# Astronomy 123

does astronomy predict the motion of planets?
No
An example of change from mythical to geometric universe is:
change from tabulated data to models
what is the difference between mythical and geometric universes?
mythical is based upon storytelling (constellations and folklore) and geometric universe is based off of data, reasoning, math and written explanations.
what is an example of the difference between the Physical and the Platonic world?
The laws of physics that describe your car engine is of the platonic world, and the actual driving of your car is the physical. The world of absolutes, what is called the Platonic world, has existence only through the physical world.The Platonic world exists and physical world is a shadow of the truths in the Platonic world.
who is responsible for: Laws of motion i.e.(velocity, idea of force, natural state of velocity aka 0 velocity, inertia=resist to change in motion)
Galileo
Using the Greek theory of matter, a plant that uses air, earth, and water has properties of:
Wetness and coldness. see chart:
http://abyss.uoregon.edu/~js/images/greek_elements.gif
Eratosthenes hitched a ride on Apollo 11, and performed his experiment, again, on the Moon. He places two sticks in the ground where the solar angle is 7 degrees for one stick and zero for the other. How many stadia between the sticks did he mark out? (you need to figure out the circumference of the Moon in kilometers from a book value or the web)
If Earth’s orbit were larger, than the parallax angle of a star would increase or decrease
increase.
what is a star’s parallax?
the effect whereby the position or direction of an object appears to differ when viewed from different positions
what are some inferior configurations?
Object at greatest western elongation = “morning star”
Object at greatest eastern elongation = “evening star”
Aristotelian Universe is:
finite in size
composed of spheres
lacking of a void or vacuum
Stoic universe is:
infinite in size
Which of the following did the Church have to abandon from Aristotle’s cosmology?
the steady state of the universe
In Tycho’s cosmology, if you lived on Venus would you see stellar parallax’s (if you had a telescope)?
yes, throughout the year
The Earth’s orbit is an ellipse that is very close to a circle meaning
it has low eccentricity bc it is not an exact circle
is Jupiter having moons an example of the geocentric universe?
yes
Aristotle’s philosophy is based on the concept of teleology, which means
all objects have behavior that follows a plan or destiny
Which of the following is not an example of a force?
a) gravity b) magnetism c) velocity d) a push e) a pull
velocity- its a measurement of the speed of something in a given direction, therefore its caused by a force
If you are riding a sled on an ice lake and toss a ball straight up in the air, ignoring air friction, the ball will land
change in velocity is called
acceleration (caused by force)
You are floating in space and a satellite orbits around you. If your mass were reduced to zero (i.e. your gravity were turned off), then
the satellite will float off in a straight line. bc your gravity is what pulled it into orbit.
atoms were hypothesized to explain:
change in the characteristics of matter
Differing from the Greek view, the modern view of atoms is
how atoms connect determines properties
matter at its highest temperature is
plasma
Which of the following is a microscopic quantity?
velocity
The Ideal Gas law states that (assume that other quantities not mentioned are held constant)
volume increases, temperature decreases
For atoms, higher temp. means:
higher velocity
more momentum & kinetic energy &pressure
Example of a high entropy state
explosion
entropy:
the degree of disorder or randomness in the system. Important because: The second law of thermodynamics states that, in a closed system, the entropy increases, The entropy of the whole Universe always increased with time. We are simply a local spot of low entropy and our destiny is linked to the unstoppable increase of disorder in our world => stars will burn out, civilizations will die from lack of power.
Rutherford used what as “atomic bullets”?
alpha particles
Occam’s Razor states
a solution should be stated in its basic and simplest terms
At the core of Newton’s clockwork Universe is
the belief that all the motion we see around us can be explained in terms of a single set of laws
A kinematic description versus a dynamical description of the solar system means
motion vs forces
Uranus and Neptune were discovered by
accident and celestial mechanics
Our experiments with artificial life simulations shows
simple rules can lead to very complex behavior/patterns
Chaotic behavior arises because
small changes in initial conditions leads to wildly different final states
Planck’s constant is
the minimum amount of energy transfer
The rule for electric charges or magnetic poles is
like charges repel, opposites attract
Unlike classical physics which is deterministic, quantum physics
allows identical experiments to have different outcomes
can only predict the possible outcomes
finds that properties of objects do not have values except after a measurement
values occur at frequencies determined by probabilistic rules
The photoelectric effect demonstrates
the dual nature to light
The Uncertainty Principle states that you can measure position and time but not
energy and velocity
the wave function is
a mathematical description of a quantum entity
Orbits in the Bohr atoms are in multiples of
plancks constant
The absorption of a photon causes
an upward transition for an electron
The downward transition of an electron will cause
the emission of a photon
Symmetry in Nature leads to two things:
conservation laws and antimatter
A fundamental particle is one that is
simple
structureless
non-unique
cannot be broken down
The search for elementary particles is an example of
reductionism
If a particle is negatively charged, Lighter than a proton, a lepton, and of the 1st generation of matter, this particle is a(n)
electron
I discover a new particle, called the Kellyino, it has a positive charge and zero mass. Therefore, it
moves at the speed of light and is long ranged
is a neutrino found in an atom
no
What is the distance from the Sun to the Earth in Angstroms?
1.496×1021 Angstroms
A wave of light does not need to propagate through a medium, like waves of water, because
its self propagating
The Michelson-Morley experiment demonstrated that
no difference was found in speed of light regardless of the motion of the Earth
A beam of light is flashed from the back to the front of a spaceship moving at 90% the speed of light. if an outside observer is watching, what would they see?
an outside observer would see the beam would move at the speed of light
has the twin paradox been confirmed?
yes
Time is different from spatial dimensions because
we can change our velocity in space, but not our time
Minkowski diagram is used to:
understand spacetime motion
has spatial and time axes (time is shown as something that exists)
plots world lines (plot of an object in spacetime)
uses light cones to determine past and future
The spacetime continuum is non-Euclidean. This means:
it can take on a warped or curved shape
Forbidden regions in the spacetime diagram mean
we cannot communicate with those regions
what is an example of a “point” in spacetime
time and place of a meeting
If the Universe is really 4D, why do we see it as 3D space + 1D time?
thats the way our brains are built
what is spacetime?
time and the three dimensional space coordinates are so intimately bound together in their properties that it only makes sense to describe them jointly as a four dimensional continuum. Einstein introduced a new concept, that there is a four dimensional (three of space, one of time) continuum called spacetime which can best be demonstrated through the use of Minkowski diagrams and world lines.
Categories: Astronomy