July 16, 2008, 7:51 PM CT

A new way to weigh giant black holes

How do you weigh the biggest black holes in the universe? One answer now comes from a completely new and independent technique that astronomers have developed using data from NASA's Chandra X-ray Observatory.

By measuring a peak in the temperature of hot gas in the center of the giant elliptical galaxy NGC 4649, researchers have determined the mass of the galaxy's supermassive black hole. The method, applied for the first time, gives results that are consistent with a traditional technique.

Astronomers have been seeking out different, independent ways of precisely weighing the largest supermassive black holes, that is, those that are billions of times more massive than the Sun. Until now, methods based on observations of the motions of stars or of gas in a disk near such large black holes had been used.

"This is tremendously important work since black holes can be elusive, and there are only a couple of ways to weigh them accurately," said Philip Humphrey of the University of California at Irvine, who led the study. "It's reassuring that two very different ways to measure the mass of a big black hole give such similar answers".

NGC 4649 is now one of only a handful of galaxies for which the mass of a supermassive black hole has been measured with two different methods. In addition, this new X-ray technique confirms that the supermassive black hole in NGC 4649 is one of the largest in the local universe with a mass about 3.4 billion times that of the Sun, about a thousand times bigger than the black hole at the center of our galaxy......... Posted by: Brooke      Read more         Source

Tue, 24 Jun 2008 03:43:25 GMT

Martian Skies

The atmosphere of Mars is hundreds of times thinner than Earth''s atmosphere and is made of 95% carbon dioxide, 3% nitrogen, 1.6% argon, and contains traces of oxygen, water, and methane. It can support dust storms, dust devils, clouds and gusty winds.

With an amazing number of six current live probes exploring Mars, there are many thousands of images available. Only a few, however show atmospheric phenomena. Presented here are some of the best images of Martian atmosphere in action.

Related: Martian weather report. Posted by: Gerard      Read more     Source

May 22, 2008, 10:22 PM CT

Continued turbulence in Jupiter's atmosphere

Berkeley -- Increased turbulence and storms first observed on Jupiter more than two years ago are still raging, as per astronomers from the University of California, Berkeley, and the W. M. Keck Observatory in Hawaii, who snapped high-resolution pictures of the planet earlier this month.

Captured with NASA's Hubble Space Telescope (HST) and the 10-meter Keck II telescope, this so-called "major upheaval" on Jupiter involves stunning changes in the planet's atmosphere, said lead astronomer Imke de Pater, professor of astronomy at UC Berkeley.

The images are available on NASA's Web site, http://hubblesite.org/news/2008/23.

The upheaval was heralded in December 2005 by a color change from white to red of a large oval near the Great Red Spot, earning it the moniker Red Spot Jr. This oval, formally known as Oval BA, formed six years earlier through a merger of three large white ovals just south of the Great Red Spot - storms that formed in the early 1930s and were prominent in the Voyager era.

The new images, the first since Jupiter emerged from its passage behind the Sun, may show that Jupiter indeed is undergoing a major climate change, as predicted four years ago.

"One of the most notable changes we observe in both the Hubble and Keck images is the change from a rather bland, quiescent band surrounding the Great Red Spot just over a year ago to one that is incredibly turbulent at both sides of the spot," de Pater said. "During all prior HST observations and spacecraft encounters, starting with Voyager in 1979, such turbulence was seen only on the west or left side of the spot."........ Posted by: Brooke      Read more         Source

May 11, 2008, 10:22 AM CT

Evolution of "gas giants"

By shooting the high-energy Omega laser onto precompressed samples of planetary fluids, researchers are gaining a better understanding of the evolution and internal structure of Jupiter, Saturn and extrasolar giant planets.

The properties of dense helium (He) - which happens to be a principal constituent of giant gas planets like Jupiter - at thermodynamic conditions between those of condensed matter and high-temperature plasmas are theoretically challenging and unexplored experimentally.

Laboratory researchers collaborating with scientists at the Laboratory for Laser Energetics, CEA France and UC Berkeley were able to determine the equation of state (EOS) for fluid He at pressures above 100 GPa (one million times more pressure than the Earth's atmosphere - one GPa (gigapascal) equals 10,000 atmospheres).

The only prior high temperature and pressure He EOS data available for constraining planetary models waccording toformed at LLNL by Bill Nellis and his team using a two-stage gas gun. However, those earlier experiments used cryogenic techniques at ambient pressure so their densities were significantly lower than those achieved with the precompressed samples. Also, the final pressures, 16 GPa for a single shock, were significantly lower than the new laser shock data......... Posted by: Kevin      Read more         Source

April 28, 2008, 8:27 PM CT

Satellite Mission To Map Earth's Water Cycle

MIT Professor Dara Entekhabi will lead the science team designing a NASA satellite mission to make global soil moisture and freeze/thaw measurements, data essential to the accuracy of weather forecasts and predictions of global carbon cycle and climate. NASA announced recently that the Soil Moisture Active-Passive mission (SMAP) is scheduled to launch December 2012.

At present, researchers have no network for gathering soil moisture data as they do for rainfall, winds, humidity and temperature. Instead, that data is gathered only at a few scattered points around the world.

"Soil moisture is the lynchpin of the water, energy and carbon cycles over land. It is the variable that links these three cycles through its control on evaporation and plant transpiration. Global monitoring of this variable will allow a new perspective on how these three cycles work and vary together in the Earth system," said Entekhabi, director of the Parsons Laboratory for Environmental Science and Engineering in MIT's Department of Civil and Environmental Engineering.

"Additionally because soil moisture is a state variable that controls both water and energy fluxes at the land surface, we anticipate that assimilation of the global observations will improve the skill in numerical weather prediction, particularly for events that are influenced by these fluxes at the base of the atmosphere," he said......... Posted by: Brooke      Read more         Source

March 9, 2008, 4:45 PM CT

GLAST Spacecraft Arrives in Florida

NASA's Gamma-ray Large Area Space Telescope, or GLAST, arrived Tuesday at the Astrotech payload processing facility near the Kennedy Space Center to begin final preparations for launch. Liftoff of GLAST aboard a Delta II rocket is currently targeted for 11:45 a.m. EDT on May 16.

GLAST is a collaborative mission with the U.S. Department of Energy, international partners from France, Gera number of, Italy, Japan and Sweden, and numerous academic institutions from the U.S. and abroad. The spacecraft will explore the most extreme environments in the universe, and answer questions about supermassive black hole systems, pulsars and the origin of cosmic rays. It also will study the mystery of powerful explosions known as gamma-ray bursts.

The milestones to be accomplished over the next two months include attaching the Ku-band communications antenna and the two sets of solar arrays, a complete checkout of GLAST's scientific instruments, installing the spacecraft's battery, and loading aboard the observatory's propellant. These activities will be performed by General Dynamics, builder of the spacecraft for NASA. GLAST currently is scheduled to be transported to Pad 17-B at Cape Canaveral Air Force Station on May 1.

The rocket that will launch GLAST is a Delta II 7920-H, manufactured and prepared for launch by United Launch Alliance. It is a heavier-lift model of the standard Delta II that uses larger solid rocket boosters. The first stage is scheduled to be erected on Pad 17-B the week of March 17......... Posted by: Brooke      Read more         Source

March 9, 2008, 4:43 PM CT

Canadian astronomers on hunt for meteor

Astronomers from The University of Western Ontario in London, Ontario, have captured rare video of a meteor falling to Earth.

The Physics and Astronomy Department at Western has a network of all-sky cameras in Southern Ontario that scan the sky monitoring for meteors. Associate Professor Peter Brown, who specializes in the study of meteors and meteorites, says that Wednesday evening (March 5) at 10:59 p.m. EST these cameras captured video of a large fireball and the department has also received many calls and emails from people who actually saw the light.

Brown along with Wayne Edwards, a post doctorate student, hope to enlist the help of local residents in recovering one or more possible meteorites that may have crashed in the Parry Sound area.

Most meteoroids burn up by the time they hit an altitude of 60 or 70 kilometres from Earth, says Edwards. We tracked this one to an altitude of about 24 kilometres so we are pretty sure there are at least one, and possibly a number of meteorites, that made it to the ground.

Edwards says the lab can narrow the ground location where the meteorite would have fallen, to about 12 square kilometres and have created a map that may assist in locating the meteorite. The rock, or rocks, would probably weigh a kilogram or slightly more......... Posted by: Brooke      Read more         Source

February 24, 2008, 10:25 PM CT

The light and dark of Venus

Venus Express has revealed a planet of extraordinarily changeable and extremely large-scale weather. Bright hazes appear in a matter of days, reaching from the south pole to the low southern latitudes and disappearing just as quickly. Such 'global weather', unlike anything on Earth, has given researchers a new mystery to solve.

The cloud-covered world of Venus is all but a featureless, unchangeable globe at visible wavelengths of light. Switch to the ultraviolet and it reveals a truly dynamic nature. Transient dark and bright markings stripe the planet, indicating regions where solar ultraviolet radiation is absorbed or reflected, respectively.

Venus Express watches the behaviour of the planet's atmosphere with its Venus Monitoring Camera (VMC). It has seen some amazing things. In July 2007, VMC captured a series of images showing the development of the bright southern haze. Within days, the high-altitude veil continually brightened and dimmed, moving towards equatorial latitudes and back towards the pole again.

Such global weather suggests that fast dynamical, chemical and microphysical processes are at work on the planet. During these episodes, the brightness of the southern polar latitudes increased by about a third and faded just as quickly, as sulphuric acid particles coagulate......... Posted by: Brooke      Read more         Source

January 14, 2008, 3:19 PM CT

Pulses in Saturn's rings

In 2005, the Cassini spacecraft began a series of experiments to profile ring structure and measure the size distribution of particles in Saturn's rings. During these experiments, Cassini flew behind the ring plane and transmitted radio waves through ring particles to Earth. Researchers on Earth analyzed the signals' diffraction patterns to help determine properties of the rings. Thomson et al.

Typically study these data and find that in limited regions of rings a and b (a and b lie close to the outside of saturn's ring system), the diffraction pattern reveals the presence of fine-scale structures that are characterized by periodic radial variation in optical depth. They define specific periods of variation in optical depth for distinct regions of rings A and B. Past research suggests that the dynamic interplay of gravitational and collisional forces leads to the formation of viscous oscillations and gravity wakes in Saturn's rings. The authors speculate that the number density of ring particles contracts and relaxes to form periodic structures that affect the radio signals seen on Earth......... Posted by: Brooke      Read more         Source

November 29, 2007, 10:53 PM CT

Youngest solar systems detected

ANN ARBOR, Mich.---Astronomers at the University of Michigan have found what are thought to besome of the youngest solar systems yet detected.

The systems are around the young stars UX Tau A and LkCa 15, located in the Taurus star formation region just 450 light years away. Using a telescope that measures levels of infrared radiation, the scientists noticed gaps in the protoplanetary disks of gas and dust surrounding these stars. They say those gaps are most likely caused by infant planets sweeping those areas clear of debris.

A paper on the findings by astronomy doctoral student Catherine Espaillat, professor Nuria Calvet, and their colleagues is reported in the Dec. 1 issue of Astrophysical Journal Letters.

"Previously, astronomers were seeing holes at the centers of protoplanetary disks and one of the theories was that the star could be photoevaporating that material," said Espaillat, first author of the paper.

Photoevaporation refers to the process of heating up the dust and gas in the surrounding cloud until it evaporates and dissipates.

"We observed that in some stars, including these two, instead of a hole, there's a gap," Espaillat said. "It's more like a lane has been cleared within the disk. That is not consistent with photoevaporation. The existence of planets is the most probable theory that can explain this structure"......... Posted by: Brooke      Read more         Source

November 13, 2007, 9:28 PM CT

Regional variation in warming from sun

A NASA satellite designed, built and controlled by the University of Colorado at Boulder is expected to help researchers resolve wide-ranging predictions about the coming solar cycle peak in 2012 and its influence on Earth's warming climate, as per the chief scientist on the project.

Senior Research Associate Tom Woods of CU-Boulder's Laboratory for Atmospheric and Space Physics said the brightening of the sun as it approaches its next solar cycle maximum will have regional climatic impacts on Earth. While some researchers predict the next solar cycle -- expected to start in 2008 -- will be significantly weaker than the present one, others are forecasting an increase of up to 40 percent in the sun's activity, said Woods.

Woods is the principal investigator on NASA's $88 million Solar Radiation and Climate Experiment, or SORCE, mission, launched in 2003 to study how and why variations in the sun affect Earth's atmosphere and climate. In August, NASA extended the SORCE mission through 2012. The extension provides roughly $18 million to LASP, which controls SORCE from campus by uploading commands and downloading data three times daily to the Space Technology Building in the CU Research Park.

Solar cycles, which span an average of 11 years, are driven by the amount and size of sunspots present on the sun's surface, which modulate brightness from the X-ray to infrared portion of the electromagnetic spectrum. The current solar cycle peaked in 2002......... Posted by: Tyler      Read more         Source

November 1, 2007, 8:26 PM CT

Phoenix:Tasks En Route to Mars Include Course Tweak, Gear Checks

NASA's Phoenix Mars Lander, launched on Aug. 4 and headed to Mars, fired its four trajectory correction thrusters Wednesday for only the second time. The 45.9-second burn nudged the spacecraft just the right amount to put it on a course to arrive at the red planet seven months from today.

At Mars, Phoenix will face a challenging 7-minute descent through the atmosphere to land in the far north on May 25, 2008. After landing, it will use a robotic digging arm and other instruments during a three-month period to investigate whether icy soil of the Martian arctic could have ever been a favorable environment for microbial life. The solar-powered lander will also look for clues about the history of the water in the ice and will monitor weather as northern Mars' summer progresses toward fall.

The second course adjustment had been postponed a week to allow time for carefully returning the spacecraft to full operations after a cosmic-ray strike disrupted a computer memory chip Oct. 6. Experiences with prior spacecraft have shown hits by cosmic rays are a known hazard in deep space. The Phoenix spacecraft properly followed its onboard safety programming by putting itself into a precautionary standby state when the event occurred. Mission controllers then followed step-by-step procedures to understand the cause and resume regular operations......... Posted by: Brooke      Read more         Source

October 28, 2007, 4:18 PM CT

Mars With Ice, Shaken, Not Stirred

Mars, like Earth, is a climate-fickle water planet. The main difference, of course, is that water on the frigid Red Planet is rarely liquid, preferring to spend almost all of its time traveling the world as a gas or churning up the surface as ice. That's the global picture literally and figuratively coming into much sharper focus as various Mars-orbiting cameras send back tomes of unprecedented super high-resolution imagery of ever vaster tracts of the planet's surface.

What were just a few years ago small hints about Mars' water and climate, as seen in a few "postage-stamp" high-resolution images and topography, have given way to broader theory that explains not only the features seen on the planet today, but imply a dynamic history of Martian climate change.

"When you have postage stamps, it's like studying a hair on an arm instead of the whole arm," said Mars researcher James Head III of Brown University. Head will present the latest integrated global view of Martian surface features and how they fit with Martian climate models on Sunday, 28 October 2007, at the Geological Society of America Annual Meeting in Denver.

The pictures now reveal a range of ice-made features that show a strong preference to certain latitudes, Head explains. As on Earth, latitude-dependent features can mean only one thing: latitude-dependent climate......... Posted by: Brooke      Read more         Source

October 24, 2007, 7:31 PM CT

First-Known Belt Of Moonlets In Saturn Rings

A narrow belt harboring moonlets as large as football stadiums discovered in Saturn's outermost ring probably resulted when a larger moon was shattered by a wayward asteroid or comet eons ago, as per a University of Colorado at Boulder study.

Images taken by a camera onboard the NASA Cassini spacecraft revealed a series of eight propeller-shaped "wakes" in a thin belt of the outermost "A" ring, indicating the presence of corresponding moonlets, said CU-Boulder Research Associate Miodrag Sremcevic, lead author of the study reported in the Oct. 25 issue of Nature. The propeller wakes highlight tiny areas of the belt where ring material has been perturbed by the gravitational forces caused by individual moonlets, Sremcevic said.

The team calculated that there likely are thousands of moonlets ranging in size from semi-trailers to sports arenas embedded in the "A" ring's thin moonlet belt that circles the planet. At about 2,000 miles across, the belt of moonlets is only about 1/80th the diameter of Saturn's total ring system, which at roughly 155,000 miles across would stretch about two-thirds of the way from Earth to the moon.

"This is the first evidence of a moonlet belt in any of Saturn's rings," said Sremcevic of CU-Boulder's Laboratory for Atmospheric and Space Physics. "We have firmly established these moonlets exist in a relatively narrow region of the "A" ring, and the evidence indicates they are remnants of a larger moon that was shattered by a meteoroid or comet."........ Posted by: Brooke      Read more         Source

October 8, 2007, 9:28 AM CT

Satellite methods for monitoring volcanic activity

The central part of the Andes situated between southern Peru and Chile bears 50 active or potentially volcanoes, spread along a 1500 km-long arc. These volcanic structures mostly rise to between 4000 and 7000 m, are very remote with abrupt slopes and are often cloaked in snow. Few studies have been made on them as such conditions make field surveying extremely difficult. A team of IRD scientists working in partnership with the University of Chile (Santiago) and the Observatoire de Physique du Globe of Clermont-Ferrand (1) focused special attention on the Lastarria-Cordon del Azufre volcanic complex. With a surface area of 1600 km, it is situated in the central Andes Cordillera at the border between Argentina and Chile near Antofagasta.

Research projects on deformations of the earth crust, conducted in this region between 1992 and 2000 by a North American team, had led to the detection of a long wavelength signal over the areas topography, extracted from analysis of data collected by the European Space Agency (ESA) satellite ERS-1. This deformation would correspond to crustal inflation affecting the whole Lastarria-Cordon del Azufre complex. Eventhough this volcano is not considered as active, as the last eruption dates back 9000 years, such inflation could express an underlying activity correlation to the dynamics of a functioning magma chamber......... Posted by: Tyler      Read more         Source

October 2, 2007, 10:22 PM CT

Light on mysterious 'dark matter'

Weve all been taught that our bodies, the Earth, and in fact all matter in the universe is composed of tiny building blocks called atoms. Now imagine if this werent the case. This mind-bending concept is at the core of the scientific research that one Florida State University professor -- and hundreds of his colleagues all over the world -- are pursuing.

Recent scientific breakthroughs have shown that most of the matter in the universe -- about four-fifths -- is not made up of atoms, but of something else, called dark matter, said Howard Baer, FSUs J.D. Kimel Professor of Physics. The evidence for dark matter is now overwhelming, and the mandatory amount of dark matter is becoming precisely known.

Baer explained that dark matter is believed to exist in the form of tiny particles that do not interact with light. Because they dont emit or reflect electromagnetic radiation the way atomic, or baryonic, matter does, these dark matter particles havent been directly observed. However, researchers have long theorized their existence based on their gravitational effects on visible matter throughout the universe.

For example, the gravitational effect of dark matter makes galaxies spin faster than one would otherwise expect, Baer said. Also, dark matters gravitational field distorts the light of objects behind it -- creating the so-called lensing effect. By measuring these sorts of phenomena, we can tell that the universe is full of some sort of stuff that we just cant see......... Posted by: Brooke      Read more         Source