Posted on by Nancy Atkinson

New “Sunglasses” Help Astronomers See Light Near Black Holes

Looking at the sunset on Mauna Kea through IRPOL. Credit: U of Hawaii

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Although we can’t actually see a black hole, we can see the black hole’s effect on nearby matter. But even that is difficult because infrared light from clouds of dust and gas usually pollutes the view. But astronomers have found a way to get a clean view of the disks surrounding black holes by using a polarizing filter in the infrared. This technique works in particular when the region immediately surrounding the black hole emits a small amount of scattered light. Since scattered light is polarized, astronomers can use a filter that works like polarized sunglasses on large telescopes to detect this small amount of scattered light and measure it with unprecedented accuracy. Scientists have theorized these luminous disks existed around black holes, but until now have not been able to observe them.

The United Kingdom Infrared Telescope (UKIRT) on Mauna Kea in Hawaii has such an infrared filter, called a polarimeter (IRPOL). Astronmers have been using UKIRT and IRPOL and other telescopes for many years to search for proof that such a luminous supermassive black hole is accreting materials in a particular form of disk, where the disk shines directly using the gravitational binding energy of the black hole. Theorists have long thought that such disks should exist, and while there is a well-developed theory for it, until now theory and observations have been contradictory.

Dr. Makoto Kishimoto of the Max Planck Institute, principal investigator of this project, says: “After many years of controversy, we finally have very convincing evidence that the expected disk is truly there. However, this doesn’t answer all of our questions. While the theory has now been successfully tested in the outer region of the disk, we have to proceed to develop a better understanding of the regions of the disk closer to the black hole. But the outer disk region is important in itself – our method may provide answers to important questions for the outer boundary of the disk.”

A polarizing filter allows the colors of disk to be seen. Figure by M. Kishimoto, with cloud image by Schartmann
A polarizing filter allows the colors of disk to be seen. Figure by M. Kishimoto, with cloud image by Schartmann

Dr. Robert Antonucci of the University of California at Santa Barbara, a fellow investigator, says: “Our understanding of the physical processes in the disk is still rather poor, but now at least we are confident of the overall picture.”

Astronomers are hoping this new method will provide more information about the disks surrounding black holes in the near future.

Now, next on the agenda should be developing a suitable gravitational wave detector to confirm the existence of black holes!

Original News Source: University of Hawaii

Posted on by Nancy Atkinson

Ancient Galactic Magnetic Fields Stronger than Expected

Spiral galaxy M 51 with magnetic field data. Credit: MPIfR Bonn

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The origin of magnetic fields in our universe is a mystery. But magnetic fields are a key part of the interstellar medium and scientists are finding they may play a major role in galactic formation, such as helping to form the spiral arms of galaxies. Until recently, however scientists believed the strength of galactic magnetic fields increased over time as galaxies matured, and in the early universe, these magnetic fields were initially very weak. But, recently a team of scientists looking back to probe the ancient universe as it existed 8 to 9 billion years ago has found that the magnetic fields of ancient galaxies were just as strong as they are today, prompting a rethinking of how our galaxy and others may have formed.

Using the European Southern Observatory’s 8-meter telescope located in Chile, a team of scientists from the Los Alamos National Laboratory and the Swiss Federal Institute of Technology studied 70 galaxies similar to the Milky Way at optical wavelengths. They combined their data with 25 years of radio wave observations of magnetic fields that measured how far the radio waves were pulled toward the red end of the spectrum, known as “redshift” using Faraday rotation measures.

Serving as a looking glass into the past, the powerful telescope at the European Southern Observatory, adding to the radio rotation measures, allowed the scientists to observe surprisingly high magnetic fields between 8 billion and 9 billion years ago in the 70 galaxies studied. That means that several billion years before the existence of our own sun, and within only a few billion years of the Big Bang, ancient galaxies were exerting the tug of these strong magnetic fields.

“It was thought that, looking back in the past, earlier galaxies would not have generated much magnetic field,” said Philipp Kronberg of LANL. “The results of this study show that the magnetic fields within Milky Way-like galaxies have been every bit as strong over the last two-thirds of the Universe’s age as they are now-and possibly even stronger then.”

Astronomers had thought a mechanism called a dynamo, which transfers mechanical energy into magnetic energy was responsible for galactic magnetic fields. In that case, with the right configuration gas flow could generate a higher magnetic field from a weaker seed field. (Again, we have yet to understand how galactic magnetic fields originally form.) But this new research suggests that the magnetic fields in galaxies did not arise due to a slow, large-scale dynamo effect, which would have taken 5 billion to 10 billion years to reach their current measured levels.

“There must be some other explanation for a much quicker and earlier amplification of galactic magnetic fields,” Kronberg said. “From the time when the first stars and galaxies formed, their magnetic fields have probably have been amplified by very fast dynamos. One good possibility is that it happened in the explosive outflows that were driven by supernovae, and possibly even black holes in the very earliest generations of galaxies.”

This realization brings a new focus on the broader question of how galaxies form. Instead of the commonly held view that magnetic fields have little relevance to the genesis of new galaxies, it now appears that they are indeed important players. If so, strong magnetic fields a long time ago are one of the essential ingredients that explain the very existence of our galaxy and others like it.

Original News Source: Los Alamos National Lab

Posted on by Nancy Atkinson

Phoenix Lander Couldn’t Sleep At All Last Night

TEGA oven doors wide open. Credit: NASA/JPL-Caltech/University of Arizona/Texas A&M University

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For the first time, the Phoenix lander stayed up all night. But there was no partying for the little lander, just hard work. Phoenix coordinated its schedule to work together with the Mars Reconnaissance Orbiter to make joint observations to study Mars’ atmosphere. More on that in a minute, but the other big news from the Phoenix lander is that the doors to the Thermal and Evolved Gas Analyzer (TEGA) oven successfully opened, and the device is now ready to accept a sample of icy soil. If you remember, way back in the beginning of the mission, on about Sol 8, the first time the science team relayed orders for the spring-loaded oven doors to open, the doors only opened partially and the team had to vibrate the oven to get the soil inside. But this time, the 10 cm (4 inch) doors stands wide open, and today Phoenix will perfect its techniques to quickly get the icy soil sample inside the oven before the ice sublimates.

Now, about those atmospheric observations: Phoenix used its weather station, stereo camera and conductivity probe to monitor changes in the lower atmosphere and ground surface at the same time MRO studied the atmosphere and ground from above. The orbiter flew repeatedly over Phoenix’s location last evening, so it was good timing for a coordinated effort.

“We are looking for patterns of movement and phase change,” said Michael Hecht, lead scientist for Phoenix’s Microscopy, Electrochemistry and Conductivity Analyzer, which includes the lander’s fork-like thermal and conductivity probe. “The probe is working great. We see some changes in soil electrical properties, which may be related to water, but we’re still chewing on the data.”

The probe was inserted into the soil Sunday for more than 24 hours of measurements coordinated with the atmosphere observations. One goal is to watch for time-of-day changes such as whether some water alters from ice phase to vapor phase and enters the atmosphere from the soil.

The Phoenix team’s plans also include commanding the lander to conduct additional testing of the techniques for collecting a sample of icy soil. When the team is confident about the collecting method, it plans to use Phoenix’s robotic arm to deliver an icy sample to an oven of TEGA.

The team wants to make sure their techniques will quickly bring the soil into the oven, as it’s possible the oven will only work for one more test. The vibrating done to get the soil into the oven for the previous test caused a short circuit that may happen again the next time the oven is activated. The short could be fatal to the oven, but of course, we’re all still holding out hope for a better case scenario.

Original News Source: Phoenix News site

Posted on by Nancy Atkinson

No Life Possible at Edges of the Pinwheel Galaxy

The bright red spots at the edge of the Pinwheel Galaxy means bad news for life. Image credit: NASA/JPL-Caltech/STScI

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Another beautiful image from the Spitzer Space Telescope; in this case, it’s Messier 101, more commonly known as the Pinwheel Galaxy. But the pretty red highlights at the edges of the galaxy are bad news for anyone looking for evidence of life. “If you were going look for life in Messier 101, you would not want to look at its edges,” said Karl Gordon of the Space Telescope Science Institute. “The organics can’t survive in these regions, most likely because of high amounts of harsh radiation.” The red color highlights a zone where organic molecules called polycyclic aromatic hydrocarbons (PAHs), which are present throughout most of the galaxy, suddenly disappear.

PAHs are dusty, carbon-containing molecules found in star nurseries. They’re also found on Earth in barbeque pits, exhaust pipes and anywhere combustion reactions take place. Scientists believe this space dust has the potential to be converted into the stuff of life.

The Pinwheel galaxy is located about 27 million light-years away in the constellation Ursa Major. It has one of the highest known gradients of metals (elements heavier than helium) of all nearby galaxies in our universe. In other words, its concentrations of metals are highest at its center, and decline rapidly with distance from the center. This is because stars, which produce metals, are squeezed more tightly into the galaxy’s central quarters.

Gordon’s team also wanted to learn more about the gradient of the PAHs. Using Spitzer’s Infrared Array Camera and the Infrared Spectograph to carefully analyze the spectra of the PAHs, astronomers can more precisely identify the PAH features, and even deduce information about their chemistry and temperature. The astronomers found that, like the metals, the polycyclic aromatic hydrocarbons decrease in concentration toward the outer portion of the galaxy. But, unlike the metals, these organic molecules quickly drop off and are no longer detected at the very outer rim.

“There’s a threshold at the rim of this galaxy, where the organic material is getting destroyed,” said Gordon.

The findings also provide a better understanding of the conditions under which the very first stars and galaxies arose. In the early universe, there were not a lot of metals or PAHs around. The outskirt of the Pinwheel galaxy therefore serves as a close-up example of what the environment might look like in a distant galaxy.

In this image, infrared light with a wavelength of 3.6 microns is colored blue; 8-micron light is green; and 24-micron light is red. All three of Spitzer instruments were used in the study: the infrared array camera, the multiband imaging photometer and the infrared spectrograph.

Original News Source: JPL

Posted on by Nancy Atkinson

NASA to Develop GPS-Like System for the Moon

Future astronauts may use GPS-like system. Credit: The Ohio State University

During the second moonwalk of the Apollo 14 mission, Alan Shepard and Edgar Mitchell were hoping to walk to the 300 meter (1,000 feet) wide Cone Crater on the moon, not far from their landing site. However, the two astronauts were not able to find the crater’s rim amid the rolling, repetitive terrain. Later analysis using pictures the two astronauts took determined they had come within 65 feet of the crater. People are used to having certain visual cues to judge distances, such as the size of a building or another car on the horizon, said Ron Li, who has been awarded a $1.2 million grant to develop a navigation system to be used on the moon. Since the moon has no landmarks or cues to help determine distance, getting lost, or misjudging a distant object’s size and location would be easy, and extremely dangerous. New technology like sensors, inertial navigation systems, cameras, computer processors, and image processors will make the next trip to the moon easier for astronauts.

Li, from The Ohio State University, developed software for the Mars rovers Spirit and Opportunity, which has helped him learn a lot about navigation. The navigation system to help future astronauts find their way around moon won’t use satellites; instead the system will rely on signals from a set of sensors including lunar beacons, stereo cameras, and orbital imaging sensors.

Images taken from orbit will be combined with images from the surface to create maps of lunar terrain. Motion sensors on lunar vehicles and on the astronauts themselves will allow computers to calculate their locations. Signals from lunar beacons, the lunar lander, and base stations will give astronauts a picture of their surroundings similar to what drivers see when using a GPS device on Earth. The researchers have named the entire system the Lunar Astronaut Spatial Orientation and Information System (LASOIS).

Astronauts will have a keypad and screen, possibly right on their spacesuits, to view their location and search for new destinations.

Keeping astronauts safe will be a top priority for Li’s team, which includes experts in psychology and human-computer interaction as well as engineering.

“We will help with navigation, but also with astronauts’ health as well,” Li said. “We want them to avoid the stress of getting lost, or getting frustrated with the equipment. Lunar navigation isn’t just a technology problem, it’s also biomedical.”

News Source: The Ohio State University

Posted on by Nancy Atkinson

NASA’s Use of Cadavers to Test the Orion Capsule

Orion Crew Capsule. Credit: Howstuffworks.com

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NASA is debating whether the new Orion capsule should land in the water, like Apollo, or on land, similar to how the Russian Soyuz capsule returns to Earth. To help them determine the potential for human injuries with each possible landing scenario, NASA has used human cadavers during their tests. At first, this revelation may seem quite morbid or even gruesome. But as Keith Cowing said in his expose article on Space Ref and NASA Watch on this subject, “Given the potentially hazardous nature of the tests required, cadavers must be used in the place of living persons.” Sometimes, crash-test dummies or computer simulations don’t provide the crucial information needed, such as the forces on the spinal cord or internal organs. If NASA doesn’t have that information, they can’t get accurate test results. Living test subjects could possibly be killed during the landing tests. Imagine the headlines if that happened. So they have used cadavers. The cadavers NASA used were donated to science to be used for exactly this type of purpose, and NASA, of course, went through the proper channels to obtain the cadavers and treats them in an ethical manner. So while this may seem a little grisly, NASA is doing the right thing.

Marc Carreau from the Houston Chronicle also wrote an article on this subject, and he interviewed David Steitz, a spokesman for NASA’s medical division. “It’s a socially awkward topic,” Steitz said. “The bodies are all carefully handled through all of the tests. We follow ethical medical procedures with these bodies that have been donated for science.”

Three human bodies were used during testing last year, said NASA seat engineer Dustin Gohmert, to help determine the potential for serious human injury during descent and landing. “The interface between the spacesuit and the seats is relatively complex, much more so than in an automobile, even one from the racing industry,” Gohmert said. “The (forces) we anticipate have never been studied before. We are using this research to help define and refine the suits and the seats.”

Tests using human bodies has been done for previous spacecraft, as well.

Cowing received this statement from NASA on the use of cadavers:

“In limited cases, postmortem human subject tests may be performed when insufficient data are available from simulations that use dummies or from mathematical modeling of the human body responses. This is particularly critical where the dynamic responses of internal organs and soft tissue must be evaluated. Using a combination of test methods, the engineering and scientific teams at NASA are able to enhance astronaut safety by designing landing attenuation systems that will minimize accelerations imparted to the crew and significantly reduce the potential for injuries.”

Personally, I could imagine donating my body for this type of research. Even if I never get to fly to space when I’m alive, I’d be proud to help the rest of the human race get there and return safely by giving my body for tests such as this.

News Sources: NASA Watch, Space Ref, Houston Chronicle

Posted on by Nancy Atkinson

Hubble Survey of Gravitational Lenses Yields Measure of Dark Matter in Distant Galaxies

Hubble Space Telescope image shows Einstein ring of one of the SLACS gravitational lenses, with the lensed background galaxy enhanced in blue. A. Bolton (UH/IfA) for SLACS and NASA/ESA.

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An international team of astronomers have compiled the largest-ever single collection of “gravitational lens” galaxies, and their survey yielded information on the masses of galaxies, including an inference of the amount of dark matter. Gravitational lensing occurs when two galaxies happen to aligned with one another along our line of sight in the sky. The gravitational field of the nearer galaxy distorts the image of the more distant galaxy into multiple arc-shaped images. Sometimes this effect even creates a complete ring, known as an “Einstein Ring.” The findings of this survey helps settle a long standing debate over the relationship between and mass and luminosity in galaxies.

Using the Advanced Camera for Surveys on the Hubble Space Telescope to image galaxies that had been identified as gravitational lens galaxies by the Sloan Digital Sky Survey, the team was able to measure the distances to both galaxies in each “lensing” set, as well as measure the masses of each galaxy.

Gravitational lensing creates a “mirage” of a ring, and the Einstein ring images can be up to 30 times brighter than the image of the distant galaxy would be in the absence of the lensing effect. By combining Hubble and Sloan data into the Sloan Lens ACS (or SLACS) Survey, the team was able to make a mathematical model describing the lensing effect and use that model to illustrate what we would see if we could remove the lensing effect.

Animation of the lensing effect.

“The SLACS collection of lenses is especially powerful for science,” said Adam Bolton from the University of Hawaii, lead author of two papers describing these latest results. “For each lens, we measured the apparent sizes of the Einstein rings on the sky using the Hubble images, and we measured the distances to the two galaxies of the aligned pair using Sloan data. By combining these measurements, we were able to deduce the mass of the nearer galaxy.”

By considering these galaxy masses along with measurements of their sizes, brightnesses, and stellar velocities, the SLACS astronomers were able to infer the presence of “dark matter” in addition to the visible stars within the galaxies. Dark matter is the mysterious, unseeable material that is the majority of matter in the universe. And with such a large number of lens galaxies across a range of masses, they found that the fraction of dark matter relative to stars increases systematically when going from galaxies of average mass to galaxies of high mass.

Mosaic of the SLACS galaxies. Credit: SLACS and NASA/ESA.
Mosaic of the SLACS galaxies. Credit: SLACS and NASA/ESA.

Albert Einstein predicted the existence of gravitational lenses in the 1930’s, but the first example was not discovered until the late 1970s. Since then, many more lenses have been discovered, but their scientific potential has been limited by the disparate assortment of known examples. The SLACS Survey has significantly changed this situation by discovering a single large and uniformly selected sample of strong lens galaxies. The SLACS collection promises to form the basis of many further scientific studies.

Original News Source: University of Hawaii

Posted on by Nancy Atkinson

Mars Arctic in 3D from Phoenix

OK, everyone: get out your funky 3-D glasses for a whole new look at Mars! We’ve seen the smooth plains of Meridiani from Opportunity in 3-D; we’ve gazed upon the rocky terrain of Gusev Crater from Spirit in more than two dimensions. But now it’s time to feast your eyes on Mars’ arctic tundra as its never been seen before: in super frozen 3-D from the Phoenix lander! The image above shows a color, stereoscopic 3D view of the Martian surface near the lander, and is one of Phoenix’s workplaces called “Wonderland.” But wait! There’s more…..


This 3-D view is from an image acquired by Phoenix’s Surface Stereo Imager on Sol 33, the 33rd Martian day of the mission (June 28, 2008). Phoenix’s solar panel is seen in the bottom right corner of the image.


Here’s a close up view of where all the action has been taking place recently: the trench called “Snow White.” The hole to the left of the trench, seen in the upper left of the image, is informally called “Burned Alive. This image was taken on Sol 22, but recently, Phoenix has scooped and rasped the area in an effort to get “shaved ice” samples.

Here’s a great touchy-feely 3-D image (don’t you just want to reach out and touch that rock?) The largest rock seen in this image is called “Midgard.” The edge of Phoenix’s deck is seen in the bottom right corner of the image.

There’s lots more 3-D loveliness at the Phoenix Image Gallery. Have fun!

Posted on by Nancy Atkinson

Super-Sensitive, Ultra-Small Device Heightens Infrared Capabilities

Physics Prof. Michael Gershenson with laboratory equipment used to fabricate ultra-sensitive, nano-sized infrared light detector. Credit: Carl Blesch

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A tiny new circuit could make a big difference in the way astronomers can see infrared light. This newly developed nano-sized electronic device is 100 times smaller than the thickness of a human hair, and is sensitive to faint traces of light in the far-infrared spectrum, well beyond the colors humans see. Infrared light makes up 98% of the light emitted since the Big Bang. Better detection methods with this new device should provide insights into the earliest stages of star and galaxy formation almost 14 billion years ago.


“In the expanding universe, the earliest stars move away from us at a speed approaching the speed of light,” said Michael Gershenson, professor of physics at Rutgers and one of the lead investigators. “As a result, their light is strongly red-shifted when it reaches us, appearing infrared.”

But Earth’s thick atmosphere absorbs far-infrared light, and ground-based radio telescopes cannot detect the very faint light emitted by these far-away stars. So scientists are proposing a new generation of space telescopes to gather this light. But new and better detectors are needed to take the next step in infrared observing.

Currently bolometers are used, which detect infrared and submillimeter waves by measuring the heat generated when photons are absorbed.

“The device we built, which we call a hot-electron nanobolometer, is potentially 100 times more sensitive than existing bolometers,” Gershenson said. “It is also faster to react to the light that hits it.”
The new device is made of titanium and niobium metals. Its about 500 nanometers long and 100 nanometers wide and was made using techniques similar to those used in computer chip manufacturing. The device operates at very cold temperatures – about 459 degrees below zero Fahrenheit, or one-tenth of one degree above absolute zero on the Kelvin scale.

Photons striking the nanodetector heat electrons in the titanium section, which is thermally isolated from the environment by superconducting niobium leads. By detecting the infinitesimal amount of heat generated in the titanium section, one can measure the light energy absorbed by the detector. The device can detect as little as a single photon of far infrared light.

“With this single detector, we have demonstrated a proof of concept,” said Gershenson. “The final goal is to build and test an array of 100 by 100 photodetectors, which is a very difficult engineering job.”

Rutgers and the Jet Propulsion Laboratory are working together to build the new infrared detector.
Gershenson expects the detector technology to be useful for exploring the early universe when satellite-based far-infrared telescopes start flying 10 to 20 years from now. “That will make our new technology useful for examining stars and star clusters at the farthest reaches of the universe,” he said.

The team’s orginal paper can be found here.
Original News Source: Rutgers State University

Posted on by Nancy Atkinson

How Future Missions Could Detect Organisms Inside Rocks on Mars

Jarosite in New Zealand. Credit: Michelle Kotler

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For a geologist, looking inside a rock is essential to help determine the makeup and history of the rock sample. That’s why geologists have rock hammers, and also why the Mars Exploration Rovers, Spirit and Opportunity, have their Rock Abrasion Tool. For future missions to Mars, or even for a sample return mission, one of the main goals will be to look for signs of life, past or present, that might be hiding inside the rocks. Scientists are working on a new, simple technique for detecting biological and pre-biotic molecules that become trapped inside the minerals in rocks.

This new technique utilizes a laser-based optical and chemical imager or LOCI. A single laser shot vaporizes a small portion of the surface into individual ions. These pass through a mass spectrometer, which can identify each ion by how much mass and charge it has. The great thing about this technique is that the sample requires no preparation: just shoot and detect.

Previous techniques for required that the minerals be dissolved in a solution or mixed in with some other medium, which dilutes the sample and runs the risk of introducing contamination.

Jill Scott of Idaho National Laboratory with the laser-based optical and chemical imager (LOCI). Credit: Idaho National Lab
Jill Scott of Idaho National Laboratory with the laser-based optical and chemical imager (LOCI). Credit: Idaho National Lab
This procedure was tested on Earth using samples of the mineral jarosite. Jarosite is a yellowish-brown sulfate mineral containing iron, potassium and hydroxide. It is found in places around the world such as southern California beaches and volcanic fields in New Zealand. It forms only in the presence of highly acidic water.

In 2004, jarosite was discovered on Mars by the rover Opportunity. Scientists immediately recognized the find as clear evidence for past water on the red planet.

But there is something else about jarosite that makes it interesting. On Earth, for jarosite to form, oxidation of the rock must occur – usually the rock is pyrite (ferrous sulfide). And on Earth, the oxidation reaction is usually performed by certain “rock-eating” microorganisms.

Scientists say the rate of the jarosite formation would be extremely slow without microbes, as well as without the presence of water.

Whether jarosite can form without the assistance of these microbes is very difficult to say, since every corner of Earth is occupied by little bugs of some sort or another.

And yet, there remains the tantalizing possibility that jarosite on Mars exists because of some little, rock-eating microbes. If so, remnants of these organisms may be locked in the mineral. And there’s only one way to find out: look inside Mars rocks.

Right now, this method couldn’t be used on the next bigger Mars rover, the Mars Science Laboratory, which will hopefully launch in 2009. The LOCI instrument is just too big and too complex to use remotely, said David Beaty, chief scientist of the Mars Exploration Directorate at the Jet Propulsion Laboratory.

But it could be used on a sample return mission. But hopefully, scientists will be able to develop a smaller, simpler version to be used on future missions to look for signs of life in rocks on Mars.

Original News Source: Astrobiology Magazine