Preconceptions and Misunderstandings:
Stars and Galaxies

Students may think that our Sun is the biggest star. Most of the stars we see at night
without a telescope are bigger than our Sun.

Students may not know that our Sun is a star.

Students may confuse stars with shooting stars (meteors).

Students may place many stars in the Solar System, rather than just our Sun.
None of the stars we see at night are in our Solar System; the only star in our Solar System is our
Sun.

Students may not recognize that our Solar System is part of our Galaxy

Students have no conception of the scale of the Milky Way
o One analogy described was the Milky Way as a cinnamon bun, with our solar system
located as a toothpick halfway to the edge

Students think more “stuff” is in the Universe/ that matter is denser than it really
is.

Students may think that the North Star is the brightest star in the sky. The North
Star, Polaris, is barely in the top fifty brightest stars. (The Sun is the brightest, as seen from
Earth, and Sirius the Dog Star is the brightest seen in the nighttime sky.)

Students may think we see the same stars every night. The stars we see change
from month to month and throughout the night.

Students may think all stars look the same. Stars have different colors, difficult for many
human eyes to detect.

Students may have very confused scales for star sizes and distances. Stars are
not small and they do not fall from the sky; they are huge and very far away.

Students may have heard that the biggest star is Betelgeuse. Betelgeuse is not the
biggest star in the Galaxy; it is one of the biggest stars we can see with the “naked eye.” We’ve
found many stars that are much bigger with telescopes like Hubble.

Students who confuse terms like “Galaxy” with “Solar System” or who have no
conception of the scale of the Milky Way may think that the stars in the night sky
are from other galaxies. All the stars we see with our “naked eyes” are in the Milky Way
Galaxy –we cannot see individual stars in other galaxies without powerful telescopes.

Students may assume that the drawings that they’ve seen for constellations are
the official positions of the stars in that constellation. There is no “right” way to draw a
constellation; they have official boundaries and official names, but no official line drawings.