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Newly Found Dwarf Galaxies Could Help Reveal the Nature of Dark Matter

By Guest PostNovember 12, 2011Scienceandromeda, andromeda xxviii and xxix, astronomers, colin slater, dwarf galaxies, dwarf galaxies around andromeda, dwarf spheroidal galaxy 200 kpc from andromeda, earth, eric bell, gemini north telescope, gravitational effects, gravity, hawaii, how matter relates to dark matter, hypothesis, invisible substance, light years, night sky, predictions, satellites of andromeda, sloan digital sky survey, spiral galaxy, star counting technique, telescopes, understanding of dark matter, universe mass, university of michigan

ANN ARBOR, Mich.— In work that could help advance astronomers’ understanding of dark matter, University of Michigan researchers have discovered two additional dwarf galaxies that appear to be satellites of Andromeda, the closest spiral galaxy to Earth.

Eric Bell, an associate professor in astronomy, and Colin Slater, an astronomy Ph.D. student, found Andromeda XXVIII and XXIX—that’s 28 and 29. They did it by using a tested star-counting technique on the newest data from the Sloan Digital Sky Survey, which has mapped more than a third of the night sky. They also used follow-up data from the Gemini North Telescope in Hawaii. (more…)

NASA Captures New Images of Large Asteroid Passing Earth

By Guest PostNovember 8, 2011Science2005 yu55, aircraft carrier sized asteroid, asteroid, asteroid 2005 yu55, deep space network antenna, earth, flyby, goldstone, hazardous to planet, jet propulsion laboratory, moon orbit, NASA, radar images, spaceguard, trajectory of asteroid, venus and mars

PASADENA, Calif. –– NASA’s Deep Space Network antenna in Goldstone, Calif. has captured new radar images of Asteroid 2005 YU55 passing close to Earth.

The asteroid safely will safely fly past our planet slightly closer than the moon’s orbit on Nov. 8. The last time a space rock this large came as close to Earth was in 1976, although astronomers did not know about the flyby at the time. The next known approach of an asteroid this size will be in 2028. (more…)

NASA’s Spitzer Detects Comet Storm in Nearby Solar System

By Guest PostOctober 20, 2011Sciencealien solar system, almahata sitta meteorite, bright star in the northern sky, carey lisse, comets, dark seas, earth, Epoch, eta corvi, hailstorm, kuiper belt, late heavy bombardment, man in the moon, maria, NASA, solar system, spitzer space telescope

PASADENA, Calif. — NASA’s Spitzer Space Telescope has detected signs of icy bodies raining down in an alien solar system. The downpour resembles our own solar system several billion years ago during a period known as the “Late Heavy Bombardment,” which may have brought water and other life-forming ingredients to Earth.

During this epoch, comets and other frosty objects that were flung from the outer solar system pummeled the inner planets. The barrage scarred our moon and produced large amounts of dust. (more…)

Extreme Space Weather at Mercury Blasts the Planet’s Poles

By Guest PostOctober 4, 2011Scienceatmosphere, aurora borealis, charged particles, earth, exosphere, fast imaging plasma spectrometer, fips, fundamental science about the sun, jim raines, magnetosphere, mercury, messenger spacecraft, NASA, oxygen particles, polar regions, sodium, solar system, solar wind sandblasts, space environment, squall of hot plasma, surface of planet mercury, thomas zurbuchen, university of michigan

ANN ARBOR, Mich.— The solar wind sandblasts the surface of planet Mercury at its poles, according to new data from a University of Michigan instrument on board NASA’s MESSENGER spacecraft.

The sodium and oxygen particles the blistering solar wind kicks up are the primary components of Mercury’s wispy atmosphere, or “exosphere,” the new findings assert. Through interacting with the solar wind, they become charged in a mechanism that’s similar to the one that generates the Aurora Borealis on Earth. (more…)

Deep Oceans May Mask Global Warming for Years at a Time

By Guest PostSeptember 22, 2011Environmentatlantic, climate system, community climate system model, computer simulations of global climate, coupled model intercomparison project phase 5, earth, el niño, eric deweaver, gerald meehl, global air temperatures, greenhouse gas, ice and snow, john fasullo, kevin trenberth, la niña, missing heat, national center for atmospheric research, ncar, oceanic circulation, rate of global warming, software tool, temperature, tropical pacific, warming the upper ocean

*Computer simulations of global climate lead to new conclusions*

Earth’s deep oceans may absorb enough heat at times to flatten the rate of global warming for periods of as long as a decade–even in the midst of longer-term warming. This according to a new analysis led by scientists at the National Center for Atmospheric Research (NCAR).

The study, based on computer simulations of global climate, points to ocean layers deeper than 1,000 feet as the main location of the “missing heat” during periods such as the past decade when global air temperatures showed little trend. (more…)

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…)

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