Friday, July 18, 2014

Ten-Year Endeavor: NASA's Aura Tracks Pollutants

Ten-Year Endeavor: NASA's Aura Tracks Pollutants:

The maps show the Antarctic ozone hole on September 16 in 2006 and 2011
The maps show the Antarctic ozone hole on September 16 in 2006 and 2011, the two years with the lowest ozone concentrations ever measured. They were made with data from the Ozone Monitoring Instrument on Aura. Image Credit: NASA's Earth Observatory

› Larger image


July 16, 2014

NASA's Aura satellite, celebrating its 10th anniversary on July 15, has provided vital data about the cause, concentrations and impact of major air pollutants. With instruments providing key measurements of various gases - including two built and managed by NASA's Jet Propulsion Laboratory: the Tropospheric Emission Spectrometer (TES) and Microwave Limb Sounder (MLS) -- Aura gives a comprehensive view of one of the most important parts of Earth -- the atmosphere.

Aura has improved our understanding of ozone, a versatile gas that both benefits and harms the atmosphere, depending on its location. Near the ground, ozone is a pollutant that damages plants and can decrease lung function in humans. Somewhat higher in the atmosphere, ozone affects climate as a greenhouse gas. Aura's TES instrument provides measurements of ozone and other greenhouse gases.

The majority of ozone, about 90 percent, is even higher -- in the stratosphere, 12 to 90 miles above the surface -- where it shields us from the sun's ultraviolet light and makes life possible on Earth. Over the Antarctic, cold temperatures and human-produced chlorine gases destroy ozone each spring. Scientists use Aura's Microwave Limb Sounder (MLS) instrument to measure ozone and other trace gases in and around the ozone hole every year. In 2006 and 2011, Aura's instruments revealed two of the largest and deepest ozone holes in the past decade, and also helped scientists understand the different causes of the two large holes.

Shortly after Aura's launch, the Ozone Monitoring Instrument (OMI) began monitoring levels of another major pollutant -- nitrogen dioxide. This brownish gas can lead to respiratory problems and is an ingredient in ground-level ozone pollution. OMI data show that nitrogen dioxide levels in the United States decreased 4 percent per year from 2005 to 2010, a time when stricter policies on power plant and vehicle emissions came into effect. As a result, concentrations of ground-level ozone also decreased. During the same period, global nitrogen dioxide levels increased a little over half a percent per year. China's level increased about 6 percent per year.

OMI also measures sulfur dioxide, a gas that combines with other chemicals in clouds to produce acid rain or reacts to form sulfate aerosols, which affect health and climate. OMI has identified large concentrations of sulfur dioxide around power plants and volcanoes.

Aura's decade of work has set the stage for future air quality monitoring instruments. The European Space Agency will be launching the follow-up TROPOspheric Monitoring Instrument, which will continue Aura's OMI measurements with better ground resolution and precision. NASA plans to launch the Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument, which will observe ozone, nitrogen dioxide, sulfur dioxide, formaldehyde and aerosols over the United States, Canada and Mexico.

"Pollution is a global issue because it can travel long distances in the wind," said Anne Douglass, Aura project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "By using satellites, we can develop a valuable global inventory of pollutants and understand how air quality may be changing."

For more on Aura's 10-year contribution to atmospheric chemistry research, visit:

http://www.nasa.gov/content/goddard/ten-year-endeavor-nasa-s-aura-and-the-ozone-layer/

and

http://www.nasa.gov/content/goddard/ten-year-endeavor-nasa-s-aura-tracks-pollutants/

For more on TES, visit:

http://tes.jpl.nasa.gov/

For more on MLS, visit:

http://mls.jpl.nasa.gov/index-eos-mls.php

NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA's Earth science activities in 2014, visit:

http://www.nasa.gov/earthrightnow

Alan Buis

818-354-0474

Jet Propulsion Laboratory, Pasadena, Calif.

Alan.Buis@jpl.nasa.gov


Written by Kasha Patel

NASA Goddard Space Flight Center, Greenbelt, Md.


2014-233
Posted by Nelio Inacio at 7:22 AM 0 comments

Rosetta Spacecraft Approaching Twofold Comet

Rosetta Spacecraft Approaching Twofold Comet:

Rosetta Mission's Destination: Comet 67P/Churnyumov-Gerasimenko
The OSIRIS instrument on the European Space Agency's Rosetta spacecraft photographed the mission's destination comet on July 14, 2014, from about 7,500 miles away. The images show that comet 67P/Churyumov-Gerasimenko has a two-part shape. The version at right is enhanced with interpolated data. Credit: ESA/Rosetta/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
› Full image and caption


July 17, 2014

As the European Space Agency's spacecraft Rosetta is slowly approaching its destination, comet 67P/Churyumov-Gerasimenko, the comet is again proving to be full of surprises. New images obtained by OSIRIS, the onboard scientific imaging system, confirm the body's peculiar shape hinted at in earlier pictures. Comet 67P is obviously different from other comets visited so far.

"The distance still separating Rosetta from 67P is now far from astronomical," said OSIRIS Principal Investigator Holger Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany. "It's a trip of less than 14,000 kilometers [about 8,700 miles]. That's comparable to traveling from Germany to Hawaii on a summer holiday."

However, while taking a snapshot of Mauna Kea, Hawaii's highest mountain, from Germany is an impossible feat, Rosetta's camera OSIRIS is doing a great job at catching ever clearer glimpses of its similarly sized destination. Images obtained on July 14 clearly show a tantalizing shape. The comet's nucleus consists of two distinctly separated parts.

"This is unlike any other comet we have ever seen before," said OSIRIS project manager Carsten Güttler from the MPS. "The images faintly remind me of a rubber ducky with a body and a head." How 67P received this intriguing shape is still unclear. "At this point we know too little about 67P to allow for more than an educated guess," said Sierks. In the next months, the scientists hope to determine more of the comet's physical and mineralogical properties. These could help them determine whether the comet's body and head were formerly two individual bodies.

In order to get an idea of what seems to be a very unique body, the observed image data can be interpolated to create a smoother shape. "There is, of course, still uncertainty in these processed, filtered images, and the surface will not be as smooth as it now appears," Güttler pointed out. "But they help us get a first idea."

Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by the German Aerospace Center, Cologne; Max Planck Institute for Solar System Research, Gottingen; French National Space Agency, Paris; and the Italian Space Agency, Rome. NASA's Jet Propulsion Laboratory, Pasadena, California, a division of the California Institute of Technology, Pasadena, manages the U.S. participation in the Rosetta mission for NASA's Science Mission Directorate in Washington. Rosetta carries three NASA instruments in its 21-instrument payload.

For more information on the U.S. instruments aboard Rosetta, visit:

http://rosetta.jpl.nasa.gov

More information about Rosetta is available at:

http://www.esa.int/rosetta

Guy Webster

Jet Propulsion Laboratory, Pasadena, Calif.

818-354-6278

guy.webster@jpl.nasa.gov


Dwayne Brown

NASA Headquarters

202-358-1726

dwayne.c.brown@nasa.gov


Markus Bauer

European Space Agency, Noordwijk, Netherlands

011-31-71-565-6799

markus.bauer@esa.int


Birgit Krummheuer

Max Planck Institute for Solar System Research

011-49-551-384-979-462

krummheuer@mps.mpg.de


2014-234
Posted by Nelio Inacio at 7:21 AM 0 comments

A 10-Year Endeavor: NASA's Aura and Climate Change

A 10-Year Endeavor: NASA's Aura and Climate Change:

NASA's 10-year-old Aura satellite, which studies Earth's atmosphere
NASA's 10-year-old Aura satellite, which studies Earth's atmosphere, continues to help scientists understand Earth's changing climate.
Credit: NASA


› Larger image


July 17, 2014

Nitrogen and oxygen make up nearly 99 percent of Earth's atmosphere. The remaining one percent is comprised of gases that -- although present in small concentrations -- can have a big impact on life on Earth. Trace gases called greenhouse gases warm the surface, making it habitable for humans, plants and animals. But these greenhouse gases, as well as clouds and tiny particles called aerosols in the atmosphere, also play vital roles in Earth's complex climate system.

Celebrating its 10th anniversary this week, NASA's Aura satellite and its four onboard instruments measure some of the climate agents in the atmosphere, including greenhouse gases, clouds and dust particles. These global datasets provide clues that help scientists understand how Earth's climate has varied and how it will continue to change.

Measuring Greenhouse Gases

When the sun shines on Earth, some of the light reaches and warms the surface. The surface then radiates this heat back outward, and greenhouse gases stop some of the heat from escaping to space, keeping the surface warm. Greenhouse gases are necessary to keep Earth at a habitable temperature, but since the Industrial Revolution, greenhouse gases have increased substantially, causing an increase in temperature. Aura provides measurements of greenhouse gases such as ozone and water vapor, helping scientists understand the gases that influence climate.

People, plants and animals live in the lowest layer of the atmosphere, called the troposphere. In this layer, the temperature decreases with altitude, as mountain climbers experience. The temperature starts to increase again at the tropopause, about 8 miles (12.9 kilometers) above the surface at temperate latitudes, like those of the United States and Europe. Closer to the equator, the tropopause is about 11 miles (17.7 kilometers) from the surface.

In the middle and upper troposphere, ozone acts as a greenhouse gas, trapping heat in Earth's atmosphere. Tropospheric ozone is one of the most important human-influenced greenhouse gases.

Aura's Tropospheric Emission Spectrometer (TES) instrument, built and managed by NASA's Jet Propulsion Laboratory, Pasadena, California, delivers global maps showing annual averages of the heat absorbed by ozone, in particular in the mid troposphere. Using these maps and computer models, researchers learned that ozone trapped different amounts of heat in Earth's atmosphere depending on its geographic location. For instance, ozone appeared to be a more effective greenhouse gas over hotter regions like the tropics and cloud-free regions like the Middle East.

"If you want to understand climate change, you need to monitor the greenhouse gases and how they change over time," said Bryan Duncan, an atmospheric scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Along with ozone, Aura measures other important greenhouse gases such as methane, carbon dioxide and water vapor.

Improving Climate Models

In addition to greenhouse gases, Aura measures several other constituents relevant to climate -- smoke, dust and clouds including the ice particles within the clouds -- that are important for testing and improving climate models.

"If you don't have any data, then you don't know if the models are right or not," said Anne Douglass, Aura project scientist at Goddard. "The models can only be as good as your knowledge."

The way clouds affect Earth's climate depends on their altitude and latitude. Two of Aura's instruments have provided information about tropical clouds. Like greenhouse gases, high, thin clouds in the tropics absorb some of Earth's outgoing heat and warm the surface. Aura's High Resolution Dynamics Limb Sounder (HIRDLS) instrument provided global maps showing cirrus clouds in the upper altitudes in the tropics. Researchers have used these data along with data records from previous satellites going back to 1985 to show that the tropical cirrus cloud distribution has been steady, giving scientists information about the interplay among water vapor, ice and the life cycle of these clouds.

Aura's Microwave Limb Sounder (MLS) instrument, also built and managed by JPL, made the first global measurements of cloud ice content in the upper troposphere, providing new data input for climate models. MLS showed cloud ice is often present over warm oceans. Along with satellite rainfall data, MLS shows that dirty, polluted clouds rain less than clean clouds. The novel relationships obtained from HIRDLS and MLS connect ocean temperatures with clouds and ice and quantify effects of pollution on tropical rainfall -- which are important assessments for climate models.

Aerosols influence climate, but their influence is challenging to decipher because they play several different roles. Aerosols reflect radiation from the sun back into space; this tends to cool Earth's surface. Aerosols such as dust and smoke also absorb radiation and heat the atmosphere where they are concentrated. Aura's Ozone Monitoring Instrument (OMI) is especially good at observing these absorbing aerosols above clouds and bright deserts. Both OMI and TES also provide data on gases, such as sulfur dioxide and ammonia, which are primary ingredients for other types of less-absorbing aerosols. Aura data, in conjunction with other satellite data, are helping scientists understand how aerosols interact with incoming sunlight in Earth's atmosphere; this, in turn, helps scientists improve long-term predictions in climate models.

Learning from Long Data Sets

Researchers investigated how natural phenomena such as El Niño affect tropospheric ozone concentrations -- a study made possible by Aura's extensive data set.

El Niño is an irregularly occurring phenomenon associated with warm ocean currents near the Pacific coast of South America that changes the pattern of tropical rainfall. The occasional appearance of areas of warmer temperatures in the Pacific Ocean shifts the stormiest area from the west to the east; the region of upward motion -- a hallmark of low ozone concentrations over the ocean -- moves along with it.

Without a decade-long data record, researchers would not be able to conduct such a study. Using the extensive data set, researchers are able to separate the response of ozone concentrations to the changes in human activity, such as biomass burning, from its response to natural forcing such as El Niño.

"Studies like these that investigate how the composition of the troposphere responds to a natural variation are important for understanding how the Earth system will respond to other forcing, potentially including changes in climate," said Douglass. "The Earth system is complex, and Aura's breadth and the length of the composition data record help us to understand this important part of the system."

For more information on Aura, visit:

http://aura.gsfc.nasa.gov/

For more on TES, visit:

http://tes.jpl.nasa.gov/

For more on MLS, visit:

http://mls.jpl.nasa.gov/index-eos-mls.php

NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA's Earth science activities in 2014, visit:

http://www.nasa.gov/earthrightnow

Alan Buis

818-354-0474

Jet Propulsion Laboratory, Pasadena, California

Alan.buis@jpl.nasa.gov


Written by Kasha Patel

NASA Goddard Space Flight Center, Greenbelt, Maryland


2014-236
Posted by Nelio Inacio at 7:21 AM 0 comments

Wednesday, July 16, 2014

Colossal Hot Cloud Envelopes Colliding Galaxies

Colossal Hot Cloud Envelopes Colliding Galaxies:

NGC 6240

Scientists have used
Chandra to make a detailed study of an enormous cloud of hot gas
enveloping two large, colliding galaxies. This unusually large
reservoir of gas contains as much mass as 10 billion Suns, spans
about 300,000 light years, and radiates at a temperature of more
than 7 million degrees.

This giant gas cloud,
which scientists call a "halo," is located in the system called NGC
6240. Astronomers have long known that NGC 6240 is the site of the
merger of two large spiral galaxies similar in size to our own
Milky Way. Each galaxy contains a supermassive black hole at its
center. The black holes are spiraling toward one another, and may
eventually merge to form a larger black hole.

Another consequence of the collision between the galaxies
is that the gas contained in each individual galaxy has been
violently stirred up. This caused a baby boom of new stars that has
lasted for at least 200 million years. During this burst of stellar
birth, some of the most massive stars raced through their evolution
and exploded relatively quickly as supernovas.

The scientists involved with this study argue that this
rush of supernova explosions dispersed relatively high amounts of
important elements such as oxygen, neon, magnesium, and silicon
into the hot gas of the newly combined galaxies. According to the
researchers, the data suggest that this enriched gas has slowly
expanded into and mixed with cooler gas that was already
there.

During the extended baby boom, shorter
bursts of star formation have occurred. For example, the most
recent burst of star formation lasted for about five million years
and occurred about 20 million years ago in Earth's timeframe.
However, the authors do not think that the hot gas was produced
just by this shorter burst.

More at http://chandra.harvard.edu/photo/2013/ngc6240/

-Megan Watzke, CXC









Posted by Nelio Inacio at 4:16 PM 0 comments

NGC 2392: A Beautiful End to a Star’s Life

NGC 2392: A Beautiful End to a Star’s Life:

NGC 2392

Stars like the Sun can become remarkably photogenic at the end of their life. A good example is NGC 2392, which is located about 4,200 light years from Earth. NGC 2392, (nicknamed the "Eskimo Nebula") is what astronomers call a planetary nebula. This designation, however, is deceiving because planetary nebulae actually have nothing to do with planets. The term is simply a historic relic since these objects looked like planetary disks to astronomers in earlier times looking through small optical telescopes.

Instead, planetary nebulae form when a star uses up all of the hydrogen in its core -- an event our Sun will go through in about five billion years. When this happens, the star begins to cool and expand, increasing its radius by tens to hundreds of times its original size. Eventually, the outer layers of the star are carried away by a 50,000 kilometer per hour wind, leaving behind a hot core. This hot core has a surface temperature of about 50,000 degrees Celsius, and is ejecting its outer layers in a much faster wind traveling six million kilometers per hour. The radiation from the hot star and the interaction of its fast wind with the slower wind creates the complex and filamentary shell of a planetary nebula. Eventually the remnant star will collapse to form a white dwarf star.

More at http://chandra.harvard.edu/photo/2013/ngc2392/

-Megan Watzke, CXC









Posted by Nelio Inacio at 4:16 PM 0 comments

X-RAY WHISPERS IN A NOISY PUB

X-RAY WHISPERS IN A NOISY PUB:

We are delighted to welcome Katja Poppenhaeger as a guest blogger today. Katja is the first author of a new paper describing the first exoplanet transit ever seen in X-rays, the subject of our latest press release [URL to be added]. Katja studied physics at Frankfurt University in Germany, followed by a PhD in astrophysics at Hamburg Observatory in Germany, before coming to Harvard-Smithsonian Center for Astrophysics (CfA) as a postdoc. She will be a Sagan Fellow at CfA beginning in September 2013.

K.Poppenhaeger

Credit: K.Poppenhaeger
I remember when, back in grad school, my colleagues and I were watching the launch of the Kepler space telescope on the internet. We were really excited because this telescope would - and, in retrospect, has - discovered thousands of planet candidates around other stars, using the transit method. Back then I thought to myself, wouldn't it be cool if I could observe such a transit in X-rays? X-rays are absorbed high up in our Earth's atmosphere, which makes the Earth's X-ray radius about 100 km larger than its optical radius - that is about 1.5% in terms of extra radius. I wanted to use that effect to test how far the outer atmosphere of a Hot Jupiter extends. These Hot Jupiters orbit so close to their central star that they get heated up to temperatures over 1000 K, and their atmospheres can even boil away (which let me hope that there might be more than just an extra 1.5% in radius to find for such planets).

So the first thing I did was to check the data archives of the two big X-ray telescopes, Chandra and XMM-Newton, to see if someone had - by chance or on purpose - observed a planet-hosting star in X-rays while its planet was transiting in front of it. And I couldn't believe my luck: there was indeed a fifteen hour long observation of the star HD 189733 with XMM-Newton, and its Hot Jupiter HD 189733b was crossing in front of the star during that observation.

But when I looked at the light curve, I was rather disappointed: The star is magnetically active, meaning that its corona is bright and flickering, so its X-ray light curve showed lots of scatter. Looking for a transit signal in this light curve was like trying to hear a whisper in a noisy pub. But playing with the light curve for a bit, I realized that during the two hours of the observation where I knew the transit was happening, the X-ray signal was slightly weaker than before and after the transit. It might just have been luck, but I was determined: I had to get more data. With more transits that I could add up, the flickering of the corona would finally average out, and the transit signal would become clearer.

impression of the HD 189773

An artist's impression of the HD 189773 system, showing the Hot Jupiter transiting the star.
Credit: NASA/CXC/M.Weiss
So I applied for new observations and was granted time to observe six transits with the Chandra X-ray Observatory. When the data arrived, I combined the signal of all observations and was finally successful: I could detect the transit of the planet in X-rays. What surprised me was how deep the transit was: The planet swallowed about 6-8% of the X-ray light from the star, while it only blocked 2.4% of the starlight at optical wavelengths. That means that the planet's atmosphere blocks X-rays at altitudes of more than 60,000 km above its optical radius - a 75% larger radius in X-rays! That is pretty big, and I calculated that the outer atmosphere has to be heated up to about 20,000 K to sustain itself at such high altitudes. The bigger X-ray radius also means that the planet loses its atmosphere about 40% faster than thought before.

So what's next? I'd like to know if the X-ray radius of other hot exoplanets is extended as well - and if yes, does the extent depend on the heating of the planet by the host star, or more on things like the overall density of the planet? Together with my former colleagues from Hamburg Observatory, we will test this for the even hotter Jupiter CoRoT-2b, using XMM-Newton. Personally, I'd like it best if the CoRoT-2b experiment had a completely surprising outcome as well - we'll know next year!



Posted by Nelio Inacio at 4:15 PM 0 comments

Dwarf Galaxy Caught Ramming Into a Large Spiral

Dwarf Galaxy Caught Ramming Into a Large Spiral:

NGC 1232

Observations with NASA's Chandra X-ray Observatory have revealed a massive cloud of multimillion-degree gas in a galaxy about 60 million light years from Earth. The hot gas cloud is likely caused by a collision between a dwarf galaxy and a much larger galaxy called NGC 1232. If confirmed, this discovery would mark the first time such a collision has been detected only in X-rays, and could have implications for understanding how galaxies grow through similar collisions.


An image combining X-rays and optical light shows the scene of this collision. The impact between the dwarf galaxy and the spiral galaxy caused a shock wave - akin to a sonic boom on Earth - that generated hot gas with a temperature of about 6 million degrees. Chandra X-ray data, in purple, show the hot gas has a comet-like appearance, caused by the motion of the dwarf galaxy. Optical data from the European Southern Observatory's Very Large Telescope reveal the spiral galaxy in blue and white. X-ray point sources have been removed from this image to emphasize the diffuse emission.

More at http://chandra.harvard.edu/photo/2013/ngc1232/

-Megan Watzke, CXC







Posted by Nelio Inacio at 4:15 PM 0 comments

Too Hot to Swallow

Too Hot to Swallow:

Wang
We are delighted to welcome Q. Daniel Wang as a guest blogger today. Daniel is the first author of a paper dissecting the X-ray-emitting gas around the center of our Galaxy, the subject of our latest press release. He is a professor in astronomy at University of Massachusetts Amherst. He was the Principal Investigator of the first large-scale Chandra and Hubble surveys of the Galactic center to explore various components of this exotic ecosystem. He recently enjoyed a four-month stay at University of Cambridge as a Beverley Sackler Distinguished Visiting astronomer, where much of the work reported in the paper was finished.

It has been known for a while that almost all massive galaxies contain a giant black hole at their centers. Most of such black holes, including the one at the center of our own Galaxy, are, however, far dimmer than quasars typically seen in the early universe. This dimness cannot simply be explained by decreasing amounts of material that the black holes could capture. Have the black holes lost their appetite? Or do they just swallow everything that is captured without much radiation? Many theories have been developed. But direct observational tests are hard to come by.


Sgr A*

Because of its proximity, our own giant black hole (or Sgr A*, discovered first in radio) allows for a unique close-up view of what might be going on. Indeed, very weak X-ray emission with occasional flaring has been detected from the Galaxy's center for years. But even the nature of this emission has remained greatly uncertain. In particular, it has recently been theorized that the emission may be largely due to stellar flares from a putative concentration of low-mass stars around Sgr A*, which are too faint to have been detected at other wavelengths. This theory was motivated by a marginal detection of a distinct fluorescent emission line – the absorption of radiation followed by emission at lower energies – in the spectrum of the center from early X-ray observations. The fluorescence of the stellar flaring radiation is expected to occur at the relatively cool surface of the stars, which are presumably more active because of their fast rotation caused by black hole tugging.

Black Hole

With the greatly improved counting statistics and spectral resolution, as well as the superb spatial resolution, of the three million seconds of Chandra observations (an X-ray Visionary Project), we can now rule out the stellar scenario. The fluorescent line is not detected in the spectrum of the quiescent or flare emission from the center. As detailed in a separate paper, about 40 or so flares are detected, which have very short time spans, typically lasting for about an hour or so, and can be isolated quite easily in the data stream. These flares account for about one third of the X-ray emission of the center and all seem to arise spatially from a point, or Sgr A*. We can further constrain and remove the residual point-like contribution, which is less than about 20% of the quiescent emission and can be explained at least partly by weak flares that are too faint to be identified individually in the observations.

We further find that the extended quiescent emission around Sgr A* has a shape and orientation similar to those of the surrounding disk of massive stars, providing direct evidence that stellar winds are being fed to Sgr A*. Because of high-speed collisions, wind material in this crowded central region is expected to be hot and thus hard for the black hole to capture. But more importantly, even the captured material appears to be too hot to swallow for the black hole. As the material flows inward, it inevitably becomes hotter and swirls faster because of the so-called energy and momentum conservations. The spectrum of the X-ray emission shows that the amount of the material decreases with the increasing temperature, suggesting that it is being removed from the flow. We infer that > 99% of the material needs to be thrown out or sacrificed to allow for a tiny fraction of it to reach the inner most region around the black hole, where the thermal energy generation is most efficient. The fraction of the material eventually falling into the black hole should then be even smaller, severely limiting its growth rate.

But, a black hole may occasionally capture large amounts of cold and dense gas, which is more plentiful in the early universe than at the present. Such gas tends to form an accretion disk around the black hole, allowing for effective dissipation of energy and angular momentum. As a result, a large fraction of the gas can reach the innermost region, which indeed dominates the emission as observed from a quasar, and can eventually fall into the black hole.



Posted by Nelio Inacio at 4:14 PM 0 comments

Clues to the Growth of the Colossus in Coma

Clues to the Growth of the Colossus in Coma:

Coma Cluster

A team of astronomers has discovered enormous arms of hot gas in the Coma cluster of galaxies by using NASA's Chandra X-ray Observatory and ESA's XMM-Newton. These features, which span at least half a million light years, provide insight into how the Coma cluster has grown through mergers of smaller groups and clusters of galaxies to become one of the largest structures in the Universe held together by gravity.

A new composite image, with Chandra data in pink and optical data from the Sloan Digital Sky Survey appearing in white and blue, features these spectacular arms. In this image, the Chandra data have been processed so extra detail can be seen.

The X-ray emission is from multimillion-degree gas and the optical data shows galaxies in the Coma Cluster, which contain only about one-sixth the mass in hot gas. Only the brightest X-ray emission is shown here, to emphasize the arms, but the hot gas is present over the entire field of view.

Researchers think that these arms were most likely formed when smaller galaxy clusters had their gas stripped away by the head wind created by the motion of the cluster through the hot gas, in much the same way that the headwind created by a roller coaster blows the hats off riders.

Coma is an unusual galaxy cluster because it contains not one, but two giant elliptical galaxies near its center. These two giant elliptical galaxies are probably the vestiges from each of the two largest clusters that merged with Coma in the past. The researchers also uncovered other signs of past collisions and mergers in the data.

More at http://chandra.harvard.edu/photo/2013/coma/

-Megan Watzke, CXC







Posted by Nelio Inacio at 4:13 PM 0 comments

NASA's Hubble and Chandra Find Evidence for Densest Nearby Galaxy

NASA's Hubble and Chandra Find Evidence for Densest Nearby Galaxy:

M60

The densest galaxy in the nearby Universe may have been found, as described in our latest press release. The galaxy, known as M60-UCD1, is located near a massive elliptical galaxy NGC 4649, also called M60, about 54 million light years from Earth.

This composite image shows M60 and the region around it, where data from NASA's Chandra X-ray Observatory are pink and data from NASA's Hubble Space Telescope (HST) are red, green and blue. The Chandra image shows hot gas and double stars containing black holes and neutron stars and the HST image reveals stars in M60 and neighboring galaxies including M60-UCD1. The inset is a close-up view of M60-UCD1 in an HST image.

Packed with an extraordinary number of stars, M60-UCD1 is an "ultra-compact dwarf galaxy". It was discovered with NASA's Hubble Space Telescope and follow-up observations were done with NASA's Chandra X-ray Observatory and ground-based optical telescopes.

It is the most luminous known galaxy of its type and one of the most massive, weighing 200 million times more than our Sun, based on observations with the Keck 10-meter telescope in Hawaii. Remarkably, about half of this mass is found within a radius of only about 80 light years. This would make the density of stars about 15,000 times greater than found in Earth's neighborhood in the Milky Way, meaning that the stars are about 25 times closer.

The 6.5-meter Multiple Mirror Telescope in Arizona was used to study the amount of elements heavier than hydrogen and helium in stars in M60-UCD1. The values were found to be similar to our Sun.

Another intriguing aspect of M60-UCD1 is that the Chandra data reveal the presence of a bright X-ray source in its center. One explanation for this source is a giant black hole weighing in at some 10 million times the mass of the Sun.

More at http://chandra.harvard.edu/photo/2013/m60/

-Megan Watzke, CXC









Posted by Nelio Inacio at 4:13 PM 0 comments

Neutron Star Undergoes Wild Behavior Changes

Neutron Star Undergoes Wild Behavior Changes:

IGR J18245-2452

These two images from NASA's Chandra X-ray Observatory show a large change in X-ray brightness of a rapidly rotating neutron star, or pulsar, between 2006 and 2013. The neutron star - the extremely dense remnant left behind by a supernova - is in a tight orbit around a low mass star. This binary star system, IGR J18245-2452 (mouse over the image for its location) is a member of the globular cluster M28.


As described in a press release from the European Space Agency, IGR J18245-2452 provides important information about the evolution of pulsars in binary systems. Pulses of radio waves have been observed from the neutron star as it makes a complete rotation every 3.93 milliseconds (an astonishing rate of 254 times every second), identifying it as a "millisecond pulsar."

The widely accepted model for the evolution of these objects is that matter is pulled from the companion star onto the surface of the neutron star via a disk surrounding it. During this so-called accretion phase, the system is described as a low-mass X-ray binary because bright X-ray emission from the disk is observed. Spinning material in the disk falls onto the neutron star, increasing its rotation rate. The transfer of matter eventually slows down and the remaining material is swept away by the whirling magnetic field of the neutron star as a millisecond radio pulsar forms.

The complete evolution of a low-mass X-ray binary into a millisecond pulsar should happen over several billion years, but in the course of this evolution, the system might switch rapidly between these two states. The source IGR J18245-2452 provides the first direct evidence for such drastic changes in behavior. In observations from July 2002 to May 2013 there are periods when it acts like an X-ray binary and the radio pulses disappear, and there are times when it switches off as an X-ray binary and the radio pulses turn on.

The latest observations with both X-ray and radio telescopes show that the transitions between an X-ray binary and a radio pulsar can take place in both directions and on a time scale that is shorter than expected, maybe only a few days. They also provide powerful evidence for an evolutionary link between X-ray binaries and radio millisecond pulsars.

More at http://chandra.harvard.edu/photo/2013/igr/

-Megan Watzke, CXC







Posted by Nelio Inacio at 4:12 PM 0 comments

Discover and Explore with the Chandra Skymap

Discover and Explore with the Chandra Skymap:

American Archives Month (each October) is an exciting time around here. We spend a lot of time working through the Chandra archive to bring you the best and most interesting objects in the X-ray Universe that have made their way across space and time (via photons) to Chandra's detectors.

Skymap

It has been a personal goal of mine, since taking this job as Chandra science imager about four years ago, to create an interactive tool for the public to engage with the Chandra archive of released imagery in a new and innovative way. For this to work, a few pieces of the puzzle had to fall into place.

I've blogged about metadata before and -- as you might expect -- accurate, detailed and complete metadata for our entire archive of public images is the keystone to creating a tool such as the new Chandra Skymap. Metadata is what drives all of the content behind the application. Since there's no good way to automate the “retro-tagging” (that is, tagging images we’ve already released in the past) of our image archive, it took a few years to get through all of those images by hand. We finally completed that task at the end of last year and then set our sights upon creating the Skymap tool.

There were some false starts along the way, mainly due to limitations as a programmer, learning new languages and libraries. But as I was pulling my hair out trying to figure this out last summer, a colleague recommended utilizing javascript with the D3 (Data-Driven Documents) visualization library. I was vaguely familiar with D3, mainly from playing around with interactive data visualizations published by The New York Times and written by Mike Bostock (the creator of D3). D3 turned out to be the answer to the coding problems, but the new challenge was to learn javascript. Thankfully, the D3 documentation is extensive and Mike Bostock and many other programmers have provided a wealth of resources in the form of small bits of example code that could be utilized as part of a larger project. Through all of this, I developed two new skills: first, the ability to completely tax my computer by testing how many browser tabs I could hold open at once, and, second, honing the ability to construct the perfect Google query regarding a particular javascript or D3 question. Utilizing countless examples and answers to questions on StackExchange, I was able to build the Skymap I had pictured in my head years ago. This has been an extremely rewarding and fulfilling project and I'm very excited to share this new application with you today!

Here are some helpful tips to get you started using the new Chandra Skymap:

1. Everything about this tool is interactive. You can zoom into the map using your mouse scroll wheel, or by pinch-zoom, or using the buttons at the top left. You can also pan around by clicking and dragging while in zoom-mode.

2. You'll notice that as you hover over data points, the points are highlighted and a small information window pops up with a synopsis of the press release for that particular object. Each data point is also a link to the release for that object. Click on the point and you will go to its Photo Album page.

3. The controls at the bottom offer up various ways for you to filter the data to your liking. Also note that most of the text in the controls are actually links to more information -- click on them to find out more. If you're only interested in which distant galaxies Chandra has observed, de-select everything but "Galaxies & Galaxy Clusters" in the "Categories" panel and you'll only see distant galaxies in the Skymap.

4. If you would like to filter the data by the date of the release, click and drag to draw a box in the bottom panel "Release Date Filter" and then resize to your liking or drag it across the timeline to watch press releases pop into and out of the Skymap as you pan across time.

5. You might notice that some areas are clustered with overlapping data points. Some of these are multiple releases for the same object at different times, or closely spaced but separate objects. Careful use of the zoom feature and/or filters should allow you to uncover any data point. For example, if you happen to notice two data points from two different categories overlapping each other, you can toggle the category underneath off and then on to bring it to the front. Using the "Release Data Filter" can also help to uncover buried data points.

6. If you see a term on the map that you are unfamiliar with, click on the underlined link to find out more either from the Chandra site, or from Wikipedia.

Be sure to come back often, as the Chandra Skymap will instantly populate with new releases as they are published. We also envisioned some new features that will hopefully be added in the near future.

Enjoy discovering all that Chandra has to offer!

-Joe DePasquale, CXC



Posted by Nelio Inacio at 4:12 PM 0 comments

Preserving the Legacy of the X-ray Universe

Preserving the Legacy of the X-ray Universe:

Chandra Archive Collection

Every year, October is designated as American Archive Month. While many people may think "archive" means only dusty books and letters, there are, in fact, many other types of important archives. This includes the use of archives for major telescopes and observatories like NASA's Chandra X-ray Observatory.


The Chandra Data Archive (CDA) plays a central role in the mission by enabling the astronomical community - as well as the general public - access to data collected by the observatory. The primary role of the CDA is to store and distribute data, which the CDA does with the help of powerful search engines. The CDA is one of the legacies of the Chandra mission that will serve both the scientific community and the public for decades to come.

To celebrate and support American Archive Month, we have selected images from a group of eight objects in the CDA to be released to the public for the first time. These images represent the observations of thousands of objects that are permanently available to the world thanks to Chandra's archive.

More at http://chandra.harvard.edu/photo/2013/archives/

-Megan Watzke, CXC

Posted by Nelio Inacio at 4:11 PM 0 comments

FITS and Starts

FITS and Starts:

In continued recogintion of American Archives month, we've dusted off some raw data from recent Chandra press releases over the past year for inclusion in our openFITS collection. This brings the total collection up to 20 objects including supernova remnants, active galaxies, star forming regions, black holes, and pulsars and neutron stars. These data are ripe for exploration. The new data sets include the Vela Pulsar Jet, and supernova remnants

W49B and G1.9+0.3 (which also happens to be the Milky Way's most recent supernova remnant).

W49B



W49B is a special case for openFITS. We have somewhat broken with tradition and have provided more data than what was used in creating the press image (though technically, this isn't more data, just a different representation of the same data). W49B has been extensively observed with Chandra with over 2 days worth of observation time devoted to collecting information about this source. As a result, we have a very rich data set to work with, which can be sliced and diced into many different component images emphasizing different elements emitting X-ray light. I wrote a blog post about the quality of this data and provided some behind-the-scenes insight into the image earlier this year. In creating a multi-wavelength composite image, we decided to take a "less-is-more" approach and utilize two low and high energy, broad-band X-ray images colored green and blue in combination with radio and infrared data colored magenta and yellow respectively. This allowed for a dynamic, feature-rich and aesthetically pleasing image in which the component parts were clearly distinguishable, allowing the science behind this supernova remnant to shine through.

Well, now is your chance to dig in to the X-ray data and see what you can do with up to 6 different wavelengths of X-ray light!

-Joe DePasquale, Chandra Science Imager

Posted by Nelio Inacio at 4:11 PM 0 comments

Getting a Sense of Place in our Universe

Getting a Sense of Place in our Universe:

The biggest news this week, by far, has been a new study suggesting that Earth-sized planets in habitable zones may be very common. This is exciting news – who wouldn't want to have more cosmic planetary friends out there that maybe one day we'll be able to explore? By the latest accounts, there could be billions of Earth-like planets out there in our Milky Way galaxy.

Solar System

While this is indeed mind-boggling, it got us thinking about the sheer vastness and the enormous scale of the Universe that we can explore using modern telescopes. We live in one galaxy - the Milky Way - that astronomers estimate contains roughly 400 billion stars. The Earth is not in a particularly special place in this giant collection of stars. We're about two-thirds away from the center in one of the spiral arms, in the galactic suburbs, so to speak.

What's happening in the downtown where the supermassive black hole lies and the density of stars is much higher? Chandra and other telescopes have been looking to see. We've learned an incredible amount about this area over the years with Chandra including:

- How the black hole behaves,

- What it likes to eat,

- And even what it has done hundreds of years before we had the technology to observe it.

It's very humbling to consider our small place in the very big Galaxy. It's even more so when we think about our Galaxy being just one of billions of galaxies (each of which has its own billions of stars and probably planets). Most of these galaxies aren't alone in space. Rather, they belong to groups or clusters of galaxies that are bound together by gravity. Chandra has done some amazing work studying these collections of galaxies since most of them are filled with hot gas that emits X-rays. It's hard to summarize all that the mission has done in this area of astrophysics, but a decent snapshot can be found by perusing the images we've released on the subject.

And just when you think you've wrapped your head around what the cosmos has to offer, we have to throw in the mysteries of dark energy and dark matter that account for 96% of the Universe. That's right, all of the stuff we can see with telescopes - planets, stars, galaxies, clusters - account for a mere tiny fraction of what is out there in the Universe. So take a few minutes to enjoy the incredible work Kepler is doing in discovering planets in our Galaxy, and then maybe take another one to consider how much we still have yet to explore.

-Megan Watzke, CXC







Posted by Nelio Inacio at 4:10 PM 0 comments

Exploring the Third Dimension of Cassiopeia A

Exploring the Third Dimension of Cassiopeia A:

Casa

One of the most famous objects in the sky - the Cassiopeia A supernova remnant – will be on display like never before, thanks to NASA's Chandra X-ray Observatory and a new project from the Smithsonian Institution. A new three-dimensional (3D) viewer, being unveiled today, will allow users to interact with many one-of-a-kind objects from the Smithsonian as part of a large-scale effort to digitize many of the Institutions objects and artifacts.


Scientists have combined data from Chandra, NASA's Spitzer Space Telescope, and ground-based facilities to construct a unique 3D model of the 300-year old remains of a stellar explosion that blew a massive star apart, sending the stellar debris rushing into space at millions of miles per hour. The collaboration with this new Smithsonian 3D project will allow the astronomical data collected on Cassiopeia A, or Cas A for short, to be featured and highlighted in an open-access program -- a major innovation in digital technologies with public, education, and research-based impacts.

To coincide with Cas A being featured in this new 3D effort, a specially-processed version of Chandra's data of this supernova remnant is also being released. This new image shows with better clarity the appearance of Cas A in different energy bands, which will aid astronomers in their efforts to reconstruct details of the supernova process such as the size of the star, its chemical makeup, and the explosion mechanism. The color scheme used in this image is the following: low-energy X-rays are red, medium-energy ones are green, and the highest-energy X-rays detected by Chandra are colored blue.

More at http://chandra.harvard.edu/photo/2013/casa/

-Megan Watzke, CXC







Posted by Nelio Inacio at 4:10 PM 0 comments

Carnival of Space #328

Carnival of Space #328:

Welcome to this week's Carnival of Space. It's been a busy Universe out there so let's jump right into it.

The Urban Astronomer has an excellent recap of Hubble's observations of a very unusual asteroid. This asteroid not only has a comet-like tail, it has six of them. Oh yeah, and they apparently change.

Over at the Smithsonian's Air & Space blog, they discuss a very provocative issue: if we go back to the Moon, where should we go and, maybe more importantly, where shouldn't we?

In advance of the recent Maven launch to Mars, the good folks over at Universe Today feature an excellent video that summarizes where the Curiosity rover has been and also where it will be heading in the future.

Here at the Chandra blog, we discuss how the 3D model of the Cassiopeia A supernova remnant is now being featured in an exciting new 3D viewer created by the Smithsonian that was just rolled out last week.

Casa

The Here, There, and Everywhere (HTE) project traveled to the Phillips Library in Aurora, Illinois, and you can find out the reaction to the exhibit at the HTE blog.

Saturn

The stunning new image of Saturn (and Mars, Venus, and the Earth too) is highlighted in this post of the Meridian Journal. Learn more about this image that made the rounds of many news outlets and websites last week.

The Next Big Thing (NBT) looks at current research and testing being done to determine the best ways to bring back sample returns from destinations such as the Moon and asteroids. The NBT also reports that NBC will follow Virgin Galactic's development of SpaceShipTwo and broadcast Richard Branson and his children going into orbit in August 2014.

Stay tuned for more news from our very own Universe.

-Megan Watzke, CXC
Posted by Nelio Inacio at 4:09 PM 0 comments

Getting the Upper Hand on Understanding Neutron Stars

Getting the Upper Hand on Understanding Neutron Stars:

posted by chandra
on Wed, 2013-12-11 16:30


PSR B1509-58

When we released Chandra’s image of the pulsar known as PSR B1509-58 (or, B1509, for short), it received a lot of attention. It's a fascinating object. The pulsar at the center of the image is a rapidly spinning dense star that is spewing out energetic particles into beautiful structures spanning trillions of miles that glow in X-ray light. And, it looks like a giant hand. This fact helped trigger a whole host of other comments about this object found some 17,000 light years from Earth.

This month, scientists announced that they've been studying B1509 for reasons that have nothing to do with its hand-shaped appearance. Rather, they are trying to figure out how such a tiny object (the 12-mile-wide pulsar) can be so powerful. Researchers at the Los Alamos National Laboratory in New Mexico put out a press release that talks about this fascinating work.

In short, neutron stars like the one found in B1509 give scientists an opportunity to study forces in nature so extreme that they are impossible to recreate here on Earth.

This is an exciting and important example of how science in space can help research here on the ground, and vice versa. That's just the hand we've been dealt in our Universe (ba-da-dum).

-Megan Watzke, CXC
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Doubling Down With Rare White Dwarf Systems

Doubling Down With Rare White Dwarf Systems:

amcvn

In the middle of the twentieth century, an unusual star was spotted in the constellation of Canes Venatici (Latin for "hunting dogs"). Years later, astronomers determined that this object, dubbed AM Canum Venaticorum (or, AM CVn, for short), was, in fact, two stars. These stars revolve around each other every 18 minutes, and are predicted to generate gravitational waves - ripples in space-time predicted by Einstein.

The name AM CVn came to represent a new class of objects where one white dwarf star is pulling matter from a very compact companion star, such as a second white dwarf. (White dwarf stars are dense remains of Sun-like stars that have run out of fuel and collapsed to the size of the Earth.) The pairs of stars in AM CVn systems orbit each other extremely rapidly, whipping around one another in an hour, and in one case as quickly as five minutes. By contrast, the fastest orbiting planet in our Solar System, Mercury, orbits the Sun once every 88 days.

Despite being known for almost 50 years, the question has remained: where do AM CVn systems come from? New X-ray and optical observations have begun to answer that with the discovery of the first known systems of double stars that astronomers think will evolve into AM CVn systems.

The two binary systems - known by their shortened names of J0751 and J1741 - were observed in X-rays by NASA's Chandra X-ray Observatory and ESA's XMM-Newton telescope. Observations at optical wavelengths were made using the McDonald Observatory's 2.1-meter telescope in Texas, and the Mt. John Observatory 1.0-meter telescope in New Zealand.

The artist's illustration depicts what these systems are like now and what may happen to them in the future. The top panel shows the current state of the binary that contains one white dwarf (on the right) with about one-fifth the mass of the Sun and another much heavier and more compact white dwarf about five or more times as massive (unlike Sun-like stars, heavier white dwarfs are smaller).

More at http://chandra.harvard.edu/photo/2013/amcvn/

-Megan Watzke, CXC

Posted by Nelio Inacio at 4:08 PM 0 comments

Finding Patterns

Finding Patterns:

Clouds

Image: Frank Kovalchek, Wikimedia Commons

One of our favorite games to play with our kids is trying to find recognizable objects in clouds as they pass by on a sunny day. One cloud might look like an elephant, the next, a pirate ship.

The phenomenon where our brains find seemingly significant patterns in images or sounds has an actual name: pareidolia. For example, we might think we see a human on the face of the Moon, a lizard on Mars (see below) or recognize words when we play a recording in reverse. Even Leonardo da Vinci – a man of many talents - suggested that artists could use pareidolia as a creative exercise for painting.

NASA's Curiosity Image of Mars
pareidolia

Image: NASA/JPL-Caltech

One of our favorite places to experiment with pareidolia is in images from space. Take a look at this image of the object known as B1509-58, which was released from NASA's Chandra X-ray Observatory back in 2009.

B1509-58

Credit: NASA/CXC/SAO/P.Slane, et al.

Not surprisingly, this object was nicknamed the “Hand of God,” which quickly became a much more popular name than its slightly dull astronomical handle.

At the center of B1509 is a tiny dense spinning dead star known as a pulsar. This little dynamo is responsible for spewing energized particles that, in turn, are responsible for the “fingers” and other structures seen in this X-ray image. Even though scientists can explain this object’s shape without any references to extremities or deities, pareidolia is alive and well. http://chandra.harvard.edu/photo/2009/b1509/

There have been many posts about pareidolia in astronomy images and you can read some great examples here and here.

Here we present our version of cosmic cloud watching, but with Chandra, Spitzer or Hubble images. Starting at the top, we’ve placed the strongest visual objects (to us). Towards the end of the list, you might have to get more creative to find some shapes.

Horsehead Nebula

This object is probably the most obviously named. The image of a horse's head and neck is iconic and has been published in many forms over the past 100 years since its discovery. Hubble's latest image of the Horsehead Nebula shows it in infrared light where we get to see pillars of gas and dust formed by stellar winds and radiation.

What we see: a horse's head and neck.

Horsehead Nebula

Image: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Circinus X-1

A system where a neutron star is in orbit around a star several times the mass of the Sun, about 20,000 light years from Earth, within our Milky Way Galaxy.

Circinus X-1

Image: X-ray: NASA/CXC/Univ. of Wisconsin-Madison/S.Heinz et al; Optical: DSS; Radio: CSIRO/ATNF/ATCA

What we see: A skull!

Colliding Galaxy Pair

What looks like a celestial hummingbird is really the result of a collision between a spiral and an elliptical galaxy at a whopping 326 million light- years away. The flat disk of the spiral NGC 2936 is warped into the profile of a bird by the gravitational tug of the companion NGC 2937. The object was first cataloged as a "peculiar galaxy" by Halton Arp in the 1960s. This interacting galaxy duo is collectively called Arp 142.

Arp 142

Image: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

What we see. Definitely a penguin’s head coming out of the water.

NGC 602

The Small Magellanic Cloud - also known as the SMC - is one of the closest galaxies to the Milky Way. Because the SMC is so close and bright, it offers a chance to study phenomena that are difficult to examine in more distant galaxies. This image, a composite of X-ray, infrared and optical data, shows a cluster of bright young stars with masses similar to that of our Sun.

NGC 602

Image: X-ray: NASA/CXC/Univ.Potsdam/L.Oskinova et al; Optical: NASA/STScI; Infrared: NASA/JPL-Caltech

What we see: Many people see a face, but we see a Pac man eating its dots.

Eta Carinae

Eta Carinae is a mysterious, extremely bright and unstable star located a mere stone's throw - astronomically speaking - from Earth at a distance of only about 7,500 light years. Eta Carinae is about 100 times bigger than our sun and is burning about one million times brighter than our own star. Radiation and stellar winds from Eta Carinae are sculpting and destroying the surrounding nebula, shown here in this infrared image of its gas and dust.

Eta Carinae

Image: NASA/JPL-Caltech

What we see. A person, in the carved out green areas inside the nebula.

W49b

Supernova remnants—that is, the debris field left behind after the explosion—are like snowflakes: No two are ever exactly the same. W49b has evolved into an unusual shape. Its expanding shell of gas contains important elements such as sulfur and silicon, oxygen and iron. These elements, which are critical to our existence here are Earth, were created both when the star was still living and in the explosion itself.

W49b

Image: X-ray: NASA/CXC/MIT/L.Lopez et al.; Infrared: Palomar; Radio: NSF/NRAO/VLA

What we see: Could be a flying bat.

On Pinterest? Pin horseheads and faces from http://www.pinterest.com/kimberlyarcand/2013-interesting-astronomy-images/

-Kim Arcand & Megan Watzke, CXC

Adapted from an earlier blog post at http://www.huffingtonpost.com/kimberly-k-arcand/i-spy-a-horses-head_b_45...
Posted by Nelio Inacio at 4:06 PM 0 comments
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