Atmosphere - Gravitational Effects Flashcards
General Relativity
This says that large objects curve the fabric of spacetime around it, warping the geometry of the universe.
What is curvature related to?
Mass and Energy content, whilst gravitational field to spacetime curvature.
Equivalence Principle
This says that inertial mass(acceleration) and gravitational mass are equivalent, where laws of gravitation are independent of velocity and location.
Time Dilation
This is where time apparently slows down to an observer who is moving relative to another observer.
What is the basis of time dilation?
This says that time and space are a single entity called spacetime.
What does GR suggest?
Time is slower in regions of stronger gravitational fields like black holes.
How is slower times in gravitational fields explained?
Light follows a curved path, passing more slowly as energy required to escape these fields is higher.
Analogise Time Dilation…
If two observers, A and B, moving relative to each other observed clocks each other held, from eithers perspective the others clock is ticking slower than their own.
Length Contraction
Describes how the length of a moving object is measured to be shorter than its proper length
Why is light constant?
Light in an EM wave of oscillating electric and mangetic fields.
Why does time dilation fundamentally occur?
Speed of light is constant and affected by spacetime geometry.
Why does light emitted from A take longer to reach B?
Due to the geometry of spacetime, so B percieves events occuring more slowly in A’s time of refernece.
How do gravitational fields interact with particles?
Changing of frequency.
Why does gravity change with latitude?
The Earth is an oblate spherioid being flattened at the poles and bulging at the equator due to rotation.
Why does the equator bulge?
The centrifugal force is stronger at the equator with faster linear veloecity.
Centrifugal Force
This is a fictious force being motion away from a point.
Hydrostatic Equilibirum
This describes a state of balance between gravitational force and pressure gradients resulting in no net force on a fluid.
What is pressure determined by?
Weight of fluid above that point, determined by gravitational acceleration and fluid density.
What does PGF derive from?
The fact pressure is determined by overlying air, where pressure decreases with alitutde as there is less air above.
Where is the PGF important?
Lapse rate of the atmosphere.
How do pressure systems depend on region found in?
HPS PGF directed outwards, CW in NH and CCW in SH, whilst LPS directed inwards, being opposite.
How do HPS form?
Subsidence, like the subtropic ridge.
