False
Moons are satellites that orbit stars
Earth, Solar System, Milky Way Galaxy, Local Group, Local Supercluster, Universe
Which of the following correctly lists our "cosmic address" from small to large?
The average distance between galaxies is growing with time
When we say that the universe is expanding, we mean that:
No, because it would be beyond the bounds of our observable universe
could we see a galaxy that is 20 billion light-years away?
We won't know about it until 425 years from now
The star Betelgeuse is about 425 light-years away, if it explodes tonight:
the universe is explaning
the fact that nearly all galaxies are moving away from us, with more distant ones moving faster, helped us to conclude that:
300,000 Km/s
How fast does light travel?
4 billion years
what is the approximate age of our solar system?
the distance light travels in one year
What is light year?
13.6 billion years
what is the approximate age of our Universe
false
Our solar system is bigger than some galaxies
false
Astronomers recently discovered a moon that does not orbit a planet
false
the observable universe is the same size today as it was a few billion years ago
true
photographs of distant galaxies show them as they were when they were much younger than they are today
determining the season
Stonehenge was useful for:
the planet actually goes backward in its orbit around earth
In the greek geocentric model, the retrograde motion of a planet occurs when:
false
Astronomy is a new science that developed in the last century
planets in our solar system
the days of the week are named after:
Eudoxus
Who first developed the geocentric model?
Elliptical orbits
which one of the following is not a feature of the ptolemaic model:
1,500 years
the Ptolemaic model stood for
that the earth orbits the sun
Parallax can be used to prove
they didn't think the stars could be as far away as they are
Why were the greeks unable to correctly explain retrograde motion?
eratosthenes
who first measured the circumference of the earth
40,100 km
what is the modern value for the circumference of the earth?
it made significantly better predictions of planetary positions in our sky
Which of the following was a major advantage of copernicus's sun centered model over the ptolemaic model?
in some parts of its orbit it is much closer to the sun than in other parts.
when we say that a planet has a highly eccentric orbit, we mean that:
earth travels faster in its orbit around the sun in january than in july
Earth is closer to the sun in january than july. therefore:
planets move faster in their orbits as they get closer to the sun
according to kepler's second law:
collecting data that enabled kepler to discover the law of planetary motion
tycho Brahe's contribution to astronomy included:
making observations and conducting experiments that dispelled scientific objections to the sun-centered model
Galileo's contribution to astronomy included:
the orbit of each planet is an ellipse with the sun at one focus
What is kepler's first law of motion
true
planet 2 is much further away from the sun than planet 1, then the period of orbits of planet 2 is much greater than that of planet 1
the sun was put at the center of the solar system
what do we mean by copernican revolution?
you are at latitude 35 degree north
the north celestial pole is 35 degree above your northern horizon. this tell you that
will look the same
beijing and philadelphia have about the same latitude but very different longitudes. therefor tonight's night sky in these two places:
3600 arcsec
how many arcseconds are in a degree?
21,600 arcmin
how many arcminutes are in a full circle
no, because there is lots of dust there, absorbing radiation from stars
can one look at the center of the milky way galaxy?
the path on the celestial sphere that the sun moves in a year
the ecliptic is
an imaginary sphere with the earth at its center on which stars are located.
the celestial sphere is
stars close to the celestial pole
circumpolar stars are
circumpolar stars never rise or set
for an observer at the north pole
false
zenith is defined as the point directly below an observer
23.5 degrees
what is the angle between the ecliptic plane and the plane of the equator?
radio waves, infrared rays, visible light, ultraviolet radiation, x-ray radiation, gamma rays
Place the waves in order from the longest wavelength to shortest
winter in the united states
when it is summer in australia, it is
because the sun shrines on the summer hemisphere more directly
why summer is warmer than winter?
because of the distribution of land and water in the north compared to the south
the contrast between seasons is greater in the northern hemisphere. why?
26,000 YEARS
how long is the period of precession of the earth's axis?
polaris will not always be the north star
due to the precession of the earth's axis
combined effect of the gravity of the sun, the moon, and the rotational motion of the earth in its orbit
what causes the precession of the earth's axis?
the moon's phase is full
if there is going to be a total lunar eclipse tonight, then you know that
when the earth lies between the sun and the moon
what causes lunar eclipses?
change in the velocity of an object per unit time
define acceleration
velocity is the same as speed but with a specified direction
what is the difference between speed and velocity?
a car going around a circular track at a steady 100 miles per hour
which one of the following describes an object that is accelerating?
your mass would be the same as on earth, but your weight would be different
suppose you visit another planet:
mass is the amount of matter in an object whereas weight is the force acted on mass
how is mass different from weight?
false
there's no gravity in space
fire an engine that shoots out gas to the right
if you want to make a rocket turn left, you need to
exactly the same as its angular momentum at aphelion
earth's angular momentum when it is at perihelion (nearest to the sun) in its orbit is
one-quarter as strong
if earth were twice as far from the sun, the force of gravity attracting earth to the sun would be
earth's orbit would not change
according to the law of universial gravitation, what would happen to earth if the sun were somehow replaced by a black hole of the same mass?
be higher than they are now
if the moon were closer to earth, high tides would:
it reflects yellow light
why is a sunflower yellow?
higher energy and shorter wavelength than red light
blue light has higher frequency than red light. thus, blue light has
a form of light
radio waves are
is very tiny but has most of the mass
compared to an atom as a whole, an atomic nucleus
a thermal radiation spectrum
if you heat a rock until it glows, its spectrum will be
chemical composition
the set of spectral lines that we see in a star's spectrum depends on the star's
cooler than our sun
a star whose spectrum peaks in the infrared is
both will hit the surface at the same time
an astronaut on the moon drops a hammer and a feather at the same time. which of them is going to hit the surface first?
redshifted
a spectral line that appears at a wavelength of 321 nm in the laboratory appears at a wavelength of 328 nm in the spectrum of a distant object. we say that the object's spectrum is
the energy of light emitted by the object depends on temperature
what is the principle spectral property of a blackbody?
thermal radiation
what is another name for blackbody radiation?
hotter objects emit light with higher average energy
what is wien's law?
the relation between the energy and the wavelength of light
what is planck's law?
protons and neutrons
what does the nucleus of an atom consist of?
photon
what particle is light made up of?
false
visible light is less energetic than microwaves
true
a galaxy moving towards earth will look bluer
true
energy can be converted into mass
four times
how much greater is the light-collecting area of a 6-meter telescope than a 3-meter telescope?
one point of light that is the blurred image of both stars
suppose that two stars are separated in the sky by 0.1 arcsecond.if you look at them with a telescope that has an angular resolution of 0.5 arcsecond, what will you see?
A telescope's angular resolution
the diffraction limit is a limit on
above earth's atmosphere
the hubble space telescope obtain higher-resolution images than ground-based telescoped because it is
motion of air in our atmosphere
the twinkling of stars is caused by
much larger
if you want a radio telescope to achieve the same angular resolution as a visible-light telescope, it would need to be
in earth orbit
where should you put a telescope designed for ultraviolet observations?
adaptive optics
which technology can allow a single ground-based telescope to achieve images as sharp as those from the hubble space telescope?
true
spectroscopy employs a diffraction grating to separate different wavelengths of light for study
chandra observatory
which of these is used to study x-rays?
false
most professional telescopes used today are refractive telescopes
false
lenses focus by using the index of reflection of light
terrestrial
which type of planet is closer to the sun?
true
interferometry uses two or more telescopes to achieve an angular resolution equivalent to that of a muchlarger telescope
asteroids
which of these resides closer to the sun on average?
jovian planets
which have more moons on average?
hydrogen and helium
98% of the solar nebula was
concentrating denser materials nearer the sun
which of the following did not occur during the collapse of the solar nebula?
hydrogen and helium
what is jupiter's main ingredient?
comets
leftover ice-rich planetesimals are called
jupiter's gravity kept planetesmials from accreting
why didn't a terrestrial planet form at the location of the asteroid belt?
4.5 billion years
about how old is the solar solar system?
the line beyond which hydrogen compounds condense
what is the frost line?
by accretion of metals and rocks
how did the terrestrial planets form?
false
in our solar system, jovian planets are much smaller than terrestrial planets
false
laplace and kant proposed the close encounter hypothesis for the formation of the solar system
true
stars are formed in gaseous nebula such as the orion nebula
in both the kuiper belt and the oort cloud
comets are mainly located
false
visual and radio light can only be observed from space
to get rid of atmospheric absorptions
why we observe from space?
false
the sun was formed at the center of the solar nebula, because metals were already there
angular momentum is conserved
the solar nebula spins faster as it shrinks because
false
chromatic aberration of light does not depend on its wavelength
reflective telescopes do not suffer from chromatic aberration, are much lighter, and can be made much larger than refraction telescopes
what is the main advantage of a reflective telescope to that of a refractive telescope?
being close to a city
what is not a factor for determining an astronomical site?
core, radiation zone, convection zone, photosphere, chromosphere, corona
list the layers of the sun in the correct order starting from the inside
nuclear fusion
the sun is mainly fueled by a process called
the center has a much higher temperature than the surface
how does the temperature of the sun change from the center to the surface?
false
the amount of energy per second per square meter received on earth from the sun is called solar wind
no, because if it was the main source the sun would only last for about 25 million years
is gravitational contraction the main source of heat production in the sun?
true
neutrinos are produced in the proton-proton cycle
false
sunspots are hotter regions on the surface of the sun
the sun's magnetic field
sunspots, solar flares, and solar prominences are all caused by
because hot gas is less dense than cool gas
why does convection occur in the sun?
photosphere
the visible surface of our sun with temperature of around 6000k is called
true
sun's differential rotation wraps and distorts the solar magnetic field
pressure is proportional to density times temperature
what is the ideal gas law?
planets found orbiting stars other than our Sun.
The term exoplanet (or extrasolar planet) refers to:
the large planet size.
Which of the following is not a difficulty associated with the detection of exoplanets?
the planet's orbit, the planet's radial speed, the mass of the planet
Using the Doppler method, we can determine:
the transit method
Which detection method relies on the planet eclipsing its star?
the Doppler method
What method is most efficient in finding extrasolar planets?
jovian planets.
The extrasolar planets discovered so far most resemble:
between 100 and 1000
How many extrasolar planets have been detected so far?
the eccentricity of orbit
Which one of the following cannot be measured by the transit method?
astrometric technique
Which method could detect a planet in an orbit that is face-on (the orbit appears as
a circle around the star) to the Earth?
current detection methods are more sensitive to larger planets.
Most known extrasolar planets are more massive than Jupiter because:
have already been discovered.
Earth-sized planets orbiting normal stars:
TRUE
Planets exert enough gravitational force on the stars they orbit to cause the star to
move.
in molecular clouds
Where are stars born?
we may find extraterrestrial life someday, we can test theories about the formation of the solar system, It helps us to better understand the Earth
Why do we search for exoplanets?
TRUE
Astrometric method is a technique for searching for exoplanets through their gravity
Only a small fraction of the planets have the proper orientation
Search for Earth-like planets is difficult because:
FALSE
The Doppler technique is based upon monitoring changes in the brightness of a star
due to the passage of a planet.
Kepler Mission
Which of these is mainly dedicated to search for exoplanets?