A long thin cloud that stretched from directly overhead to the western horizon would have an angular size of
f the Moon's orbit around Earth were a little larger, solar eclipses would be
more likely to be annular
According to "The Zodiac" Figure shown above, in June we would see the Sun in the direction of the constellation(s)...
In the Figure below (Figure 0.20A - Parallax), a smaller Earth would result in
a smaller parallax angle.
How, and by roughly how much, would the length of the solar day change if Earth's rotation were suddenly to reverse direction?
A solar day would be approximately 8 minutes shorter than the current one.
Why don't we have solar and lunar eclipses every month?
ecause the Moon's orbit around Earth is tilted by about 5° out of the ecliptic.
he average distance from the Earth to the Sun, 149,600,000 km, can be written in scientific notation as
1.496 × 108 km.
If there are about 6000 stars in the entire sky that can be seen by the unaided human eye, about how many stars would be seen at a particular instant on a given dark night from a single location with an uninterrupted distant horizon?
Are the constellations seasonal?
Yes. On a summer night many of the constellations you can see are different from the constellations you can see on a winter night. But there are some constellations you can see all year long.
At what time of the year in the northern hemisphere will your shadow in sunlight at midday be shortest?
first day of summer, about June 21
How long does it take light to travel a distance of one light year?
One year or about π×107 seconds.
What is the unit that we use to measure distances in the solar system?
The astronomical unit or AU is very convenient.
The most southern location on Earth where the Sun can be seen directly overhead at noon is called
the Tropic of Capricorn
How long would a radar signal take to complete a round trip between Earth to Mars and back to Earth when the two planets are 0.7 AU apart
about 11.6 minutes
Copernicus' important contribution to astronomy was
proposing a simpler model for the motions of planets in the solar system.
Which of Galileo's initial observations was most challenging to established geocentric beliefs?
moons of Jupiter
In the geocentric model of the solar system developed by Ptolemy, the planets move
in circular epicycles while the centers of the epicycles move in circular orbits around the Earth.
he major contribution of Tycho Brahe to the development of modern astronomy was
measuring planetary positions very accurately.
hich of the following sentences correctly states the significance of Galileo's observation that Jupiter has satellites (moons)?
The observation showed that bodies can orbit an object other than the Earth.
Suppose that a planet of the same mass as the Earth were orbiting the Sun at a distance of 10 AU. The gravitational force on this planet due to the Sun would be
1/100 of the gravitational force the Sun exerts on the Earth.
Rigel appears as a bright bluish star, whereas Betelgeuse appears as a bright reddish star.
hotter than Betelgeuse.
the light from a distant star is approaching you, you will observe
its spectral lines are shorter in wavelength.
What types of electromagnetic radiation from space will reach the surface of Earth without being significantly absorbed by the Earth's atmosphere?
visible light and radio waves
For lecture on "Waves", a sound wave can travel through ________.
molten rock, solid rocks
How many times lower would the intensity of light from a given star become if the star is 2 times farther away?
forms of light have what property in common? (Light in this case refers to the whole spectrum, not just the visible range.
All forms of light are electromagnetic radiation.
What is the one fundamental difference between X rays and radio waves?
the wavelengths of X rays and radio waves are very different.
ieces of metal are heated by varying amounts in a flame. The hottest of the pieces will be the one that shows most prominently which color?
What changes would you expect to see in the resulting spectrum of emitted light from a piece of metal when it is heated slowly in an intense flame from 500 K to 1500 K?
he intensity of radiation would increase greatly, and the color would change from red through white to blue.
An ideal blackbody in physics and astronomy is an object that
absorbs and emits electromagnetic radiation at all wavelengths.
According to the Doppler effect
the wavelength of light is shifted to a shorter wavelength if the source of light is moving nearer to the observer.
The Doppler effect is the change in the wavelength of light caused by the source
moving with respect to the observer.
he dark absorption lines in the solar spectrum are caused by
a cooler layer of gas overlying the hot solar surface, which contains many elements, including hydrogen, helium, magnesium, calcium, and iron.
Atoms in a low-density, hot gas (e.g., in a fluorescent lamp or a neon tube) emit a spectrum that is
a series of specific colors unique to the type of atom in the tube but fixed in position when the gas temperature changes.
The main reason that most professional research telescopes are reflectors is that
mirrors produce sharper images than lenses do since there is no chromatic aberration.
he PRIMARY reason professional observatories are built on the highest mountain tops is to
reduce atmospheric blurring
the Spitzer Space Telescope is stationed far from Earth because
This infrared telescope actually does not orbit the Earth, but follows our planet around the Sun, reducing the heat interference from Earth
The best way to study young stars hidden behind interstellar dust clouds would be to use
An FSU student is observing the phases of Venus with his 16 inch reflector telescope, and a UF student is doing the same with a 8 inch reflector telescope. How much more light gathering power does the FSU telescope have?
4 times more
again, an FSU student is observing the phases of Venus with his 16 inch reflector telescope, and a UF student is doing the same with an 8 inch reflector telescope. How much "more" resolving power (i.e. angular resolution) does the FSU telescope have?
Twice as much.
an advantage of CCDs over photographic film is
they don't require chemical development,digital data is easily store and transmitted, CCDs are more light sensitive than film, CCD images can be developed faster.
All of the above are true.
Radio telescopes are useful because
observations can be made day and night, radio waves are not blocked by interstellar dust, we can see objects that don't emit visible light, they can be linked to form interferometers.
Correct: All of the above are true.
The Hubble Space Telescope (HST) offers sharper images than ground telescopes primarily because
HST orbits above the atmosphere.
the light-gathering power of a telescope depends directly on the
area of its primary mirror or lens.
What is the main reason for placing astronomical telescopes and detectors on satellites?
to get above the absorption in the Earth's atmosphere
Any theory of the origin of the solar system must explain all of these EXCEPT
the direction that planets orbit the Sun is opposite to the Sun's spin.
The condensation sequence theory explains why
terrestrial planets are different from jovian planets.
xtrasolar planets the size of Earth have NOT been seen yet with current techniques because
large planets orbiting near to their stars are more easily detected.
In the solar nebular theory, the dusty disk condensing around the Sun's equator became the ecliptic plane in which the planets then formed.
Strong evidence for the existence of planetary systems in the process of formation around other stars comes from
photographs and infrared observations of disks of dust.
The Moon's internal structure is similar to Earth's, but the Moon lacks
Correct: It lacks all of the above
At what lunar phase would the variation between high and low tides be greatest?
both new and full moon
he magnetic field of the Earth probably arises from what process or condition?
A dynamo effect due to the motion of the electrically conducting molten iron core.
Without the greenhouse effect operating in our atmosphere,
Earth would have an average temperature of -23 degrees Celsius.
Why did Earth's earliest atmosphere, composed primarily of hydrogen and helium, not last long?
Hydrogen and helium are light gases, and they soon escaped into space.
What is the distribution of maria on the Moon's surface?
Maria are largely confined to the hemisphere facing Earth; there is only one small mare on the distant side.
Mercury has extreme high and low temperatures between night and day because
it has no atmosphere to moderate temperatures over the globe.
Venus and Mars probably evolved differently from Earth because
they orbit at different distances from the Sun.
How does Mercury's rotation rate relate to its orbit around the Sun?
Its rotation rate is 2× as long as its year, due to tidal resonances.
Why are Mars's seasons more extreme than those of the Earth?
weather is driven by evaporation from the polar ice in its summer.
orbit is more eccentric than our almost circular one.
seas dried up long ago.
axial tilt is slightly more than our 23.5 degrees.
Correct: All of the above contribute to the huge barometric changes that Mars experiences.
Why doesn't Venus have a magnetic field?
Its extremely slow rotation doesn't produce a significant dynamo effect.
Mercury can be seen easily from the Earth only
when Mercury is near the Sun, just after sunset or just before sunrise.
the best images of the overall topology of Venus have been produced by
reflection of microwave and short radio wave radiation from the surface by an orbiting spacecraft.