Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Community
Ask the community for help and clear up your study doubts
Discover the best universities in your country according to Docsity users
Free resources
Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors
A comprehensive set of questions and answers covering key concepts in introductory astronomy. It covers topics such as the sun, earth's seasons, the moon's phases, eclipses, the history of astronomy, and newton's laws of motion. Ideal for students preparing for an introductory astronomy exam.
Typology: Exams
1 / 12
This page cannot be seen from the preview
Don't miss anything!
In what wavelength ranges do Hubble, Spitzer, and Chandra primarily operate? - ANSWERS-Hubble=visible
Spitzer=infrared
Chandra=x-ray
How much larger in diameter is the Sun than the Earth? - ANSWERS-100x larger than the Earth in diameter
What are the most common elements in the Sun? - ANSWERS-Hydrogen (75%)
Helium (24%)
Other elements (1%)
What are the surface and central temperatures of the Sun? - ANSWERS-surface temp=6000K
core temp=15 million K
What are sunspots? How are they produced? - ANSWERS-They're created when the magnetic field loops and kinks poke through the Sun's surface; they absorb energy from areas on the surface that they pass through, making those spots cooler, and therefore darker.
What are aurorae? What kind of spectra do they produce? - ANSWERS-When the solar wind hits the Earth's atmosphere, the particles excite electrons bound to atoms of oxygen and nitrogen. When the electrons fall back down, they produce emission lines (light emitted from a gas cloud).
What causes the seasons? What are the solstices and equinoxes? - ANSWERS- The tilt of the Earth (in addition to the revolving around the sun) causes our seasons.
June 21st=summer solstice (northern hemisphere tilted toward Sun)
December 21st=winter solstice (southern hemisphere tilted toward Sun)
Neither hemisphere is tilted toward the Sun (vernal and autumnal equinoxes)
How do the number of hours of daylight and maximum height of
the Sun in the sky change with seasons? with latitude? - ANSWERS-When one hemisphere is tilted toward the Sun (summer for that hemisphere), the Sun reaches higher in the sky and is in the sky longer than at the same latitude in the other hemisphere that's experiencing winter.
somewhere in the world (once every 360 years for a given location). A total lunar eclipse occurs about twice a year. They're more common than solar because Earth is larger than the moon; it's easy for the small Moon to fall within the large shadow of Earth.
Why don't we see solar and lunar eclipses every month? - ANSWERS-The moon's orbital plane is tilted relative to Earth's orbital plane; the moon is usually above or below the Sun during a new Moon (no solar eclipse) and above or below the Earth's shadow during a Full Moon (no lunar eclipse).
What 2 pieces of evidence did Aristotle cite for a spherical Earth? - ANSWERS-1. Said there was a curved shadow that Earth casts on the moon
What are the zenith, the meridian, and the horizon? - ANSWERS-zenith: point directly overhead
meridian: line in the sky passing overhead from north to south
horizon: what you can see from where you're standing
What is the name of the point in the sky above the North Pole? What is the name of the star near that point? - ANSWERS-The point above the North Pole is the North Celestial Pole, and the star next to it is Polaris (aka the North Star).
What is diurnal motion? What causes it? How does diurnal motion of stars appear from the North Pole? The Equator? - ANSWERS-Diurnal motion is the daily motion of the Sun, Moon, stars, and planets. It's caused by Earth's spin. During diurnal motion, stars in the northern half of the sky appear to move in circles around the north celestial pole. If at the Equator, the North and South Celestial Poles will be on your horizon.
Some constellations can be seen at night during only part of the year. Why is that? - ANSWERS-Because of Earth's orbit around the Sun (some constellations-- like the Zodiac--may be behind the Sun at a given time).
How are the zodiac constellations different from other constellations? - ANSWERS-The constellations that the Sun moves through are the zodiac constellations. They differ from other constellations because you can only see them for a portion of the year when they aren't blocked from view by the Sun.
What is parallax? Which model of the solar system was supported by its apparent absence among stars? - ANSWERS-Parallax is the apparent motion of a nearby object relative to a distant object due to the changing position of the observer. The geocentric model of the solar system was supported by an apparent absence of parallax.
Which model did each of the following prefer? Aristotle, Ptolemy, Copernicus, Tycho, Galileo, Kepler - ANSWERS-Aristotle--geocentric
Ptolemy--geocentric
Copernicus--heliocentric
Tycho--heliocentric & geocentric
What are Newton's Laws of Motion? - ANSWERS-1. A body's velocity will remain constant, unless acted upon by an outside force (inertia)
What Is the equation for the force of gravity? What is the equation for the acceleration experienced because of gravity? - ANSWERS- gravity=F=(Gm1m2)/d^
acceleration=a=(GM)/d^
Why do we feel weight? In what circumstances does weightlessness occur? - ANSWERS-We feel weight because of the third law (for every force, there's an equal and opposite force): gravity is pulling you down but the ground isn't allowing you to fall. If the ground prevented you from falling, you'd be in free- fall, and experience weightlessness.
Why doesn't the Earth fall into the Sun? - ANSWERS-Earth has inertia that makes it stay in its orbit.
What is a tidal force? - ANSWERS-A tidal force is the difference in gravity from one side of a body to the other that's exerted by a 2nd object.
How does the tidal force of the Moon affect the Earth? - ANSWERS-The tidal force of the moon on the Earth causes the oceans facing the Moon to bulge out toward it, & the oceans on the opposite side of the Earth to bulge out away from the Moon.
How has the tidal force of the Earth affected the Moon? - ANSWERS-Earth's tidal forces are much stronger (due to it being larger than the Moon); Earth's tidal forces have already slowed the Moon's rotation to the point that it always keeps the same face towards Earth.
What's the difference between the far side and the dark side of the Moon? When are they the same? - ANSWERS-Far side: the face of the moon not facing the Earth.
Dark side: face not illuminated by the sun.
These two sides are the same during a full moon.
How can you determine if you experience a low tide or high tide based on the time of day and phase of the Moon? During which phases of the Moon are the tides most extreme? - ANSWERS-Look at the graph.
When the Sun and Moon are aligned (during New and Full Moons), they pull the oceans the same direction, causing the highest highs & lowest lows.
What is the Doppler shift? - ANSWERS-The wavelength emitted from an object isn't always the same wavelength you observe. If an object is moving towards you, the wavelength is shorter (bluer) than what its wavelength actually is. If an object is moving away from you, you'll see light that's redshifted compared to the light that was emitted.
What is the inverse square law of light? - ANSWERS-The inverse square law of light describes how much fainter an object appears at larger distances.
brightness is proportional to 1/d^2 where d=distance
If a light source moves 2 times farther away, its brightness changes by ¼, i.e., it becomes 4 times fainter.
Why is the sky blue? - ANSWERS-Air molecules in the Earth's atmosphere scatters light. Shorter wavelengths (bluer) are scattered more than longer wavelengths (redder). When we look at the sky, we see the bluer photons scattering in the atmosphere.
How do peak wavelength and total energy of a blackbody depend on temperature? - ANSWERS-At higher temps, the peak of the spectrum appears at shorter (bluer) wavelengths; more light is produced (the object is brighter), where the total amount of light is proportional to T^4.
Something that's hotter is naturally going to be brighter.
What are the 3 kinds of spectra? What type of light source produces each one? - ANSWERS-*continuous: blackbody light has no interference
*absorption: blackbody light is blocked by a gas cloud, not showing full spectrum
*emission: light emitted from a gas cloud
How are emission and absorption lines produced? - ANSWERS-To produce emission lines, a gas needs to have electrons that are excited to the high levels. One way of exciting electrons is heating the gas since this increases # of collisions between atoms.
An absorption line spectrum is produced when light passes through a cloud of gas.
What kind of spectrum does the Sun produce? - ANSWERS-Continuous absorption lines.
How are the sizes of telescopes characterized? What is meant by a "1 meter" telescope? - ANSWERS-The size of a telescope is characterized by the diameter of its lens or mirror. A "1 meter" telescope means that its lens/mirror is 1 meter in diameter.
What are the 2 kinds of telescopes? Which one is used in modern telescopes? Why? - ANSWERS-There are refraction (lens) telescopes and reflection (mirror) telescopes. Reflection telescopes are used in modern telescopes because it's difficult to build a frame holding a large lens by its edges, and because no matter where you put your ever, certain colors will be out of focus depending on where you look.
