final Flashcards
the strip of the sky through which the sun, moon, and planets appear to move in the course of a year is:
the zodiac
an idealized object that does not reflect or scatter any radiation that hits, but simply absorbs every bit of radiation that falls on it:
a blackbody
when we see an eclipse of the moon, the earth is between the sun and the moon (T/F)
true
Newton showed that to change the direction in which an object is moving, one needs to apply:
force
If you could see the new moon, at what time of day would it rise?
sunrise
the strength of gravity is inversely proportional to the mass (T/F)
false
what phase is the moon during a lunar eclipse
full
what phase is the moon during a solar eclipse
new
a planet in the solar system whose period is 1 year is what distance from the sun
1 AU
when the moon rises at 9pm, what phase is it
waning gibbous
in stars moving away from us, the spectral line shows a blue shift (T/F)
false
if the earth had no tilt, how would this affect our view solar and lunar eclipses
we would see then the way we normally do
an icy dwarf planet orbits the sun with a period of 20 years, whats the semi-major axis of its orbit in AU
7.4
a reflector doesn’t have to deal with the twinkling of stars, a refractor does (T/F)
true
The absorption lines of helium have the same wavelength as its emission lines (T/F)
true
on the celestial sphere, halfway between the celestial poles lies the…
celestial equator
the slow tipping of earths axis in a circle with a period of about 26,000 years is called a
precession
13.8 billion in scientific notation
1.38 x 10^10
which of the following is an important part of the reason it is hotter during the summer in North America than during the winter?
the suns rays hit earth more directly in the summer and spread out less
if you want to locate someone precisely on the surface of the Earth, you specify her exact latitude and longitude. if you want to locate a star precisely on the sky you need to specify its exact
right ascension and declination
when a planet, in its orbit, is closer to the sun it
moves faster than avg
the scientist who formulated the 3 laws of planetary motion by analyzing the data on the precise location of planets in the sky
johannes kepler
someone observing the night sky in boston will NEVER get to see the
south circumpolar zone
the moon shows retrograde motion (T/F)
false
what kind of rays are you likely to detect from earths surface
radio waves
ice planet Hoth has the same radius but half the earths mass, if you weigh 100 lbs on earth, how much would you weigh on Hoth?
50 lbs
why do astronauts float around the international space station instead of falling?
the station is falling around earth and everything aboard is in free fall
who used epicycles to explain retrograde motion
ptolemy
from a city in the US, where in the sky would you look to see a star that is not turning with the motion of the sky in the corse of the night
at the north celestial pole
what time is it when the new moon is highest in the sky
noon
Wien’s law relates the wavelength at which a star gives off the greatest amount of energy to the stars
temperature
the South celestial pole and North celestial pole lie in the sky directly above
the earths axis
first discovered the moons of jupiter
galileo
x-rays have the light with the highest energy on the electromagnetic spectrum (T/F)
true
the shortest night in mass is on the
summer solstice
if the earths rotation axis was not tilted, winter and summer would be extremely different (T/F)
false
analyzing the light in the spectrum of a star can tell astronomers the stars temperature, what elements are in it, and its speed to or away from us (T/F)
true
the moon revolves around the sun once every
month
earths period of rotation is equal to 1 year (T/F)
false
when a small asteroid collides with a planet the acceleration of the asteroid is grater than the acceleration of the planet (T/F)
true
distance travelled by light or by an object moving with a constant speed is equal to speed multiplied by
time
the star closest to the north celestial pole
polaris
the reason for seasons is the varying distance between the sun and the earth (T/F)
false
on the autumn equinox, our days and nights are the same length (T/F)
true
the peak wavelength of light from the sun is about 500 nm, is a star with a peak wavelength of 1500 nm hotter or colder than the sun
colder
the type of spectral feature usually observed from a hot gas with no star behind it along the line of sight is the absorption line (T/F)
false
who found that gravity could account for the motion of the planets
newton
if a galaxy of stars is moving towards us, the light in its spectrum will show a red shift when compared to the lines we measure in such a spectrum on earth (T/F)
false
an asteroid is in circular orbit of 3 AU from the sun. its period of revolution is how many years
√27
when a small amount of gas is heated up in a transparent container until the gas glows, it generally gives off an emission line spectrum (T/F)
true
a light year is
the distance light travels in one year
6400 in scientific notation
6.4 x 10^3
in the north hemisphere, the altitude of the north star is always roughly equal to the
latitude of the observer
gamma-ray astronomy is only done from space (T/F)
true
where are you on earth if polaris is on your horizon
the equator
a star is 230 light years away. the light we see tonight from a star that left it
230 years ago
if earths orbit changed to be a perfect circle around the sun so the distance never changes over the course of a year, how does this affect our experience of seasons
essentially experience them the same way we do now
the moon is believed to have formed by a collision with earth and a mars-sized object (T/F)
true
