It's not strictly correct to say that a planet orbits its parent star.
Given that each exerts a gravitational pull on the other, how could we expect the star to remain absolutely fixed while the planet orbits around it?
In fact bothorbit; and they orbit around a common point called the Center of Mass (CM)
Wikipedia defines the Center of Mass (CM) as,
a specific point at which, for many purposes, the system's mass behaves as if it were concentrated
Physicists have used the concept of "balance" to define CM,
The center of mass is familiar to anyone who has ever played on a see-saw. The fulcrum point at which the see-saw will exactly balance two people sitting on either end is the center of mass for the two persons sitting on the see-saw.
The figure below depicts a two-body system; X marks its center of mass.
If X were the fulcrum of a see-saw, the two bodies would balance.
For a two body system, the center of mass can be determined through these equations: where m denotes mass; d, distance; and R, the total separation between the two bodies.
When the a planet and star orbit their center of mass, CM will almost certainly be located within the star itself, but not at its center, as shown in the video below.
James Thurber (1894-1961) has been called "the greatest American humorist since Mark Twain"
he is best known for The Secret Life of Walter Mitty (1939), a short story about a timid, henpecked man who often escapes into heroic fantasies
Thurber's writing and cartoons are edgy and absurdist: he places odd people in strange situations; highlighting the stresses and frustrations of modern life -
Defense Mechanisms are psychological processes
that protect the conscious mind from threatening
impulses, thoughts and feelings
they do so by denying or distorting reality, and
they are largely unconscious
defense mechanisms are normal and, if used in
moderation, they can be helpful -
helpful in that they can give us time to recognize
our discomfort, identify its source and find ways
to consciously deal with it
however, the extensive and prolonged use of
defense mechanisms can be problematic in that
underlying difficulties remain, energy is wasted
and stress builds
Sigmund Freud first used “defense” as a psycho-
analytic term in 1894; and it was his daughter, Anna Freud, who refined and expanded his theories
in the 1930s
the defense mechanism referred to as undoing
is an unconscious attempt to take back, nullify or
“un-do” a thought or action that had resulted in
guilt or anxiety
for example,
A physician may become over-solicitous or may
over-medicate a patient in whose treatment he
had made an error.
- Leigh & Reiser (1992)
a husband who showers his wife with roses and
chocolates on Valentine’s Day may be unconsciously
seeking to undo a year of neglect