptic
What do main sequence stars do?
They fuse hydrogen atoms to form helium atoms
How does the gravity of a neutrion star compare to the gravity of a black hole?
They have an immense amount of gravity, but not as much as a black hole.
What is the fate of larger stars (larger than the sun)?
They will explode. Supernova explosion.
Explain the importance of a supernova explosion
This is where we get most of our elements
