Brian H. Gill
4th to 1st century BC
|
The Earth is a huge plate, surrounded
by water. Another huge plate hangs over it. The Sun, moon, stars
and planets move along the upper plate. |
The Earth is a sphere at the center
of the universe. The sun, moon, stars and planets revolve around it in
perfect circles. |
16th century AD
|
The Earth is a sphere at the center
of the universe. |
The sun is at the center of the
universe. The Earth, stars and planets revolve around the Sun. The
moon revolves around Earth. All these motions are circular. |
17 century AD
|
The Earth, planets and stars revolve
around the sun in perfect circles. |
Bodies revolve around the sun in
elliptical orbits. The stars are fixed to a sphere about 2,560
Earth-orbit-radii from the Sun (about 1/25 light year). The Milky
Way is made of many very dim stars. |
18th to 19th century AD
|
The sun is the center of a huge
sphere which holds the stars. |
The sun is one star
among many in a huge
collection of stars, and moving among those stars. Some
astronomers think that nebulosities, fuzzy patches in the sky, may
be other "island universes." |
20th century AD
|
The sun is one star among many in a huge
collection of stars. |
The sun is one star of billions in
the Milky Way galaxy. The Milky Way galaxy is one of a group of
galaxies. There are more galaxies in the universe than there are
stars in the Milky Way galaxy. |
??
|
The sun is one star among billions in
one galaxy, in a universe which contains many more billions of
galaxies. |
?? |
copyright © Brian H. Gill 2003