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CU study: 66 million years ago, an asteroid turned Earth into a crispy critter
Mar 27th
A new look at conditions after a Manhattan-sized asteroid slammed into a region of Mexico in the dinosaur days indicates the event could have triggered a global firestorm that would have burned every twig, bush and tree on Earth and led to the extinction of 80 percent of all Earth’s species, says a new University of Colorado Boulder study.
Led by Douglas Robertson of the Cooperative Institute for Research in Environmental Sciences, or CIRES, the team used models that show the collision would have vaporized huge amounts of rock that were then blown high above Earth’s atmosphere. The re-entering ejected material would have heated the upper atmosphere enough to glow red for several hours at roughly 2,700 degrees Fahrenheit — about the temperature of an oven broiler element — killing every living thing not sheltered underground or underwater.
The CU-led team developed an alternate explanation for the fact that there is little charcoal found at the Cretaceous-Paleogene, or K-Pg, boundary some 66 million years ago when the asteroid struck Earth and the cataclysmic fires are believed to have occurred. The CU researchers found that similar studies had corrected their data for changing sedimentation rates. When the charcoal data were corrected for the same changing sedimentation rates they show an excess of charcoal, not a deficiency, Robertson said.
“Our data show the conditions back then are consistent with widespread fires across the planet,” said Robertson, a research scientist at CIRES, which is a joint institute of CU-Boulder and the National Oceanic and Atmospheric Administration. “Those conditions resulted in 100 percent extinction rates for about 80 percent of all life on Earth.”
A paper on the subject was published online this week in the Journal of Geophysical Research-Biogeosciences, a publication of the American Geophysical Union. Co-authors on the study include CIRES Interim Director William Lewis, CU Professor Brian Toon of the atmospheric and oceanic sciences department and the Laboratory for Atmospheric and Space Physics and Peter Sheehan of the Milwaukee Public Museum in Wisconsin.
Geological evidence indicates the asteroid collided with Earth about 66 million years ago and carved the Chicxulub crater in Mexico’s Yucatan Peninsula that is more than 110 miles in diameter. In 2010, experts from 33 institutions worldwide issued a report that concluded the impact at Chicxulub triggered mass extinctions, including dinosaurs, at the K-Pg boundary.
The conditions leading to the global firestorm were set up by the vaporization of rock following the impact, which condensed into sand-grain-sized spheres as they rose above the atmosphere. As the ejected material re-entered Earth’s atmosphere, it dumped enough heat in the upper atmosphere to trigger an infrared “heat pulse” so hot it caused the sky to glow red for several hours, even though part of the radiation was blocked from Earth by the falling material, he said.
But there was enough infrared radiation from the upper atmosphere that reached Earth’s surface to create searing conditions that likely ignited tinder, including dead leaves and pine needles. If a person was on Earth back then, it would have been like sitting in a broiler oven for two or three hours, said Robertson.
The amount of energy created by the infrared radiation the day of the asteroid-Earth collision is mind-boggling, said Robertson. “It’s likely that the total amount of infrared heat was equal to a 1 megaton bomb exploding every four miles over the entire Earth.”
A 1-megaton hydrogen bomb has about the same explosive power as 80 Hiroshima-type nuclear bombs, he said. The asteroid-Earth collision is thought to have generated about 100 million megatons of energy, said Robertson.
Some researchers have suggested that a layer of soot found at the K-Pg boundary layer roughly 66 million years ago was created by the impact itself. But Robertson and his colleagues calculated that the amount of soot was too high to have been created during the massive impact event and was consistent with the amount that would be expected from global fires.
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City of Boulder begins seasonal grassland raptor closures
Mar 12th
The City of Boulder Open Space and Mountain Parks (OSMP) is temporarily closing areas in order to protect nesting and roosting burrowing owls and osprey. Properties where burrowing owls nest will be closed from March 15 through Oct 31. Properties closed for the protection of nesting osprey will be closed from March 15 through Sept. 10. Closures may be lifted early if monitoring indicates it is appropriate.
The following property will be closed for the protection of osprey:
Axelson (northwest of Boulder Reservoir; portions closed).
The following properties will be closed for the protection of burrowing owls:
- Damyanovich/Yunker (north of Marshall Drive, between Cherryvale Road and US 36);
- Jafay/Lynch (north of Lookout Road and east of 75th Street);
- Cosslett/Knaus (South of Lookout Road and east of 75th Street);
- Kelsall (north of High-Plains Trail, trail remains open);
- Mesa Sand and Gravel (east of 66th Street, south of Marshall Drive); and
- Superior Associates (north of High-Plains Trail, trail remains open).
These closures were established to protect sensitive species. Burrowing owls nest in prairie dog burrows and their populations are declining in Colorado. This bird is listed as threatened by the Colorado Division of Wildlife has been listed as endangered or as a species of “special concern” in 12 US states and in Canada. Staff will be monitoring these sites and others during the spring and summer to understand more about the distribution and breeding biology of this owl on city property.
City of Boulder relies heavily on the public to respect the closures, and the cooperation of visitors to avoid these areas is greatly appreciated. Trespass violations can result in a summons with penalties up to 90 days in jail and/or a $1,000 fine.
More detailed information and maps can be found on the Open Space and Mountain Parks’ website: www.osmp.org. or call 303-441-3440.
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CU Boulder study: More power leads to more dehumanization (No sh*t, Sherlock)
Mar 6th
“I think a lot of us have the intuition that some powerful people can be pretty dehumanizing,” said Jason Gwinn, a doctoral student in the Department of Psychology and Neuroscience and lead author of the study. “But our goal was to test if power, when randomly assigned to ordinary students, would have that effect. That would say something about power itself rather than about the sort of people who have the drive to take power.”
The researchers enlisted about 300 CU-Boulder students taking an introductory psychology course to participate in two experiments. In the first experiment, students were assigned to be either a manager or an assistant for a mock hiring task. The assistants were asked to review resumes for an open job and then list the strengths and weaknesses of each applicant. The managers then reviewed the list made by their assistants and made a final decision about whom to hire.
In the second experiment, participants were asked to play a game and were assigned to be either an allocator or a recipient. For the game, one allocator and one recipient were tasked with splitting a pot of money. The allocator, the higher-power role, made the first offer, suggesting how the money be split. If the recipient, the lower-power role, accepted the offer, both people received their share of the money. If the recipient declined the offer, neither person received any of the money.
At the end of each experiment, the participants were asked to rate each other on 40 traits. The result was that students in higher-power roles assigned fewer uniquely human traits to the students in lower-power roles than vice versa. Examples of traits considered to be more uniquely human, as defined and tested in a 2007 Australian study, include being ambitious, imaginative, frivolous and insecure. Examples of traits that are less uniquely human — those that could be used to describe a pet as well as a friend, for example — include being passive, timid, friendly and shy.
The question of whether power leads to dehumanization has part of its roots in the renowned Stanford Prison Experiment conducted in 1971. Twenty-four male students were randomly assigned to play the role of either inmate or guard in a mock prison in the basement of the Stanford psychology building. During the study, the guards were psychologically abusive to the prisoners, many of whom passively accepted the abuse, despite the fact that the participants knew that they were all students at the same elite university.
Though the guards were described as dehumanizing the prisoners, the term “dehumanization” was well defined at the time and the experiment was not designed to allow the researchers to confidently state that it was the increase in power that lead to the dehumanization. By contrast, Gwinn’s study, now available online, was designed specifically to test the relationship between power and dehumanization.
Gwinn cautions that the researchers cannot yet say whose perspective is being changed by the power differential imposed on participants in the CU study. It’s possible that being in a position of less power makes a person see those in power as more human rather than the other way around, or that both people are affected.
“We haven’t pinned down why this happens,” Gwinn said. “We don’t know whose perception is being affected.”
Charles Judd and Bernadette Park, both professors in CU-Boulder’s Department of Psychology and Neuroscience, co-authored the study.