NASA Spacecraft Closes in on Comet Tempel 1

February 9, 2011: NASA is about to discover how solar heat devours a comet.

Stardust-NExT chases a comet, an artist's concept. [more]

"For the first time, we'll see the same comet before and after its closest approach to the sun," explains Joe Veverka, principal investigator for NASA's Stardust-NExT mission.

The comet is Tempel 1, which NASA's Deep Impact probe visited in 2005. Now another NASA spacecraft, Stardust-NExT, is closing in for a second look on Valentine's Day, Feb. 14, 2011. The two visits bracket one complete orbit of the comet around the sun--and a blast of solar heat.

"Close encounters with the sun never go well for a comet," says Veverka. "Fierce solar heat vaporizes the ices in the comet's core, causing it to spit dust and spout gas. The cyclic loss of material eventually leads to its demise."

Researchers suspect the flamboyant decay doesn't happen evenly all over a comet's surface*, but until now they've lacked a way to document where, exactly, it does occur. Stardust NExT will image some of the same surface areas Deep Impact photographed 6 years ago, revealing how these areas have changed and where material has been lost.

"Deep Impact gave us tantalizing glimpses of Temple 1," says Veverka. "And we saw strange and unusual things we'd like a closer look at."

At a January 2011 press conference, Veverka and other Stardust-NExT team members listed the features they're most interested in seeing again:

For starters, parts of the comet's surface are layered like pancakes.

"Earth has layers because water and wind move dirt and debris around here, but layering on a comet was a surprise – and a mystery," says Veverka.

Pancake-layers and a possible powdery flow are among the surface features of interest highlighted in this July 4, 2005, Deep Impact photo of Comet Tempel 1. The bright flash is where Deep Impact dropped an 820 lb copper projectile onto the comet. Stardust-NExT could get a first look at the aftermath of the blast. [more]

"One idea is that two protocometary bodies collided at low speeds and smushed together to form something like a stack of flapjacks," says Pete Shultz, Stardust-NExT co-investigator.

Is that right? Data obtained by Stardust-NExT will provide clues and possibly reveal what made the "comet pancakes."

Another area intrigues the research team even more.

"There's a large plateau that looks like a flow," says Shultz. "If it really is a flow, it means there was recently gas and dust emanating from the [surface]."

Stardust-NExT will reveal how the plateau has changed (Is it flowing?), helping the team determine its origin. Whatever their origin, the plateau and layering show that comets have a much more complicated geologic history than previously thought.

A close-up view of a possible flow on Tempel 1. [more]

"Tempel 1 is not just a fuzzy ball," says Shultz. "It has history."

It's a history NASA has had a hand in. During its 2005 visit, Deep Impact dropped an 820-pound projectile into the comet's core. In a development that surprised mission scientists, the impact excavated so much material that the underlying crater was hidden from view. Deep Impact's cameras were unable to see through the enormous cloud of dust the impactor had stirred up. Stardust NExT could provide a long anticipated look at the impact site.

"The dust has settled there, so if the right part of the comet is facing us, we could see the crater and learn its size," says Veverka. "That would answer some key questions. For instance, is a comet's surface hard or soft?"

In a future mission, a spacecraft may land on a comet and gather samples for analysis. To design a suitable lander, researchers need to know what kind of surface it would land on. They'll also need to know which tools to send – drills for hard surfaces or scoops for something softer.

Like Deep Impact, the Stardust spacecraft has already had a productive career. Launched in 1999, it approached Comet Wild 2 close enough in 2004 to image its feature-rich surface and even gather dust particles from the comet's atmosphere. (A key finding in the sample was the amino acid glycene – a building block of life.)

"We could have just let this old spacecraft rest on those laurels, leaving it to forever orbit the sun," says Veverka. "But instead, we're doing first-class comet science with it -- again."

As for Tempel 1, a hungry sun awaits.

Author: Dauna Coulter | Editor: Dr. Tony Phillips | Credit: Science@NASA

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

NASA' SOLAR STEREO - A & STEREO - B SATELLITES IN SLIGHTLY DIFFERENT ORBITS AROUND THE SUN HAVE SEPARATED

TO BE PRECISELY OPPOSITE THE SUN ON 2011 FEB 6 ABOUT 7:30 PM EST - NEAR SUPERBOWL HALF-TIME.

NASA WILL THEN RELEASE TO THE WORLD THE FIRST PICTURE EVER TAKEN OF THE ENTIRE SUN 360* AROUND

(from these two satellites) - YOU CAN LOOK FOR YOURSELF AT THE STEREO WEBSITE FOR UPDATES WHICH IS:

http://stereo.gsfc.nasa.gov/beacon/

360* SUN - 2011 FEB 7

AT 18:35:30 UT = 1:35 PM EST

FROM BOTH STEREO A & B

STILL 360* IMAGE OF ROTATING SUN ABOVE

First Ever STEREO Images of the Entire Sun

February 6, 2011: It's official: The sun is a sphere.

On Feb. 6th, NASA's twin STEREO probes moved into position on opposite sides of the sun, and they are now beaming back uninterrupted images of the entire star—front and back.

"For the first time ever, we can watch solar activity in its full 3-dimensional glory," says Angelos Vourlidas, a member of the STEREO science team at the Naval Research Lab in Washington, DC.

NASA released a 'first light' 3D movie on, naturally, Super Bowl Sun-day:

The solar sphere as observed by STEREO and the Solar Dynamics Observatory on January 31, 2011. Because the STEREO separation was still slightly less than 180^o at that time, a narrow gap on the far side of the Sun has been interpolated to simulate the full 360^o view. The gap and quality of farside imaging will improve even more in the days and weeks ahead. [YouTube video] [full 42MB movie]

"This is a big moment in solar physics," says Vourlidas. "STEREO has revealed the sun as it really is--a sphere of hot plasma and intricately woven magnetic fields."

Each STEREO probe photographs half of the star and beams the images to Earth. Researchers combine the two views to create a sphere. These aren't just regular pictures, however. STEREO's telescopes are tuned to four wavelengths of extreme ultraviolet radiation selected to trace key aspects of solar activity such as flares, tsunamis and magnetic filaments. Nothing escapes their attention.

An artist's concept of STEREO surrounding the sun. [more]

"With data like these, we can fly around the sun to see what's happening over the horizon—without ever leaving our desks," says STEREO program scientist Lika Guhathakurta at NASA headquarters. "This could lead to significant advances in solar physics and space weather forecasting."

Consider the following: In the past, an active sunspot could emerge on the far side of the sun completely hidden from Earth. Then, the sun's rotation could turn that region toward our planet, spitting flares and clouds of plasma, with little warning.

"Not anymore," says Bill Murtagh, a senior forecaster at NOAA's Space Weather Prediction Center in Boulder, Colorado. "Farside active regions can no longer take us by surprise. Thanks to STEREO, we know they're coming."

NOAA is already using 3D STEREO models of CMEs (billion-ton clouds of plasma ejected by the sun) to improve space weather forecasts for airlines, power companies, satellite operators, and other customers. The full sun view should improve those forecasts even more.

The forecasting benefits aren't limited to Earth.

"With this nice global model, we can now track solar storms heading toward other planets, too," points out Guhathakurta. "This is important for NASA missions to Mercury, Mars, asteroids … you name it."

Observing solar storms from two points of view has allowed forecasters to made 3D models of advancing coronal mass ejections (CMEs), improving predictions of Earth impacts.

Credit: NOAA/SWPC [movie]

NASA has been building toward this moment since Oct. 2006 when the STEREO probes left Earth, split up, and headed for positions on opposite sides of the sun (movie). Feb. 6, 2011, was the date of "opposition"—i.e., when STEREO-A and -B were 180 degrees apart, each looking down on a different hemisphere. NASA's Earth-orbiting Solar Dynamics Observatory is also monitoring the sun 24/7. Working together, the STEREO-SDO fleet should

be able to image the entire globe for the next 8 years.

The new view could reveal connections previously overlooked. For instance, researchers have long suspected that solar activity can "go global," with eruptions on opposite sides of the sun triggering and feeding off of one another. Now they can actually study the phenomenon. The Great Eruption of August 2010 engulfed about 2/3rd of the stellar surface with dozens of mutually interacting flares, shock waves, and reverberating filaments. Much of the action was hidden from Earth, but plainly visible to the STEREO-SDO fleet.

"There are many fundamental puzzles underlying solar activity," says Vourlidas. "By monitoring the whole sun, we can find the missing pieces."

Researchers say these first-look images are just a hint of what's to come. Movies with higher resolution and more action will be released in the weeks ahead as more data are processed. Stay tuned!

Author: Dr. Tony Phillips | Credit: Science@NASA

THE STORY (from UNIVERSETODAY.COM ) IS BELOW:

NASA Robot and First Whole Sun Picture .. Coming on Super Bowl SUNday

by Ken Kremer on February 5, 2011

What do NASA, Robots, the Sun and the NFL have in common ?

Well … its Super SUNday … for Super Bowl XLV on Feb. 6, 2011

The unlikely pairing of Football and Science face off head to head on Super Bowl SUNday. Millions of television viewers will see NASA’s Robonaut 2, or R2, share the the limelight with the Steelers and the Packers of the NFL. The twin brother of R2 is destined for the International Space Station (ISS) and will become the first humanoid robot in space. It will work side by side as an astronaut’s assistant aboard the space station.

The fearsome looking R2 is set to make a first ever special guest appearance during the FOX Networks Super Bowl pre-game show with FOX sports analyst Howie Long.

The pre-game show will air starting at 2 p.m. EST on Feb. 6.

And there’s more.

On Super SUNday Feb. 6, NASA will publish Humankinds first ever image of the ‘Entire Sun’ courtesy of NASA’s twin STEREO spacecraft. And given the stunningly cold and snowy weather in Dallas, the arrival of our Sun can’t come soon enough for the ice covered stadium and football fans. See photos above and below.

The two STEREO spacecraft will reach positions on opposite sides of the Sun on Sunday, Feb. 6 at about 7:30 p.m. in the evening, possibly coinciding with the Super Bowl half time show.

At opposition, the STEREO duo will observe the entire 360 degrees sphere of the Sun’s surface and atmosphere for the first time in the history of humankind.

The nearly identical twin brother of R2 is packed aboard Space Shuttle Discovery and awaiting an out of this world adventure from Launch Pad 39 A at NASA’s Kennedy Space Center (KSC) in Florida. Blast off of the first humanoid robot is currently slated for Feb. 24.

R2 is the most dextrously advanced humanoid robot in the world and the culmination of five decades of wide-ranging robotics research at NASA and General Motors (GM).

This newest generation of Robonauts are an engineering marvel and can accomplish real work with exceptionally dexterous hands and an opposable thumb. R2 will contribute to the assembly, maintenance and scientific output of the ISS

“R2 is the most sophisticated robot in the world,” says Rob Ambrose, Chief of NASA’s Johnson Space Center’s (JSC) Robotics Division.

“We hope R2 should help to motivate kids to study science and space,” Ron Diftler told me in an interview at KSC. Diftler is NASA’s R2 project manager at JSC.

The amazingly dexterity of the jointed arms and hands enables R2 to use exactly the same tools as the astronauts and thereby eliminates the need for constructing specialized tools for the robots –saving valuable time, money and weight.

The robot is loaded with advanced technology including an optimized overlapping dual arm dexterous workspace, series elastic joint technology, extended finger and thumb travel, miniaturized 6-axis load cells, redundant force sensing, ultra-high speed joint controllers, extreme neck travel, and high resolution camera and IR systems.

R2 weighs some 300 pounds and was manufactured from nickel-plated carbon fiber and aluminum. It is equipped with two human like arms and two hands as well as four visible light cameras that provide stereo vision with twice the resolution of high definition TV.

“With R2 we will demonstrate ground breaking and innovative robotics technology which is beyond anything else out there and that will also have real world applications as GM works to build better, smarter and safer cars,” according to Susan Smyth, GM Director of Research and Development.

“Crash avoidance technology with advanced sensors is a prime example of robonaut technology that will be integrated into GM vehicles and manufacturing processes.”

I was fortunate to meet R2 and the Robonaut team at KSC. R2 is incredibly life like and imposing and I’ll never forget the chance to shake hands. Although its motions, sounds, illuminated hands and muscular chest gives the unmistakable impression of standing next to a lively and powerful 300 pound gorilla, it firmly but gently grasped my hand in friendship – unlike a Terminator.

So its going to make for a mighty match up some day between the fearsome looking R2 and the NFL players.

Well apparently, R2 and Howie will be making some predictions on which player will win the MVP award and a GM Chevrolet. Stay tuned.

So come back on SUNday Feb. 6 for NASA’s release of the first ever images of our entire Sun from the STEREO twins.

Tagged as: ISS, NASA, Robonaut 2, Solar Astronomy, Space Shuttle, STEREO, STEREO mission, sun

Rob Bowman February 6, 2011 at 1:47 am

R2 has no lower half, yet weighs 300lbs. IMHO this is yet another case in the world’s space program of throwing good money after bad. It will cost a mint to get him up there, in money and pollution, just so he can tool around with a Rubik cube or some such, giving engineers data they could have got in the lab.

The space/astronaut program is now degenerate – thank goodness for Planck, Herschel, Hubble, SDO etc., drawing attention away from this zero gravity nonsense.

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

THE ASTRONOMY PICTURE OF THE DAY FOR 2010 April 19

Ash and Lightning Above an Icelandic Volcano

Credit & Copyright: Marco Fulle (Stromboli Online)

Explanation: Why did the recent volcanic eruption in Iceland create so much ash? Although the large ash plume was not unparalleled in its abundance, its location was particularly

noticeable because it drifted across such well populated areas. The Eyjafjallajökull volcano in southern Iceland began erupting on March 20, with a second eruption starting under the

center of small glacier on April 14. Neither eruption was unusually powerful. The second eruption, however, melted a large amount of glacial ice which then cooled and fragmented lava

into gritty glass particles that were carried up with the rising volcanic plume. Pictured above two days ago, lightning bolts illuminate ash pouring out of the Eyjafjallajökull volcano.

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

NASA Probe (EPOXI) Delivers Dazzling Portraits of a Comet Aglow

Deep Impact takes thousands of pictures during flyby

• • 1. Video

This contrast-enhanced image obtained during Deep Impact's Nov. 4th flyby of Comet Hartley 2 reveals a cloud of icy particles surrounding the comet's active nucleus.

[larger image]

"We've never seen anything like this before," says University of Maryland professor Mike A'Hearn, principal investigator of Deep Impact's EPOXI mission. "It really took us by surprise."

Before the flyby of Hartley 2, international spacecraft visited four other comet cores—Halley, Borrelly, Wild 2, and Tempel 1. None was surrounded by "comet snow." Tempel 1 is particularly telling because Deep Impact itself performed the flyby. The very same high resolution, high dynamic range cameras that recorded snow-chunks swirling around Hartley 2 did not detect anything similar around Tempel 1.

"This is a genuinely new phenomenon," says science team member Jessica Sunshine of the University of Maryland. "Comet Hartley 2 is not like the other comets we've visited."

The 'snowstorm' occupies a roughly-spherical volume centered on Hartley 2's spinning nucleus. The dumbbell-shaped nucleus, measuring only 2 km from end to end, is tiny compared to the surrounding swarm. "The ice cloud is a few tens of kilometers wide--and possibly much larger than that," says A'Hearn. "We still don't know for sure how big it is."

Data collected by Deep Impact's onboard infrared spectrometer show without a doubt that the particles are made of frozen H₂O, i.e., ice. Chunks consist of micron-sized ice grains loosely stuck together in clumps a few centimeters to a few tens of centimeters wide.

This plot compares the infrared spectra of particles surrounding Comet Hartley 2 (black crosses) to spectra of pure water ice grains in the laboratory (purple lines). Micron-sized grains provide the best match. What it means: Hartley 2's snowballs are made of small bits of H₂0.

"If you held one in your hand you could easily crush it," says Sunshine. "These comet snowballs are very fragile, similar in density and fluffiness to high-mountain snow on Earth."

Even a fluffy snowball can cause problems, however, if it hits you at 12 km/s (27,000 mph). That's how fast the Deep Impact probe was screaming past the comet’s nucleus. An impact with one of Hartley 2's icy chunks could have damaged the spacecraft and sent it tumbling, unable to point antennas toward Earth to transmit data or ask for help. Mission controllers might never have known what went wrong.

"Fortunately, we were out of harm's way," notes A'Hearn. "The snow cloud does not appear to extend out to our encounter distance of 700 km. Sunlight sublimates the icy chunks before they can get that far away from the nucleus."

The source of the comet-snow may be the very same garish jets that first caught everyone's eye.

The process begins with dry ice in the comet's crust. Dry ice is solid CO₂, one of Hartley 2's more abundant substances. When heat from the sun reaches a pocket of dry ice—poof!—it instantly transforms from solid to vapor, forming a jet wherever local topography happens to collimate the outrushing gas. Apparently, these CO₂ jets are carrying chunks of snowy water ice along for the ride.

An artist's concept of Comet Hartley 2 shows how CO₂ jets drag water ice out of nucleus, producing a 'comet snowstorm.' [larger image]

Because the snow is driven by jets, "it's snowing up, not down," notes science team member Peter Schultz of Brown University.

Ironically, flying by Hartley 2 might be more dangerous than actually landing on it. The icy chunks are moving away from the comet’s surface at only a few m/s (5 to 10 mph). A probe that matched velocity with the comet's nucleus in preparation for landing wouldn't find the drifting snowballs very dangerous at all--but a high-speed flyby is another matter. This is something planners of future missions to active comets like Hartley 2 will surely take into account.

Comet snowstorms could be just the first of many discoveries to come. A’Hearn and Sunshine say the research team is only beginning to analyze gigabytes of data beamed back from the encounter, and new results could be only weeks or months away.

Stay tuned for updates from Comet Hartley 2.

Author: Dr. Tony Phillips | Credit: Science@NASA

Science News

• • Science@NASA Headline News

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Earth's Dust Tail Points to Alien Planets

November 12, 2010: Did you know that the Earth has a dust tail? The Spitzer Space Telescope sailed right through it a few months ago, giving researchers a clear idea of what it looks like. That could be a big help to planet hunters trying to track down alien worlds.

An artist's concept of Spitzer passing through Earth's dusty tail. [more]

"Planets in distant solar systems probably have similar dust tails," says Spitzer project scientist Mike Werner. "And in some circumstances these dust features may be easier to see than the planets themselves. So we need to know how to recognize them."

It's extremely challenging – and usually impossible – to directly image exoplanets. They're relatively small and faint, hiding in the glare of the stars they orbit.

"A dust tail like Earth's could produce a bigger signal than a planet does. And it could alert researchers to a planet too small to see otherwise."

Earth has a dust tail not because the planet itself is particularly dusty, but rather because the whole solar system is. Interplanetary space is littered with dusty fragments of comets and colliding asteroids. When Earth orbits through this dusty environment, a tail forms in the rear, akin to swaths of fallen leaves swirling up behind a streetsweeper.

"As Earth orbits the sun, it creates a sort of shell or depression that dust particles fall into, creating a thickening of dust – the tail – that Earth pulls along via gravity," explains Werner. "In fact, the tail trails our planet all the way around the sun, forming a large dusty ring."

A computer simulation of Earth's dust tail/ring seen from a vantage point outside our solar system. Colors indicate density; purple is lowest, red is highest.

Credit: Christopher Stark, GSFC [larger image]

Spitzer's recent observations have helped astronomers map the structure of Earth's dust tail and figure out what similar "tell-tale tails" attached to alien planets might look like.

Like our own solar system, other planetary systems are infused with dust that forms a dusty disk encircling the central star. And like Earth, exoplanets interact with their dust disk gravitationally, channeling and drawing strange features into it.

"In some stars' dust disks there are bumps, warps, rings, and offsets telling us that planets are interacting with the dust," explains Mark Clampin of NASA's Goddard Space Flight Center. "So we can 'follow the dust' to the planets. So far, we've seen about 20 dust disks in other solar systems. And in some of those cases, following the dust has already paid off."

Clampin, Paul Kalas, and colleagues were looking for a planet around the bright southern star Fomalhaut when they unexpectedly found a dust ring. The shape of that ring led them to their goal. "We suspected that the ring's sharp inner edge was formed by a planet gravitationally clearing out the surrounding debris," says Clampin. "We tracked the planet by this 'footprint' in the dust." (See the footprint here.)

Another Hubble image shows a dusty disk around Beta Pictoris, a star in the constellation Pictor, or "Painter's Easel," pictured below:

A Hubble image of dusty material circling the star Beta Pictoris. [more]

"Note the smaller dust ring that's tilted with respect to the larger dust disk," says Clampin. "Like Earth, this planet is shepherding the dust into its orbital plane."

Clampin and Werner say Spitzer's observation of Earth's dust tail and these initial observations of dust structures in distant solar systems set the stage for the planet hunting debut of the James Webb Space Telescope. They fully expect the huge and powerful new telescope to spot many tell-tale tails ... of the alien variety.

Author: Dauna Coulter | Editor: Dr. Tony Phillips | Credit: Science@NASA

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Last “Missing” Normal Matter Is Found

All the things in the universe that we can easily see — stars, nebulae, and so on — amount to less than 1% of all the matter and energy that's known to be out there.

"Dark matter" and "dark energy" account for 95.4% of everything, judging by many lines of converging evidence (see the June Sky & Telescope, page 14). But that still leaves 4.6% of everything as “ordinary” matter: material made of protons, neutrons, and electrons, the stuff of atoms. Until recent years, astronomers could only tally up about half as much ordinary matter as cosmologists said there ought to be, judging from the state of the universe soon after the Big Bang.

Now the mystery seems solved. In recent years astronomers had already found signs that the missing ordinary matter indeed exists, as a thin, elusive gas between galaxies known as the “warm-hot intergalactic medium,” or WHIM.

The evidence for WHIM has now turned firmer. Its signature showed up (weakly) in a spectrum of X-rays arriving from a distant source. Absorption lines revealing WHIM were imprinted on the X-rays where they passed through the Fornax Wall, an enormous structure of thousands of galaxies in the vast web of galaxy strings, walls, and clusters pervading the cosmos.

The spectral signature matches both the predicted amount and temperature (about 1 million kelvins) of the elusive intergalactic gas. One reason it has gone unseen is that it is very sparse:

there's only about 6 hydrogen atoms' worth per cubic meter, compared with the 1 million atoms per cubic meter that's typical of the interstellar gas within galaxies.

As mysterious as ever is the nonbaryonic dark matter: the 22% of the cosmic inventory that is matter but is not made of protons, neutrons, and electrons.

Here's a NASA science feature on the new finding. And if you really want to dive in deep, here's the researchers' paper

Posted by Alan MacRobert, May 14, 2010 from http://www.skyandtelescope.com/news/93797364.html

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

from UniverseToday.com

June 30th, 2010

Mysterious Giant Gas Ring Explained

Written by Nancy Atkinson

From a Canada-France-Hawaii Telescope press release:

An international team unveiled the origin of the giant gas ring in the Leo group of galaxies. With the Canada-France-Hawaii Telescope, the scientists were able to detect an optical signature of the ring corresponding to star forming regions. This observation rules out the primordial nature of the gas, which is of galactic origin. Thanks to numerical simulations made at CEA, a scenario for the formation of this ring has been proposed: a violent collision between two galaxies, slightly more than one billion years ago. The results will be published in the Astrophysical Journal Letters.

In the current theories on galaxy formation, the accretion of cold primordial gas is a key-process in the early steps of galaxy growth. This primordial gas is characterized by two main features: it has never sojourned in any galaxy and it does not satisfy the conditions required to form stars. Is such an accretion process still ongoing in nearby galaxies? To answer the question, large sky surveys are undertaken attempting to detect the primordial gas.

The Leo ring, a giant ring of cold gas 650,000 light-years wide surrounding the galaxies of the Leo group, is one of the most dramatic and mysterious clouds of intergalactic gas. Since its discovery in the 80s, its origin and its nature were debated. Last year, studies of the metal abundances in the gas led to the belief that the ring was made of this famous primordial gas.

Thanks to the sensitivity of the Canada-France-Hawaii Telescope MegaCam camera, the international team observed for the first time the optical counterpart of the densest regions of the ring, in visible light instead of radio waves. Emitted by massive young stars, this light points to the fact that the ring gas is able to form stars.

A ring of gas and stars surrounding a galaxy immediately suggests another kind of ring: a so-called collisional ring, formed when two galaxies collide. Such a ring is seen in the famous Cartwheel galaxy. Would the Leo ring be a collisional ring too?

In order to secure this hypothesis, the team used numerical simulations (performed on supercomputers at CEA) to demonstrate that the ring was indeed the result of a giant collision between two galaxies more than 38 million light-years apart: at the time of the collision, the disk of gas of one of the galaxies is blown away and will eventually form a ring outside of the galaxy. The simulations allowed the identification of the two galaxies which collided: NGC 3384, one of the galaxies at the center of the Leo group, and M96, a massive spiral galaxy at the periphery of the group. They also gave the date of the collision: more than a billion years ago!

The gas in the Leo ring is definitely not primordial. The hunt for primordial gas is still open!

A Response to “Mysterious Giant Gas Ring Explained”

• 1. Jon Hanford Says:

  2. June 30th, 2010 at 8:46 am

     1. Yeah, their has been a lot of debate on the age of this object since it was first discovered by radio astronomers in the 1980's. A few years back, observations by the GALEX observatory detected a few clumps of very young stars in the Leo Ring. Primordial gas proponents claimed that these were the first stars to form from gas in the ring since the Big Bang. But these new observations cast doubt on the primordial nature of this feature. The paper, "A collisional origin for the Leo ring" can be found here: http://arxiv.org/PS_cache/arxiv/pdf/1005/1005.4208v2.pdf

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Thu, 15 April, 2010

Obama Pledges 2025 Mission to Asteroid

By Brian Berger

P/2010 A2: Unusual Asteroid Tail Implies Powerful Collision

Credit: NASA, ESA, D. Jewitt (UCLA)

Explanation: What is this strange object? First discovered on ground based LINEAR images on 2010 January 6, the object appeared unusual enough to investigate further with the Hubble Space Telescope last week. Pictured above, what Hubble saw indicates that P/2010 A2 is unlike any object ever seen before. At first glance, the object appears to have the tail of a comet. Close inspection, however, shows a 140-meter nucleus offset from the tail center, very unusual structure near the nucleus, and no discernable

gas in the tail. Knowing that the object orbits in the asteroid belt between Mars and Jupiter, a preliminary hypothesis that appears to explain all of the known clues is that P/2010 A2 is the debris left over from a recent collision between two small asteroids. If true, the collision likely occurred at over 15,000 kilometers per hour -- five times the speed of a rifle bullet -- and liberated energy in excess of a nuclear bomb. Pressure from sunlight would then spread out the debris into a trailing tail. Future study of P/2010 A2 may better indicate the nature of the progenitor collision and may help humanity better understand the early years of our Solar System, when many similar collisions occurred.

-------------------------------------------------------------------------------------------------------------------------------------

Warmth in the Dark Age

Lower reflectivity kept Earth from freezing under a fainter young sun

By Sid Perkins

Web edition : Wednesday, March 31st, 2010 from www.ScienceNews.org

Though the sun was so much dimmer billions of years ago that the young Earth should have been literally freezing, the planet remained largely covered with liquid water. That was thanks to a substantially darker surface and a dearth of light-scattering clouds, a new study suggests.

“All other things being equal, Earth should have been frozen over for the first half of its existence,” says James F. Kasting, a geoscientist at Pennsylvania State University in University Park who was not involved in the research. “But it wasn’t.”

Previously scientists have explained the presence of liquid water during that low-light time, known as the Archean, by suggesting that Earth’s atmosphere held large amounts of planet-warming greenhouse gases such as carbon dioxide and methane. But new analyses show that greenhouse gases weren’t dramatically higher then compared with today, a team of earth scientists reports in the April 1 Nature. The researchers now propose that early Earth stayed above freezing because the planet was darker then and therefore absorbed more of the sun’s energy — the same phenomenon that renders dark vinyl car seats scorching hot while light-colored seats stay relatively cool.

Early in the sun’s lifetime, the portion of solar core where the light- and heat-generating fusion reactions take place was much smaller than it is today. So, for an extended period, the sun could have been up to 30 percent dimmer than it is now, says Minik Rosing, a geologist at the University of Copenhagen’s Nordic Center for Earth Evolution. Although Earth’s surface temperature should have been well below freezing, geological signs of liquid water in that era abound — a puzzler that scientists have dubbed the “faint young sun paradox.”

Some studies have suggested that carbon dioxide concentrations in Earth’s early atmosphere were more than 100 times current levels. But the new analyses of ancient rocks known as banded iron formations reveal proportions of iron-bearing minerals that could appear only if carbon dioxide levels were no more than three times modern values — a concentration too low to keep the planet from freezing beneath a faint young sun. Methane probably didn’t help make up the difference, Rosing adds, because at high concentrations methane reacts chemically to form a light-scattering haze that would have cooled Earth’s surface rather than warming it.

What probably kept Earth above freezing during the dim-sun era was its darker surface, Rosing and his colleagues contend. The continents were much smaller then, so the planet’s oceans — which are typically much darker than landmasses — could absorb more heat. About 3.8 billion years ago, continents covered less than 5 percent of Earth’s surface, a proportion that gradually rose to reach today’s value of 30 percent around 1.5 billion years ago.

Second, the researchers suggest, light-scattering clouds covered much less of Earth’s surface long ago — another net gain for surface warmth. Because early Earth lacked plants and other complex life, the biologically produced particles and chemicals that water droplets coalesce around weren’t available. In the few clouds that did form, droplets were larger and scattered light less efficiently, allowing more warming radiation to reach ground level.

In their paper, the researchers present a numerical simulation that shows how these two rather straightforward phenomena could have kept Earth’s average temperature above freezing.

“A lot of the reviewers of our paper were kicking themselves and asking, ‘Why didn’t we think of this first?’” Rosing notes.

Despite the new findings, the faint young sun problem may not be fully solved, Kasting notes. For one thing, the new analyses don’t consider the effect of high-latitude ice masses on the planet’s albedo. “We clearly need additional constraints to understand why the Archean Earth remained habitable,” he comments in Nature.

--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

FROM PBS NEWSHOUR

SUPERCOLLIDER -- March 30, 2010

World's Largest Particle Collider Sees First Successful Smash

By: Lea Winerman

Scientists in Geneva fired up the world's most powerful particle-smashing machine Tuesday, beginning a run that they hope will provide insight into fundamental questions about what makes up the universe.

"This opens the door to a totally new era of discovery," the project's director of research Sergio Bertolucci told news agencies. "It is a step into the unknown where we will find things we thought were there and perhaps things we didn't know existed."

It was certainly seen as a triumph for researchers who've worked for more than a decade building the Large Hadron Collider at the European Center for Nuclear Research (CERN). The collider is intended to smash together protons and other tiny particles at previously unheard-of speeds.

Watch an animation of the collision, provided by CERN:

You'll need Flash 9 or better to view this content. Download it now

The resulting collisions could produce evidence of types of matter that physicists have theorized exist for decades, but have never seen. That includes "dark matter," the hypothetical substance than some scientists think makes up as much as 80 percent of the universe, and the elusive Higgs Boson particle, the so-called "God particle" scientists believe gives all other matter its weight.

The Large Hadron Collider has had problems and false starts over the past few years, including an explosion and helium leak in 2008 that caused a long delay. Today, though, the accelerator worked.

Beams of protons began circulating through the 17 miles of magnetic tubes that traverse the French-Swiss border, gathering speed, Tuesday morning. At 1:06 p.m. the beams collided, smashing into each other in a 7-trillion electron-volt collision.

In 2008, when the scientists first tested the collider by sending one beam of particles through the tubes, physicist Brian Greene explained on the NewsHour how the collider would work.

You'll need Flash 9 or better to view this content. Download it now

And in 2007, NOVA ScienceNow took a tour of the collider, which was then being built

--------------------------------------------------------------------------------------------------------------------------------------------------------------.

NOTE THAT THE INTERNATIONAL SUPERCONDUCTING SUPERCOLLIDER THAT WAS BEING BUILT IN TEXAS AND WAS SUDDENLY SUMMARILY CANCELLED BY THE US GOVERNMENT IN 1993 DUE TO COST (ALTHOUGH INTERNATIONAL CONTRIBUTIONS WERE STEADILY COMING IN) WOULD HAVE REACHED AN ASTOUNDING 40 TRILLION ELECTRON VOLT COLLISION CAPACITIES.

SEE ARTICLE BELOW FROM WIKIPEDIA:

Superconducting Super Collider

From Wikipedia, the free encyclopedia

(Redirected from Super-conducting Super-collider)

Jump to: navigation, search

This article is about the particle accelerator. For the programming language, see SuperCollider. For the electronic duo, see Super Collider (Band).

The Superconducting Super Collider (SSC) was a particle accelerator complex under construction in the vicinity of Waxahachie, Texas that was set to be world's largest and most energetic, surpassing the current record held by the Large Hadron Collider. Its planned ring circumference was 87.1 kilometres (54.1 mi) with an energy of 20 TeV per beam of protons. The project's director was Roy Schwitters, a physicist at the University of Texas at Austin and Harvard University. The project was canceled in 1993.

Development

The system was first envisioned in the December 1983 National Reference Designs Study, which examined the technical and economic feasibility of a machine with the design capacity of 20 TeV per beam. After an extensive Department of Energy review during the mid-1980s, a site selection process began in 1987. The project was awarded to Texas in November 1988 and major construction began in 1991. Seventeen shafts were sunk and 23.5 km (14.6 mi) of tunnel were bored by late 1993.

Cancellation

During the design and the first construction stage, a heated debate ensued about the high cost of the project. In 1987, Congress was told the project could be completed for $4.4 billion, and it gained the enthusiastic support of Speaker Jim Wright of nearby Fort Worth.^[1] By 1993, the cost projection exceeded $12 billion. A recurring argument was the contrast with NASA's contribution to the International Space Station (ISS), which was of a similar amount.^{[citation needed]} Critics of the project argued that the US could not afford both of them.

Congress canceled the project in 1993. Many factors contributed to the cancellation: rising cost estimates; poor management by physicists and Department of Energy officials; the end of the need to prove the supremacy of American science with the collapse of the Soviet Union; belief that many smaller scientific experiments of equal merit could be funded for the same cost; Congress's desire to generally reduce spending; the reluctance of Texas Governor Ann Richards;^[2] and President Bill Clinton's initial lack of support for a project begun during the administrations of Richards's predecessor, Bill Clements, and Clinton's predecessors, Ronald Reagan and George H. W. Bush. However, in 1993, Clinton tried to prevent the cancellation by asking Congress to continue "to support this important and challenging effort" through completion because "abandoning the SSC at this point would signal that the United States is compromising its position of leadership in basic science".^[3]

The closing of the SSC had adverse consequences for the southern part of the Dallas–Fort Worth Metroplex, and resulted in a mild recession, most evident in those parts of Dallas which lay south of the Trinity River.^[4] When the project was canceled, 22.5 km (14.0 mi) of tunnel and 17 shafts to the surface were already dug, and nearly two billion dollars had already been spent on the massive facility.^[5]

Comparison to the Large Hadron Collider

The SSC's planned collision energy of 40 TeV was almost triple the 14 TeV of its European counterpart, the Large Hadron Collider (LHC) at CERN in Geneva. The LHC was less expensive to build because, in addition to its smaller size, the LHC took over the existing engineering infrastructure and 27 km long underground cavern of the Large Electron-Positron Collider. The LHC eventually cost the equivalent of about 5 billion US dollars to build.

Current Status of Site

After the project was canceled, the main site was deeded to Ellis County, Texas, and the county tried numerous times to sell the property. The property was finally sold in August 2006 to an investment group led by the late J.B. Hunt.^[6] Collider Data Center has contracted with GVA Cawley to market the site as a tier III or tier IV data center.^[7]

See Also

• Fermilab

• DESY

  • Einstein's Bridge, a science fiction novel about the SSC

-------------------------------------------------------------------------------------------------------------------------------------

Almost-Close Encounter:

Meteorite Hits Lorton Doctor's Office

By Paul Duggan

Washington Post Staff Writer Thursday, January 21, 2010

Much later, after the hole in the roof had been fixed and the debris cleaned up, after the cause of the damage finally had become clear, Frank Ciampi wondered: What are the odds?

He is a doctor. He has worked for 18 years in the two-story building in Lorton that houses the Williamsburg Square Family Practice, in the 9500 block of Richmond Highway. He spends his days walking in and out of examining rooms, seeing patients.

What are the chances, as he goes about his routine, that he'll get hit by a meteorite?

Not impossible.

It almost happened.

"I was in my office doing charts," Ciampi recalled. It was Monday, a little after 5:30 p.m. He was on the building's second floor. "And I heard a loud boom, almost like a small explosion."

At first, he said, he thought a bookcase had toppled nextdoor. "So I ran toward the office. And then I saw all the debris in the hallway," he said.

The floor just outside examination room No. 2 -- about 10 feet from where Ciampi had been doing paperwork -- was littered with small pieces of wood, plaster and insulation. Upon inspection, more debris lay inside the room. He saw three chunks of stone on the floor that together formed a rock about the size of a tennis ball, with a glassy-smooth surface. Then he saw a hole about the size of the rock in the tile ceiling, and a tear in the maroon carpet where the rock had landed.

"The first thing we thought was maybe something had fallen from a plane," Ciampi said.

For most of the day, the 10 examination rooms used by Ciampi and two other medical professionals in the practice had been occupied by patients. Had the falling object crashed through the ceiling a little earlier, it might have killed someone.

"I thank God," Ciampi said.

Later, he said, "I was up all night, wondering what it was." No one else in the practice could figure it out, either. Then on Tuesday, the office manager, Rhonda Lawrence, offered a suggestion from her husband Jeffrey, who has a background in geology.

"Jeff said that maybe it was a meteorite," Ciampi said. "We didn't think of that. You know, a meteorite -- that's not the first thing you think of."

Cari Corrigan, a planetary scientist at the Smithsonian Institution's Museum of Natural History, confirmed it.

"It's beautiful," she gushed on Wednesday, after examining the rock.

"The first thing we look at is what's called the fusion crust on the outside," she said. "It's kind of a black, shiny coating, because when it passes through the atmosphere, it's melting a little at a time. So it's like an outer layer of glass, of melted rock."

That, plus flecks of metal in the rock, confirmed it had come from space, she said.

Corrigan said small meteorites hit Earth "fairly often." "We're bombarded by stuff like that all the time," she said. Since most of the planet's surface is uninhabited, most meteorites land a long, long way from people. And most of those that do hit inhabited areas go unnoticed, she said.

Every now and then, though, there's a landing like the one in Lorton. She said the meteorite weighs just over a half pound and probably was traveling about 220 mph when it hit the building.

If the folks at the medical practice want her to, Corrigan said, she will submit the stone to the Meteorite Nomenclature Committee.

"They'll give it an official name and an official description and it'll go on the books as being an official meteorite," she said. "I would imagine it would be called the Lorton, Va., Meteorite, or something like that."

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

ON 2010 JANUARY 7 MARKED THE 400th ANNIVERSARY OF GALILEO's DISCOVERY

OF JUPITER'S LARGEST MOONS THROUGH HIS CRUDE BUT EFFECTIVE TELESCOPE

SEE THE SKETCHES BELOW WHICH ARE FROM http://www.optcorp.com/edu/articleDetailEDU.aspx?aid=1047

Galileo's Sketch of Jupiter's Moons

Galileo's most striking discovery was that of four moons orbiting Jupiter...

THE ASTRONOMY PICTURE OF THE DAY FOR 2009 December 22

Planetary Systems Now Forming in Orion

Credit: NASA, ESA, M. Robberto (STScI/ESA), the HST Orion Treasury Project Team, & L. Ricci (ESO)

Explanation: How do planets form? To help find out, the Hubble Space Telescope was tasked to take a detailed look at one of the more interesting of all astronomical nebulae, the Great Nebula in Orion. The Orion nebula, visible with the unaided eye near the belt in the constellation of Orion, is an immense nearby starbirth region and probably the most famous of all astronomical nebulas. Insets to the above mosaic show numerous proplyds, many of which are stellar nurseries likely harboring planetary systems in formation. Some proplyds glow as close disks surrounding bright stars light up, while other proplyds contain disks further from their host star, contain cooler dust, and hence appear as dark silhouettes against brighter gas. Studying this dust, in particular, is giving insight for how planets are forming. Many proplyd images also show arcs that are shock waves - fronts where fast moving material encounters slow moving gas. The Orion Nebula lies about 1,500 light years distant and is located in the same spiral arm of our Galaxy as our Sun.

--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------