A model for how the solar system formed must explain observations and reasoning. Identify each statement as
an example of an observation or reasoning. If a statement
is false or invalid, identify it as such.
a. Most of the mass of the solar system is in the sun.
b. The sun is composed primarily of hydrogen and
helium.
c. The sun formed more than 13.8 billion years ago when
the universe formed.
d. Most objects in the solar system orbit the sun in the
same direction.
e. If most of the mass of the solar system is in the sun
and the sun is mostly hydrogen and helium, then the
solar system must primarily be hydrogen and helium.