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Which of the following was probably important in contributing to extinction of most species at the same time the dinosaurs became extinct?

A) Cold from the change in Earth's orbit caused when the meteorite shoved the planet farther from the sun.
B) Heat from the change in Earth's orbit caused when the meteorite shoved the planet closer to the sun.
C) Centrifugal forces caused when the meteorite impact temporarily stopped the rotation of the Earth, causing the sun to appear to stand still.
D) Silicosis caused by dissolution of the meteorite in Pepsi in the ocean.
E) "Impact winter" caused when tiny pieces of dust or other materials, which were put in the air by the impact, blocked incoming sunshine for months or years, after larger pieces had fallen back to Earth.


Which of the following was probably important in contributing to extinction of most species at the same time the dinosaurs became extinct?

A) Cold from the change in Earth's orbit caused when the meteorite shoved the planet farther from the sun.
B) Heat from the change in Earth's orbit caused when the meteorite shoved the planet closer to the sun.
C) Changed weather patterns because the meteorite caused large true polar wander (the north pole shifted rapidly in comparison to the continents because the meteorite rolled the planet on its side).
D) Silicosis caused by dissolution of the meteorite in the ocean.
E) Acid rain, from sulfuric acid from the meteorite hitting sulfur-bearing rocks, and from nitric acid from the heat of the meteorite burning the air.
E) "Impact winter" caused when tiny pieces of dust or other materials, which were put in the air by the impact, blocked incoming sunshine for months or years, after larger pieces had fallen back to Earth.

Feedback: The "impact winter" likely did occur; we know that the materials thrown up by a big volcano cool the planet a degree or two for a year or two, and the meteorite would have thrown up a lot more stuff. The meteorite impact was not nearly large enough to move the planet notably or to stop the rotation. Silicosis is a lung disease caused by breathing too much silica-laden dust; other dust materials are typically more damaging, but too much of any dust can be bad. Dissolution in water does not cause lung disease. (Just for your information, some dictionaries list the long version of one form of the disease, pneumonoultramicroscopicsilicovolcanoconiosis, as the longest word in the English language.)


E) Acid rain, from sulfuric acid from the meteorite hitting sulfur-bearing rocks, and from nitric acid from the heat of the meteorite burning the air.

Feedback: The acid rain very likely did occur, at levels far above those from human-produced air pollution. The meteorite impact was not nearly large enough to move the planet notably or to roll the planet over. Silicosis is a lung disease caused by breathing too much silica-laden dust; other dust materials are typically more damaging, but too much of any dust can be bad. Dissolution in water does not cause lung disease. (Just for your information, some dictionaries list the long version of one form of the disease, pneumonoultramicroscopicsilicovolcanoconiosis, as the longest word in the English language.)
B) Your new idea does a better job than the previously accepted idea in predicting the outcomes of an interlocking web of important experiments or observations.

Feedback: At last observation, Pepsi commercials were not highly scientific, even if science is involved in figuring out what sells. It is a romantic notion that you could overturn great knowledge with a single observation; however, observing nature is not easy, and nature occasionally fools us (you can, rarely, flip an honest coin twenty times and get twenty heads), so if a single observation disagrees with a lot of other information, that single observation will be checked in various ways to see if the new result "stands up" before the older body of knowledge is discarded. Before an idea gains wide currency, that idea is tried in various ways, in many labs, in many places in nature, while models are run and theory is developed. The interlocking of all of these provides the confidence that scientists can use in doing things successfully. Although received wisdom from sacred books can be used for inspiration, scientific ideas must be tested against nature. Social scientists have quite rightly learned that scientists are affected by their prejudices, their funding sources, their mating habits, and other things, and that the path of science is not nearly the straight-ahead road to understanding presented in some textbooks. Unfortunately, some of those social scientists have then gone off the deep end and claimed that science is no more useful than any other human story—claiming that astrology and astronomy are equally valid, for example, or palm-reading and modern medicine. These same social scientists seem to know where to find a real doctor when they get in trouble, however. Science is appealed to nature, and builds on the learning of people from around the world. Airplanes that fly, computers that calculate, small devices that make big explosions, etc. are not socially conditioned ideas but instead are demonstrations of the success of science coupled to engineering.
Dave Janesko holds two rocks next to each other.
The black one (to the upper left in the picture) is from a lava flow, and is much younger than the red one (to the lower right in the picture), which is a lake sediment. In nature, these rocks are found the way Dave is showing, with the younger black one next to the older red one rather than being on top of the older red one. This actually is related to Death Valley, although these rocks are a good
bit east of Death Valley. As described by Dave Janesko in the online video, what happened here?
A) The lava flow set the red rocks on fire, giving them their red color, the way forest fires have colored some of the rocks of Death Valley.
B) A collision between two continents bent the rocks, forcing the lava flow next to the lake sediments, the way the drifting plates of California have bent the rocks to make Death Valley.
C) The lake sediments were deposited, eroded into a big cliff, and then the lava flow filled the valley next to the cliff, the way lava flows sometimes flow down from the peaks to fill Death Valley.
D) There once was a mid-ocean ridge here, and the black lava squirted up through a crack in the red lake sediments and then hardened the way volcanoes do in Death Valley; Dave Janesko is demonstrating what one side of the crack looks like.
E) The lake sediments were deposited, then the lava flowed on top, and then a pull-apart Death-Valley-type fault formed, breaking the rocks and dropping the lava flow to be next to the lake sediments.
C) Absorbing some of the infrared radiation emitted from the Earth.

Feedback: Although it is true that squeezing air warms it, the pressure does not set the temperature (change in pressure brings change in temperature), and, the greenhouse gases are really very rare and don't affect pressure much. Clouds are not caused by greenhouse gases, and while clouds warm nights, clouds cool days, and the net effect of clouds is probably slight cooling of the planet. Convection currents are blocked by the glass of greenhouses, but not by greenhouse gases. But CO2 does absorb some of the infrared radiation emitted from the planet. Absorbing an infrared photon puts a CO2 molecule into an excited state, and fairly quickly the molecule returns to its unexcited state by emitting a photon of the same energy. Some of those photons emitted by excited CO2 molecules head back toward Earth (the emission direction is random). So, the CO2 serves to trap energy in the Earth system, warming the planet so that it glows more brightly to shove infrared radiation past the CO2, achieving a new balance.


A) Absorbing some of the infrared radiation emitted from the Earth.

Notes: CO2 has very little interaction with the ozone, which is not big on cooling the planet anyway, and CO2 does little to the sunlight reflected from the Earth. But CO2 does absorb some of the infrared radiation emitted from the planet. Absorbing an infrared photon puts a CO2 molecule into an excited state, and fairly quickly the molecule returns to its unexcited state by emitting a photon of the same energy. Some of those photons emitted by excited CO2 molecules head back toward Earth (the emission direction is random). So, the CO2 serves to trap energy in the Earth system, warming the planet so that it glows more brightly to shove infrared radiation past the CO2, achieving a new balance.
The United Nations, under the auspices of the Intergovernmental Panel on Climate Change, has attempted to assess the scientific understanding of how greenhouse-gas emissions will affect the climate, and thus people. The UN reports show that if we continue on our present path, burning fossil fuels at a faster and faster rate:

A) Climate will change, primarily getting warmer, and these changes will hurt everyone, equally.
B) Climate will change, with cooling at high latitudes that primarily will hurt wealthy people living in those cold places.
C) Climate will change, primarily getting warmer, and those changes will primarily hurt the poor people in warm places who are the main causes of the climate changes through deforestation and other actions.
D) Climate will change, primarily getting warmer, and those changes will primarily hurt poor people in warm places, but the climate changes are primarily being caused by wealthier people in colder places.
E) Climate will change, primarily getting colder, and those changes will especially hurt those people living in northwestern Europe.


Regarding global warming, most scientists (including those who have advised the United Nations through the Intergovernmental Panel on Climate Change) agree that if we continue to burn fossil fuels at an accelerating rate:

A) Climate changes will primarily hurt poor people in warm places, but the climate changes are primarily being caused by wealthier people in colder places.
Correct!
B) Climate changes will help everyone.
C) Climate changes will primarily hurt poor people who live in warm places and who are the major contributors to climate change through cutting of tropical rain forests and other activities.
D) Climate changes will hurt everyone, equally.
E) Climate changes will primarily hurt wealthy people in cold places.
D. Fossil-fuel burning, plus a bit of cow flatulence. 72%

Notes: You're on a roll—the majority of you nailed this one, too. We have had satellites watching the sun for more than 30 years, and the sun hasn't gotten brighter, just little wiggles with the sunspot cycle and perhaps a very slight dimming. (We believe that the sun did get a bit brighter about a century ago, giving a little boost to the temperatures, but the warming accelerated during the slight dimming more recently.) Single large volcanic eruptions tend to cool the world a bit by blocking the sun. If you were to "turn up"
volcanism, you would get centuries or longer of cooling, followed eventually by warming as the slow buildup of carbon dioxide came to outweigh the sun-blocking effect of the particles. But, there have been no large trends in volcanism (we actually have pretty good records from icecore and other samples). The cold of the Little Ice Age was caused more by a small blip of extra volcanic eruptions than by the weak drop in the sun, and the warming of about a century ago involved a coincidental drop in volcanic
eruptions with the slight rise in solar output. More recently, a couple of big volcanic eruptions pushed toward cooling, yet the world warmed overall. Orbits matter over 10,000 years, but have almost no effect over a century or less. All the evidence points strongly to D, with a slight warning: although cow flatulence is real, cows emit most of their methane out the front rather than out the back. We often hear people agree that the world is warming, but suggest that a lot or all of the warming trend is coming from something other than greenhouse gases. But, over the last few decades nature has pushed weakly toward cooling, and we have put up a lot of particles that mimic volcanic particles in blocking the sun. Thus, if someone asks "How
much of the recent warming was caused by human greenhouse gases", some uncertainty remains, but the central estimate is "More than all of it", because the world has warmed in response to greenhouse gases despite the cooling influence of our particles, a couple of big volcanic eruptions, and a slightly dimming sun, and us cutting dark forests to replace them with more reflective grasslands (corn, wheat, ...). Furthermore, because heat is now going into the big, cold ocean, but as the ocean warms more of the heat will stay in the atmosphere, we have not seen the full warming from our greenhouse gases yet. So in some sense our greenhouse gases have caused notably more warming than has occurred.