Posted on by Nancy Atkinson

The Battle for the Space Vote

Barack Obama and John McCain

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Remember a few months ago when “space” seemed to be a non-issue for the candidates in this year’s US presidential election? But now space seems to be a hot topic. John McCain was in Florida today where he met with 20 leaders from the space industry for a roundtable discussion, and Barack Obama was in Florida last week, to stump for votes. Perhaps both candidates are recalling the 2000 presidential election that hinged on the Florida vote. Hanging chads aside, an important issue in Florida these days is the projected job losses that will be incurred in the gap after the space shuttle is retired in 2010 and before the Constellation program makes its first flights in about 2015, and both candidates have met with members of NASA’s workforce and other NASA officials to discuss this issue. Also, both McCain and Obama recently updated their positions on their space-related agendas on their websites, with both devoting quite a bit of “space” to space.

If you’re still undecided, or haven’t seen the candidate’s latest views on space, take a look at Barack Obama’s position paper on space and John McCain’s space policy statement. If that’s too much reading for you, the folks at Florida Today.com have outlined the major points of each candidate’s space policies:
• Major points of Obama’s space policy:

1. Re-enacting the National Aeronautics and Space Council to oversee and coordinate the civilian, commercial and military space programs and report to the president.
2. Closing the gap between the retirement of the Space Shuttle and the introduction of its successor through adding another Shuttle flight, accelerating the development of the next generation vehicle, and working with the industry to retain our workforce and technical capabilities.
3. Completing and enhancing the International Space Station so it can host the innovative scientific and technological research projects it was intended to facilitate.
4. Embracing human and robotic space exploration with a goal of sending human missions to the Moon by 2020, as a precursor in an orderly progression to missions to more distant destinations, including Mars.
5. Emphasizing NASA’s research function to study climate change and advance aeronautics research.
6. Expanding public/private partnerships to develop cutting-edge technologies.
7. Inspiring the next generation through expanded education programs.

Major points of McCain’s space policy:

1. Ensure that space exploration is top priority and that the U.S. remains a leader.
2. Commit to funding the NASA Constellation program to ensure it has the resources it needs to begin a new era of human space exploration.
3. Review and explore all options to ensure U.S. access to space by minimizing the gap between the termination of the Space Shuttle and the availability of its replacement vehicle.
4. Ensure the national space workforce is maintained and fully utilized; Complete construction of the ISS National Laboratory.
5. Seek to maximize the research capability and commercialization possibilities of the ISS National Laboratory.
6. Maintain infrastructure investments in Earth-monitoring satellites and support systems.
a. Seek to maintain the nation’s space infrastructure.
7. Prevent wasteful earmarks from diverting precious resources from critical scientific research.
8. Ensure adequate investments in aeronautics research.

News Sources: Florida Today

Posted on by Nancy Atkinson

NASA Cancels Spacesuit Contract to Avoid Litigation

Proposed spacesuits from Oceaneering, Inc. Image: NASA

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NASA has terminated a contract with the company it hired to design and construct new spacesuits for use with the new Orion spacecraft after determining it made a mistake in evaluating costs. In terminating the contract NASA hopes to avoid litigation. In June, NASA announced it had selected Oceaneering International, Inc. to build the new spacesuits, but Hamilton Sundstrand, the lead contractor that has supplied spacesuits for NASA since the 1960’s filed a formal protest with the Government Accounting Office on the decision, asking NASA to review its reasoning on the contract award. Hamilton Sundstrand disagreed with the way NASA evaluated the costs for their proposal. NASA has now issued a press release saying “corrective action is appropriate,” and they have “determined that a compliance issue requires the termination of the contract” with Oceaneering “for the convenience of the government.” It appears NASA did some bad math, or used questionable processes to make its decision for the contract.

Hamilton Sundstrand claimed it never received adequate information from NASA about why its bid did not win. Also, NASA failed to request a “cost-accounting standards disclosure statement from Oceaneering during its deliberations,” according to a Wall Street Journal article. A government accounting office letter also said that “The agency must re-examine both offers’ cost proposals. To the extent that any irregularities are identified, appropriate re-evaluation must be made.”

The three-phase $745 million contract called for 109 suits, 24 of which will be the lunar suits.

NASA may have start again from scratch and reopen the bidding for the spacesuit contract.
In a statement Friday, Hamilton Sundstrand said its wants “corrective action” and they are concerned that revisions to the proposal may not correct the “significant errors and deficiencies in the procurement we have protested thus far.”

Sources: Wall Street Journal, NASA press release

Posted on by Nancy Atkinson

Astronomers Find a New “Minor Planet” near Neptune

Orbit of solar system object SQ372 (blue) compared with the orbits of Neptune Pluto and Sedna (white, green, red). Credit: N. Kaib.

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Astronomers announced today that a new “minor planet” with an unusual orbit has been found just two billion miles from Earth, closer than Neptune. Using the Sloan Digital Sky Survey, astronomers detected a small, comet-like object called 2006 SQ372, which is likely made of rock and ice. However, its orbit never brings it close enough to the sun for it to develop a tail. Its unusual orbit is an ellipse that is four times longer than it is wide, said University of Washington astronomer Andrew Becker, who led the discovery team. The only known object with a comparable orbit is Sedna — the distant, Pluto-like dwarf planet discovered in 2003. But 2006 SQ372’s orbit takes it more than one-and-a-half times further from the Sun, and its orbital period is nearly twice as long.

2006 SQ372 is beginning the return leg of a 22,500-year journey that will take it to a distance of 150 billion miles, nearly 1,600 times the distance from the Earth to the Sun. Scientists believe the object is only 50-100 kilometers (30-60 miles) across.

Click here for an animation showing the detection of SQ372 by SDSS.

Becker’s team was actually using the SDSS to look for supernova explosions billions of light-years away to measure the expansion of the universe. “If you can find things that explode, you can also find things that move, but you need different tools to look for them,” said team member Lynne Jones, also of the University of Washington. The only objects close enough to change position noticeably from one night to the next are in our own solar system, Jones explained.

The SDSS-II supernova survey scanned the same long stripe of sky, an area 1,000 times larger than the full moon, every clear night in the fall of 2005, 2006, and 2007.

SQ372 was first discovered in a series of images taken in 2006 by the SDSS, and were verified from images taken in 2005 and 2007.

The researcher team is trying to understand how the object acquired its unusual orbit. “It could have formed, like Pluto, in the belt of icy debris beyond Neptune, then been kicked to large distance by a gravitational encounter with Neptune or Uranus,” said UW graduate student Nathan Kaib. “However, we think it is more probable that SQ372 comes from the inner edge of the Oort Cloud.”

Even at its most distant turning point, 2006 SQ372 will be ten times closer to the Sun than the supposed main body of the Oort Cloud, said Kaib. “The existence of an ‘inner’ Oort cloud has been theoretically predicted for many years, but SQ372 and perhaps Sedna are the first objects we have found that seem to originate there. It’s exciting that we are beginning to verify these predictions.”

Becker noted that 2006 SQ372 was bright enough to find with the SDSS only because it is near its closest approach to the Sun, and that the SDSS-II supernova survey observed less than one percent of the sky.

“There are bound to be many more objects like this waiting to be discovered by the next generation of surveys, which will search to fainter levels and cover more area,” said Becker. “In a decade, we should know a lot more about this population than we do now.”

“One of our goals,” said Kaib, “is to understand the origin of comets, which are among the most spectacular celestial events. But the deeper goal is to look back into the early history of our solar system and piece together what was happening when the planets formed.”

The discovery of 2006 SQ372 was announced today in Chicago, at an international symposium about the Sloan Digital Sky Survey. A paper describing the discovery technique and the properties of 2006 SQ372 is being prepared for submission to The Astrophysical Journal.

News Source: SDSS press release

Posted on by Tammy Plotner

August 17, 2008 Partial Lunar Eclipse Caught “Down Under”

Lunar Eclipse 'Down Under' by Joe Brimacombe

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If you read this week’s SkyWatcher’s Forecast, then you knew several areas of the world were in for a partial lunar eclipse event. While the Moon basically just did a glancing pass through the umbral shadow, the effect was still dramatic and I was hoping that at least one photographer out there would have a picture and story to share!

As luck would have it, one of our favorite AORAIA imagers, Joe Brimacombe was watching from his apartment in the city center in Cairns, Queensland, Australia. To the west: is the start of the Great Dividing Range – an 800 m plateau that extends almost to Melbourne and to the east – the Great Barrier Reef and the Coral Sea. But, this isn’t the outback, this is the city. When Dr. Brimacombe isn’t practicing anaesthesiology… Joe does a lot of imaging from the roof of his eight story apartment building.

Says Brimacombe: “Imaging the partial eclipse from Cairns was not easy as twilight was underway before the umbral phase began with the moon always less than 15 degrees above the horizon. To make the best of it I used four imaging systems.” While all of the shots were unique and incredibly beautiful in their own way, the one I chose to share “was done with the 70-200 telephoto – shows the last 3 minutes before setting and the colors have not been adjusted.”

In the hours just before dawn in Australia, the was Moon quietly slipping into the Earth’s penumbral shadow, gently changing its coloration. During maximum, about two-thirds of the Moon immersed into the deeper shadow cone called the umbra, causing the darkening you see in these outstanding photographs. Part of the beauty of the event was the timing at which it happened. For Austalia, the event was at moonset, while for Western Europe, the United Kingdom and South Africa, the event was occuring at moonrise. The very best time and place to be was 9:24:49 p.m. Saturday evening in Cairo, Africa. Even though the last eclipse of 2008 is now over, let’s take a lesson from the event.

For SkyWatcher’s who live in the city – take heart! Sometimes practicing astronomy can be just as easy as taking the elevator to the roof. From there you can easily study solar and lunar activity and even the bright planets. While metropolitan lighting can obscure most starry vistas, about the only thing that can obscure moonlight is an eclipse! Just ask Dr. Joe…

Posted on by Ian O'Neill

India has Big Plans for Lunar Exploration

The Indian Polar Satellite Launch Vehicle (ISRO)

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India will send their first mission to the Moon in September. Chandrayaan-1 has been built and will be launched from Indian soil and sent on a mission to study the lunar surface. The Indian Space Research Organization (ISRO) will use its highly successful Polar Satellite Launch Vehicle (PSLV) to get the lunar probe into space. This is an impressive mission for a small space agency, making huge strides in the exploration of space…

It seems like everybody is doing it these days. First, Russia did it (in 1959) by landing a probe on the lunar surface and taking pictures of the far side of the Moon. Then the Soviets put the first artificial lunar satellite into orbit in 1966. Not to be out done, President Kennedy had already begun the US quest to get man on the Moon, and in 1969 the superpower achieved that goal. For a long time it was only the two competitors in the Space Race who had visited the Moon, but in 1990, Japan joined the “Lunar Club” (with the Hiten spacecraft). Then in 1997 Hong Kong (China) succeeded in two flybys (HGS-1, a commercial satellite). Eventually, in 2006, the European SMART-1 space vehicle made it into lunar orbit. But since then, it’s been China (with the Chang’e program) and Japan (with SELENE, or “Kaguya”) who have been most active around the natural satellite.

And now there is a new kid on the block: India. One of the most populous nations in the world is pushing ahead with its own aspirations for lunar exploration. Although comparatively small, the Indian space agency ISRO was established in 1972 to develop space-based technologies in the aim of enriching the nation’s economy. Until the early 1990’s, India had to rely on Russia to launch payloads into space, but 1994 saw the first successful launch of the powerful Polar Satellite Launch Vehicle (PSLV), lifting domestic and commercial satellites into orbit. Now the PSLV will launch India’s most valuable payload yet, the Chandrayaan-1 lunar orbiter and impactor. It is scheduled for launch on September 19th.

In a speech on India’s 61st Independence Day from the historic Red Fort in Delhi, the Indian Prime Minister Manmohan Singh called the Chandrayaan-1 mission “an important milestone” for the nation. However, although a date has been set for launch, some of the text seemed a little uncertain. “This year we hope to send an Indian spacecraft, Chandrayan, to the moon. It will be an important milestone in the development of our space programme,” Singh said. Whether the “we hope” was accidental or whether the launch date is only tentative remains to be seen.

Regardless, the mission appears to be good to go, obviously a huge boost to national pride. “I want to see a modern India, imbued by a scientific temper, where the benefits of modern knowledge flow to all sections of society,” he continued.

Source: IBN

Posted on by Nancy Atkinson

Dark Matter is Missing From Cosmic Voids

Map of distribution of galaxies. Credit: M. Blanton and the SDSS.

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Cosmic voids really are devoid of matter. Astronomers have found that even the pervasive ‘dark matter’ which accounts for about 80% of the mass of the universe is not present in these voids, which are areas of vast emptiness in space that can be tens of millions of light-years across. “Astronomers have wondered for a quarter-century whether these voids were ‘too big’ or ‘too empty’ to be explained by gravity alone,” said University of Chicago researcher Jeremy Tinker, who led the new study using data from the Sloan Digital Sky Survey II (SDSS-II). “Our analysis shows that the voids in these surveys are exactly as big and as empty as predicted by the ‘standard’ theory of the universe.”

The largest 3-dimensional maps of the universe show that galaxies lie in filamentary superclusters interlaced by cosmic voids that contain few or no bright galaxies. Researchers using SDSS-II and the
Two-Degree Field Galaxy Redshift Survey (2dFGRS) have concluded that these voids are also missing the “halos” of invisible dark matter that bright galaxies reside in.

A central element of the standard cosmological theory is cold dark matter, which exerts gravity but does not emit light. Dark matter is smoothly distributed in the early universe, but over time gravity pulls it into filaments and clumps and empties out the spaces between them. Galaxies form when hydrogen and helium gas falls into collapsed dark matter clumps, referred to as “halos,” where it can form luminous stars.

But astronomers were not sure if the areas that are devoid of galaxies were also devoid of dark matter, or if the dark matter was there, but for some reason stars just didn’t form in these voids.
The research team used bright galaxies to trace the structure of dark matter and compared it with computer simulations to predict the number and sizes of voids.
Princeton University graduate student Charlie Conroy measured the sizes of voids in the SDSS-II maps. “When we used galaxies brighter than the Milky Way to trace structure, the biggest empty voids we found were about 75 million light years across,” said Conroy. “And the predictions from the simulations were bang-on.”

The sizes of voids are ultimately set, Conroy explained, by the small variations in the primordial distribution of dark matter, and by the amount of time that gravity has had to grow these small variationsinto large structures.

The agreement between the simulations and the measurements holds for both red (old) and blue (new) galaxies, said Tinker. “Halos of a given mass seem to form similar galaxies, both in numbers of stars and in the ages of those stars, regardless of where the halos live.”

Tinker presented his findings today at an international symposium in Chicago, titled “The Sloan Digital Sky Survey: Asteroids to Cosmology.” A paper detailing the analysis will appear in the September 1 edition of The Astrophysical Journal, with the title “Void Statistics in Large Galaxy Redshift Surveys: Does Halo Occupation of Field Galaxies Depend on Environment?”

News Source: SDSS and The Ohio State University

Posted on by Nancy Atkinson

Phoenix Camera Snaps Frost on Mars

Morning Frost on Mars. Image credit: NASA/JPL-Caltech/University of Arizona/Texas A&M University

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It’s getting a little nippy at night on Mars. The Phoenix lander’s Surface Stereo Imager took this image at 6 a.m. on Sol 79 (August 14, 2008 here on Earth), and a thin layer of water frost is visible on the ground around the landing area. From subsequent images, the frost begins to disappear shortly after this image was taken as the sun rises on the Phoenix landing site.

The sun was about 22 degrees above the horizon when the image was taken, enhancing the detail of the polygons, troughs and rocks around the landing site.

This view is looking east southeast with the lander’s eastern solar panel visible in the bottom lefthand corner of the image. The rock in the foreground is informally named “Quadlings” and the rock near center is informally called “Winkies.”

This false color image has been enhanced to show color variations.

Earlier images taken in June, and put together here in sequence to form a movie, appears to show frost forming on Phoenix’s own legs.

What appears to be frost appears on Phoenix's legs. Credit: Wanderingspace.net
What appears to be frost appears on Phoenix's legs. Credit: Wanderingspace.net

But this isn’t the first time that frost has been imaged on Mars. The Viking lander took the picture below in 1979 of its landing site at Utopia Planetia showing ample amounts of frost on the surface.

frost on Mars in a photograph taken by the Viking 2 lander on May 18, 1979. NASA/JPL
frost on Mars in a photograph taken by the Viking 2 lander on May 18, 1979. NASA/JPL

In other news, the Phoenix lander also announced on Twitter that it has opened another TEGA oven door in preparation for receiving another sample of Martian soil to “bake and sniff.”

New Source: Phoenix Image Gallery, Wanderingspace.net

Posted on by Ian O'Neill

Video of SpaceX Falcon 1 Flight 3 Launch Shows Stage Separation Anomaly

Falcon 1 lifts off from Kwajalein Atoll, South Pacific August 2nd (SpaceX)

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On August 2nd, SpaceX made the surprise announcement that the third flight of the Falcon 1 rocket system would launch at 8pm (PST) that day. The world rushed to watch the first commercial flight of this impressive private-sector rocket via the web from a live feed on board. The first launch attempt was aborted due to a minor parameter fluctuation of 1% out of “normal” operating conditions, but the launch crew very quickly re-fuelled and prepared Falcon 1 for a second launch attempt within the hour. The second launch attempt appeared to be flawless, Merlin 1c engine roaring to life, lifting the rocket into the atmosphere. All seemed good, SpaceX seemed on track and very confident. However, minutes into the flight, the live video feed was cut and it was being reported an anomaly had occurred. It wasn’t until later in the week that SpaceX CEO Elon Musk gave details about the “anomaly.” SpaceX recently released video footage of the entire launch, up to the point where the stage separation problem occurred, spinning the ill-fated vehicle out of control…

So what did happen on that frustrating Sunday evening? On August 6th, Elon Musk announced the findings of the investigation into the launch anomaly. According to the launch engineers, the SpaceX Merlin 1c engine in the first stage performed perfectly. Even after the false-start on the launchpad, the engine was ready to go within the hour. This fast turnaround from launch abort to re-launch is a huge advantage for the company, a great testament to the flexibility of the technology SpaceX has developed in-house. The problems started during stage separation at an altitude of 35 km.

The problem arose due to the longer thrust decay transient of our new Merlin 1C regeneratively cooled engine, as compared to the prior flight that used our old Merlin 1A ablatively cooled engine. Unlike the ablative engine, the regen engine had unburned fuel in the cooling channels and manifold that combined with a small amount of residual oxygen to produce a small thrust that was just enough to overcome the stage separation pusher impulse. – Elon Musk, Aug. 6th statement.

From this statement and from viewing the video, it would seem that during first stage separation a small amount of fuel left over creating a small thrust just after the stages were forced away from one another (a.k.a. “stage separation pusher impulse”). At separation, it would appear that just as the first stage was beginning to fall away from Falcon 1, it regained some forward thrust, making it crash into the second stage engine. This small thrust anomaly prevented the spent first stage from falling clear of the igniting second stage. This sequence of events is captured in the series of screenshots below:

First stage separation appears to be going well until frame 3. Frame 4 shows the first stage thrust back into the second stage. Frame 5 shows the second stage firing when the first stage is not clear, Falcon 1 tumbles out of control (SpaceX)
The Falcon 1 separation anomaly at an altitude of 35 km. From left to right: First stage separation appears to be going well until frame 3. Frame 4 shows the first stage thrust back into the second stage. Frame 5 shows the second stage firing when the first stage is not clear, Falcon 1 tumbles out of control (SpaceX)

As the first stage was not clear, the second stage engine fired into the spent first stage. This would have caused a loss in control in rocket trajectory. However, the SpaceX editors appear to cut the video from the instant the second stage fires to when the rocket is in full tumble, blacking the frames out in between with the text “Faring Separation.” It’s not obvious what this means and there is no mention of it in the accompanying text. Most probably it means the camera was blown away from the rocket after second stage ignition.

See the full Falcon 1 launch »

The anomaly was down to what has been called a “thrust transient” and Musk points the blame at the tiny thrust that couldn’t be measured on the ground during test firing as the force generated was simply too small to be detected. However, in the vacuum of zero-gravity space, any thrust, large or small, matters:

The question then is why didn’t we catch this issue? Unfortunately, the engine chamber pressure is so low for this transient thrust — only about 10 psi — that it barely registered on our ground test stand in Texas where ambient pressure is 14.5 psi. However, in vacuum that 10 psi chamber pressure produced enough thrust to cause the first stage to recontact the second stage – Elon Musk, Aug. 6th statement.

Although this event is an obvious set back, and deeply saddening for SpaceX and the owners of the payloads Falcon 1 was supposed to put into orbit, lessons have been learnt and Musk is positive the next launch will be a total success. After all, no one said rocket science was easy…

Source: SpaceX

Posted on by Nancy Atkinson

Milky Way Creates a Mess by Stealing Stars from Nearby Galaxies

Model of a our galaxy showing trails of stars torn from disrupted satellite galaxies. Credit: K. Johnston, J. Bullock

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The halo of stars that envelops the outer Milky Way galaxy is like a “jumble of pasta” said one researcher, describing criss-crossed patterns of stellar streams revealed in new data from the Sloan Digital Sky Survey (SDSS). These stars appear to have been ripped away from the dwarf galaxies that are companions to our own galaxy, creating messy, spaghetti-like streams of stars in the outer edge of the Milky Way. The SEGUE (Sloan Extension for Galactic Understanding and Exploration) of the Sloan Survey is mapping the structure and stellar makeup of the Milky Way Galaxy and has found numerous new small streams of stars mixed and tangled among larger streams that had been mapped out over the last decade. It appears the Milky Way’s thievery is creating quite a mess.

While the center of galaxy is quite orderly, the outer Milky Way is a cluttered mess. Kathryn Johnston from Columbia University explained how dwarf galaxies that pass close to the Milky Way can be stretched by gravitational tides into spaghetti-like strands, which wind around the Galaxy as stars trace out the same orbital paths at different rates.

“In the center of the Galaxy, these stellar strands crowd together and you just see a smooth mix of stars,” said Johnston. “But as you look further away you can start to pick out individual strands, as well as features more akin to pasta shells that come from dwarfs that were on more elongated orbits.” Johnston described the new smaller strands recently detected as “angel hair” that came from smaller dwarf or ones that were destroyed longer ago.

Heidi Newberg of Rensselaer Polytechnic Institute and her thesis student Nathan Cole have been trying to follow some of the larger strands as they weave across the sky. “It’s a big challenge to piece things together,” said Cole, “because the stream from one dwarf galaxy can wrap around the Galaxy and pass through streams of stars ripped from other dwarf galaxies.”

Toward the constellation Virgo, where SDSS images revealed an excess of stars covering a huge area of sky, there are at least two superposed structures, and possibly three or more. The SEGUE velocity measurements can separate systems that overlap in sky maps, Newberg explained. “Part of what we see toward Virgo is a tidal arm of the Sagittarius dwarf galaxy, whose main body lies on the opposite side of the Milky Way, but we don’t know the origin of the other structures. There really aren’t enough pasta varieties to describe all the structures we find.”

“The SDSS has taught us a huge amount about the Milky Way and its neighbors,” said Johnston. “But we’re still just beginning to map the Galaxy in a comprehensive way, and there’s a trove of discoveries out there for the next generation of surveys, including the two new Milky Way surveys that will be carried out in SDSS-III,” the next set of surveys slated for Sloan.

Original News Source: SSDS press release, The Ohio State University

Posted on by Nancy Atkinson

Astronomers Answer Your Questions About “Celestial Geode”

Hubble image of N44F, the Celestial Geode.

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Last week, we posted the image above as part of our “Where In The Universe” challenge, where we test our readers’ visual knowledge of our universe. This incredible and unusual Hubble image of object N44F, known as the “Celestial Geode” is a gas cavity carved by the stellar wind and intense ultraviolet radiation from a hot young star. Readers were fascinated by the object and wanted to know more. One of our regular readers, Jorge, asked this question about N44F: “Why is it that we see the back “wall” of the bubble, we see the side walls, but we don’t see the front wall?” I wasn’t able to answer that question, so I sought out one of the astronomers responsible for this image, Dr. You-Hua Chu, professor at the University of Illinois, Urbana-Champaign. Not only did Dr. Chu provide wonderful information about the image, but one of her former students, Dr. Rosie Chen provided Universe Today with an exclusive Spitzer Space Telescope image of the Celestial Geode that has never been published before on the internet.

Dr. Chu explained in more detail what we see in the Hubble image. “This picture shows a cluster of stars that were formed recently, maybe about a million years ago,” she said. “The entire geode was a dense ball of gas and dust. It collapsed under its own gravity to form the cluster of stars.”

Once some massive stars were formed, there was enough UV radiation to ionize the remaining gas, and the stellar wind blows the gas outward. “Depending on how much material exists in each direction,” said Dr. Chu, “an expanding blister may form in the direction with low densities, or a stalled wall is formed in the direction with high densities.”

In response to the question about why we don’t see the front wall of the bubble, Dr. Chu compared the Celestial Geode to a store’s display case. The front wall is so thin, it is as transparent as glass. “You might ask how come we are so lucky to be peering through the thinnest wall of this geode,” said Dr. Chu. “Well, if we were looking at the geode in directions where thick walls exist, we wouldn’t be able to see the inside.”

Dr. Chu said the walls are like a balloon with uneven thickness. The thinnest part will be inflated most and become transparent.

“The interesting thing about this geode is that along its dense wall there are dust pillars sticking out and young stars are being formed at the tips of these pillars. We have obtained Spitzer Space Telescope images of this region and find IR (infrared) sources at the tips of the pillars and the spectral properties of these IR sources suggest that they contain young stars that are still enshrouded in dust.” And here is the Spitzer color composite image, provided by Dr. Rosie Chen, a researcher at the University of Virginia, and created by Dr. Adeline Caulet:

Spitzer/Hubble color composite image of N44F. Credit: Dr. Adeline Caulet
Spitzer/Hubble color composite image of N44F. Credit: Dr. Adeline Caulet

Both Drs. Chu and Chen warned that the Spitzer image may be a bit of a disappointment after seeing the Hubble image. “As you can see the HST images show clearly the detail structure while the Spitzer image is more fuzzy,” said Dr. Chen. “This is because HST’s resolution is over 10 times better than Spitzer.”

When I asked Dr. Chu about how the Hubble image was obtained, she said it was somewhat an accident that this particular part of N44 was imaged. “I proposed to Hubble to observe the superbubble N44 because it had X-ray emissions and I wanted to use high-resolution images to search for supernova remnant shocks,” she said. “The observation was made, but not properly made, so I requested a make-up observation at a slightly different location in N44 to allow an arbitrary roll angle of the space craft.” The Celestial Geode was at the new central position. Dr. Chu said she chose that position because she had always been interested to see what was going on in the ionized gas region, but didn’t have a convincing excuse to propose an observation. “You can say that I took advantage of the make-up observation to sneak in this object,” she said.

Dr. You-Hua Chu
Dr. You-Hua Chu

In researching this article, I noticed Dr. Chu’s name associated with many outstanding astronomical images. I told her she must be a busy astronomer. “I have to say that I am a lucky astronomer,” she said. “I try to pursue truth and beauty at the same time.”

Chu and Chen’s paper on N44: “Chen, C.-H.R., and Chu, Y.-H. Gruendl, R.A., Gordon, K.D., and Heitsch, F., “Spitzer View of Young Massive Stars in the LMC HII Complex N44,” 2008, ApJ, submitted.”