Geology 104, Unit 1 Review
How many stars are in average galaxy?
Billions
Your zenith is at your east, and nadir at your west? How are you situated on the ground? Which direction are your arms pointed?
IDK
How is temperature related to wavelength?
Longer wavelength equals lower temperature
What is name of our galaxy? What is the name of our star?
Milky Way, Sol/Sun
When do see Mercury and Venus?
Morning and Evening
Which phases of the Moon are visible at noon?
New Moon
Difference between Milky Way and Milky Way Galaxy?
Same thing, one object in sky which is other.
Why is it difficult to detect exo-planets?
Small, faint, difficult to see with glow of parent stars.
What causes seasons? Be able to diagram?
Tilt of the earth on its axis
How long ago did the Milky Way form?
13.2 Billion years ago
3. How long does it take for one retrograde cycle of Mars as viewed from Earth, and in which direction is the retrograde motion? What fraction of Mars's orbit around the Sun is the duration of retrograde motion as viewed from Earth?
2.14 years
Celestial Sphere
3-D model of night sky, fixed projection of earth's latitude and longitude on night sky. Earth slanted. Zenith, true north, Nadir-True south, horizon roughly around true equator. Celestial Equator projected from actual equator.
What is the speed of light?
300,000 km/s
Age of Solar System/Planets
4.6 Billion Years Old
What wavelength range is visible light?
400-700 nanometers
How Long is a light year? How Long is an AU
63,000 AU, 150 million km.
How do we get space borne observation/scientific platforms to other planets?
By transporting them on a satellite, spacecraft etc.
Which two-dimensional (2D) and three-dimensional (3D) shapes did Plato and Aristotle consider perfect? Give an example of a 2-D and 3-D nonperfect geometrical shape..
Circle and Sphere, an ellipse
Why did Copernicus have to keep small epicycles in his model? Which planet has the longest duration of retrograde motion as viewed from Earth? The shortest?
Circular model of planetary motion was not accurate, needed corrected with epicycles, Venus has shortest, Neptune has longest.
Be able to do problems involving gravity formulas
Circular orbit velocity is square root of gravity times mass divided by distance. Formula for gravity is gravity times mass one times mass two divided by distance squared. Escape velocity= sqaure root of gravity times mass divded by distance. double check all in notebook.
Does the Earth rotate clockwise or counter-clockwise when looking down on the north pole?
Counter-Clockwise
How do the stars move around the North and South poles, respectively?
Counter-Clockwise and Clockwise.
Why are light-years more convenient than other units of measurements in some cases?
Distances are so big, all other measurements give extremely large numbers, easier to just use light years.
What is light?
Electra-magnetic radiation.
What is a hypothesis? What happens if it is contradicted or supported?
Explanation for what is known, the hypothesis is continually refined and revised in accordance with new evidence regardless or whether that evidence supports or refutes the original statement.
How are wavelength and frequency related?
Frequency times wavelength equals the speed of light.
On what did Plato base his knowledge? Was it opinions, policies, marketing, public relations, myths, evidence, hypotheses, beliefs, laws, principles, theories? On what do modern astronomers base their knowledge?
He based his knowledge on principles. Modern astronomers bases them on evidence.
Why did Plato propose that all heavenly motion was uniform and circular?
He thought heavens were perfect, circles, uniform motion also perfect, therefore heavenly motion must be in uniform circles.
Why is Pluto a dwarf planet?
It is too small to have cleared its orbit, one of 3 requirements to be a planet, along with orbiting the sun and being round.
What does size of a star's image tell you?
Its brightness
Should you ever look at a solar eclipse without protection?
Minime
List the observations of Galileo that disproved the geocentric model of the universe. Could you explain them?
Moons orbit Jupiter, stuff can orbit around things other than earth. Venus has phases, proved it orbited sun rather than earth.
In Ptolemy's model, did all planets travel at constant speeds as viewed from Earth, and did each planet have its own rotating sphere around Earth?
No appeared to move at constant rate from point in space called equant, and yes each had rotating sphere around earth.
If earth did not rotate, could you still define the celestial poles and celestial equator?
No, as the poles are the points on which the earth appaerntly rotates, without rotation there would be no poles, and thus no equator, which lies between the two poles.
When you see Milky way, do you see sprial arms?
No, we is in spiral arms, looking at center of galaxy.
Where would you need to go on earth if the celestial equator is to be seen very near your horizon?
One of the poles.
What is a partial Lunar eclipse?
Only part of the moon is covered by the earth's shadow rather than all of it.
How is a planetary body's orbital period related to its average distance from the sun?
Orbital Period in years squared = distance from sun in AU cubed.
What is an exoplanet?
Planet outside our solar system
List three astronomical influences on Earth's climate, draw examples of each, period of each, plot for each?
Precession-wobbling of earth's axis like spinning top, 23,000 years Eccentricity- variation in shape of earth's orbit, 100000 years Inclination-variation in tilt of the earth 41,000 years
Name 3 objects that move East to West in Sky?
Sun, Moon, Stars
How much flux from the Sun does the Northern Hemisphere receive compared to the Southern Hemisphere on the first day of fall at noon?
The amount of flux is equal
Why does the number of circumpolar constellations depend on the latitude of the observer?
The area of the night sky visible to you changes based on your latitude, you can't see the circumpolar stars from the equator.
What are the conditions for an annular eclipse?
The conditions for a solar eclipse are meet: the moon is directly between the earth and the sun at new moon, and the moon is at apogee (farthest from the sun) and earth is at perihelion (closest to sun)
How does the date of the beginning of Summer in Earth's Southern Hemisphere differ from the date in the northern hemisphere?
The date of the beginning of summer in the South, is the date of the beginning of winter in the north and vice versa.
If it the first day of spring in your hemisphere, what day is it in the opposite hemisphere?
The first day of fall
Why do we see the same side of the Moon at all times?
The moon is tidally locked to the earth
Explain two reasons why winter days are colder than summer days?
The sun shines for less time on winter days, and the light it shines is more spread out.
Are bright objects in sky close to each other or not?
They appear close to one another in the sky, but they could actually be really far apart, difference caused by 3-D space being condensed into 2-D image in nightsky.
What was the false evidence that for the Greeks weighed against a heliocentric model of the universe?
They observed no stellar parallax, there actually is but its undetectable without fancy modern instruments.
It is the first day of summer, how will the days change?
They will get shorter.
How frequently do Lunar eclipses occur?
Typically 1-2 every year
24. Explain how each of Galileo's telescopic discoveries contradicted the Ptolemaic theory.
Valleys on Moon, sunspots on sun showed heavens not perfect. Jupiter's moon showed other objects could have stuff orbiting them, new stars seen through telescope disproved heavens were unchanging. Phases of Venus showed that it orbited Sun
What wavelengths do we use everyday (even before modern technologies were invented)?
We use wavelengths of visual light to see, infrared wavelengths warm us.
Was Copernicus' model more correct than previous models? Explain
Yes, it showed heliocentric model but wrongly showed uniform circular orbits.
Is the precessing top a scientific model? If so which parts are true and which parts are not true?
Yes,the tilt of the earth is accurate, as it the motion of precession shown, but the model itself may not be to scale in respect to the size of precession.
What is the equation for the speed of light?
frequency times wavelength
What is frequency?
how many crests of waves pass by point in 1 second