The Birth of Astronomy
List the top four telescopic discoveries by Galileo
1. the moons of Jupiter
2. the phases of Venus
3. the surface of the Moon
4. stars and star clusters
If a planets distance from the sun was doubled, how would the force on it change
a. 2x larger
b. 4x larger
c. 2x smaller
d. 4x smaller
D
how many days are in a synodic month
29.5
1 nano-meter (nm) = 10^__ m
9
what temperature is needed for protons to get close enough:
10 million degrees
Is the ecliptic the same thing as the celestial equator?
No,
1. ecliptic is the apparent path that the sun follows through the sky as seen from earth.
2. celestial equator is the projection of Earths equator into the celestial sphere.
An asteroid is discovered in an orbit with a semi-major axis of 2 AU. Which of the following is necessarily true
a. It is always farther from the sun than the earth
b. It has a longer orbital period
c. It always move more slowly in its orbit then the earth does
d. All the above
B
if the moon rises at sunrise, its phase is...
new
cooler object em radiation: ___ intense/___ wavelengths
less, longer
what is the stars energy source located in their core
thermonuclear fusion
for the stars to be culminating, which direction must you be looking
South
The semi-major axis of Jupiter’s orbit is about 5 AU, what is its approximate orbital period?
approx. 10 years
lunar eclipses only happen at ___ moon
full
describe a blackbody and give an example
an idealized object in physics that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence
eg. sun and/or glowing star
what is the sun approx. lifetime
about 10 billion years
what is the limit of the observable universe
13 billion light years
what are Newtons three laws
1. An object in motion tends to stay in motion, and an object at rest tends to stay at rest, unless the object is acted upon by an outside force
2. acceleration = force/mass (f=ma)
3. every action has an equal and opposite re-action
Earth axis is tilted with respect to its orbit around the sun
list the names of radiation as taught in class from longest waves to shortest
Radio, Microwave, Infrared, Visible, UV, X-ray, Gamma
what is the overall outcome of the proton-proton chain
4^1H → 4He + energy +2ν
from northern latitudes, stars appear to rotate ______ around pole star
counter clockwise
name and describe Keplers three laws
(shape) Planets move in oval-shaped paths around the Sun, with the Sun slightly off-center
(speed) A planet moves faster when it is closer to the Sun and slower when it is farther from the Sun
(time) The square of a planet’s orbital period is proportional to the cube of its semi-major axis
true rotation can be judged by the stars:___ day
but what "matters" on Earth is the day as judged by the Sun:___ day
sidereal
solar
what are Kirchoffs three "laws" of spectroscopy
1. solids, liquids, dense gases radiate at all wavelengths
2. excited low-density gas emits light at specific wavelengths (emission spectrum) determines by composition
3. radiation passing through cool low-density emerges with specific wavelengths absorbed (absorption spectrum)
hydrogen fusion in the sun:
only ___% of input mass is converted to energy
0.7%