Posted on by Ken Kremer

Dramatic 3 D Imagery Showcases Vesta’s Pockmarked, Mountainous and Groovy Terrain

3 D Anaglyph of Craters at Rheasilvia - the South Polar Region of Vesta. This 3-D image shows the topography, craters and grooves of Vesta’s south polar region obtained by the framing camera instrument aboard NASA’s Dawn spacecraft on Aug. 23 and 28, 2011. The image has a resolution of about 260 meters per pixel.

[/caption]

Try not to plummet off a steep crater cliff or be buried under a landslide while gazing at the irresistibly alluring curves of beautiful Rheasilvia – the mythical mother of Romulus and Remus – whose found a new home at the South Pole of the giant Asteroid Vesta.

3 D is undoubtedly the best way to maximize your pleasure. So whip out your cool red-cyan anaglyph glasses to enhance your viewing experience of Rheasilvia, the Snowman and more – and maximize your enjoyment of this new 3 D collection showcasing the heavily cratered, pockmarked, mountainous and groovy terrain replete at Vesta.

3D Details of Wave-Like Terrain in the South Pole of Vesta
This image was obtained by NASA’s Dawn spacecraft from an orbit of about 1,700 miles (2,700 kilometers) above the surface of the giant asteroid Vesta. Topography in the area surrounding Vesta's south pole area shows impact craters, ridges and grooves. These images in 3D provide scientists with a realistic impression of the solid surface of the celestial body.
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Can you find the location of the 3 D image above in the 2 D South Pole image below?

Scientists and mortals have been fascinated by the enormous impact crater Rheasilvia and central mountain unveiled in detail by NASA’s Dawn Asteroid Orbiter recently arrived at Vesta, the 2nd most massive object in the main asteroid belt. Ceres is the largest object and will be Dawn’s next orbital target in 2015 after departing Vesta in 2012.

3D - A Big Mountain at Asteroid Vesta’s South Pole
Scientists were fascinated by this enormous mound inside a big circular depression at the south pole- dubbed Rheasilvia. This stereo image was recorded from an altitude of about 1,700 miles (2,700 kilometers) above the surface and shows the structure of the mountain, displayed in the right half of this 3D image. The base of the mountain has a diameter of about 125 miles (200 kilometers), and its altitude above the surroundings is about 9 miles (15 kilometers). The vicinity of the peak of the mountain shows landslides that occurred when material from the flanks of the mountain were slipping down. Also visible are tectonic structures from tension in Vesta's crust. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

“Vesta is the smallest terrestrial planet in our Solar System”, said Chris Russell in an interview with Universe Today. “We do not have a good analog to Vesta anywhere else in the Solar System.”

And the best is yet to come. In a few days, Dawn begins snapping images from a much lower altitude at the HAMO mapping orbit of ca. 685 km vs the initial survey orbit of ca, 2700 km. where most of these images were taken.

Can you find the location of the 3 D South Pole images above in the 2 D South Pole image below?

Topography of Densely Cratered Deformed Terrain
This 3 D anaglyph image shows the topography of Vesta's densely cratered terrain obtained by the framing camera instrument aboard NASA's Dawn spacecraft on August 6, 2011. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Anaglyph 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
Vesta's Ancient, Cratered Surface in 3D
This image of the giant asteroid Vesta obtained by NASA's Dawn spacecraft shows the surface of the asteroid from an orbit of about 1,700 miles (2,700 kilometers) above the surface. Numerous impact craters illustrate the asteroid's violent youth. By counting craters on distinct geological surfaces scientists can deduce relative ages of the asteroid's surface. This 3D view provides scientists the opportunity to learn more about the morphology of craters on asteroids and physical properties of the material at Vesta's surface.. Image resolution is about 260 meters per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Viewing the South Pole of Vesta and Rheasilvia Impact Basin
This image obtained by Dawns framing camera shows the south pole of the giant asteroid Vesta. Scientists are discussing whether the Rheasilvia circular structure that covers most of this image originated by a collision with another asteroid, or by internal processes early in the asteroid's history. Images in higher resolution from Dawn's next lowered orbit might help answer that question. The image was recorded from a distance of about 1,700 miles (2,700 kilometers). The image resolution is about 260 meters per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Rhea Silvia, torso from the amphitheatre at Cartagena in Spain that was rediscovered in 1988. Rhea Silvia was the mother of Romulus and Remus, the mythical founders of Rome. Source: Wikipedia

Read Ken’s continuing features about Dawn and Vesta

Rheasilvia – Super Mysterious South Pole Basin at Vesta
Space Spectacular — Rotation Movies of Vesta
3 D Alien Snowman Graces Vesta
NASA Unveils Thrilling First Full Frame Images of Vesta from Dawn
Dawn Spirals Down Closer to Vesta’s South Pole Impact Basin
First Ever Vesta Vistas from Orbit – in 2D and 3D
Dawn Exceeds Wildest Expectations as First Ever Spacecraft to Orbit a Protoplanet – Vesta
Dawn Closing in on Asteroid Vesta as Views Exceed Hubble
Dawn Begins Approach to Asteroid Vesta and Snaps First Images
Revolutionary Dawn Closing in on Asteroid Vesta with Opened Eyes

Posted on by Steve Nerlich

Astronomy Without A Telescope – Star Formation Laws

NGC 1569 - a relatively close (11 million light years) starburst galaxy - presumably a result of fairly efficient star formation Credit: NASA/HST

[/caption]

Take a cloud of molecular hydrogen add some turbulence and you get star formation – that’s the law. The efficiency of star formation (how big and how populous they get) is largely a function of the density of the initial cloud.

At a galactic or star cluster level, a low gas density will deliver a sparse population of generally small, dim stars – while a high gas density should result in a dense population of big, bright stars. However, overlying all this is the key issue of metallicity – which acts to reduce star formation efficiency.

So firstly, the strong relationship between the density of molecular hydrogen (H2) and star formation efficiency is known as the Kennicutt-Schmidt Law. Atomic hydrogen is not considered to be able to support star formation, because it is too hot. Only when it cools to form molecular hydrogen can it start to clump together – after which we can expect star formation to become possible. Of course, this creates some mystery about how the first stars might have formed within a denser and hotter primeval universe. Perhaps dark matter played a key role there.

Nonetheless, in the modern universe, unbound gas can more readily cool down to molecular hydrogen due the presence of metals, which have been added to the interstellar medium by previous populations of stars. Metals, which are any elements heavier than hydrogen and helium, are able to absorb a wider range of radiation energy levels, leaving hydrogen less exposed to heating. Hence, a metal-rich gas cloud is more likely to form molecular hydrogen, which is then more likely to support star formation.

But this does not mean that star formation is more efficient in the modern universe – and again this is because of metals. A recent paper about the dependence of star formation on metallicity proposes that a cluster of stars develops from H2 clumping within a gas cloud, first forming prestellar cores which draw in more matter via gravity, until they become stars and then begin producing stellar wind.

Relationship between the power of stellar winds and stellar mass (i.e. big star has big wind) - with the effect of metallicity overlaid. The solid line is the metallicity of the Sun (Z=Zsol). High metallicity produces more powerful winds for the same stellar mass. Credit: Dib et al.

Before long, the stellar wind begins to generate ‘feedback’, countering the infall of further material. Once the outward push of stellar wind achieves unity with the inward gravitational pull, further star growth ceases – and bigger O and B class stars clear out any remaining gas from the cluster region, so that all star formation is quenched.

The dependence of star formation efficiency on metallicity arises from the effect of metallicity on stellar wind. High metal stars always have more powerful winds than any equivalent mass, but lower metal, stars. Thus, a star cluster – or even a galaxy – formed from a gas cloud with high metallicity, will have lower efficiency star formation. This is because all stars’ growth is inhibited by their own stellar wind feedback in late stages of growth and any large O or B class stars will clear out any remaining unbound gas more quickly than their low metal equivalents.

This metallicity effect is likely to be the product of ‘radiative line acceleration’, arising from the ability of metals to absorb radiation across a wide range of radiation energy levels – that is, metals present many more radiation absorption lines than hydrogen has on its own. The absorption of radiation by an ion means that some of the momentum energy of a photon is imparted to the ion, to the extent that such ions may be blown out of the star as stellar wind. The ability of metals to absorb more radiation energy than hydrogen can, means you should always get more wind (i.e. more ions blown out) from high metal stars.

Further reading:
Dib et al. The Dependence of the Galactic Star Formation Laws on Metallicity.

Posted on by VirtualAstro

UARS: When and Where Did It Go Down?

Credit: NASA

[/caption]
After a night of changing predictions and hopes of many to see a fireball in the sky, the UARS (Upper Atmosphere Research Satellite) finally met it’s fiery demise.

The decommissioned, 6.5 ton satellite is believed to have re-entered the Earths atmosphere over the Pacific Ocean, and in it’s death throes the massive satellite broke up, and the surviving debris likely landed in the ocean, off of the West coast of North America.

In regard to the exact re-entry point and position of the debris field, Nicholas Johnson, chief orbital debris scientist at NASA’s Johnson Space Center, said “We don’t know where the debris field might be… We may never know.”

The US Department of Defense’s Joint Space Operations Center at Vandenberg Air Force Base in California and the U.S. Strategic Command radar tracking assessed that the satellite reentered the atmosphere sometime between 0323 and 0509 GMT on September 24, 2011 (the Strategic Command predicted it would re-enter at 04:16 GMT). During this period, the satellite was heading across the Pacific Ocean on a southwest-to-northeast trajectory approaching Canada’s west coast. The mid-point of that groundtrack and a possible reentry location is 31 N latitude and 219 E longitude (green circle marker on the above map).

“If the re-entry point was at the time of 04:16 GMT, then all that debris wound up in the Pacific Ocean,” Johnson said during a media briefing on Saturday. “If the re-entry point occurred earlier than that, practically the entire pass before 04:16 was over water. So the only way debris could have probably reached land would be if the re-entry occurred after 04:16.”

NASA says there are no reports of damage or injury caused by the surviving components that made it to the surface, and there are so far no credible visual reports of anyone seeing the UARS satellite burning up.

The Earth-observing satellite was in orbit for 20 years and 10 days.

Credit: NASA
Posted on by Tammy Plotner

Faster Than The Speed Of Light… OPERA Update

Artistic view of the SPS/CNGS layout. The CNGS beam is produced by accelerating protons to 400 GeV/c with the CERN Super Proton Synchrotron (SPS). These protons are ejected with a kicker magnet towards a 2 m long graphite neutrino production target in two extractions, each lasting 10.5 ?s and separated by 50 ms. Each CNGS cycle in the SPS is 6 s long. Secondary charged mesons are focused by two magnetic horns, each followed by a helium bag to minimise the interaction probability of the 5 mesons. Mesons decay in flight into neutrinos in a 1000 m long vacuum tunnel.

[/caption]

A few days ago, the physics world was turned upside down at the announcement of “faster than the speed of light”. The mighty neutrino has struck again by breaking the cosmic speed limit and traveling at a velocity 20 parts per million above light speed. To absolutely verify this occurrence, collaboration is needed from different sources and we’re here to give you the latest update.

“This result comes as a complete surprise,” said OPERA spokesperson, Antonio Ereditato of the University of Bern. “After many months of studies and cross checks we have not found any instrumental effect that could explain the result of the measurement. While OPERA researchers will continue their studies, we are also looking forward to independent measurements to fully assess the nature of this observation.”

Since the OPERA measurements go against everything we think we know, it’s more important than ever to verify its findings through independent research.

“When an experiment finds an apparently unbelievable result and can find no artifact of the measurement to account for it, it’s normal procedure to invite broader scrutiny, and this is exactly what the OPERA collaboration is doing, it’s good scientific practice,” said CERN Research Director Sergio Bertolucci. “If this measurement is confirmed, it might change our view of physics, but we need to be sure that there are no other, more mundane, explanations. That will require independent measurements.”

To get the job done, the OPERA Collaboration joined forces with CERN metrology experts and other facilities to establish absolute calibrations. There cannot be any error margin in parameters between the source and detector distances – and the neutrino’s flight time. In this circumstance, the measurements of the initial source of the neutrino beam and OPERA has an uncertainty value of 20 cm over the 730 km. The neutrino flight time has an accuracy of less than 10 nanoseconds, and was confirmed through the use of highly regarded GPS equipment and an atomic clock. Every care was given to ensure precision.

“We have established synchronization between CERN and Gran Sasso that gives us nanosecond accuracy, and we’ve measured the distance between the two sites to 20 centimetres,” said Dario Autiero, the CNRS researcher who will give this afternoon’s seminar. “Although our measurements have low systematic uncertainty and high statistical accuracy, and we place great confidence in our results, we’re looking forward to comparing them with those from other experiments.”

“The potential impact on science is too large to draw immediate conclusions or attempt physics interpretations. My first reaction is that the neutrino is still surprising us with its mysteries.” said Ereditato. “Today’s seminar is intended to invite scrutiny from the broader particle physics community.”

Original Story Source: CERN Press Release. For Further Reading: Measurement of the neutrino velocity with the OPERA detector in the CNGS beam.

Read our previous article on this paper.

Posted on by Nancy Atkinson

UARS Update: Satellite Fell in Pacific Ocean

UARS satellite at 22:56 on Sept. 22, 2011, as seen from Puerto Rico. Credit: Effrain Morales Rivera.

[/caption]
NASA has confirmed that it’s decommissioned Upper Atmosphere Research Satellite fell back to Earth on Sept. 24 between 03:23 GMT and 05:05 GMT (11:23 p.m. EDT Friday, Sept. 23 and 1:09 a.m. EDT Sept. 24.) The Joint Space Operations Center at Vandenberg Air Force Base in California said the satellite entered the atmosphere over the North Pacific Ocean, off the west coast of the United States. The precise re-entry time and location of any debris impacts are still being determined. NASA is not aware of any reports of injury or property damage.

NASA will provide more information during a media telecon at 18:00 GMT (2 p.m. ET) to discuss the re-entry.

Artist concept of the UARS Satellite in orbit. Credit: NASA
Posted on by Fraser Cain

SGU-24 Starts Soon

Our good friends at the Skeptic’s Guide to the Universe are about to punish themselves in a feat of skepticism that will shock and amaze mankind for generations to come. What will be seen, can never be unseen!

To help raise money for the show, the rogues have decided to put on a 24-hour video show, drawing in legends and supporters from across skeptic-kind. At some point you’ll see Adam Savage, Phil Plait, Richard Wiseman, Brian Brushwood, Richard Saunders, George Hrab, and more.

And you’ll also see me and Dr. Pamela Gay, my co-host from Astronomy Cast (I think we’re scheduled for 3pm Eastern time on Saturday).

The show gets started at 8:00pm Eastern Time on Friday, September 23rd, and runs for 24 non-stop hours.

You can find more, and actually watch the show here.

And if you really want to show your support for the SGU, take a moment and donate. Show them how much you appreciate their science news and skepticism.

Posted on by Ray Sanders

Finding NEEMO: NASA’s Underwater Simulations Focus on Human Asteroid Mission

NEEMO engineering crew diver simulates anchoring to an asteroid surface. Image credit: NASA

[/caption]
The sight of NASA mission specialists performing mission training underwater has been fairly common over the years. On October 15th, NASA astronaut and former ISS crew member Shannon Walker will lead a different kind of underwater training mission. Walker will be leading the 15th expedition of NASA Extreme Environment Mission Operations (NEEMO), and interestingly, the crew includes Steve Squyres, head of the Mars Rover Exploration Project.

What makes NEEMO different from the other NASA underwater training simulations we’ve seen in the past?

Think asteroid.

With manned exploration of an asteroid on NASA’s roadmap, new technologies and procedures need to be created in order to ensure astronaut safety and achieve mission science goals. The NEEMO program at NASA will be putting experts to the task of developing solutions to the new challenges presented with near-Earth asteroid exploration. During NEEMO 15, NASA will test new tools, techniques and communication technologies.

Before now, NASA hasn’t given much thought to the operations necessary for a manned mission to an asteroid. With the nearly non-existent surface gravity of an asteroid, astronauts won’t be able to walk on the surface. One idea being tested is for the astronauts to anchor themselves to the asteroid. One difficulty with using anchors is that not all asteroids are made of the same materials – some asteroids are mostly metal, others are loose rubble and some are a mix of rock, metal and dust. Underwater testing on the ocean floor provides an environment that is perfectly suited for the NEEMO 15 mission, allowing NASA to simulate an environment with weak gravity and diverse materials.

Artist's concept of anchoring to the surface of an asteroid. Image credit: NASA

There are three main goals for the NEEMO 15 mission. First NASA will test methods for anchoring to the surface of the asteroid. Moving on the surface of an asteroid will require a method of connecting multiple anchors. The second major goal of the mission is to determine the best way to connect the anchor system. The third major goal will explore methods of collecting samples on the surface of an asteroid.

In addition to mission leader Shannon Walker, and Steve Squyres, the crew of NEEMO 15 includes astronaut Takuya Onishi (Japan Aerospace Exploration Agency) and David Saint-Jacques (Canadian Space Agency). Also joining the astronauts on the NEEMO 15 crew are: James Talacek and Nate Bender (University of North Carolina). Squyres is principal investigator for the Mars Exploration Rover (Spirit and Opportunity) mission, while Talacek and Bender are professional aquanauts.

Serving as support crew, NASA astronauts Stan Love, Richard Arnold and Mike Gernhardt, will participate in the NEEMO mission from the DeepWorker submersible, which they will pilot. NASA is using the DeepWorker submarine as an underwater stand-in for the Space Exploration Vehicle (SEV) which NASA has been testing separately in the “Desert RATS” field trial mission.

If you’d like to learn more about NASA’s NEEMO field test mission, visit: http://www.nasa.gov/neemo

You can view information on the NEEMO 15 crew at: http://www.nasa.gov/mission_pages/NEEMO/NEEMO15/crew.html, and follow the mission on Twitter and Facebook

Source: NASA NEEMO Press Release

Posted on by Nancy Atkinson

What Does NASA Sound Like?

Atlantis launches one last time on July 8, 2011. Credit: Alan Walters (awaltersphoto.com) for Universe Today.

[/caption]

When you think of NASA, do certain sounds and/or soundbites come to mind?

“3…2…1…0 and Liftoff!”

“That’s one small step,….”

“Ignition sequence start…”

“We’re on our way Houston!”

You can now listen to a collection of distinct NASA sounds at the NASA Sounds website where you can download various clips for ringtones, or for your computer errors, alarms and notifications, or just add to your audio collection.

“NASA has been making historic sounds for over 50 years,” said Jerry Colen, NASA App project manager at the agency’s Ames
Research Center in Moffett Field, Calif. “Now we’re making some of these memorable sounds easy to find and use.”

The NASA sounds are available in both MP3 and M4R (iPhone) files, and also includes the sounds of spacecraft beeping and crackling. NASA will update the collection as new sounds become available.

Posted on by Fraser Cain

Happy Equinox!

We’re now in Autumn (in the Northern Hemisphere), the time when the length of day and night are roughly the same. And from here on out, the nights will be getting longer and the days shorter. It’s often difficult to explain to people how the Earth’s tilt defines how much sunlight we get every day, and how it causes the changing seasons. Here’s the easy thing to do. Show this amazing video to anyone, and they’ll totally get it. It’s a full year’s snapshots of Earth taken by NASA’s Meteosat satellite.

The Bad Astronomer, Phil Plait, has a great explainer on the Equinox, and details what you’re seeing in this video. Check it out.

Posted on by Tammy Plotner

Water, Water Everywhere… And A Few Drops For Saturn, Too!

Recent Cassini images of Saturn's moon Enceladus backlit by the sun show the fountain-like sources of the fine spray of material that towers over the south polar region. This image was taken looking more or less broadside at the "tiger stripe" fractures observed in earlier Enceladus images. It shows discrete plumes of a variety of apparent sizes above the limb (edge) of the moon. This image was acquired on Nov. 27, 2005. Image Credit: NASA/JPL/Space Science Institute

[/caption]

In 2005, NASA’s Cassini spacecraft gave us an incredible view of Enceladus chuffing out fountains of water vapor and ice. This action creates an enormous halo of gas, dust and ice that surrounds this Saturnian satellite and enables the planet’s E ring. Now Enceladus is once again in the spotlight as the only moon in the Solar System known to significantly contribute to its parent planet’s chemistry.

Earlier this year, ESA announced that its Herschel Space Observatory had observed a huge torus of water vapor around Saturn which apparently originated from Enceladus. It spans approximately 600,000 kilometers across and runs about 60,000 kilometers deep, but more so than its size is what it appears to be doing… adding water to Saturn’s upper atmosphere. Because the vapor isn’t detectable at visible wavelengths, this observation came as revelation for the Herschel scope.

“Herschel is providing dramatic new information about everything from planets in our own solar system to galaxies billions of light-years away,” said Paul Goldsmith, the NASA Herschel project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, California.

While the Herschel infrared observation is new, the indication of a vapor torus around Saturn isn’t. NASA’s Voyager and Hubble missions had given astronomers clues in the past. In 1997, the European Space Agency’s Infrared Space Observatory cited water in Saturn’s atmosphere and two years later NASA’s Submillimeter Wave Astronomy Satellite confirmed it again. But this confirmation only added up to a puzzle. Water found in Saturn’s lower cloud levels couldn’t rise past the colder, upper deck… So where was the water coming from? The answer came in the form of Herschel’s observations and some very astute computer modeling.

“What’s amazing is that the model, which is one iteration in a long line of cloud models, was built without knowledge of the observation.” says Tim Cassidy, a recent post-doctoral researcher at JPL who is now at the University of Colorado’s Laboratory for Atmospheric and Space Physics, Boulder. “Those of us in this small modeling community were using data from Cassini, Voyager and the Hubble telescope, along with established physics. We weren’t expecting such detailed ‘images’ of the torus, and the match between model and data was a wonderful surprise.”

Through these simulations, researchers hypothesized that much of the water in the torus was simply lost to space and some is pulled back by gravity to add material to Saturn’s rings. However, it’s the 3-5% that made it back to Saturn’s atmosphere that’s the most interesting. Just how much water vapor is out there? Thanks to combining information from both Herschel and the Ultraviolet Imaging Spectrograph (UVIS) instrument aboard the Cassini spacecraft, we’ve learned that about 12,000 kilograms is being ejected from Enceladus every minute. Can you image how much that would add up to in the period of a year… or more?!

“With the Herschel measurements of the torus from 2009 and 2010 and our cloud model, we were able to calculate a source rate for water vapor coming from Enceladus,” said Cassidy. “It agrees very closely with the UVIS finding, which used a completely different method.”

“We can see the water leaving Enceladus and we can detect the end product — atomic oxygen — in the Saturn system,” said Cassini UVIS science team member Candy Hansen, of the Planetary Science Institute, Tucson, Ariz. “It’s very nice with Herschel to track where it goes in the meantime.”

A tiny percentage adds up to some mighty big numbers, and the water molecules from the torus impact Saturn’s atmosphere to a great degree by contributing hydrogen and oxygen.

“When water hangs out in the torus, it is subject to the processes that dissociate water molecules,” said Hansen, “first to hydrogen and hydroxide, and then the hydroxide dissociates into hydrogen and atomic oxygen.” This oxygen is dispersed through the Saturn system. “Cassini discovered atomic oxygen on its approach to Saturn, before it went into orbit insertion. At the time, no one knew where it was coming from. Now we do.”

Very few days go by that we don’t learn something new about the Solar System and its inner workings. Thanks to observations like those done by the Herschel Space Observatory and missions like Cassini-Huygens, we’re able to further understand the dynamics behind the beauty… and how a tiny player can carry a major role.

“The profound effect this little moon Enceladus has on Saturn and its environment is astonishing,” said Hansen.

Original Story Source: JPL News Release.