- red giant
- a star that has low surface temperature and a
diameter that is large relative to the Sun.
- regio
- region.
- Relativity,
Theory of
- more accurately describes the motions of bodies
in strong gravitational fields or near the speed of light than newtonian mechanics. All
experiments done to date agree with relativity's
predictions to a high degree of accuracy.
(Curiously, Einstein
received the Nobel prize in 1921 not specifically
for Relativity but rather for his 1905 work on
the photoelectric effect and "services to
Theoretical Physics".) (see Spacetime
Wrinkles, an excellent WWW site from NCSA)
- resolution
- the amount of small detail visible in an image;
low resolution shows only large features, high
resolution shows many small details
- resonance
- A state in which one orbiting object is subject
to periodic gravitational perturbations
by another.
- reticulum
- reticular (net-like) pattern
- retrograde
- rotation or orbital motion in a clockwise
direction when viewed from the north pole of the
primary (i.e. in the opposite sense to most
satellites); the opposite of direct. The north pole is
the one on the same side of the ecliptic as the
Earth's north pole.
- rift valley
- an elongated valley formed by the depression of a
block of the planet's crust between two faults or
groups of faults of approximately parallel
strike.
- rima
- fissure.
- Roche limit
- the closest a fluid body can orbit to its primary
without being pulled apart by tidal forces. A
solid body may survive within the Roche limit if
the tidal forces do not exceed its structural
strength. The Roche limit is calculated with the
equation
RL = 2.456*R*(p'/p)^(1/3)
where p' is the density of the planet, p is
the density of the moon, and R is the radius of
the planet.
- rupes
- scarp.
|
R
