National Aeronautics and Space Administration
Goddard Space Flight Center
Imagine the Universe!
Home
Science
Astronomer's Toolbox
Cosmic Objects
Big Questions
Featured Science
Observatories
Special Exhibits
Scientist Profiles
You Be the Astrophysicist
The Cosmic Distance Scale
Educators' Corner
Lesson Plans
Materials
Programs
Ask an Astrophysicist
Resources
Other Resources
Dictionary
Search
Astronomer's Toolbox
Stars Quiz - Level 2
Stars Quiz
Heat generated by fusion in a star's core is carried outwards towards the surface by radiation and by convection. Convection is most like:
[A] the way heat from the Sun is transferred to the Earth
[B] the way the heat from a stovetop is transferred through a pot of water
[C] the way heat in a radiator is transferred throughout a room
During its main sequence lifetime, a star is kept from collapsing under its own weight by:
[A] fusing lighter elements into heavier ones. This generates heat, and the pressure from hot stellar gas acts like the pressure in a pressure cooker, an outward force.
[B] the strong nuclear force.
[C] the fact that stars are made up of gas, and gases don't weigh that much!
[D] weightlifting
Massive stars have the shortest main sequence lifetimes because:
[A] the star goes supernova.
[B] they process stellar materials in nuclear reactions at a faster rate, and use up their available fuel more quickly.
[C] only the good die young.
[D} we don't know why
The mass of a star determines its evolutionary endpoint because:
[A] how much mass a star has determines what process can halt the star's gravitational collapse.
[B] a star's mass determines how quickly it will leave the main sequence.
[C] the less massive a star is, the higher the probability that it will undergo a supernova explosion.
Stars less massive than the Sun:
[A] can become neutron stars.
[B] may not have had enough time since the beginning of the Universe to complete their life cycle.
[C] are real whimps.
[D] are seen primarily in X-rays.
