Astronomy Flashcards
What is the life cycle of a star?
The life cycle of a star includes stages: nebula, main sequence, red giant, and end stages such as white dwarf, neutron star, or black hole.
True or False: A star spends most of its life in the main sequence stage.
True
Fill in the blank: The initial material for star formation is a _____
nebula
What process powers a star during the main sequence phase?
Nuclear fusion of hydrogen into helium.
Which element is primarily fused in the core of a main sequence star?
Hydrogen
What happens to a star when it exhausts its hydrogen fuel?
It expands into a red giant.
Multiple Choice: What is the final stage of a low to medium mass star?
White dwarf
What is the fate of a massive star after it goes supernova?
It can become a neutron star or a black hole.
True or False: All stars end their life cycle as black holes.
False
What is a supernova?
A supernova is a powerful explosion that occurs at the end of a massive star’s life cycle.
What is the main sequence phase of a star?
The period in which a star fuses hydrogen into helium in its core.
What is the significance of nuclear fusion in stars?
It releases energy that makes stars shine.
What is a neutron star?
A dense remnant of a supernova explosion, primarily composed of neutrons.
Fill in the blank: A black hole is formed when a massive star collapses under its own _____
gravity
What determines whether a star becomes a white dwarf, neutron star, or black hole?
The star’s initial mass.
Multiple Choice: Which stage comes after the red giant phase for a low mass star?
White dwarf
Fill in the blank: The remnants of a supernova can lead to the formation of a _____ star.
neutron
What is a planetary nebula?
A shell of gas ejected from a red giant star at the end of its life cycle.
True or False: Massive stars have shorter life spans than smaller stars.
True
What is the order of the planets in out solar system?
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
What are smaller planets primarily made of ?
Rock
What are larger planets primarily made of?
Gas
What is the geocentric model ?
The initial idea that the earth is the centre of our solar system and the moon planet and sun orbited earth
What is the heliocentric model?
The sun is the centre of our solar system and planets orbit the sun
What does the gravitational force cause the planets to do ?
To constantly change direction (it moves in a circle around the sun)
True or False the speed of the planets is constant ?
True
What does red shift show ?
Galaxies are moving away from earth
True or False as the red shift increases so does the galaxies distance from earth
True
Is red shift evidence for the Big Bang theory
Yes
What does CMB stand for
Cosmic microwave background
Does CMB prove the Big Bang ?
Yes
Does the red shift prove the steady state theory?
Yes
What is the steady state theory
As the universe expands matter is constantly being created so the is density of matter in the universe
Does CMB support the steady state theory
No
What is a nebula?
A nebula is a large cloud of dust and gas.
What happens when a nebula becomes very large?
Gravity pulls the particles of dust and gas together to form a protostar.
What happens when a protostar becomes very large?
Gravity becomes stronger, which pulls the particles closer together and increases the temperature and pressure.
At some point nuclear fusion will start fusing hydrogen nuclei together.
What do we call a protostar once nuclear fusion starts?
A main sequence star.
Which two forces are in balance in a main sequence star?
The energy released from nuclear fusion creates an outward force that balances against the inward force from gravity.
Which elements undergo nuclear fusion in a main sequence star?
Hydrogen nuclei fuse to make helium nuclei.
How long does a main sequence star last?
Until all of the hydrogen is used up.
This could be millions or billions of years.
What two things could a main sequence star become once it runs out of hydrogen?
What determines which it becomes?
If it is relatively small, it will become a red giant.
If it is relatively large, it will become a red super giant.
For a red giant, what are the final phases of the star’s lifecycle?
The red giant will become a white dwarf, which will then become a black dwarf as it cools.
Which elements can be formed in the red giant or red super giant phase?
Elements heavier than helium, up to iron on the periodic table.
For a red super giant, what happens next in the star’s lifecycle?
It will explode in a supernova.
Which elements can be formed in a supernova?
Supernovas form elements heavier than iron, which are fired across the universe as they explode.
What two things could form after a supernova?
What determines which is formed?
If the star was large, it would condense to form a neutron star.
If it was very large, it would collapse to form a black hole.
What is a neutron star?
An extremely dense mass of neutrons.
What is a black hole?
A black hole is a region where gravity is so strong that nothing can escape.
This means no particles, or even electromagnetic radiation such as light, can escape.
