astro final
Q4.50* From lecture, briefly describe the giant impact theory for the origin of the Earth's moon. How does the giant impact theory explain (a) the lack of metal in the Moon relative to the Earth, (b) the fact that Earth and Moon rocks have very similar isotope fingerprints, and (c) the relative lack of volatiles in lunar rocks compared to the Earth.
The giant impact theory is that a large object collided with Earth and knocked off a large amount of Earth's crust that then formed the moon. A) It explains the lack of metal because the crust of earth is primarily made of rock, which is the part that is proposed to have been knocked off. B) They would have similar isotope fingerprints because it is proposed that the moon is a chunk of Earth, so they would be composed similarly. C) the impact could have heated the material to the point that the volatiles vaporized
Q3.3* From your textbook's chapter 21.4, explain how we deduce the approximate size (or radius) of transiting exoplanets. Also, how do we deduce the density of these exoplanets in order to determine whether they are rocky or gaseous?
The method to deduce the approximate size is based on brightness. When the orbital plane of the planet is tilted so there is an edge-on view, we see the planet cross in front of the star once per orbit, causing the star to dim slightly. The amount of light blocked depends on the area of the planet (its size) compared to that of the star. If the object can be measured using both doppler and transit techniques you can derive the average density (mass/volume) allowing you to look at it density compared to its radius gives us an idea of it is rocky or gaseous
Q2.60* From lecture, explain why Earth can hold on to gases like Carbon Dioxide but not Hydrogen. As part of your answer, explain why lighter gases tend to move more quickly compared to heavier gases in a planetary atmosphere.
The velocity of gas depends inversely on the mass of gas. Meaning heavier gasses move slower than lighter gasses. C02 is much heavier than hydrogen and is less likely to reach escape velocity and stays on earth.
Q2.19* From the Scientific American article "What Is a Planet?" - In the year 1851, the number of planets had grown to 15. What were all of these extra planets and why were they eventually disqualified from planet status?
They are asteroids and they were disqualified from from planet status because the number of them was unwieldy.
Q4.58* From lecture, describe the evidence (3 parts) from the Magellan explorer that led scientists to the conclusion that Venus resurfaced itself somehow about 500 million years ago.
Venus has about 5 times more craters vs Earth. So the solidification age of Venus' surface is about 500 million years old -Craters are distributed uniformly on Venus. Tells us that the entire surface of Venus was solidified at the same time -Craters on Venus show no sign of erosion or decay. So there is no gradual way to erase craters, it must be quick and catastrophic.
Q4.40* From the video "Venus Could Have Supported Life for Billions of Years:" in the simulation described in the video, Venus is supposed to have started with a thick atmosphere of mostly Nitrogen and oceans of water all over the surface. What did the simulations show about the long-term evolution of Venus' atmosphere over the first 3 billion years or so of its history (asking specifically about temperatures and carbon dioxide levels)?
Venus was able to maintain stable temperatures ranging from a maximum temperature of 50 Celsius to a minimum of 20 Celsius and it kept these stable temperatures for almost 3 billion years. In the beginning, the planet had an incredibly thick atmosphere of carbon dioxide but as it cooled down over the next three billion years this carbon would have been drawn out of the atmosphere and locked away into silicate rocks.
From the Scientific American article "The Permafrost Prediction," if the permafrost in a given region thaws, some Carbon will be released from the soil, but it is also true that the same region will absorb more Carbon from the atmosphere. (a) Explain why, and (b) explain whether the net result is more Carbon added to the atmosphere or more absorbed from the atmosphere.
Warming the ground with snow along the fences helps plants grow faster and larger, pulling and storing more carbon dioxide from the air. But it also helps microbes decompose more carbon in the soilIn the summertime, the extra plant growth completely offsets additional carbon release from the soil, but continued microbial activity throughout the long autumn and winter, when plants are dormant, shifts the annual balance to net carbon loss to the atmosphere
Q5.49* From lecture, normally, when a comet's orbit is different than we expect, it is because of something like the Yarkovsky Effect mentioned in question 6.19. Explain two reasons why we do not believe cometary jets are the cause of Oumuamua's peculiar path through the solar system.
We do not see any jets (tail or comas) coming off the asteroid.It's light curve is constant, indicating it's rotation is not speeding up or slowing down like it most likely would if there were jets.
Q3.53* From lecture, (a) once we have a graph of a star's radial velocity vs time, what two things on that graph do we measure? (b) For each of these two things, explain what property of the companion planet do deduce (explain why is there is a relation between what we measure and the property of the planet).
We measure the orbital period(star-planet distance) and the amplitude(mass of companion planet), which is the max radial velocity.The period of wobble is proportional to the star planet distance.The max radial velocity is proportional to the planet's mass
Q3.52* From lecture, in the Doppler wobble method of exoplanet detection, explain what we observe and how that turns into a graph of radial velocity vs time.
We observe the doppler shift from the exoplanet. Then we graph this infrared light with time on the X -axis and radial velocity is given with time.
Q2.13* From your textbook's chapter 7.3, (a) describe how we estimate how old a planetary surface is (how long since it has undergone a major change). Also, (b) describe how we determine the age of a rock (how long ago it solidified). Specifically for (b), what three things do we have to know in order to estimate the solidification age of a rock?
a) by looking at impact craters b) natural radioactivity to get that we need how much parent radioactivity is there compared to daughter radioactivity, and its halflife.
Q2.9* From your textbook's chapter 6.4, (a) explain why radio telescopes typically have much worse resolution than optical telescopes, and (b) briefly describe how interferometry can be used to overcome this problem.
a) they tend to be blurry because of the amount of radio wavelengths b) you can have a very big aperture diameter
Q4.22* From the Scientific American article "Mars in Motion," the "gullies" observed frequently on Mars were originally thought to be some manifestation of flowing water (though there were problems with this hypothesis as mentioned at the opening of the article). Eventually, the HiRISE mission came up with enough observational data to convince scientists that the gullies are caused by sublimation of carbon dioxide frost. Explain two lines of evidence that led scientists to this conclusion.
all gullies were on pole-facing slopes(pattern matched distribution of frost) and the sublimation of carbon dioxide creates "spiders," radial networks of channels from the flow and erosion of gas trapped underneath dry ice
Q4.49* From lecture, briefly describe the capture theory for the origin of the Earth's moon, and explain two problems with the theory from a scientific standpoint.
formed independently and earth captured moon during close encounter- too massive to slow down and can't have same isotopes if formed independently
From the article "The Physical Science Behind Climate Change," explain two patterns in our atmosphere that the authors consider to be a fingerprint of human influence, showing humans are caused the changes and not natural sources (like changes in solar activity).
greater warming over land than ocean and greater warming at surface of the sea than in deeper layers. Second is troposphere has warmed the stratosphere just above it has cooled. And if it wasn't caused by humans then warming would be expected in both layers.
Q5.4* From your textbook's chapter 11.3, explain what causes the color difference between the light and dark bands in the atmosphere of Jupiter.
high and low pressure systems- light bands are upward moving convection currents and darker are where cooler atmosphere moves downwards and completes convection cycle
Q4.28* From the Scientific American article "How to Search for Life on Mars," describe two important factors that make it more probable for life to be present, which will then help us to select a landing site for this proposed mission to Mars.
icy sites that may have harbored recent life—such as the Phoenix landing site near Mars's north pole—or sites where erosion has recently exposed the ancient material.
Q3.30* From the "Crash Course: Exoplanets" video: What was so significant about the discovery of the exoplanet HD 209458b, discovered in 1999? Explain.
it was the first time we could point out a planet and tell its mass
Q3.5* From your textbook chapter 21.5, figure 21.23 is a bar chart showing the percentage of each category of planet size detected by the Kepler mission. Figure 21.24 is a bar chart showing the ACTUAL percentage of each category of planet size in the galaxy. Explain why these two bar charts are different (in other words, why are there more small-sized planets out there compared to what Kepler found).
kepler had a difficult time finding small planets. bias towards big and close to star planets
Q5.35* From the video "The Bizarre Characteristics of Titan," explain what is thought to be the cause of Titan's orbital eccentricity and tilted orbital plane.
large collisions of moons in the past
Q3.39* From the TESS Planet Hunter discover video, NASA scientists have created two possible models to represent TOI 700 d, the Earth-sized planet orbiting in the habitable zone of its parent star. They predict that the mostly-rocky planet will have an extra feature in its spectrum that wouldn't appear in a mostly-water planet model. What is the extra spectral signature?
methane
Q4.17* From your textbook's chapter 10.4, a small sample of meteorites found on Earth's surface over many years is composed mostly of volcanic basalts. Explain the two arguments Astronomers have used to deduce that the meteorites likely originated from the surface of Mars.
moon has no volcanoes and venus has too high of a escape velocity meaning it could most likely only come from mars
Q1.21* From the article "The Last Great Global Warming," after an initial buildup of Carbon Dioxide in the atmosphere caused perhaps by volcanic eruptions 56 million years ago, describe three other changes that occured (likely due to the initial Carbon buildup) to add even more heat-trapping gases to the atmosphere in a geologically short time (thousands of years).
natural stirring of the oceans that led to methane gas bubbled up to the surface, adding more carbon into the atmosphere.Thawing permafrost releasing co2/methaneDrought leads to wildfires lead to carbon into the atmosphere
Q5.21* From the "Interstellar Interlopers" article, describe three differences between the 2nd interstellar object (2I/Borisov) and Oumuamua that indicate Borisov is more like the kind of object we expected to find.
no extreme light curve, and its non-gravitational motion is simply a consequence of asymmetric outgassing as ice comes off its surface, just as in solar system comets
Q3.25* From the Scientific American article "Alone in the Milky Way," explain two reasons why life is less likely to thrive on planets orbiting stars that are further from the center of the galaxy.
stars are sparser low metallicity
Q4.55* From lecture, explain how we use Argon to argue the Earth and Venus originally had similar atmospheres. Describe the logical sequence that starts with Argon measurements and ends with the conclusion that the two worlds had similar atmospheres originally.
the argon levels are around the same on both planets, and argon abundance doesn't change overtime, meaning they were likely to have the same amount of gases originally= argon reconstruction
Q3.49* From the film "Life Beyond Earth, Part 2," explain why it will be easier to communicate (or find) other intelligent alien civilizations if the average lifetime of a civilization is extremely long (millions or tens of millions of years) instead of short (less than 100,000 years or so).
the longer our or another civilization is, the more likely we are to overlap
Q5.28* From the video "Crash Course: Saturn," explain what properites of the lakes on the surface of Titan make us think there is active weather in the atmosphere of Saturn's moon Titan.
the shorelines of the lakes change over time, hinting very strongly that Titan has weather driven by methane as opposed to water here on Earth.
Q5.30* From the video "Kingdom of Saturn," name and explain three observed properties of Saturn's moon Enceladus that led us to believe there is liquid water in the interior near the South Pole of the moon.
the southern pole looked resurfaced, heat signatures were 100 degrees warmer, and it aligns with four stripes that are fissures.
From the reading "Cargo Cult Science," how would you explain to the "cargo cult" people of the South Seas why the planes don't land? Answer in a simple, direct way: what are they doing wrong, or why is what they are doing not working? Hint: think about why the planes REALLY landed and what has changed.
the war is over, so no planes land in the south seas
Q4.12* From your textbook's chapter 9.3, describe the evidence in the lunar maria and highlands that indicates the cratering rate on the Moon hasn't always been constant, but instead there was an early era of heavy bombardment, then a slower, constant rate from that point forward.
their are 10x more craters in highlands than maria, yet the highlands aren't much older, meaning if it was constant they would be 10x older
Q5.51* From lecture, explain what are the Kirkwood gaps and how they are formed. As part of your answer, explain why an asteroid in one of the gaps would be affected so radically while an asteroid just to one side or the other of the gap isn't affected.
they are resonance gaps, formed when force is applied in a period system with the same frequency, transferring energy- the resonance frequency of asteroids in one of the gaps causes them to align with Jupiter periodically and when they align, they receive a gravitational push from Jupiter and are pushed out of its orbit- asteroids on one side or the other of the gaps do not have resonance frequency, so Jupiter's forces have no effect on it
Q2.31* From the video on climate science, explain how Dave Montgomery and Anne Bickle's research into farming/gardening techniques may help reduce the overall amount of carbon in the atmosphere if adopted on a broad scale (talk about the example of Dave Legvold's farm).
to use "no till" technique and let the dead material to naturally decompose in the soil
Q4.25* From the Scientific American article "How to Search for Life on Mars," (a) describe how the first Viking experiment searched for life in the Martian soil, and (b) explain how the presence of perchlorate in the soil explains the "false positive" results from Viking.
took a scoop of soil and added carbon compounds as food for any potential micro organisms, percholate is a bleach like compound on mars that could release the same reaction
Q3.18* From the Scientific American article "A Planet is Born," what is the main weakness (or bias) in the two most popular exoplanet detection techniques (transit and radial velocity), and how do the observations of the ALMA telescopes enable us to spot solar systems more like our own?
warps or gaps in the rings favors large planets with short orbits
Q3.59* From lecture, if we were to encounter or detect evidence (by finding artificial signals through our searches of the sky) another intelligent, communicative civilization besides our own, it is highly likely that that other civilization will be much more advanced than our own. Explain why they would likely be more advanced than us (this is also covered in OpenStax Chapter 30.4).
we are only 1% of our estimated average life time, so its very likly if we were to find life they would more advanced
Q5.50* From lecture, explain why Iridium is more common in the interior of the Earth than in the surface rocks and crust of the Earth.
when the earth differantes, all the iridium sinks lower.
Q4.23* From the Scientific American article "Mars in Motion," another type of feature observed on Mars is the "Recurring Slope Lineae" (or RSL). Describe two arguments to suggest these are associated with flowing water (one from page 62, one from page 65).
Water that darkens the soil and flows only when warm, before freezing again at night, best explained the observations.
Q3.42* From the TED talk about ALMA,, one of the ALMA observations discussed is an observation of Carbon Monoxide snow around the newly formed star TW Hydrae. How is this related to the possible origin of life on Earth?
comets pick up snow and crash into planets and this is how earth might of gotten water
Q3.20* From the short Scientific American article "The Earth Next Door," name and briefly explain three potential problems Proxima b might have due to its close orbit that may prevent the planet from providing a stable environment in which to host life?
continued flares, short orbit/tidal heating, and much brighter in earlier existence.
Q2.29* From the video on climate science, explain how perovskites may fundamentally change the way we harvest solar energy, how it differs from using silicon.
it's a cheap material that can easily be applied, and has the same output
Q5.6* From your textbook's chapter 12.2, why aren't all four of Jupiter's major moons composed primarily of ice, given that ice was by far the most abundant solid substance in the outer solar system?
jupiter produced infrared radiation and any ice was vaporized on nearby moons
Q5.41* From the video "Asteroids," from the Arizona site and the Sudbury site, the video discusses 3 additional features, aside from those in the previous question, that are common indicators of impact sites. Describe each of these three, and briefly explain how the impact process results in each feature.
shatter cones, the pressence of irdium, vast mineral wealth.
Q2.34* From the video "Can We Cool the Planet," several scientists in the video discuss their efforts to understand the effects of geoengineering (e.g. making clouds bright or releasing reflecting particles high the atmosphere). Describe two potential drawbacks to this approach as a "solution" to human-caused climate change.
1 - Unintended and unknown side effects 2 - Acts as disincentives to pursue alternative energy/lower CO2 emissions.
From the Scientific American article "Meltdown," we learn that when "permanent" ice melts (either on the ocean or on land) due to warming, feedback effects from this can cause even more warming. Explain three ways the melting ice causes further warming in the Arctic.
1) Ice melting and allowing the earth to absorb heat rather than reflect it away2) Sea ice traps heat in the ocean and prevents it from being released, but when the sea ice melts, it releases heat into the atmosphere3) Permafrost releasing greenhouse gases into the atmosphere
Q5.16* From your textbook's chapter 14.1, (a) what is the radiant of a meteor shower? (b) What causes the radiant effect that makes meteor trails all seem like they originate from (or point back towards) a specific place on the sky?
1. The radiant of a meteor shower is a single point in the sky from which meteor shower particles appear to originate.2. The dust particles and pebbles that produce meteor showers are moving together in space before they encounter Earth. Thus, as we look up at the atmosphere, their parallel paths seem to come toward us from a place in the sky.
Q5.59* From lecture, explain the four lines of evidence that indicate some kind of catastrophic event in the Saturn system about 100 million years ago.
1. ring system is 100m years old 2. titan's surface age 3. titan's large mass+ energetic orbit suggets a large collison 4.saturn's rings are mostly ice, little dust. simulations show rings get darker from dust after 100m yrs
From the article "The Physical Science Behind Climate Change," explain the evidence found in computer models of the climate that indicate that natural climate forcings are not sufficient to explain the rise in average temperature since the mid-20th century and that anthropogenic (human-caused) factors must be largely responsible.
5 years ago we have data of what parameters are and new model should tell us what temperature we should be at today. Atherogenic= man made/human sources can't be left out in models because won't be accurate
Q2.5* From the Scientific American article "Gather the Wind," explain how electrolyzers work. Specifically, (a) describe how the energy is stored, and (b) describe how a fuel cell releases this stored energy for later use.
As electrolyzer splits h20 into hydrogen and oxygen, hydrogen is stored in fuel cells for later consumption. The hydrogen is later recombined with oxygen from the air and produces energy
From the article "The Last Great Global Warming," how do we know the temperature of the water at the time these ancient sediment deposits occured?
As sediments are laid down slowly, layer by layer, they trap minerals—including the skeletal remains of sea life—that retain signatures of the composition of the surrounding oceans or atmosphere as well as life-forms present at the time of deposition. The mix of different forms, or isotopes, of oxygen atoms in the skeletal remains revealed the temperature of the water, for instance
Q2.15* From your textbook's chapter 14.2, although iron-type meteorites account for only about 3% of meteorites that fall to the Earth, about 42% of meteorites that have been found on Earth are iron meteorites. Explain why this is true.
Because pure iron never occurs naturally on earth either man made or from meteorites it's distinct
From the decoding weather video, explain how Dr. Andrea Dutton is able to reconstruct the history of temperature in the Earth's atmosphere over the past 800,000 years (explain how is oxygen used in the process).
By looking at the different oxygen isotopes found in the shells layers and seafloor cores, she can evaluate the temperature of the see water up to 800,000 years ago
From the article "The Last Great Global Warming," describe the two chemical changes that occured in the oceans due to the buildup of CO2 in the atmosphere
Created a surplus of of carbonic acid leading to acidificationas oceans warmed, Oxygen content dwindled causing disaster for foriminifera
Q3.37* From the video "Life Beyond Earth, Part 1," Freeman Dyson explains that there are two possibilities regarding the origin of life. Either it came into being gradually through chemistry and steps we could hope to retrace (and could presumably be reproduced elsewhere) or life is some kind of extraordinary fluke. (a) If the answer to the question of the origin of life is the first possibility, what does that imply about life beyond Earth? (b) What if the answer is the latter possibility?
First answer: Then it should happen all over the cosmos, and we should be able to find life- Second answer: If it's a fluke then we won't find life
Q2.49* From lecture, two other variables that are associated with costs are subsidies and future costs. Explain what subsidies are and why they help to make fossil fuels cheaper, and explain why fossil fuel use may have costs that are eventually paid by later generations (even though they will get no benefit from using the energy, obviously).
Government paying for cost and offset losses for drilling oil. this makes gas cheaper around the country. future generations pay the price of higher c02 emissions
From the decoding weather video, we find there is an imbalance in carbon. When we calculate how much carbon we are emitting, only about half of it shows up in the atmosphere, so we want to know where the rest of the carbon goes. Explain (a) how Dr. Greg Asner is attempting to answer this question (what instrument does he use and what does he measure), and (b) explain about what fraction of emitted carbon is being accounted for with Asner's measurements.
He used an instruments that measures the amount of CO2 in a forest (b)¼ of co2 is being absorbed by trees
Q2.23* From the Scientific American article "Secrets of Primitive Meteorites" - The author asserts that carbonaceous chondrites probably orbit furthest from the Sun compared to any other type of chondrite. Explain why the author thinks this is true.
High temperatures tend to break them down so they would be farther where it is cooler.
Q4.13* From your textbook's chapter 9.5, describe how radar measurements of Mercury revealed its rotation rate to astronomers on Earth (explain or use a simple diagram to show what the observations would look like if Mercury were rotating slowly vs quickly and explain the difference).
If a planet is turning, one side seems to be approaching Earth while the other is moving away from it. The resulting Doppler shift spreads or broadens the precise transmitted radar-wave frequency into a range of frequencies in the reflected signal. The degree of broadening provides an exact measurement of the rotation rate of the planet. (less spanned= slow more spanned=fast)
From the "Flat Earth" video, in one popular variant of the Flat Earth theory, our apparent weight is not caused by gravity but rather a constant upward acceleration of the flat disk of the Earth. Describe an observational fact that refutes this model.
If the earth was a disk, you would stay the same weight at every pointWe know that the gravitational acceleration is not the same everywhere on earth if you measure weight, it is slightly different everywhere
Q2.25* From the Scientific American article "The Seven Year Mission," describe two reasons why the target for the OSIRIS-Rex mission was the asteroid Bennu. Note that the sample has now been successfully collected and is due to return to Earth in September 2023. If you are interested, there is a video available at Films on Demand, the same database where our "Decoding the Weather" video is found. While on that site, search for "Touching the Asteroid," but much of the 53-minute video repeats what is in this article, so I'm not assigning the video or asking any specific questions about it.
It could be filled with organic compounds and water-rich minerals that could sow the seeds of life.- It could pose as a threat to Earth if it landed (suffering/deaths).
Q4.43* From the video "Crash Course - Mars:" why does the narrator argue that life could have potentially formed on Mars even before it formed on Earth, billions of years ago?
Mars was once very wet. There's tons of evidence for flowing water on the surface long ago, including dry river beds, dry lakes, sedimentary layers, and minerals we know we need water to form. There's even evidence Mars had oceans. Billions of years ago Mars was almost certainly warmer and had a thicker atmosphere. Mars was also smaller and cooled faster than Earth did, which gave life more time to grow and evolve.
From the Scientific American article "The Permafrost Prediction," if the permafrost in a given region thaws, (a) not all of its Carbon will be released and (b) what is released will be released slowly over decades or centuries. Explain each of these two claims (the first two of three key questions posed about Carbon release in the article).
Microorganisms can easily metabolize and release some of the carbon but not all. As a result, some fraction of the carbon will simply remain in the ground because it is so inaccessible or inedible by microbes Rapidly decomposing carbon can become airborne in less than a year after thaw, but more of the carbon will most likely be released gradually over decades after thaw, in part because it is already in a semi decomposed state that microbes only further degrade slowly.
Q5.13* From your textbook's chapter 13.2, we learn that discoveries small asteroids that may be hazards to the Earth is very difficult, so it is important to know as we find them, how many more are still left to be discovered. Describe two ways in which we know that our surveys to date have found roughly 90% of these hazardous asteroids larger than 1 kilometer in size.
One way is to look at the numbers of large craters on the dark lunar maria. The number of impacts is directly related to the number of asteroids and comets on Earth-crossing orbits.2. Another approach is to see how often the surveys rediscover a previously known asteroid. The more rediscoveries each survey experiences, the more complete our inventory of these asteroids must be.
Q2.45* From the video "Chasing Pluto," describe the theory proposed in the video that explains why Pluto is so small. Explain what interrupted its formation process.
Pluto originally formed somewhat closer to the Sun, but as the giant planets formed and got larger, they eventually pushed Pluto to a more distant orbit. Pluto became the remains of the planet formation process because the further a planet gets from the Sun, the less material there is to continue planet forming.
Q4.37* From the video "Crash Course: Tides," what causes "extra high" high tides, even higher than what you would normally see during Spring tides? These kinds of tides are called proxigean tides.
Proxigean tides occur when the moon's closest point to Earth in its orbit overlaps with a full moon.
Q5.3* From your textbook's chapter 11.2, how do we know Saturn has an additional internal heat source not found on Jupiter?
Saturn has a internal energy half as large, but only has a quarter as great in mass. and has less primordial heat
Q3.27* From the Scientific American article "Alone in the Milky Way," although the appearance of life on Earth only a billion years into the planet's history would make us optimistic about discovering life elsewhere, the development of more complex life (like us) seems to be extremely unlikely because of the history of life's development since that first single-celled organism appeared. Explain why.
Single-celled organisms (prokaryotes) formed just a billion years after our planet was born, but more complex cells (eukaryotes) took two billion years more to arise from a fluke merging of cells.Even then, it was almost another billion years before multicellular life-forms proliferated in an event called the Cambrian explosion.
From the reading "Philosophy and the Scientific Method," (a) explain one of the benefits of irrefutable ideas and also (b) explain the major weakness of a system of knowledge based upon irrefutable ideas.
Strength - always true, foundational beliefWeakness - inability to resolve conflicts (how do you get people to agree)
From lecture, what is (a) the major benefit and (b) the major drawback of a system of knowledge based upon scientific principles?
Strength - objective, ability to reach consensus Weakness - often proved wrong or modified later
Q2.24* From the Scientific American article "Secrets of Primitive Meteorites" -- Explain why the author concludes that our early solar system probably resembled the dusty disks surrounding a class of young stars known as T Tour stars.
The author came to this conclusion because the dusty disks surrounding T-Tari stars are as massive as that of our Sun.
