New radar images from Encealdus' south pole show high amounts of surface texturing. NASA/JPL-Caltech/SSI.
[/caption]
Cassini’s done it again! Soaring over Saturn’s moon Enceladus back on November 6, the spacecraft obtained the highest-resolution images yet of the moon’s south polar terrain, revealing surface details with visible, infrared and radar imaging that have never been seen before.
Of particular interest are new image swaths acquired by the spacecraft’s synthetic-aperture radar (SAR) instrument, which has never before been used on Enceladus. The radar, which is highly sensitive to surface textures, reveals some extremely bright regions that have surprised scientists.
Detail of the radar-imaged area (enlarged). NASA/JPL-Caltech/SSI.
“It’s puzzling why this is some of the brightest stuff Cassini has seen,” said Steve Wall, deputy team lead of Cassini’s radar team based at NASA’s Jet Propulsion Laboratory in Pasadena. “One possibility is that the area is studded with rounded ice rocks. But we can’t yet explain how that would happen.”
The SAR images did not focus on the moon’s now-famous “tiger stripe” fractures (called sulci) which are the sources of its icy jets. Instead, Cassini scanned areas a few hundred miles around the stripes. These regions have not been extensively imaged before and this new data shows surface patterns and elevations that had been previously unknown.
Some of the steep grooves in the imaged areas were shown to be as deep as 2,100 feet (650 m), and 1.2 miles (2 km) wide.
Cassini passed by the 318-mile (511-km) -wide moon at 04:49 UTC on November 6, 2011. Cassini’s radar instrument was built by JPL and the Italian Space Agency, working with team members from the U.S. and several European countries. Previously used to image the surface of Titan, which is hidden from view by a thick atmosphere, this is the first time the instrument was used on Enceladus.
This past Saturday, an Atlas V carrying NASA’s MSL Curiosity Mars rover thundered off the launch pad on the way to Mars. Ever wondered what the rocket launch is like from the roof of the massive VAB (Vehicle Assembly Building) at NASA’s Kennedy Space Center? Videographer David Gonzales shot the launch for Universe Today using 3 different high definition cameras and recorded audio using a high definition audio device.
During ignition you can see white steam stream out the flame trench followed by the darker exhaust as the Solid Rocket Boosters come to life. The Atlas V lifts off on a pillar of bright orange fire leaving behind a white trail of smoke and an artificial cloud of condensed water droplets. Man-made thunder fills the air as Curiosity takes the first step on the journey to Mars.
Vivid Vesta Vista in Vibrant 3 D from NASA’s Dawn Asteroid Orbiter. Vesta is the second most massive asteroid and is 330 miles (530 km) in diameter. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
[/caption]
It’s time to put on your 3-D glasses and go soaring all over the giant asteroid Vesta – thanks to the superlative efforts of Dawn’s international science team.
Now you can enjoy vivid ‘Vestan Vistas’ like you’ve never ever seen before in a vibrant 3 D video newly created by Dawn team member Ralf Jaumann, of the German Aerospace Center (DLR) in Berlin, Germany – see below.
To fully appreciate the rough and tumble of the totally foreign and matchless world that is Vesta, you’ll absolutely have to haul out your trusty red-cyan (or red-blue) 3 D anaglyph glasses.
Then hold on, as you glide along for a global gaze of mysteriously gorgeous equatorial groves ground out by a gargantuan gong, eons ago.
Along the way you’ll see an alien ‘Snowman’ and the remnants of the missing South Pole, including the impressive Rheasilvia impact basin – named after a Vestal virgin – and the massive mountain some 16 miles (25 kilometers) high, or more than twice the height of Mt. Everest.
Video Caption: This 3-D video incorporates images from the framing camera instrument aboard NASA’s Dawn spacecraft from July to August 2011. The images were obtained as Dawn approached Vesta and circled the giant asteroid during the mission’s survey orbit phase at an altitude of about 1,700 miles (2,700 kilometers). To view this video in 3-D use red-green, or red-blue, glasses (left eye: red; right eye: green/blue). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
“If you want to know what it’s like to explore a new world like Vesta, this new video gives everyone a chance to see it for themselves,” Jaumann said. “Scientists are poring over these images to learn more about how the craters, hills, grooves and troughs we see were created.”
NASA’s Dawn spacecraft is humanity’s first probe to investigate Vesta, the second most massive body in the main Asteroid Belt between Mars and Jupiter.
Video caption: 2 D rotation movie of Vesta. Compare the 2 D movie to the new 3 D movie. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.
Indeed Dawn was just honored by Popular Science magazine and recognized as one of three NASA Planetary Science missions to earn a ‘Best of What’s New in 2011’ for innovation in the aviation and space category – along with the Curiosity Mars Science Laboratory (MSL) and MESSENGER Mercury orbiter.
Asteroid Vesta and Mysterious Equatorial Grooves - from Dawn Orbiter
This full view of the giant asteroid Vesta was taken by NASA’s Dawn spacecraft on July 24, 2011, at a distance of 3,200 miles (5,200 kilometers). This view shows impact craters of various sizes and mysterious grooves parallel to the equator. The resolution of this image is about 500 meters per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
The images in the 3 D video were snapped between July and August 2011 as Dawn completed the final approach to Vesta, achieved orbit in July 2011 and circled overhead during the mission’s initial survey orbit phase at an altitude of about 1,700 miles (2,700 kilometers) in August.
How was the 3 D movie created?
“The Dawn team consists of a bunch of talented people. One of those talented people is Ralf Jaumann, Dawn co-Investigator from the DLR in Berlin,” Prof. Chris Russell, Dawn Principal Investigator, of UCLA, told Universe Today.
“Jaumann and the team behind him have stitched together the mosaics we see and they have made shape models of the surface. They are also skilled communicators and have been heroes in getting the Dawn Image of the Day together. I owe them much thanks and recognition for their efforts.”
“They wanted to make and release to the public an anaglyph of the rotating Vesta to share with everyone the virtual thrill of flying over this alien world.”
“I hope everyone who follows the progress of Dawn will enjoy this movie as much as I do.”
“It is just amazing to an old-time space explorer as myself that we can now make planetary exploration so accessible to people all over our globe in their own homes and so soon after we have received the images,” Russell told me.
3 D of the ‘Snowman' Crater
This anaglyph image shows the topography of Vesta's three craters, informally named the "Snowman," obtained by the framing camera instrument aboard Dawn on August 6, 2011. The camera has a resolution of about 260 meters per pixel.
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Dawn is now spiraling down to her lowest mapping orbit known as LAMO (Low Altitude Mapping Orbit), barely 130 miles (210 kilometers) above Vesta’s surface.
“Dawn remains on course and on schedule to begin its scientific observations in LAMO on December 12,” says Dr. Marc Rayman, Dawn’s Chief Engineer from the Jet Propulsion Lab (JPL), Pasadena, Calif.
“The focus of LAMO investigations will be on making a census of the atomic constituents with its gamma ray and neutron sensors and on mapping the gravity field in order to determine the interior structure of this protoplanet.”
“Today, Dawn is at about 245 km altitude,” Rayman told Universe Today.
The 3 D video is narrated by Carol Raymond, Dawn’s deputy principal investigator at JPL.
“Dawn’s data thus far have revealed the rugged topography and complex textures of the surface of Vesta, as can be seen in this video”.
“Soon, we’ll add other pieces of the puzzle such as the chemical composition, interior structure, and geologic age to be able to write the history of this remnant protoplanet and its place in the early solar system.”
3 D Image of Vesta's South Polar Region
This anaglyph image of the south polar region was taken on July 9, 2011 by the framing camera instrument aboard NASA's Dawn spacecraft. Each pixel in this image corresponds to roughly 2.2 miles (3.5 kilometers). The anaglyph image shows the rough topography in the south polar area, the large mountain, impact craters, grooves, and steep scarps in three dimensions.
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Read continuing features about Dawn by Ken Kremer starting here:
This Large Binocular Telescope image below of the Whirlpool Galaxy, otherwise known as M51, is part of a new galaxy survey by Ohio State University, where astronomers are searching for signs that stars are about to go supernova. The insets show one particular binary star system before (left) and after (right) one of its stars went supernova. Image by Dorota Szczygiel, courtesy of Ohio State University.
[/caption] This past year has given both backyard and professional astronomers a rare treat – a very visible supernova event. Hosted in the Whirlpool Galaxy (M51), these stellar death throes may have been clued to us by a rather ordinary binary star system. In a recent study done by researchers at Ohio State University, a galaxy survey may have captured evidence of a “stellar signal” just before it went supernova!
Employing the Large Binocular Telescope located in Arizona, the OSU team was undertaking a survey of 25 galaxies for stars that changed their magnitude in usual ways. Their goal was to find a star just before it ended its life – a three-year undertaking. As luck would have it, a binary star system located in M51 produced just the results they were looking for. One star dropped amplitude just a short period of time before the other exploded. While the probability factor of them getting the exact star might be slim, chances are still good they caught its brighter partner. Despite that, principal investigator Christopher Kochanek, professor of astronomy at Ohio State and the Ohio Eminent Scholar in Observational Cosmology, remains optimistic as their results prove a theory.
“Our underlying goal is to look for any kind of signature behavior that will enable us to identify stars before they explode,” he said. “It’s a speculative goal at this point, but at least now we know that it’s possible.”
“Maybe stars give off a clear signal of impending doom, maybe they don’t,” said study co-author Krzystof Stanek, professor of astronomy at Ohio State, “But we’ll learn something new about dying stars no matter the outcome.”
Postdoctoral researcher Dorota Szczygiel, the leader of the supernova study tells us why the galaxy survey remains paramount.
“The odds are extremely low that we would just happen to be observing a star for several years before it went supernova. We would have to be extremely lucky,” she said. “With this galaxy survey, we’re making our own luck. We’re studying all the variable stars in 25 galaxies, so that when one of them happens go supernova, we’ve already compiled data on it.”
On May 31, 2011, the whole astronomy world was abuzz when SN2011dh gave both amateurs and professionals a real thrill as an easily observable event. As luck would have it, it was a binary star system being studied by the OSU team, and consisted of both a blue and red star. At this point, the astronomers surmise the red star was the one that dimmed significantly over the three-year period while the blue one blew its top. When reviewing the LBT data, the Ohio team found that when compared with Hubble images, the red star dimmed at about 10% over the final three-year period at an estimated 3% per previous years. As a curiosity, the researchers surmise the red star may have actually survived the supernova event.
“After the light from the explosion fades away, we should be able to see the companion that did not explode,” Szczygiel said.
As the team continues to collect valuable information, they estimate they could also detect another candidate set of stars at a rate of about one per year. There is also a strong possibility these detections could act as a type of test bed to predict future supernova events… looking for signals of impending doom. However, according to the news release, the Sun won’t be one to bother with.
“There’ll be no supernova for the Sun – it’ll just fizzle out,” Kochanek said. “But that’s okay – you don’t want to live around an exciting star.”
Roughly 2.4 billion years ago, Earth’s atmosphere underwent a huge change known as the “Great Oxidation Event”. This switch from an oxygen-poor to an oxygen-rich environment may be accountable for giving rise to life. However, scientists are extremely curious about what our atmosphere may have been like not long after our planet formed. Now researchers from the New York Center for Astrobiology at Rensselaer Polytechnic Institute are using some of the oldest minerals known to exist to help understand what may have occurred some five million years after Earth arose.
For the most part, scientists have theorized that early-Earth atmosphere was dominated by noxious methane, carbon monoxide, hydrogen sulfide, and ammonia. This highly reduced mixture results in a limited amount of oxygen and has led to a wide variety of theories about how life may have started in such a hostile environment. However, by taking a closer look at ancient minerals for oxidation levels, scientists at Rensselaer have proved the early-Earth atmosphere wasn’t like that at all… but held copious amounts of water, carbon dioxide, and sulfur dioxide.
“We can now say with some certainty that many scientists studying the origins of life on Earth simply picked the wrong atmosphere,” said Bruce Watson, Institute Professor of Science at Rensselaer.
How can they be so sure? Their findings depend on the theory that Earth’s atmosphere was formed volcanically. Each time magma flows to the surface, it releases gases. If it doesn’t come to the top, then it interacts with the surrounding rocks where it cools and becomes a rocky deposit in its own right. These deposits – and their elemental construction – allows science to paint an accurate portrait of the conditions at the time of their formation.
“Most scientists would argue that this outgassing from magma was the main input to the atmosphere,” Watson said. “To understand the nature of the atmosphere ‘in the beginning,’ we needed to determine what gas species were in the magmas supplying the atmosphere.”
One of the most important of all magma components is zircon – a mineral nearly as old as Earth itself. By determining the oxidation levels of the magmas that formed these ancient zircons, scientists are able to deduce how much oxygen was being released into the atmosphere.
“By determining the oxidation state of the magmas that created zircon, we could then determine the types of gases that would eventually make their way into the atmosphere,” said study lead author Dustin Trail, a postdoctoral researcher in the Center for Astrobiology.
To enable their work, the team set about cooking up magma in a laboratory setting – which led to the creation of an oxidation gauge to assist them in comparing their artificial specimens against natural zircons. Their study also included a watchful eye for a rare Earth metal called cerium that can exist in two oxidation states. By exposing cerium in zircon, the team can be confident the atmosphere was more oxidized after their creation. These new findings point to an atmospheric state more like our present day conditions… setting the stage for a new starting point on which to base life’s beginnings on Earth.
“Our planet is the stage on which all of life has played out,” Watson said. “We can’t even begin to talk about life on Earth until we know what that stage is. And oxygen conditions were vitally important because of how they affect the types of organic molecules that can be formed.”
While “life as we know it” is highly dependent on oxygen, our current atmosphere probably isn’t the ideal model for spawning primordial life. It’s more likely a methane-rich atmosphere might “have much more biologic potential to jump from inorganic compounds to life-supporting amino acids and DNA.” This leaves the door wide open to alternate theories, such as panspermia. But don’t sell the team’s results short. They still reveal the beginning nature of gases here on Earth, even if they don’t solve the riddle of the Great Oxidation Event.
Original Story Source: Rensselaer Polytechnic Institute News Release.
[/caption]
Here’s a beautiful photograph of the Moon captured by Brian Brushwood. If that name sounds a little familiar, Brian is the pointy-haired host of Scam School, NSFW, and many other podcasts and web shows. I was totally shocked and surprised to learn that Brian is actually an amateur astronomer, with a sweet 8″ dobsonian telescope. Amazingly, he captured this image by just holding up his iPhone camera to the telescope eyepiece and snapped the image.
[/caption]I know I rarely share the business side of Universe Today, but here’s a very interesting metric: visitors to Universe Today viewed a total of 5 million pages in November, 2011. That’s up about 100% from this time last year.
So, if you think that interest in science and astronomy is declining, allow me to offer this retort. You’re totally wrong. Millions of people every month are subscribed to, or seeking out, the material we’re offering here on Universe Today. People are choosing to read a website that’s only about space and astronomy. You can see the demand for shows like Mythbusters, podcasts like the Skeptic’s Guide to the Universe, or blogs like Bad Astronomy.
I’ll put most of the kudos on Nancy Atkinson’s leadership and the amazing writing team we’ve got here: 15 contributors at last count, growing every month. But the real heroes (to steal a line from Stephen Colbert) are you, the science enthusiasts. It’s your interest in science news that keeps the whole engine going; it’s thrilling to be a part of it, and I guarantee you haven’t seen anything yet.
Thank you for reading, sharing and participating in Universe Today.
Fraser Cain
Publisher
P.S. And for those of you wondering if you can actually make a living as a “blogger”. The answer is yes, and it’s getting easier every day.
Conventional wisdom has long had it that carbon-based life, so common here on earth, must surely be abundant elsewhere; both in our galaxy and the universe as a whole.
This line of reasoning is founded on two major assumptions; the first being that complex carbon chain molecules, the building blocks of life as we know it, have been detected throughout the interstellar medium. Carbon’s abundance appears to stretch across much of cosmic time, since its production is thought to have peaked some 7 billion years ago, when the universe was roughly half its current age.
The other major assumption is that life needs an elixir, a solvent on which it can advance its unique complex chemistry. Water and carbon go hand in hand in making this happen.
While the world as we know it runs on carbon, science fiction’s long flirtation with silicon-based life — “It’s life, but not as we know it” — has become a familiar catchphrase. But life of any sort should evolve, eat, excrete, reproduce, and respond to stimulus.
And although non-carbon based life is a very long shot, we thought we’d broach the issue with one of the country’s top astrochemists — Max Bernstein, the Research Lead of the Science Mission Directorate at NASA headquarters in Washington,D.C.
Bruce Dorminey — IS IT WRONG TO ASSUME THAT LIFE COULD BE BASED ON SOMETHING OTHER THAN CARBON?
Max Bernstein. Credit: NASA
Max Bernstein — It’s important for us to keep an open mind about alien life, lest we come across it and miss it. On the other hand, carbon is much better than any other element in forming the main structures of living things. Carbon can form many stable complex structures of great diversity. When carbon forms molecules containing cxygen and nitrogen, the carbon bonds to nitrogen and oxygen are stable. But not so much so that they can’t be fairly easily undone, unlike silicon-oxygen bonds, for example.
Dorminey — DOES THE RECENT NASA-FUNDED RESEARCH AT MONO LAKE, CALIFORNIA WHICH TOUTED THE DISCOVERY OF BACTERIA WITH DNA THAT USES ARSENIC INSTEAD OF PHOSPHORUS RATTLE THE CURRENT PARADIGM?
Bernstein — That was a really cool result, but the basic structure was still carbon. The arsenic was said to have replaced phosphorus, not carbon. The discovery of this putative arsenic organism may prove to be incorrect, but it’s a hypothesis with science behind it, and not just someone tossing out an idea and leaving it at the level of what if you replaced carbon with silicon?
The structure of silane, the silicon-based analogue of methane.
Dorminey — SILICON SEEMS TO BE THE MOST POPULAR NON-CARBON BASED CANDIDATE, ARE THERE OTHERS THAT ALSO MIGHT BE FEASIBLE?
Bernstein — It’s hard to imagine anything that would be more likely that silicon because there is nothing closer to carbon than silicon in terms of its chemistry. It’s in the right place on the periodic table, just below carbon. On the face of it, [silicon-based life] doesn’t seem too absurd since silicon, like carbon, forms four bonds. CH4 is methane and SiH4 is silane. They are analogous molecules so the basic idea is that perhaps silicon could form an entire parallel chemistry, and even life. But there are tons of problems with this idea. We don’t see a complex stable chemistry [solely] of silicon and hydrogen, as we see with carbon and hydrogen. We use hydrocarbon chains in our lipids (molecules that make up membranes), but the analogous silane chains would not be stable. Whereas carbon-oxygen bonds can be made and unmade — this goes on in our bodies all the time — this is not true for silicon. This would severely limit silicon’s life-like chemistry. Maybe you could have something silicon-based that’s sort of alive, but only in the sense that it passes on information.
Dorminey — IF SILICON-BASED LIFE IS OUT THERE, HOW COULD WE EVER DETECT IT REMOTELY?
Bernstein — We are seriously arguing about how we would remotely detect life just like us, so I really couldn’t say. Presumably technology-using organisms, whatever their biochemistry, will produce technology, so the Search for Extraterrestrial Intelligence (SETI) may be our best shot.
Dorminey— HOW WOULD YOU LOOK FOR SILICON-BASED LIFE HERE ON EARTH?
Bernstein — When seeking an alien organism its really tough because you just don’t know what molecules to look for. One would have to be satisfied by something a bit more ambiguous, like sets of molecules that should not be there. For example, if you were an alien Silicon organism, you might not be looking for our biochemistry, but the fact that you kept seeing exactly the same chain lengths over and over again might tip you off to the fact that those darn carbon chains might actually be the basis of an organism’s membranes.
Dorminey — WHERE ARE THE LARGEST CONCENTRATIONS OF SILICON HERE?
IN SAND?
Bernstein — In sand or rock. There are literally megatons of silicate minerals on Earth.
Dorminey — HAS ANYONE EVER CLAIMED DETECTION OF SELF-REPLICATING EXAMPLES OF SILICON HERE ON EARTH?
Bernstein — There have been ideas about minerals holding information just as DNA holds information. DNA holds information in a chain that is read from one end to the other. In contrast, a mineral could hold information in two dimensions [on its surface]. A crystal grows when new atoms arrive on the surface, building layer upon layer. So, if a crystal sheet cleaved off and then started to grow that would be like the birth of a new organism and would carry information from generation to generation. But is a replicating crystal alive? To date, I don’t think that there is actually any evidence that minerals pass information like this.
Dorminey — IS THE CRUX OF THE PROBLEM THAT SILICON-BASED LIFE WOULD BE SO SLOWLY REPLICATING THAT IT COULD NEVER MAKE IT IN A DYNAMIC UNIVERSE?
Bernstein — I don’t think that any Silicon life form could be a biological threat to us. If they were high tech, they might eat our buildings or shoot guns at us but I don’t see how they could infect us. We run hot and move fast. If we don’t, things will catch us and eat us.
If they are also tougher than we are and whatever feeds on them is also slow and Silicon based maybe being slow doesn’t matter.
Dorminey — WHAT WOULD BE THE SIGNATURES OF SILICON-BASED LIFE?
Bernstein — If they are not technological, they would be very tough to detect. We could look for unstable, unexpected silicon molecules; some high energy molecule that should not be there, or molecular chains of all the same length.
Dorminey — DO YOU THINK THAT SILICON-BASED LIFE MIGHT EXIST SOMEWHERE OUT THERE?
Bernstein — Maybe deep below the surface of a planet in some very hot hydrogen-rich, Oxygen-poor environment, you would have this complex silane chemistry. There, maybe silanes would form reversible silicon bonds with selenium or tellurium.
Dorminey — IF SUCH SILICON-BASED LIFE DID CROP UP, WHAT WOULD BE ITS EVOLUTIONARY ENDGAME?
Bernstein — If it could evolve past the protist [microorganism] stage, then I think it could evolve intelligence. I have no idea how likely it is for intelligence to evolve, but I can believe in silicon crystals passing information from layer to layer or in silicon artificial intelligence, but I don’t expect to see silicon apes playing their equivalent of “Angry Birds” on their Silicon-Phones.
Dorminey — IF SILICON-LIFE DID EVOLVE, WOULD ITS LIFESPAN BE MUCH LONGER THAN ITS CARBON-BASED ANALOGUES?
Bernstein — The replicating mineral that I described earlier would be living very, very slowly on Earth’s surface. But maybe somewhere very much hotter, its lifespan would be shorter. That’s because presumably lifespan is connected to the pace of your chemistry, which depends on temperature.
Dorminey — FINALLY, WHAT WOULD ENDANGER NON-CARBON-BASED LIFE?
Bernstein — Physical harm for sure. Presumably you could take a jackhammer to it?
But our biochemistry would not be pathogens to it; we could not “infect” them as was the case in “War of the Worlds.”
A neutron star's outer atmosphere engulfs another star in this concept rendering. (NASA/GSFC)
[/caption]
On December 25, 2010, at 1:38 p.m. EST, NASA’s Swift Burst Alert Telescope detected a particularly long-lived gamma-ray burst in the constellation Andromeda. Lasting nearly half an hour, the burst (known as GRB 101225A) originated from an unknown distance, leaving astronomers to puzzle over exactly what may have created such a dazzling holiday display.
Now there’s not just one but two theories as to what caused this burst, both reported in papers by a research team from the Institute of Astrophysics in Granada, Spain. The papers will appear in the Dec. 1 issue of Nature.
Gamma-ray bursts are the Universe’s most luminous explosions. Most occur when a massive star runs out of nuclear fuel. As the star’s core collapses, it creates a black hole or neutron star that sends intense jets of gas and radiation outwards. As the jets shoot into space they strike gas previously shed by the star and heat it, generating bright afterglows.
NASA's Swift observatory is a satellite in low-Earth orbit, scanning the sky for the presence of gamma-ray bursts and gravitational wave forces. (NASA)
If a GRB jet happens to be aimed towards Earth it can be detected by instruments like those aboard the Swift spacecraft.
Luckily GRBs usually come from vast distances, as they are extremely powerful and could potentially pose a danger to life on Earth should one strike directly from close enough range. Fortunately for us the odds of that happening are extremely slim… but not nonexistent. That is one reason why GRBs are of such interest to astronomers… gazing out into the Universe is, in one way, like looking down the barrels of an unknown number of distant guns.
The 2010 “Christmas burst”, as the event also called, is suspected to feature a neutron star as a key player. The incredibly dense cores that are left over after a massive star’s death, neutron stars rotate extremely rapidly and have intense magnetic fields.
One of the new theories envisions a neutron star as part of a binary system that also includes an expanding red giant. The neutron star may have potentially been engulfed by the outer atmosphere of its partner. The gravity of the neutron star would have caused it to acquire more mass and thus more momentum, making it spin faster while energizing its magnetic field. The stronger field would have then fired off some of the stellar material into space as polar jets… jets that then interacted with previously-expelled gases, creating the GRB detected by Swift.
This scenario puts the source of the Christmas burst at around 5.5 billion light-years away, which coincides with the observed location of a faint galaxy.
An alternate theory, also accepted by the research team, involves the collision of a comet-like object and a neutron star located within our own galaxy, about 10,000 light-years away. The comet-like body could have been something akin to a Kuiper Belt Object which, if in a distant orbit around a neutron star, may have survived the initial supernova blast only to end up on a spiraling path inwards.
The object, estimated to be about half the size of the asteroid Ceres, would have broken up due to tidal forces as it neared the neutron star. Debris that impacted the star would have created gamma-ray emission detectable by Swift, with later-arriving material extending the duration of the GRB into the X-ray spectrum… also coinciding with Swift’s measurements.
Both of these scenarios are in line with processes now accepted by researchers as plausible explanations for GRBs thanks to the wealth of data provided by the Swift telescope, launched in 2004.
“The beauty of the Christmas burst is that we must invoke two exotic scenarios to explain it, but such rare oddballs will help us advance the field,” said Chryssa Kouveliotou, a co-author of the study at NASA’s Marshall Space Flight Center in Huntsville, Alabama.
More observations using other instruments, such as the Hubble Space Telescope, will be needed to discern which of the two theories is most likely the case… or perhaps rule out both, which would mean something else entirely is the source of the 2010 Christmas burst!
Popular Science magazine names NASA’s Mars Science Laboratory, Dawn and MESSENGER missions as ‘Best of What’s New’ in innovation in 2011. Artist concept shows mosaic of MESSENGER, Mars Science Laboratory and Dawn missions. Credit: NASA/JPL-Caltech
[/caption]
A trio of NASA’s Planetary Science mission’s – Mars Science Laboratory (MSL), Dawn and MESSENGER – has been honored by Popular Science magazine and selected as ‘Best of What’s New’ in innovation in 2011 in the aviation and space category.
The Curiosity Mars Science Laboratory was just launched to the Red Planet on Saturday, Nov. 26 and will search for signs of life while traversing around layered terrain at Gale Crater. Dawn just arrived in orbit around Asteroid Vesta in July 2011. MESSENGER achieved orbit around Planet Mercury in March 2011.
Several of the top mission scientists and engineers provided exclusive comments about the Popular Science recognitions to Universe Today – below.
“Of course we are all very pleased by this selection,” Prof. Chris Russell, Dawn Principal Investigator, of UCLA, told Universe Today.
Dawn is the first mission ever to specifically investigate the main Asteroid Belt between Mars and Jupiter and will orbit both Vesta and Ceres – a feat enabled solely thanks to the revolutionary ion propulsion system.
“At the same time I must admit we are also not humble about it. Dawn is truly an amazing mission. A low cost mission, using NASA’s advanced technology to enormous scientific advantage. It is really, really a great mission,” Russell told me.
Vesta is the second most massive asteroid and Dawn’s discoveries of a surprisingly dichotomous and battered world has vastly exceeded the team’s expectations.
Asteroid Vesta from Dawn - Exquisite Clarity from a formerly Fuzzy Blob
NASA's Dawn spacecraft obtained this image of the giant asteroid Vesta with its framing camera on July 24, 2011. It was taken from a distance of about 3,200 miles (5,200 kilometers). Before Dawn, Vesta was just a fuzzy blob in the most powerful telescopes. Dawn entered orbit around Vesta on July 15, and will spend a year orbiting the body before firing up the ion propulsion system to break orbit and speed to Ceres, the largest Asteroid. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
“Dawn is NASA at its best: ambitious, exciting, innovative, and productive,” Dr. Marc Rayman, Dawn’s Chief Engineer from the Jet Propulsion Lab (JPL), Pasadena, Calif., told Universe Today.
“This interplanetary spaceship is exploring uncharted worlds. I’m delighted Popular Science recognizes what a marvelous undertaking this is.”
JPL manages both Dawn and Mars Science Laboratory for NASA’s Science Mission Directorate in Washington, D.C.
Dawn is an international science mission. The partners include the German Aerospace Center (DLR), the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute.
“Very cool!”, John Grotzinger, the Mars Science Laboratory Project Scientist of the California Institute of Technology, told Universe Today.
“MSL packs the most bang for the buck yet sent to Mars.”
Last View of Curiosity Mars Science Laboratory Rover - inside the Cleanroom at KSC.
Curiosity just before Encapsulation for 8 month long interplanetary Martian Journey and touchdown inside Gale Crater. Credit: Ken Kremer
Curiosity is using an unprecedented precision landing system to touch down inside the 154 km (96 miile) wide Gale Crater on Aug. 6, 2012. The crater exhibits exposures of phyllosilicates and other minerals that may have preserved evidence of ancient or extant Martian life and is dominated by a towering mountain.
“10 instruments all aimed at a mountain higher than any in the lower 48 states, whose stratigraphic layering records the major breakpoints in the history of Mars’ environments over likely hundreds of millions of years, including those that may have been habitable for life.”
“It’s like a trip down the Grand Canyon 150 years ago, with the same sense of adventure, but with a lot of high tech equipment,” Grotzinger told me.
MSL also has an international team of over 250 science investigators and instruments spread across the US, Europe and Russia. Curiosity Mars Science Laboratory rover soars to Mars atop an Atlas V rocket on Nov. 26 at 10:02 a.m. EST from Cape Canaveral, Florida. Credit: Ken Kremer
MESSENGER is the first probe to orbit Mercury and the one year primary mission was recently extended by NASA.
Sean Solomon, of the Carnegie Institution of Washington, leads the MESSENGER mission as principal investigator. The Johns Hopkins University Applied Physics Laboratory built and operates the MESSENGER spacecraft for NASA.
“Planetary has 3 missions there… Dawn, MESSENGER, and MSL,” Jim Green proudly said to Universe Today regarding the Popular Science magazine awards. Green is the director, Planetary Science Division, NASA Headquarters, Washington
“Three out of 10 [awards] is a tremendous recognition of the fact that each one of our planetary missions goes to a different environment and takes on new and unique measurements providing us new discoveries and constantly changes how we view nature, ourselves, and our place in the universe.”
The First Solar Day
After its first Mercury solar day (176 Earth days) in orbit, MESSENGER has nearly completed two of its main global imaging campaigns: a monochrome map at 250 m/pixel and an eight-color, 1-km/pixel color map. Apart from small gaps, which will be filled in during the next solar day, these global maps now provide uniform lighting conditions ideal for assessing the form of Mercury’s surface features as well as the color and compositional variations across the planet. The orthographic views seen here, centered at 75° E longitude, are each mosaics of thousands of individual images. At right, images taken through the wide-angle camera filters at 1000, 750, and 430 nm wavelength are displayed in red, green, and blue, respectively.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Read more about the Popular Science citations and awards here
.
Read continuing features about Curiosity, Dawn and MESSENGER by Ken Kremer starting here:
