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This image is a theory for the interior of the Sun. Credit: NASA.

In the model shown at right the Sun and hypothetical regions around it are labeled.

Heliophysics is the physics or astrophysics of the closest star to the Earth. It is a lecture from the radiation astronomy department. This is a quiz based on this lecture heliophysics that you are free to take at any time.

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True or False, A basic unit of length for measuring the diameter of the Sun is the kilometer.



True or False, By assuming gravity causes the Earth and Sun to orbit each other, and assuming a mass for the Earth, a mass for the Sun can be determined from the orbital characteristics.



True or False, By correlating the length of an Earth year to a fixed number of seconds, the length of time of a second can be determined.



Yes or No, The Sun could have an internal core of iron that generates its bipolar magnetic field.



True or False, As the principal portion of the sunspot cycle corresponds well with a periodic conjunction of Venus and Jupiter, the increased electron flux to the Sun may cause the magnetic poles to reverse.



Complete the text:

Hoyle notes that he and others in the

circles to which he was privy continued until after the

to believe that the Sun was made mostly of



The core of the Sun was believed to be made mostly of iron to explain what?

the source of neutrinos
the Sun's global magnetic field
the existence of magnetic poles like the Earth
the rotation of the Sun
surface differential rotation of the Sun
magnetic field reversals like the Earth


Complete the text:

Match up the structure of the Sun with the characteristic or property:
radiative zone - L
core - M
convection zone - N
dynamo - O
tachocline - P
photosphere - Q
atmosphere - R
temperature region - S
chromosphere - T
transition region - U
corona - V
heliosphere - W
diffusion rather than convection

bow shock

weakly ionized, relatively cold and dense plasma

X-ray emission

normally invisible

circular mass movement of plasma

coolest layer of the Sun

shear between different parts of the Sun that rotate at different rates

above the photosphere

transition from almost uniform to differential rotation

150 g/cm3

ultraviolet emission



What features occasionally show a heliographic distribution on the surface of the Sun?

granulation or supergranulation
active regions
coronal holes
the north an south heliographic poles
latitudinal bands that rotate at different rates


What effects does the distribution of angular momentum in the solar system have on the origin of the Sun?

an initially spherical and contracting nebula spinning faster as it collapses would produce the present situation in the solar system
partitioning mass and angular momentum does not seem possible with a contracting nebula
the rotation axis of the Sun from that of the system as a whole if formed by nebular collapse seems very unlikely
the angular-momentum problem does not arise with the accretion theory
surface differential rotation of the Sun results
by the nature of the floccule process the star so formed will have little angular momentum


  1. Timing the Sun is like timing a ball of gas.

See also[edit]

External links[edit]