The Scale of the Universe
Discovering Our Place Among the Galaxies
Part I: Observations and Speculations
Explore these simulations to gain a better understanding of the
material in Part I of The Scale of the Universe.
- Celestial Globe: A simulation of a celestial globe, which
illustrates the two-sphere model of the Earth and sky.
- Eratosthenes: A simulation that illustrates Eratosthenes'
method for measuring the diameter of Earth.
- Astronomical Parallax 2D: A simplified 2D simulation of astronomical parallax.
- Superior Ptolemaic:
A simulation of Ptolemy's theory for the
superior planets (Mars, Jupiter, and Saturn).
- Daily Rotation:
A simulation that illustrates the motion of the stars from either
the Aristotelian or Copernican viewpoints.
- Earth Orbit:
A simulation showing Copernicus' theory of the Earth's orbit around the sun.
- Copernican System:
A simulation of Copernicus' theory of the planetary orbits.
- Venus Phases:
Illustrates the predicted phases of Venus in both the Ptolemaic and
Copernican systems.
- Angular Diameter:
Shows how the angular diameter of an object varies with distance and
physical size.
- Astronomical Parallax 3D:
Simulates the annual parallax of a star placed in any direction at a
range of distances.
- Stellar Aberration 2D:
Illustrates why (because of Earth's motion and the finite speed of
light) we can't point out telescope at a star's true location if we
want to see it.
- Stellar Aberration 3D:
Simulates the aberration of starlight for a star placed in any
direction and with a range of speeds for Earth's orbital motion.
- Star System Models:
Illustrates various historical 3D models of our star system, showing a view
from outside the system as well as our view from the inside.
- Parallactic Proper Motion:
Illustrates how the motion of the sun through space alters the
position of stars on the Celestial Sphere.
- Herschel Star Gages:
Use William Herschel's method of "star gaging" to determine the
shape of a stellar system from the inside.