Astrophysics Flashcards
What is an Astronomical Unit?
The (mean) distance between the Earth and the Sun (1.5*10^11m). Best used when talking about inside our own solar system.
How do you convert between AU and m?
Divide by 1.5*10^11
How to convert between light years and m?
Multiply ly by 60x60x24x365.25x3*10^8
What is the definition of gravitational field strength?
The gravitational force acting on a unit mass
What is the definition of the gravitational potential of a point in space?
The work done in moving unit mass from infinity to that point
What is a conservative field?
When energy is conserved when moving between 2 points regardless of the path taken
The energy required to move mass between two points in a gravitational field is…
Independent of the path taken
Define escape velocity.
The minimum velocity required to allow a mass to escape a gravitational field to infinity, where the mass achieves zero kinetic energy and maximum (zero) potential energy
What is an inertial frame of reference?
A non-accelerating frame of reference
What is a non-inertial frame of reference?
An accelerating frame of reference
Does special relativity deal with motion in inertial or non-inertial frames of reference?
Inertial
Does general relativity deal with motion in inertial or non-inertial frames of reference?
Non-inertial
What is the Equivalence Principle?
That it is not possible to distinguish between the effects on an observer of a uniform gravitational field and of a constant acceleration
What is spacetime?
A unified representation of three dimensions of space and one dimension of time
General relativity leads to what interpretation?
That mass curves spacetime, and that gravity arises from the curvature of spacetime
