Energy From the Nucleus (Stars) Flashcards
What was the universe before galaxies and stars were formed?
dark patch cloud of hydrogen and helium
What pulled matter into galaxies and stars?
Gravity
What is a galaxy?
A collection of billions of stars held together by their own gravity
What galaxy is the sun and the solar system in?
Milky Way Galaxy
What is a protostar?
A gas and dust cloud in space that can go on to form a star
What provides the energy released by a star? What happens?
Nuclear fusion provides this, of hydrogen into helium
What is a supernova?
The explosion of a supergiant star after it collapses
What is the life cycle of a LOW mass star? (Eg our sun)5
1Protostar 2 main sequence star 3 red giant 4 white dwarf 5 black dwarf
Life cycle of HIGH mass star?6
1 protostar 2 main sequence star 3 red supergiant 4 supernova 5 neutron star 6 if sufficient mass - black hole
Where are elements as heavy as iron formed?
Inside stars as a result of nuclear fusion
Where are elements heavier than iron formed?
In supernovas
What were the sun and the rest of the solar system formed from?
From the debris of supernovas
Where are molecules of carbon based chemicals found?
In space
What is the most probable reason for the formation of life on Earth?
From chemicals reacting in lightning storms
Why are space probes sent to Mars?
To test the atmosphere, rocks and soil
What did the SETI project use radio telescopes for
To scan for signals from outer space
Roughly how long ago is it predicted that the Big Bang occurred?
13 billion years ago
How does res shift from distant galaxies provide evidence for the beginning of the universe?
Shows galaxies are moving away from the earth
More distant galaxies have bigger redshift
Suggests a point of origin
What is a nebula?
Clouds of gas and dust in space
How long ago was the Big Bang?
13 billion years ago
Before galaxies and stars formed the universe what was there?
A dark patch cloud of hydrogen and helium
What galaxy is the solar system?
Milky Way
What were the sun and solar system formed from?
From the debris of supernovas
What does the SETI do?
Used radio telescopes to scan for signals from outer place
What are space probes testing in Mars?
Atmosphere
Rock
Soil
Why were light elements formed?
As a result of fusion of stars
How does the size of a star affect the rate of nuclear fusion?
Faster in a large star than a small star
Shorter main sequence period
So faster rate of using up hydrogen
How does a protostar become a star?
As it becomes denser it becomes hotter
If it becomes hot enough hydrogen and light fusion occurs
Energy is released as the core becomes hotter and brighter
How do stars release energy?
Because of hydrogen fusion in the core
Difference between protostar and main sequence star?
Protostar does not emit radiation
As fusion reactions haven’t started
When does a supernova become a black hole?
When a high mass star is very high in mass the core collapses to form a black hole
When does a supernova become a neutron star?
If the high mass star has a smaller mass the core shrinks becoming a neutron star
How were the elements formed?
Nuclear fusion of hydrogen and helium
Elements heavier than iron were formed by a supernova
Describe a main sequence star?
Energy released in core keeps it hot
Nuclear fusion continues
Star is stable because gravity (which makes the star contract) is be lanced with the outward force of radiation from the core
How does a mainsequence star change to another type?
The forces become unbalanced when the star runs out of hydrogen to fuse
What happens to high mass star after it is a main sequence star?
Swells until it becomes a red super giant
What happens after a redsupergiant collapsed?
The outer layers explode
In the collapse matter compressed the core
The compression suddenly reversed into a supernova
The supernova causes all elements to be formed (HEAVIER THAN IRON)
After a supernova what happens to a high mass star?
If the mass is large enough the core collapses to form a black hole
If the mass is lower the compression shrinks the core into a neutron star
What is a neutron star?
An extremely dense object comprised only of neutrons
What happens to a low mass star after its done main sequence?
Swells cools turns read
Into a red giant
Helium and other light elements fuse to form heavier elements
When does a star turn into a white dwarf?
When there are no more light elements in the core fusion stops and no more radiation is released
Gravity of the star caused the star to collapse on itself
The collapse causes it to heat up and turn from red to white
How does a star go from a white dwarf to a black dwarf?
Faded out goes cold turns to a black dwarf
Describe a white dwarf?
Hot dense smaller
Why does a star collapse?
As the star runs out of hydrogen for nuclear fusion the outward force of radiation is reduced
This causes an imbalance between this and the stars own gravity
What causes a star to go from dust and gas to a star?
Gravitational attraction
How do stars produce energy in main sequence?
By converting hydrogen to helium by nuclear fusion
Where do the elements produced in a supernova go?
Distributed through the universe or space
What did CMBR important for?
Provided more evidence to support the Big Bang
What does the Big Bang describe?
The origin of he universe
Definitions of red shift?
Light moves to red part of spectrum
Wavelength of light appears to increase
How were elements distributed throught the universe?
By a supernovas explosion at the end of its life
Why is the rate of nuclear fusion faster in a large star?
Shorter main sequence period so mist have faster rate of fusion
Hydrogen used up at a faster rate
How does a red super giant form a supernova?
The outer layers explode as a supernova
What happens in a supernova to form a neutron star?
Core shrinks
What happens after a supernova?
Core shrinks
Becoming a neutron star
If mass large enough the core collapses to form a black hole
What is the name of the outward force from nuclear fusion?
Radiation pressure
How does a star form?
Dust and gas are pulled together by gravitational attraction
