Anne Minard, Author at Universe Today

April 21, 2009April 26, 2016 by Anne Minard

Nearly Earth-sized Planet, Possible Watery World Spotted Near Another Star

Astronomers are announcing a newly discovered exoplanet in the habitable zone of its star, and another one — in the same system — that’s just twice the size of Earth.

The Gliese 581 planetary system now has four known planets, with masses of about 1.9 (planet e, left in the foreground), 16 (planet b, nearest to the star), 5 (planet c, center), and 7 Earth-masses (planet d, with the bluish colour).

This diagram shows the distances of the planets in the Solar System (upper row) and in the Gliese 581 system (lower row), from their respective stars (left). The habitable zone is indicated as the blue area, showing that Gliese 581 d is located inside the habitable zone around its low-mass red star. Based on a diagram by Franck Selsis, Univ. of Bordeaux.

Michel Mayor, a well-known exoplanet researcher from the Geneva Observatory, announced the find today. The planet, “e,” in the famous system Gliese 581, is only about twice the mass of our Earth. The team also refined the orbit of the planet Gliese 581 d, first discovered in 2007, placing it well within the habitable zone, where liquid water oceans could exist.

Both planets were discovered by the so-called “wobble method,” using the HARPS spectrograph attached to the 3.6-meter (11.8-foot) ESO telescope at La Silla, Chile.

The gentle pull of an exoplanet as it orbits the host star introduces a tiny wobble in the star’s motion that can just be detected on Earth with today’s most sophisticated technology. Low-mass red dwarf stars such as Gliese 581 are potentially fruitful hunting grounds for low-mass exoplanets in the habitable zone. Such cool stars are relatively faint and their habitable zones lie close in, where the gravitational tug of any orbiting planet found there would be stronger, making the telltale wobble more pronounced.

Many more exoplanets have been discovered using the transit method being employed by NASA’s Kepler mission: as planets pass between their host stars and Earth, they cause an observable, periodic dimming.

Planet Gliese 581 e orbits its host star – located only 20.5 light-years away in the constellation Libra (“the Scales”) — in just 3.15 days.

“With only 1.9 Earth-masses, it is the least massive exoplanet ever detected and is, very likely, a rocky planet,” says co-author Xavier Bonfils from Grenoble Observatory. Being so close to its host star, the planet e is not in the habitable zone. But another planet in this system appears to be.

“Gliese 581 d is probably too massive to be made only of rocky material, but we can speculate that it is an icy planet that has migrated closer to the star,” added team member Stephane Udry. The new observations have revealed that this planet is in the habitable zone, where liquid water could exist. “‘d’ could even be covered by a large and deep ocean — it is the first serious ‘water world’ candidate,” he said.

Mayor said it’s “amazing to see how far we have come since we discovered the first exoplanet around a normal star in 1995 — the one around 51 Pegasi. The mass of Gliese 581 e is 80 times less than that of 51 Pegasi b. This is tremendous progress in just 14 years.”

But the astronomers aren’t finished yet. “With similar observing conditions an Earth-like planet located in the middle of the habitable zone of a red dwarf star could be detectable,” says Bonfils. “The hunt continues.”

The findings were presented this week at the European Week of Astronomy & Space Science, which is taking place at the University of Hertfordshire in the UK. The results have also been submitted for publication in the research journal Astronomy & Astrophysics. A preprint is available here.

Source: ESO. (The site also offers numerous videos about the find.)

April 20, 2009December 24, 2015 by Anne Minard

Stars Strip Atmospheres of Close-forming Planets

It may be a while yet before astronomers agree on a standard model for planet formation around stars. Until recently, after all, Earthlings lacked reliable techniques for glimpsing much beyond our own solar system.

Based on our own backyard, one prevailing theory is that rocky planets like Mercury, Earth and Mars form slowly, close to the sun, from collisions of smaller, solid bodies while gas giants form faster, and farther from the star — often within the first two million years of a star’s life — from smaller rocky cores that readily attract gases.

But new data are suggesting that some gas giants form close to their stars — so close that intense stellar winds rob them of those gases, stripping them back to their cores.

An international research team has found that giant exoplanets orbiting very close to their stars — closer than 2 percent of an Astronomical Unit (AU) — could lose a quarter of their mass during their lifetime. An AU is the distance between the Earth and the Sun.

Such planets may lose their atmospheres completely.

The team, led by Helmut Lammer of the Space Research Institute of the Austrian Academy of Sciences, believes that the recently discovered CoRoT-7b “Super Earth,” which has less than twice the mass of the Earth, could be the stripped core of a Neptune-sized planet.

The team used computer models to study the possible atmospheric mass loss over a stellar lifecycle for exoplanets at orbiting distances of less than 0.06 AU, where the planetary and stellar parameters are very well known from observations.

Mercury is our only neighbor orbiting the Sun in that range; Venus orbits at about .72 AUs.

The 49 planets considered in the study included hot gas giants, planets with masses similar or greater than that of Saturn and Jupiter, and hot ice giants, planets comparable to Uranus or Neptune. All the exoplanets in the sample were discovered using the transit method, where the size and mass of the planet is deduced by observing how much its parent star dims as it the planet passes in front of it.

“If the transit data are accurate, these results have great relevance for planetary formation theories,” said Lammer, who is presenting results at the European Week of Astronomy and Space Science, April 20-23 at the University of Hertfordshire in the UK.

“We found that the Jupiter-type gas giant WASP-12b may have lost around 20-25 percent of its mass over its lifetime, but that other exoplanets in our sample had negligible mass loss. Our model shows also that one major important effect is the balance between the pressure from the electrically charged layer of the planet’s atmosphere and the pressure from the stellar wind and coronal mass ejections (CMEs). At orbits closer than 0.02 AU, the CMEs — violent explosions from the star’s outer layers — overwhelm the exoplanet’s atmospheric pressure causing it to lose maybe several tens of percent of its initial mass during its lifetime.”

The team found that gas giants could evaporate down to their core size if they orbit closer than 0.015 AU. Lower-density ice giants could completely lose their hydrogen envelope at 0.045 AU. Gas giants orbiting at more than 0.02 AU lost about 5-7 percent of their mass. Other exoplanets lost less than 2 percent. Results suggest that CoRoT-7b could be an evaporated Neptune-like planet but not the core of a larger gas giant. Model simulations indicate that larger mass gas giants could not have been evaporated to the mass range determined for CoRoT-7b.

For more information:

The European Week of Astronomy and Space Science
The Royal Astronomical Society

April 20, 2009December 24, 2015 by Anne Minard

Most Complex Organics Ever Detected in Interstellar Space

Is your mouth watering? It should be. That molecule at left is called ethyl formate (C2H5OCHO), and it’s partly responsible for the flavors in brandy, butter, raspberries and rum.

As for this one, it’s a solvent called n-Propyl cyanide (C3H7CN); not so tasty.

They’re both highly complex organics, and they’ve both been detected in space, according to new research — adding mouth-watering evidence to the search for extra-terrestrial life.

The research team hails from Cornell University in Ithaca, New York and the University of Cologne and the Max Planck Institute for Radio Astronomy (MPIfR), both in Germany. Their discoveries represent two of the most complex molecules yet discovered in interstellar space.

To make the observations, the team used the Institut de RadioAstronomie Millimétrique (IRAM) 30m Telescope at Pico Veleta in southern Spain.

Their computational models of interstellar chemistry also indicate that yet larger organic molecules may be present — including the so-far elusive amino acids, believed to be essential for life. The simplest amino acid, glycine (NH2CH2COOH), has been looked for in the past, but has not been successfully detected. However, the size and complexity of this molecule is matched by the two new molecules discovered by the team.

The results are being presented this week at the European Week of Astronomy and Space Science at the University of Hertfordshire, in the UK.

The IRAM was focused on the star-forming region Sagittarius B2, close to the centre of our galaxy. The two new molecules were detected in a hot, dense cloud of gas known as the “Large Molecule Heimat,” which contains a luminous newly-formed star. Large, organic molecules of many different sorts have been detected in this cloud in the past, including alcohols, aldehydes, and acids. The new molecules ethyl formate n-propyl cyanide represent two different classes of molecule — esters and alkyl cyanides — and they are the most complex of their kind yet detected in interstellar space.

Atoms and molecules emit radiation at very specific frequencies, which appear as characteristic “lines” in the electromagnetic spectrum of an astronomical source. Recognizing the signature of a molecule in that spectrum is akin to identifying a human fingerprint.

“The difficulty in searching for complex molecules is that the best astronomical sources contain so many different molecules that their “fingerprints” overlap, and are difficult to disentangle,” says Arnaud Belloche, scientist at the Max Planck Institute and first author of the research paper.

“Larger molecules are even more difficult to identify because their “fingerprints” are barely visible: their radiation is distributed over many more lines that are much weaker,” added Holger Mueller, researcher at the University of Cologne. Out of 3,700 spectral lines detected with the IRAM telescope, the team identified 36 lines belonging to the two new molecules.

The researchers then used a computational model to understand the chemical processes that allow these and other molecules to form in space. Chemical reactions can take place as the result of collisions between gaseous particles; but there are also small grains of dust suspended in the interstellar gas, and these grains can be used as landing sites for atoms to meet and react, producing molecules. As a result, the grains build up thick layers of ice, composed mainly of
water, but also containing a number of basic organic molecules like methanol, the simplest alcohol.

“But,” says Robin Garrod, an astrochemist at Cornell University, “the really large molecules don’t seem to build up this way, atom by atom.” Rather, the computational models suggest that the more complex molecules form section by section, using pre-formed building blocks that are provided by molecules, such as methanol, that are already present on the dust grains. The computational models show that these sections, or “functional groups,” can add together efficiently, building up a molecular “chain” in a series of short steps. The two newly-discovered molecules seem to be produced in this way.

Adds Garrod, “There is no apparent limit to the size of molecules that can be formed by this process — so there’s good reason to expect even more complex organic molecules to be there, if we can detect them.”

The team believes this will happen in the near future, particularly with future instruments like the Atacama Large Millimeter Array (ALMA) in Chile.

Sources: Royal Astronomical Society. The original paper is in press in the journal Astronomy & Astrophysics.

European Week of Astronomy and Space Science
Max Planck Institute for Radio Astronomy
Cologne Database for Molecular Spectroscopy
Reference list of all 150 molecules presently known in space
Cornell University
Institut fuer Radioastronomie im Millimeterbereich (IRAM)
Atacama Large Millimeter Array (ALMA)

April 19, 2009April 26, 2016 by Anne Minard

UK, US Astronomers: That’s One Cool Star

An international team, led by astronomers at the University of Hertfordshire in the UK, has discovered one of the coolest sub-stellar bodies ever found outside our own solar system.

The new object — dubbed Wolf 940B — orbits the red dwarf star Wolf 940, 40 light years from Earth. It’s thought to have formed like a star, but has ended up looking more like Jupiter. It is roughly the same size, despite being between 20 and 30 times as heavy, and when the infrared spectral “fingerprints” of the two objects are compared, their resemblance is striking, say Wolf 940B’s discoverers.

wfcam-fisheye_md — The Wide Field Camera (long black tube) on the United Kingdom Infrared Telescope on Mauna Kea, Hawaii.

Wolf 940B was initially discovered as part of a major infrared sky survey – the UKIRT Infrared Deep Sky Survey (UKIDSS) which is being carried out using the United Kingdom Infrared Telescope (UKIRT) on Mauna Kea in Hawaii. The telescope’s wide field camera is the long black tube in the image at left.

The object was found as part of a wider effort to find the coolest and least luminous bodies in our local Galactic neighborhood, but it was then found to be a companion to the nearby red dwarf Wolf 940 through its common motion across the sky. The data used to confirm the discovery were obtained using telescopes in Chile, the Canary Islands and Hawaii.

Its temperature was then confirmed using data from the Gemini-North telescope on Mauna Kea. The findings are being reported at the European Week of Astronomy and Space Science (NAM 2009) at the University of Hertfordshire, and will soon be published in the Monthly Notices of the Royal Astronomical Society.

The new object orbits its star at about 440 times the distance at which the Earth orbits the sun. At such a wide distance, it takes about 18,000 years to complete a single orbit.

Too small to be stars, so-called “brown dwarfs” have masses lower than stars but larger than gas giant planets like Jupiter. Due to their low temperatures, these objects are very faint in visible light, and are detected by their glow at infrared wavelengths.

“Although it has a temperature of 300 degrees Celsius [572 degrees F], which is almost hot enough to melt lead, temperature is relative when you study this sort of thing, and this object is very cool by stellar standards,” said Ben Burningham, of the University of Hertfordshire. “In fact, this is the first time we’ve been able to study an object as cool as this in such detail. The fact that it is orbiting a star makes it extra special.”

Modeling the atmospheres of cool brown dwarfs is a complex task, but it is key to understanding planets that orbit other stars. Models of emitted light from such objects, which are dominated by absorption due to water and methane gas, are sensitive to assumptions about their age and chemical make-up.

In most cases, astronomers don’t initially know much about the age and composition of brown dwarfs — and this can make it hard to tell where the models are right, and where they are going wrong.

“What’s so exciting in this case, is that we can use what we know about the primary star to find out about the properties of the brown dwarf, and that makes it an extremely useful find,” Burningham said. “You can think of it as a Rosetta Stone for decrypting what the light from such cool objects is telling us.”

Wolf 940A, the red dwarf star that is Wolf 940B’s namesake, was first catalogued by the pioneering German astronomer Max Wolf 90 years ago.

“Red dwarfs are the most populous stars in the Galaxy, and systems like this may be more common than we know” said David Pinfield, also of the University of Hertfordshire. “As the generation of ongoing large scale surveys continues, we may discover a pack of Wolf-940B-like objects in our solar back yard.”

Source: Joint Astronomy Centre. For more information, visit:

The UK Infrared Telescope
NAM 2009
Gemini Observatory

April 19, 2009April 26, 2016 by Anne Minard

Orion’s Belt Sees More Action Than We Knew

Using infrared telescopes, European and American astronomers have peered through the opaque molecular cloud that obscures much of Orion’s stellar nursery from view.

They’ve discovered a rowdy scene there — a crowded stellar nursery, with young stars shooting supersonic hydrogen jets in all directions — and they’re reporting there is much more going on in Orion than previously thought.

The new survey is the most wide-ranging census ever produced of dynamical star formation in and around the well-known Great Nebula of Orion.

In the United Kingdom Infrared Telescope/Spitzer Space Telescope image above, parts of the Orion Molecular cloud are illuminated by nearby stars and glowing an eerie green. The jets punch through the cloud and can be seen as tiny pink-purple arcs, knots and filaments. The golden orange young stars that drive the jets can usually be seen nearby.

Below, a gas jet (seen in red) pops out of a busy region of star formation in Orion. All the red wisps, knots and filaments are in fact associated with jets from young stars, which in this figure are colored orange. The data were acquired with the Wide Field Camera at the United Kingdom Infrared Telescope. (Story continues beneath image.)

The Orion Molecular Cloud is more than 20 times the angular size of the full moon, spanning from far above the hunter’s head to far below his feet. Most of the action is hidden from view in visible light. Earthbound stargazers can see he brightest stars, like Betelgeuse and Rigel at the shoulder and knee of the constellation, and perhaps the Orion Nebula as a vaguely fuzzy patch around the sword. The nebula, which is really just a blister on the surface of the cloud, gives the only indication of the chaos within.

The team studied the region with the United Kingdom Infrared Telescope (UKIRT) on Mauna Kea, the Spitzer Space Telescope, which works at even longer “mid-infrared” wavelengths, and the IRAM Millimeter-wave (radio) Telescope in Spain.

The power of the census came from the combination of data from all three facilities, the researchers say. Inspired by the richness of his images from UKIRT, Chris Davis, of Hawaii’s Joint Astronomy Centre, contacted colleagues in Europe and on the United States mainland.

Tom Megeath, an astronomer from the University of Toledo, provided a catalogue of the positions of the very youngest stars – sources revealed only recently by the Spitzer Space Telescope.

Thomas Stanke, a researcher based at the European Southern Observatory in Garching, Germany, then provided extensive IRAM maps of the molecular gas and dust across the Orion cloud.

Dirk Froebrich, a lecturer at the University of Kent, later used archival images from the Calar Alto Observatory in Spain (data acquired by Stanke some 10 years ago) to measure the speeds and directions of a large number of jets by comparing them with their positions in the new images.

Armed with these data, Davis was able to match the jets up to the young stars that drive them, as well as to density peaks within the cloud – the natal cores from which each star is being created.

“Regions like this are usually referred to as stellar nurseries, but we have shown that this one is not being well run: it is chaotic and seriously overcrowded,” Davis said. “Using UKIRT’s wide field camera, we now know of more than 110 individual jets from this one region of the Milky Way. Each jet is traveling at tens or even hundreds of miles per second; the jets extend across many trillions of miles of interstellar space. Even so, we have been able to pinpoint the young stars that drive most of them.”

Andy Adamson, associate director at the UKIRT, added that the dataset “demonstrates the power of survey telescopes like UKIRT. With on-line access to data from other telescopes around the world, and the ease with which one can communicate with collaborators across the globe, massive projects like the Orion study are very much the future of astronomy.”

Several of the researchers are presenting their discoveries with colleagues at this year’s annual National Astronomy Meeting of the UK (NAM 2009).

Source: Joint Astronomy Centre. For more information, visit

The UK Infrared Telescope
The Spitzer Space Telescope
The IRAM Millimeter-wave Telescope
NAM 2009
Royal Astronomical Society

April 18, 2009April 26, 2016 by Anne Minard

A Day for Earth, but a Whole Week for Dark Skies

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Wednesday is Earth Day, but all week — Monday, April 20 through Saturday, April 26 — is National Dark Sky Week in America, when people are asked to dim the lights to see more stars.

If enough people participate, backyard and professional astronomers might be treated with a week of darker, starrier skies. The bigger idea is to raise awareness about sensible lighting practices, so skies might get a little bit darker all the time. And not just for astronomy buffs. Besides aesthetics, evidence is mounting that light pollution could have far-reaching effects for the environment and even public health.

milky-way — 360-degree panoramic picture of the Milky Way as seen from Death Valley. Credit: Dan Duriscoe, National Park Service.

Jennifer Barlow, founder of the event, said the only way National Dark Sky Week can succeed is if more people participate every year. “No reduction in light pollution can be made unless a significant number of people turn off their lights,” she said.

Besides turning out the lights, the participating groups are encouraging people to attend star parties, visit local observatories, or “dust off the old telescope from the attic,” Barlow said.

Year-round, the International Dark Sky Association encourages people to shield lights, or use fixtures that focus light downward instead of up into the sky. Reducing extraneous light, especially at ball fields, is a major step in the right direction. And certain types of lighting — like low-pressure sodium — are better than others.

Flagstaff, Arizona became the world’s first International Dark-Sky City in 2001, owing to the presence of several important observatories — it’s the home of Lowell Observatory and the U.S. Naval Observatory — along with the dedicated efforts of a handful of astronomers. The city government and the vast majority of businesses have readily complied with responsible lighting codes to protect views of the night sky for residents and astronomers alike.

The skies are noticeably dark over Flagstaff; the stars are rich at night. The Grand Canyon is even more impressive, especially on the north side. The views after dark are as stunning and magical as those during the day.

But even those skies aren’t as good as they could be, because light pollution from cities up to 200 miles away — including Las Vegas and Phoenix — is gradually creeping in. Chad Moore, a dark skies advocate who works for the National Park Service in Denver, has spent nearly a decade documenting the skies over 55 of the nation’s parks, which are usually the best places to see stars.

Parts of rare parks — Capitol Reef, Great Basin and Big Bend among them — boast truly dark skies, he said.

Moore pointed out there are reasons besides beauty to rein in light pollution: “In the last 10 years there has been a revolution in our understanding of animal habitat and what animals require,” he said. “There are links between artificial light and cancer in humans. There’s a lot we didn’t know about.”

Second photo caption: 360-degree panoramic picture of the Milky Way as seen from Death Valley. Credit: Dan Duriscoe, National Park Service.

For more information:

National Dark Sky Week
International Dark-Sky Association
IYA Dark Skies Awareness
Starlight Initiative
World Night in Defense of Starlight
American Astronomical Society
Astronomical League
NASA IYA site

April 17, 2009December 24, 2015 by Anne Minard

How to Keep Asteroids Away: Tie Them Up

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It may not look like much, but that drawing could save a life someday — or 7 billion.

David French, a doctoral candidate in aerospace engineering at North Carolina State University is proposing a new tool for the anti-asteroid arsenal.

French said his PhD advisor Andre Mazzoleni, an associate professor of mechanical and aerospace engineering at the university, were not beholden to grant funds and “we just decided to go off on a direction that’s interesting and exciting.”

Mazzoleni has worked with tethers in other applications, and the two have now come up with a way to effectively divert asteroids and other threatening objects from impacting Earth by attaching a long tether and ballast to the incoming object.

By attaching the ballast, French explains, “you change the object’s center of mass, effectively changing the object’s orbit and allowing it to pass by the Earth, rather than impacting it.”

NASA’s Near Earth Object Program has identified more than 1,000 “potentially hazardous asteroids” and they are finding more all the time. “While none of these objects is currently projected to hit Earth in the near future, slight changes in the orbits of these bodies, which could be caused by the gravitational pull of other objects, push from the solar wind, or some other effect could cause an intersection,” French explains.

He said it’s hard to imagine the scale of both the problem and the potential solutions — but he points out that some asteroid impacts on Earth have been catastrophic.

“About 65 million years ago, a very large asteroid is thought to have hit the Earth in the southern Gulf of Mexico, wiping out the dinosaurs, and, in 1907, a very small airburst of a comet over Siberia flattened a forest over an area equal in size to New York City,” he said. “The scale of our solution is similarly hard to imagine.”

The idea is to use a tether somewhere in length between 1,000 kilometers (621 miles; roughly the distance from Raleigh to Miami) to 100,000 kilometers (62,137 miles; you could wrap this around the Earth two and a half times).

Other ideas that have emerged sound no less extreme, French notes. Those include painting the asteroids in order to alter how light may influence their orbit, a plan that would guide a second asteroid into the threatening one, and nuclear weapons.

“They probably all have their merits and drawbacks,” he said. “Nuclear weapons are already accessible; we’ve already made them. I can look at my own idea and say it’s long duration and very trackable.”

A tether effort could last in the ballpark of 20 to 50 years, he said, depending on the size and shape of the asteroid and its orbit, and the size of ballast.

French acknowledges there are “technical barriers that have to be surpassed.”

“First, you would have to mitigate the rotation of the asteroid,” he said, adding that the crescent-shaped piece connecting the poles on a globe might make a good conceptual model for a tether anchor, because it would allow for the asteroid’s rotation.

Another problem is the composition,” he added. “Some asteroids are just rubble piles.”

French said his idea was never to have all the kinks worked out on his model before presenting it; he just hoped to add another option to the asteroid-preparedness table.

“We’re opening up the concept, and we invite the broader scientific community to help us solve the issues,” he said.

Source: An NC State press release, via Eurekalert, and an interview with David French.

April 16, 2009December 24, 2015 by Anne Minard

Researchers Describe ‘Most Spectacular and Most Disturbed’ Galaxy Cluster

Composite image of MACSJ0717. Credit: X-ray (NASA/CXC/IfA/C. Ma et al.); Optical (NASA/STScI/IfA/C. Ma et al.)

It’s hot. It’s crowded. And it’s one of the most raucuous space parties astronomers have ever seen.

A research team using a combination of three powerful telescopes is spilling the beans on the galaxy cluster MACSJ0717.5+3745 (MACSJ0717 for short), located about 5.4 billion light years from Earth. The wild system contains four separate galaxy clusters undergoing a triple merger — the first time such a phenomenon has been documented — and that’s just the beginning.

Galaxy clusters are the largest objects bound by gravity in the Universe. Using data from NASA’s Chandra X-ray Observatory, Hubble Space Telescope and the Keck Observatory on Mauna Kea, Hawaii, astronomers were able to determine the three-dimensional geometry and motion in MACSJ0717.

Its 13-million-light-year-long stream of galaxies, gas and dark matter — known as a filament — is pouring into a region already full of galaxies. Like a freeway of cars emptying into a full parking lot, this flow of galaxies has caused one collision after another.

“In addition to this enormous pileup, MACSJ0717 is also remarkable because of its temperature,” said lead author Cheng-Jiun Ma, of the University of Hawaii. “Since each of these collisions releases energy in the form of heat, MACS0717 has one of the highest temperatures ever seen in such a system.”

While the filament leading into MACJ0717 had been previously discovered, these results show for the first time that it was the source of this galactic pummeling. The evidence is two-fold. First, by comparing the position of the gas and clusters of galaxies, the researchers tracked the direction of clusters’ motions, which matched the orientation of the filament in most cases. Secondly, the largest hot region in MACSJ0717 is where the filament intersects the cluster, suggesting ongoing impacts.

“MACSJ0717 shows how giant galaxy clusters interact with their environment on scales of many millions of light years,” said team member Harald Ebeling, also from the University of Hawaii. “This is a wonderful system for studying how clusters grow as material falls into them along filaments.”

Computer simulations show that the most massive galaxy clusters should grow in regions where large-scale filaments of intergalactic gas, galaxies, and dark matter intersect, and material falls inward along the filaments.

“It’s exciting that the data we get from MACSJ0717 appear to beautifully match the scenario depicted in the simulations,” said Ma.

In the future, Ma and his team hope to use even deeper X-ray data to measure the temperature of gas over the full 13-million-light-year extent of the filament. Much remains to be learned about the properties of hot gas in filaments and whether infall along these structures can significantly heat the gas in clusters over large scales.

“This is the most spectacular and most disturbed cluster I have ever seen,” says Ma, “and we think that we can learn a whole lot more from it about how structure in our Universe grows and evolves.”

The paper describing these results appeared in the March 10 issue of Astrophysical Journal Letters.

Source: Harvard University’s Chandra site. More information can be found at NASA’s Chandra site, and the paper is available here.

April 13, 2009December 24, 2015 by Anne Minard

Interview with Astronaut Mike Massimino on the Hubble Servicing Mission, Viewing Earth from Space and … Twitter?

The long-awaited final Hubble servicing mission is a month out now, and the crew of seven astronauts who have been in limbo since at least October are finally gearing up to go. The space shuttle Atlantis is set to launch from NASA’s Kennedy Space Center in Florida on May 12.

This will be the second Hubble mission for Astronaut Mike Massimino, and he’s been sharing his excitement about the mission via live interviews from NASA’s Johnson Space Flight Center and Twitter, a popular social networking site. We took advantage of the chance to ask Massimino some questions.

massimino-pool — Astronaut Mike Massimino suits up for spacewalk practice in the pool. Credit: NASA

So the final Hubble servicing mission is finally going to happen. How are you feeling about it?

I’m feeling great. I’m ready, I think my crew’s ready, and looking forward to going into space and seeing Hubble again and seeing the Earth from space.

On Twitter, you “tweeted” a few days ago: “viewing the Earth from space is the most beautiful site, words cannot describe the experience, can’t wait to see that sight again!” And it made me wonder how long you’ve wanted to have that perspective, and whether you dreamed of this sort of thing as a kid?

I dreamt about being an astronaut when I was a little kid. I was 6 years old when Neil Armstrong first walked on the moon. But the view of the Earth … it is just so awesome to see the Earth from space. There’s no way to really prepare you for it; we can practice our space walks in the neutral buoyancy lab, we can go to simulators, but there’s nothing that can prepare you for what your eyes will actually see when it comes to the beauty of space and the beauty of the Earth. I can’t really describe it with words, but I can describe what my thoughts were. When I really had the chance to look, while I was spacewalking, the first thought that went through my mind was “if you were in Heaven, this is what you would see.” And then the thought that replaced it was “no, no, it’s more beautiful than that. This is what Heaven must look like.”

You performed two spacewalks to service the telescope during the STS-109 mission in 2002. Since then you’ve worked in Mission Control and taught some classes. Why so long between missions?

I flew in 2002, then I was hoping to get reassigned to another shuttle flight at some point, but the Columbia accident occurred. In the three years following Columbia, we didn’t have very many flights. I got assigned soon after STS 121 to the Hubble Space Telescope flight. Then comes that saga. My crew and I were assigned around Halloween, October 2006 … We thought we might be flying about a year and a half later. We were two weeks from launching in October of last year, and then we got delayed because something broke on the telescope. It’s been good for job security I guess. It gives you more time to get ready, and they hang onto you a little bit longer.

Have you noticed any differences between preparing for this mission and preparing for the STS-109 flight?

STS-109 was my first flight. I was trying to figure out what I was going to do not to get in everybody’s way. I was wondering how I would react to space; I was kind of concerned about how I was going to do. This flight here, I’m pretty confident about how I’ll do … and I’m concerned a little bit more about how the team will do. It’s … a little more responsibility. I’m the experienced guy on our spacewalking team now. Actually it’s a little bit more enjoyable because I know what I’m going to do and I’m looking forward to it.

You’re on Twitter! Why?

I feel very fortunate to have the opportunity to be an astronaut. I think I’m extremely lucky. We get to do so many wonderful things; one of my interests has been to try to share that with people the best I can. It seemed like this Twitter idea was a great way to share our experiences with other people. One of the great things about Twitter it doesn’t really take that long. You have 140 characters … I checked this weekend and we were up to 35,000 people–

You’re up to 40,000 now

… I figure if there are that many people listening, that’s a pretty good deal. You get responses to it. It’s just wonderful to hear the excitement and all the good wishes from people around the world.

***

The May servicing mission will be the fourth and final trip to the Hubble Space Telescope. Over the course of five spacewalks, astronauts will install two new instruments, repair two inactive instruments and replace parts that will keep the telescope functioning at least into 2014.

Check out Mike Massimino’s Twitter profile here, where he’ll continue tweeting about mission preparations. More information about the servicing mission is here, and more information about the Atlantis crew is here.

Author: Anne Minard