Tag Archives: earth

Origin of Dinosaur-Killing Asteroid Remains a Mystery

By Guest PostSeptember 21, 2011Scienceamy mainzer, asteroid belt between mars and jupiter, asteroids, baptistina, baptistina family, demise of the dinosaurs, dinosaurs extinction, earth, greatest mysteries, gulf of mexico, huge asteroid, jet propulsion laboratory, joseph masiero, jpl, lindley johnson, NASA, nasa headquarters in washington, near earth object, neo, neowise, pasadena, visible light data, wide field infrared survey explorer, wise

PASADENA, Calif. — Observations from NASA’s Wide-field Infrared Survey Explorer (WISE) mission indicate the family of asteroids some believed was responsible for the demise of the dinosaurs is not likely the culprit, keeping open the case on one of Earth’s greatest mysteries.

While scientists are confident a large asteroid crashed into Earth approximately 65 million years ago, leading to the extinction of dinosaurs and some other life forms on our planet, they do not know exactly where the asteroid came from or how it made its way to Earth. A 2007 study using visible-light data from ground-based telescopes first suggested the remnant of a huge asteroid, known as Baptistina, as a possible suspect. (more…)

Scorched Earth: The Past, Present and Future of Human Influences on Wildfires

By Guest PostSeptember 18, 2011Environmentearth, fires, human ignition, jennifer balch, pre human fire history, relative influences of climate, role of fire in natural ecosystems, sustainable fire management practices, university of california at santa barbara, western united states, wildfires

*A new framework for evaluating human influences on wildfires is developed*

Fires have continuously occurred on Earth for at least the last 400 million years. But since the 1970s, the frequency of wildfires has increased at least four-fold, and the total size of burn areas has increased at least six-fold in the western United States alone. Steadily rising, the U.S.’s bill for fighting wildfires now totals $1.5 billion per year.

How much of the increases in the frequency and size of fires are due to human activities? No one knows for sure. But a paper in this week’s issue of the Journal of Biogeography puts the role of fire in natural ecosystems into context and provides support for efforts to plan for future risks from wildfires. (more…)

Water Evaporated from Trees Cools Global Climate

By Guest PostSeptember 17, 2011Environmentatmosphere, central park, earth, emissions of carbon dioxide, evaporated water, evaporation, george ban-weiss, global balance of energy, global climate, global warming, govindasamy bala, greenhouse gas, julia pongratz, ken caldeira, new york, vegetation, water, water vapor

Washington, DC — Scientists have long debated about the impact on global climate of water evaporated from vegetation. New research from Carnegie’s Global Ecology department concludes that evaporated water helps cool the earth as a whole, not just the local area of evaporation, demonstrating that evaporation of water from trees and lakes could have a cooling effect on the entire atmosphere. These findings, published September 14 in Environmental Research Letters, have major implications for land-use decision making.

Evaporative cooling is the process by which a local area is cooled by the energy used in the evaporation process, energy that would have otherwise heated the area’s surface. It is well known that the paving over of urban areas and the clearing of forests can contribute to local warming by decreasing local evaporative cooling, but it was not understood whether this decreased evaporation would also contribute to global warming (more…)

First Global Picture of Greenhouse Gases Emerges from Pole-to-Pole Research Flights

By Guest PostSeptember 10, 2011Environmentandy watt, anne-marie schmoltner, Antarctic, Arctic, black carbon particles, britton stephens, carbon dioxide, climate, concentrations of greenhouse gases, earth, global distribution of gases, gulfstream v aircraft, harvard university, hiaper, hiaper pole to pole observations, high performance instrumented airborne platform for environmental research, hippo, Houston, industrial age, los angeles, national science foundation, natural carbon dioxide uptake and storage, new zealand, nsf, pacific, particles in the atmosphere, portrait of greenhouse gases, ryan spackman, steven wofsy

*Three-year series of scientific missions from Arctic to Antarctic produces new views of atmospheric chemistry*

A three-year series of research flights from the Arctic to the Antarctic has successfully produced an unprecedented portrait of greenhouse gases and particles in the atmosphere.

The far-reaching field project, known as HIPPO, ends this week, and has enabled researchers to generate the first detailed mapping of the global distribution of gases and particles that affect Earth’s climate. (more…)

Microbial life on Mars: Could Saltwater Make it Possible?

By Guest PostAugust 19, 2011Scienceair pressure, antarctic lakes, atmospheres, bruce block, carbon dioxide, daily and seasonal cycles, earth, forms of microbial life, gregory dick, gulf of mexico, mars, Mars Phoenix Lander, mars today, microbe, microbial life, NASA, nilton renno, organisms, perchlorate salts, salt loving extremophile microorganisms, saltwater on mars, sea level, temperatures, the centro de astrobiologia in madrid, the university of georgia, united states, university of michigan, university of texas at dallas, water vapor

ANN ARBOR, Mich.— How common are droplets of saltwater on Mars? Could microbial life survive and reproduce in them? A new million-dollar NASA project led by the University of Michigan aims to answer those questions.

This project begins three years after beads of liquid brine were first photographed on one of the Mars Phoenix lander’s legs.

“On Earth, everywhere there’s liquid water, there is microbial life,” said Nilton Renno, a professor in the Department of Atmospheric, Oceanic and Space Sciences who is the principal investigator. Researchers from NASA, the University of Texas at Dallas, the University of Georgia and the Centro de Astrobiologia in Madrid are also involved. (more…)

Rising Oceans – Too Late to Turn the Tide?

By Guest PostJuly 16, 2011Environmentantarctic ice sheets, anthropogenic reasons, atmosphere, atmosphere ocean interactions, bahamas, barbados, bette otto bliesner, cause and effect relationships, climate, climate models, computer simulations, current global warming, earth, global distribution of sea surface temperatures, great polar ice sheets, greenhouse gas concentrations, greenhouse gases, greenland, ice caps, jonathan overpeck, last interglacial period, melting ice sheets, mountain glaciers, natural reasons, nicholas mckay, paleoceanic records, paleoclimate, rising sea levels, sea level, thermal expansion of seawater, thermal expansion of warming ocean waters, university of arizona

*Melting ice sheets contributed much more to rising sea levels than thermal expansion of warming ocean waters during the Last Interglacial Period, a UA-led team of researchers has found. The results further suggest that ocean levels continue to rise long after warming of the atmosphere levels off.*

Thermal expansion of seawater contributed only slightly to rising sea levels compared to melting ice sheets during the Last Interglacial Period, a University of Arizona-led team of researchers has found.

The study combined paleoclimate records with computer simulations of atmosphere-ocean interactions and the team’s co-authored paper is accepted for publication in Geophysical Research Letters. (more…)

Astronomer Tom Gehrels, 1925-2011

By Guest PostJuly 14, 2011Scienceasteroids and comets, astronomer, astronomy, Britain, Chicago, dutch resistance, earth, England, gerard p kuiper, haarlemmermeer, harold masursky award, imaging photopolarimetry, jupiter, kitt peak, leiden university, nobel astrophysicist, saturn, saturn mysterious f ring, special operations executive, study of wavelength dependence of polarization of stars and planets, subrahmanyan chandrasekhar, the netherlands, tom gehrels, universal evolution, university of arizona, university of chicago

*In a career that spanned more than half a century, Gehrels fostered new research on asteroids and comets, including those that pose a threat to Earth.*

Tom Gehrels, an internationally noted planetary scientist and astronomer at the University of Arizona, as well as a hero of the Dutch Resistance during WWII, died Monday. He was 86.

Gehrels was among the first members of the fledgling Lunar and Planetary Laboratory when he joined the UA in 1961. During a long and distinguished career Gehrels pioneered new research on asteroids and comets, especially those that pose a collision threat to Earth. He also developed and taught introductory astronomy courses that were popular with non-science undergraduates. (more…)

Cassini Captures Images and Sounds of Saturn Storm

By Guest PostJuly 7, 2011Scienceandrew ingersoll, austrian academy of sciences, california institute of technology, cassini, cassini spacecraft, cloud, earth, georg fischer, graz, hemispheres, iowa city, journal nature, jupiter, NASA, northern hemisphere, pasadena, pictures from cassini, saturn storm, saturn storm watch, solar illumination, storm alley, university of iowa, weather on saturn

PASADENA, Calif. — Scientists analyzing data from NASA’s Cassini spacecraft now have the first-ever, up-close details of a Saturn storm that is eight times the surface area of Earth.

On Dec. 5, 2010, Cassini first detected the storm that has been raging ever since. It appears approximately 35 degrees north latitude of Saturn. Pictures from Cassini’s imaging cameras show the storm wrapping around the entire planet covering approximately 2 billion square miles (4 billion square kilometers). (more…)