SpaceJibe

February 18, 2014

NASA solves mystery of ‘jelly donut’ on Mars

This before-and-after pair of images of the same patch of ground in front of NASA's Mars Rover Opportunity 13 days apart documents the arrival of a strange, bright rock at the scene. The rock, called

This before-and-after pair of images of the same patch of ground in front of NASA’s Mars Rover Opportunity 13 days apart documents the arrival of a strange, bright rock at the scene. The rock, called “Pinnacle Island,” is seen in the right imag (NASA/JPL-CALTECH/CORNELL UNIV./ARIZONA STATE UNIV.)

It was a complete unknown — it was a rolling stone.

A mystery rock that appeared before NASA’s Opportunity rover in late January — and bore a strange resemblance to a jelly donut — is no more than a common piece of stone that bounced in front of the cameras, NASA said Friday.

The strange rock was first spied on Jan. 8, in a spot where nothing had sat a mere two weeks earlier. Dubbed “Pinnacle Island” by NASA scientists, it was only about 1.5 inches wide. But the rock’s odd appearance — white-rimmed and red-centered, not unlike a jelly donut — made many sit up and take notice.

Now researchers with NASA’s Jet Propulsion Laboratory at the California Institute of Technology have finally cleared up the mystery.

Yep. It’s a rock.

“Once we moved Opportunity a short distance, after inspecting Pinnacle Island, we could see directly uphill an overturned rock that has the same unusual appearance,” said Opportunity Deputy Principal Investigator Ray Arvidson of Washington University in St. Louis. “We drove over it. We can see the track. That’s where Pinnacle Island came from.”

‘We drove over it. We can see the track. That’s where Pinnacle Island came from.’

– Opportunity Deputy Principal Investigator Ray Arvidson

Examination of Pinnacle Island revealed high levels of elements such as manganese and sulfur, suggesting these water-soluble ingredients were concentrated in the rock by the action of water.

“This may have happened just beneath the surface relatively recently,” Arvidson said, “or it may have happened deeper below ground longer ago and then, by serendipity, erosion stripped away material above it and made it accessible to our wheels.”

 

Now that the rover is finished inspecting this rock, the team plans to drive Opportunity south and uphill to investigate exposed rock layers on the slope.

Opportunity has trolled the Martian surface since Jan. 24, 2004, far outlasting its original 90-day mission.

Steve Squyres, the rover’s lead scientist at Cornell University in Ithaca, N.Y said the Red Planet keeps surprising scientists, even 10 years later.

“Mars keeps throwing new things at us,” he said.

Source

February 15, 2014

Hubble and Spitzer space telescopes “spy” one of the youngest galaxies in the universe

Filed under: Big Bang, Cool, Cosmology — bferrari @ 6:02 pm

The Frontier Fields program is already providing new constraints on the properties of the galaxies in the early universe.

Deep image of the galaxy cluster Abell 2744 obtained with the Hubble Space Telescope. The zoomed image shows the region around the galaxy Abell2744_Y1, one of the most distant galaxies in the universe. ( NASA/ESA, J. Lotz, M. Mountain, A. Koekemoer/the HFF Team (STScI)/Nicolas Laporte et al. (IAC) )

Deep image of the galaxy cluster Abell 2744 obtained with the Hubble Space Telescope. The zoomed image shows the region around the galaxy Abell2744_Y1, one of the most distant galaxies in the universe. ( NASA/ESA, J. Lotz, M. Mountain, A. Koekemoer/the HFF Team (STScI)/Nicolas Laporte et al. (IAC) )

An international team led by astronomers from the Astrophysics Institute of the Canary Islands (IAC) and La Laguna University (ULL) has just completed the first analysis of the observations of the Abell 2744 cluster of galaxies, a coordinated program of the Hubble and Spitzer space telescopes. The first result of this study is the discovery of one of the most distant galaxies known to date, which clearly shows the potential of the HST Frontier Fields project.

This work also involves researchers from the Research Institute for Astrophysics and Planetology in Toulouse and Astrophysics Research Center of Lyon in France; Geneva University and Ecole Polytechnique Federal de Lausanne in Switzerland; and the University of Arizona in the United States.

Thanks to the high data quality of Hubble in the optical and near-infrared and Spitzer in infrared data, these astrophysicists have determined the properties of this young galaxy with a better precision than previous studies of other samples at similar cosmic epochs. This galaxy, named Abell2744_Y1, is about 30 times smaller than the Milky Way but is producing at least 10 times more stars. From Earth, this object is seen as it was 650 million years after the Big Bang. Its light has traveled about 13 billion years to reach the telescopes, being one of the brightest galaxies discovered at such distances. In astronomy, the farther one object is, the longer it takes for the light to reach us, and therefore the Frontier Fields allow the astronomers to push the limits of the observable universe. This study provides new constraints on the density and properties of the galaxies in the early universe.

“Frontier Fields”
Last month, during the meeting of the American Astronomical Society held in Washington, D.C., the Space Telescope Science Institute presented its flagship project for the next three years: the “Hubble Frontier Fields.” In the framework of this program, three of the most powerful space telescopes to date — Hubble, Spitzer, and Chandra — will dedicate a large amount of their observing time to investigate six galaxies clusters, which act as additional lenses and amplify the light from background sources, including faint galaxies to the edge of the observable universe. This will allow astronomers to study for the first time fainter and smaller galaxies in the first billion years of the universe.

The first long-exposure image of cluster Abell 2744, obtained in the last months, is the deepest one obtained so far of a cluster of galaxies and is comparable to the previous Hubble Ultra Deep Field, which is a blank region of the sky. All the Frontier Fields clusters have been carefully selected and are the best ones for this kind of study.

Thanks to the gravitational lensing by the cluster, the light of the background galaxies can be magnified by a large amount. This effect converts in practice the Hubble Space Telescope into an equivalent telescope with a collecting area several hundred times larger.

“We expected to find very distant galaxies close to the cluster core, where the light amplification is maximum,” said Nicholas Laporte from the IAC. “However, this galaxy is very close to the edge of the Hubble image where the light is not strongly amplified. We are really lucky that we could find it in the small field of view of Hubble. In a related study led by Hakim Atek from EPFL in Lausanne, more galaxies are analyzed but none is more distant than Abell2744_Y1.”

The analysis of the observations of this cluster carried out with the Spitzer Space Telescope has been crucial to estimate the properties of Abell2744_Y1. Alina Streblyanska from the IAC commented that the Spitzer observations combined with the Hubble ones provide a good estimate of the distance to this galaxy: “They also suggest that Abell2744_Y1 contains not only stars but also a large amount of gas.”

Ismael Pérez-Fournon from the La Laguna University pointed out that last year his group contributed to the discovery of an exceptional star factory in the early universe, called HFLS3, with the Herschel Space Observatory: “HFLS3 has extreme properties in the far-infrared, observed 880 million years after the Big Bang. Abell2744_Y1 is a smaller galaxy, less massive but more distant and much more representative of the early universe. Both types of galaxies are equally important to understand how galaxies formed and evolved.”

In coordination with the Hubble observations, the Spitzer Space Telescope and Chandra X-ray Observatory are taking very deep exposures of the Frontier Fields. Since the end of 2013, the data of the first cluster obtained by the first two telescopes are available to the whole scientific community.

Observations of the Frontier Fields by Hubble, Spitzer, and Chandra are in an early stage but have already shown the exceptional potential of this new project to study the first luminous objects in the universe. As it happnened with other Hubble initiatives on deep fields, many other observatories all over the world and in space will join the effort with additional observations of the Frontier Fields. An unprecedented scientific legacy for future studies with the present large telescopes as the Gran Telescopio Canarias, and the future extremely large telescopes as the E-ELT and the James Webb Space Telescope is expected.

February 13, 2014

National Ignition Facility announces promising results for nuclear fusion

Filed under: Big Bang, Black Holes, Cool, Gadgets, The Sun — bferrari @ 8:44 am
A deuterium and tritium capsule, sphere in window at center, inside a cylindrical hohlraum container about 0.4 inches tall. In research reported Wednesday, Feb. 12, 2014 by the journal Nature, scientists say they've taken a key step toward harnessing nuclear fusion as a new way to generate power. (AP PHOTO/LAWRENCE LIVERMORE NATIONAL LABORATORY, EDDIE DEWALD)

A deuterium and tritium capsule, sphere in window at center, inside a cylindrical hohlraum container about 0.4 inches tall. In research reported Wednesday, Feb. 12, 2014 by the journal Nature, scientists say they’ve taken a key step toward harnessing nuclear fusion as a new way to generate power. (AP PHOTO/LAWRENCE LIVERMORE NATIONAL LABORATORY, EDDIE DEWALD)

NEW YORK – Scientists say they’ve taken a key step toward harnessing nuclear fusion as a new way to generate power, an idea that has been pursued for decades.

They are still a long way from that goal. The amount of energy they got out of their experimental apparatus was minuscule compared to what they put into it.

Still, the new work reached some significant milestones along the path to a cleaner and cheaper source of electricity, the researchers and experts said.

Fusion is the merging of hydrogen atoms, the process that powers the sun. That’s different from nuclear fission, which is the breaking apart of atoms that lies at the heart of today’s nuclear power plants.

Both processes release energy, but scientists have been pursuing fusion power because of several advantages. The supply of hydrogen for fuel is virtually unlimited, available from seawater, for example, in contrast to the uranium used in nuclear power plants. Fusion power would avoid the need for long-term storage of radioactive waste. And unlike fossil fuels like coal, it would not produce greenhouse gases that cause global warming.

In the new work, reported online Wednesday by the journal Nature, scientists from the Lawrence Livermore National Laboratory near San Francisco, report results from two experiments done at the lab’s National Ignition Facility

In each trial, 192 laser beams briefly fired into a half-inch-long gold cylinder. The cylinder held a tiny ball that contained the fuel, which was a mix of two kinds of hydrogen, called deuterium and tritium. The energy from the lasers kicked off a process that compressed the ball by an amount akin to squeezing a basketball down to the size of a pea, said Debbie Callahan, an author of the paper.

A cylindrical hohlraum container about 0.4 inches tall containing a deuterium and tritium capsule, held by cryogenically-cooled positioning arms. In research reported Wednesday, Feb. 12, 2014 by the journal Nature, scientists say they've taken a key step toward harnessing nuclear fusion as a new way to generate power. (AP PHOTO/LAWRENCE LIVERMORE NATIONAL LABORATORY, EDDIE DEWALD)

A cylindrical hohlraum container about 0.4 inches tall containing a deuterium and tritium capsule, held by cryogenically-cooled positioning arms. In research reported Wednesday, Feb. 12, 2014 by the journal Nature, scientists say they’ve taken a key step toward harnessing nuclear fusion as a new way to generate power. (AP PHOTO/LAWRENCE LIVERMORE NATIONAL LABORATORY, EDDIE DEWALD)

That created the extremely high pressure and temperatures needed to get the hydrogen atoms to fuse. It was all over in the blink of an eye, with the reaction confined to a space smaller than the width of a human hair.

Nuclear fusion would be worthwhile only if it produces more energy than it uses, and the results were far from that. The hydrogen fuel did emit more energy than it absorbed from the lasers, an experimental goal. But the fuel took in only about 1 percent of all the energy produced by the lasers. So the apparatus is still far short of producing more energy than it requires to operate.

Another key finding was evidence that energy created by the fusion reaction was going back into the remaining fuel, a “bootstrapping” process that is key to boosting the energy output.

“Seeing that kick in is quite exciting, and it does show that there is promise” for increasing the energy output, said Omar Hurricane, lead author on the Nature paper. It’s not clear when researchers will be able to get more energy out of the reaction than the lasers pour into it, he said, but “we are working like mad … in that direction.”

The sign of bootstrapping is “really a wonderful result,” said fusion expert Robert McCrory of the University of Rochester, who was not involved in the research. “There’s a lot more that needs to be done” to reach the point where the reaction produces more energy than the lasers deliver, but “this was absolutely necessary.”

Scientists elsewhere are working on a different approach to fusion power, one that uses magnetic fields to contain super-heated hydrogen fuel. Several nations are cooperating to build a huge experimental device to explore that approach in France.

Source

February 10, 2014

Australian scientists discover oldest known star

Filed under: Big Bang, Black Holes, Cool, Cosmology — bferrari @ 3:03 pm

Stefan-Keller-and-Mike-Bessell_1600

A team of Australian astronomers say they have identified the oldest known star in our universe — one that formed a mere 200 million years after the Big Bang.

“This is the first time that we’ve been able to unambiguously say that we’ve found the chemical fingerprint of a first star,” lead researcher, Stefan Keller of the Australian National University (ANU) research school of astronomy and astrophysics said in a press release.

The star, named SMSS J031300.36-670839.3, is estimated to be 13.6 billion years old and is much older than previous stars found in 2007 and 2013, which were believed to be 13.2 billion years old.

The astronomers analyzed the light from the star to determine its chemical makeup, and extrapolated its age from there.

‘This is the first time that we’ve been able to unambiguously say that we’ve found the chemical fingerprint of a first star.’

– astronomer Stefan Keller

“The telltale sign that the star is so ancient is the complete absence of any detectable level of iron in the spectrum of light emerging from the star,” explained Keller.

The star was first spotted on January 2 in the Milky Way, 6,000 light years away from the Earth using the ANU Skymapper telescope.

“The stars we are finding number one in a million,” team member Professor Mike Bessel said in a press release. “Finding such needles in a haystack is possible thanks to the ANU SkyMapper telescope that is unique in its ability to find stars with low iron from their color.”

The newly discovered star was formed in the wake of a primordial star and had a mass 60 times that of our Sun.

“To make a star like our Sun, you take the basic ingredients of hydrogen and helium from the Big Bang and add an enormous amount of iron – the equivalent of about 1,000 times the Earth’s mass,” Keller said.

Keller explained that primordial stars were previously thought to have died in violent explosions which polluted space with iron. But his discovery shows signs of pollution of lighter elements like carbon and magnesium with no traces of iron.

“To make this ancient star, you need no more than an Australia-sized asteroid of iron and lots of carbon,” Keller continued. “It’s a very different recipe that tells us a lot about the nature of the first stars and how they died.”

Keller and his team hope that their discovery will help resolve long-standing discrepancies between observations and predictions of the Big Bang.

“This is one of the first steps in understanding what those first stars were like,” said Keller. “What this star has enabled us to do is record the fingerprint of those first stars.”

The discovery was published in the latest edition of the journal Nature.

Source

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