The Scale of the Universe
Discovering Our Place Among the Galaxies
Part III: Answers at Last (and More Questions)
Explore these simulations to gain a better understanding of the
material in Part IIII of The Scale of the Universe.
- Differential Galactic Rotation:
Illustrates Oort's model for the differential rotation of the
galaxy, shows the relative velocities and radial velocities for stars
near the sun, plots radial velocity as a function of galactic
longitude, and depicts the so-called high-velocity stars.
- Einstein Universe:
A simulation depicting two stationary observers in a "1+1" version
of Einstein's cylindrical universe with uniform time and constant
spatial curvature. Also illustrates the motion of light rays in this
universe.
- DeSitter Universe:
A simulation depicting two stationary observers in a "1+1" version
of De Sitter's spherical universe with uniform spacetime curvature and
constant/uniform spatial curvature.
Illustrates how time seems to pass at different rates for observers in
different locations. Also shows the motion of intertial observers in
this universe.
- Lemaitre Universe:
A simulation depicting two stationary observers in a "1+1" version
of Lemaitre's universe with uniform spacetime curvature and uniform
but changing spatial curvature.
- Milne Universe:
A simulation of Milne's model of a static universe that produces a
linear distance-velocity relation among the galaxies.
- Jansky Antenna:
A simulation of Karl Jansky's antenna which he used to observe radio
emissions from the Milky Way.
- Galactic Hydrogen Mapping:
A simulation illustrating how astronomers can measure Doppler shifts
of 21-cm radiation from neutral hydrogen to map out the spiral arms of
our galaxy.