First Earth-Sized Rocky Exoplanet Discovered

A team of astronomers has found the first Earth-sized planet outside the solar system that has a rocky composition like that of Earth. This exoplanet, known as Kepler-78b, orbits its star very closely every 8.5 hours, making it much too hot to support life. The results are being published in the journal Nature. This Earth-sized planet was discovered using data from NASA’s Kepler Space Telescope, and confirmed and characterized with the W. M. Keck Observatory. Every 8.5 hours the planet passes in front of its host star, blocking a small fraction of the starlight. These telltale dimmings were picked up by researchers analyzing the Kepler data.

The team led by Dr. Andrew Howard (Institute for Astronomy, University of Hawaii at Manoa) then measured the mass of the planet with the Keck Observatory on Mauna Kea, in Hawaii. Using the ten-meter Keck I telescope fitted with the HIRES instrument, the team employed the radial velocity method to measure how much an orbiting planet causes its star to wobble, to determine the planet’s mass. This is another excellent example of the synergy between the Kepler survey, which has identified more than 3,000 potential exoplanet candidates, and Keck Observatory, which plays a leading role in conducting precise Doppler measurements of the exoplanet candidates.

A handful of planets the size or mass of Earth have been discovered recently. This is the first one with both quantities measured. “When you have both the size and the mass of an object, you can calculate its density, and thereby determine what it is made of,” explained Howard.

This illustration compares Earth with the newly confirmed scorched world of Kepler-78b. Kepler-78b is about 20 percent larger than Earth and is 70% more massive. Kepler-78b whizzes around its host star every 8.5 hours, making it a blazing inferno. Credit: David A. Aguilar (CfA)

With a radius about 1.2 times that of Earth and a mass equal to about 1.7 times Earth’s, Kepler-78b has a density that is the same as Earth’s, suggesting that it also made primarily of rock and iron. Its star is slightly smaller and less massive than the sun and is located about 400 light-years from Earth in the constellation Cygnus. 

Kepler-78b is a member of a new class of “ultrashort period” planets recently identified by the Kepler spacecraft. These newfound worlds all orbit their stars with orbital periods of less than 12 hours. They’re also small, about one-to-two times the size of Earth. Kepler-78b is the first planet in this new class to have its mass measured. It is a mystery how these planets formed and made it so close to their host stars (only 1 percent of the Earth-sun separation in the case of Kepler-78b).

An artist's conception of Kepler-78b orbiting its parent star once every 8.5 hours. Credit: David A. Aguilar (CfA)

In a rather unique arrangement, a companion study led by Dr. Francesco Pepe (University of Geneva, Switzerland) that used the same Kepler data but independent radial velocity observations is being published in the same issue.

The two studies found very similar results. “The gold standard in science is having your findings reproduced by other researchers,” explained Howard. “In this case, we did not have to wait for this to happen.”

The other members of Howard’s team are Roberto Sanchis-Ojeda (MIT), who analyzed the transit data taken by the Kepler spacecraft to find the planet and calculate its size, Dr. Geoffrey Marcy (University of California, Berkeley), Dr. John Johnson (Harvard), Dr. Debra Fischer (Yale), Benjamin Fulton and Evan Sinukoff (UHM graduate students), and Dr. Jonathan Fortney (University of California, Santa Cruz).

HD 21997: Challenge to Planet Formation Theories

HD 21997 is a star in the southern constellation Fornax (the Furnace) that is yielding some surprising data about how planetary systems form. About 235 light years from Earth, the star is 1.8 times the mass of the Sun and is thought to be about thirty million years old. Observations by an international team using ESA’s Herschel Space Observatory and the Atacama Large Millimeter/sub-millimeter Array (ALMA) in Chile show a ring of material around the star that contains not only a good deal of gas but also the dust produced by the collision of planetesimals.

Image: ALMA images of the disk around HD 21997. The left image shows the emission of cold dust grains, situated in a ring around the central star. The middle image displays the emission from carbon monoxide, and shows that gas can also be found closer to the star than dust. The right image depicts the velocity of the gas. The red-colored parts of the disk move away from us, while the blue-colored parts move towards us, indicating that the gas is rotating/orbiting around the central star. Credit: Á. Kóspál (ESA) and A. Moór (Konkoly Observatory).

This is an unusual finding because our models of planet formation predict that the primordial gas should be completely out of a young system after no more than ten million years, pulled into the star itself, or aiding in the formation of gas giant planets, with the balance simply dissipating because of intense radiation from the young star. But the disk around HD 21997 is obviously a hybrid, one that links the early and late phases of disk evolution. Moreover, the dust ring and the gas ring do not coincide. Ágnes Kóspál (ESA) sees this as a clue to how the two disks formed:

“The gas ring starts closer to the central star than the dust. If the dust and the gas had been produced by the same physical mechanism, namely by the erosion of planetesimals, we would have expected them to be at the same location. This is clearly not the case in the inner disk.”

The amount of gas is striking. The team’s data show that the total gas mass is somewhere between thirty and sixty times the mass of the Earth, an indication that the gas disk really is primordial material, as the amount of gas freed by collisions between planetesimals would be insufficient to explain this quantity. What’s ahead is a search for more systems like HD 21997 for further information about how our models of planet formation may need to be revised.

This is not the first time we’ve found indications of hybrid disks. In fact, disks around β Pictoris, HD 32297, 49 Ceti, HD 172555, and HD 32297 are also known to contain small amounts of gas, a finding that has energized debate about whether the gas was produced by planetesimal collisions or was leftover material from the primordial disk. HD 21997 takes the debate to another level, because the amount of gas and the displacement of the two disks are strong indicators that the gas here is primordial, with all that implies about the need to adjust our models.

Image: Antennas of the Atacama Large Millimeter/submillimeter Array (ALMA), a compound telescope on the Chajnantor Plateau in the Chilean Andes. The final ALMA configuration has 66 antennas acting like a single telescope. Signals from this array made it possible to spatially resolve the emission of both the dust grains and the gas molecules. Credit: ESO/C. Malin.

The two papers on this work are Kóspál et al., “ALMA observations of the molecular gas in the debris disk of the 30 Myr old star HD 21997,” Astrophysical Journal Volume 776, Issue 2 (2013 – abstract) and Moór et al., “ALMA continuum observations of a 30 Myr old gaseous debris disk around HD 21997,” Astrophysical Journal Letters Volume 777, Issue 2 (2013 – abstract). 

Paleontologist Thinks He Found the Holy Grail of Science!

9 hours ago by John Davis
Meteorite bombardment left large craters that contained water and chemical building blocks for life,
which ultimately led to the first organisms.
It has baffled humans for millennia: how did life begin on planet Earth? Now, new research from a Texas Tech University paleontologist suggests it may have rained from the skies and started in the bowels of hell.
Sankar Chatterjee, Horn Professor of Geosciences and curator of paleontology at the Museum of Texas Tech University believes he has found the answer by connecting theories on chemical evolution with evidence related to our planet's early geology.
"This is bigger than finding any dinosaur," Chatterjee said. "This is what we've all searched for – the Holy Grail of science."
Thanks to regular and heavy comet and meteorite bombardment of Earth's surface during its formative years 4 billion years ago, the large craters left behind not only contained water and the basic chemical building blocks for life, but also became the perfect crucible to concentrate and cook these chemicals to create the first simple organisms. He will present his findings Oct. 30 during the 125th Anniversary Annual Meeting of the Geological Society of America in Denver. As well as discovering how ancient animals flew, Chatterjee discovered the Shiva Meteorite Crater, which was created by a 25-mile-wide meteorite that struck off the coast of India. This research concluded this giant meteorite wreaked havoc simultaneously with the Chicxulub meteorite strike near Mexico, finishing the dinosaurs 65 million years ago.
Ironically, Chatterjee's latest research suggests meteorites can be givers of life as well as takers. He said that
meteor and comet strikes likely brought the ingredients and created the right conditions for life on our planet. By studying three sites containing the world's oldest fossils, he believes he knows how the first single-celled
organisms formed in hydrothermal crater basins. Enlarge Crater basin may have been the crucible of life.
"When the Earth formed some 4.5 billion years ago, it was a sterile planet inhospitable to living organisms,"
Chatterjee said. "It was a seething cauldron of erupting volcanoes, raining meteors and hot, noxious gasses. One billion years later, it was a placid, watery planet teeming with microbial life – the ancestors to all living things."

"For may years, the debate on the origins of life centered on the chemical evolution of living cells from organic molecules by natural processes. Chatterjee said life began in four steps of increasing complexity – cosmic, geological, chemical and biological.

Most researchers believe that Life originated in deep-sea hydrothermal vents. About 4 billion years
ago, Earth was a watery planet; ocean stretched from pole to pole; any life synthesis would be
diluted. It needed a protected basin.
In the cosmic stage, a still-forming Earth and our solar system took a daily pounding from rocky asteroids and icy comets between 4.1 to 3.8 billion years ago. Plate tectonics, wind and water have hidden evidence of this early onslaught on our planet, but ancient craters on the surfaces of Mars, Venus, Mercury and our moon show just how heavy the meteorite showers once were.
Larger meteorites that created impact basins of about 350 miles in diameter inadvertently became the perfect
crucibles, he said. These meteorites also punched through the Earth's crust, creating volcanically driven
geothermal vents. Also, they brought the basic building blocks of life that could be concentrated and polymerized in the crater basins.

Hierarchical Origin of Life: Historical Contingency Parsimony principle chooses the simplest
explanation for the origin of life.
After studying the environments of the oldest fossil-containing rocks on Earth in Greenland, Australia and South Africa, Chatterjee said these could be remnants of ancient craters and may be the very spots where life began in deep, dark and hot environments.
Because of Earth's perfect proximity to the sun, the comets that crashed here melted into water and filled these basins with water and more ingredients. This gave rise to the geological stage. As these basins filled, geothermal venting heated the water and created convection, causing the water to move constantly and create a thick primordial soup.
"The geological stage provides special dark, hot, and isolated environments of the crater basins with the
hydrothermal vent systems that served as incubators for life," he said. "Segregation and concentration of organic molecules by convective currents took place here, something like the kinds we find on the ocean floor, but still very different. It was a bizarre and isolated world that would seem like a vision of hell with the foul smells of hydrogen sulfide, methane, nitric oxide and steam that provided life-sustaining energy."
Then began the chemical stage, Chatterjee said. The heat churning the water inside the craters mixed chemicals together and caused simple compounds to grow into larger, more complex ones.

Crater Basin with Hydrothermal Vent System Meteorites brought biomolecules of cell membrane.
Most likely, pores and crevices on the crater basins acted as scaffolds for concentrations of simple RNA and
protein molecules, he said. Unlike a popular theory that believes RNA came first and proteins followed,
Chatterjee believes RNA and proteins emerged simultaneously and were encapsulated and protected from the environment.
"The dual origin of the 'RNA/protein' world is more plausible in the vent environments than the popular 'RNA
world,'" he said. "RNA molecules are very unstable. In vent environments, they would decompose quickly.
Some catalysts, such as simple proteins, were necessary for primitive RNA to replicate and metabolize. On theother hand, amino acids, from which proteins are made, are easier to make than RNA components."
The question remains how loose RNA and protein material floating in this soup protected itself in a membrane. Chatterjee believes University of California professor David Deamer's hypothesis that membranous material existed in the primordial soup. Deamer isolated fatty acid vesicles from the Murchison meteorite that fell in 1969 in Australia. The cosmic fatty bubbles extracted from the meteorite mimic cell membranes.
"Meteorites brought this fatty lipid material to early Earth," Chatterjee said. "This fatty lipid material floated on top of the water surface of crater basins but moved to the bottom by convection currents. At some point in this process during the course of millions of years, this fatty membrane could have encapsulated simple RNA and proteins together like a soap bubble. The RNA and protein molecules begin interacting and communicating. Eventually RNA gave way to DNA – a much more stable compound – and with the development of the genetic code, the first cells divided."
The final stage – the biological stage – represents the origin of replicating cells as they began to store, process and transmit genetic information to their daughter cells, Chatterjee said. Infinite combinations took place, and countless numbers must have failed to function before the secret of replication was broken and the proper selection occurred.
"These self-sustaining first cells were capable of Darwinian evolution," he said. "The emergence of the first cells on the early Earth was the culmination of a long history of prior chemical, geological and cosmic processes."
Chatterjee also believes that modern RNA-viruses and protein-rich prions that cause deadly diseases probably represent the evolutionary legacy of primitive RNA and protein molecules. They may be the oldest cellular particles that predated the first cellular life. Once cellular life evolved, RNA-viruses and prions became redundant, but survived as parasites on the living cells.
The problem with theories on the origins of life is that they don't propose any experiments that lead to the
emergence of cells, Chatterjee said. However, he suggested an experiment to recreate the ancient prebiotic
world and support or refute his theory.
"If future experiments with membrane-bound RNA viruses and prions result in the creation of a synthetic
protocell, it may reflect the plausible pathways for the emergence of life on early Earth," he said.

Explore further: New findings challenge assumptions about origins of life
More information: community.geosociety.org/2013AnnualMeeting/Home

Astronomy and Space News - Astro Watch: Carbon Worlds May be Waterless, Finds NASA Study

Planets rich in carbon, including so-called diamond planets, may lack oceans, according to NASA-funded theoretical research. Our sun is a carbon-poor star, and as result, our planet Earth is made up largely of silicates, not carbon. Stars with much more carbon than the sun, on the other hand, are predicted to make planets chock full of carbon, and perhaps even layers of diamond. By modeling the ingredients in these carbon-based planetary systems, the scientists determined they lack icy water reservoirs thought to supply planets with oceans.

"The building blocks that went into making our oceans are the icy asteroids and comets," said Torrence Johnson of NASA's Jet Propulsion Laboratory in Pasadena, Calif, who presented the results Oct. 7 at the American Astronomical Society Division of Planetary Sciences meeting in Denver. Johnson, a team member of several NASA planetary missions, including Galileo, Voyager and Cassini, has spent decades studying the planets in our own solar system.

"If we keep track of these building blocks, we find that planets around carbon-rich stars come up dry," he said.

Johnson and his colleagues say the extra carbon in developing star systems would snag the oxygen, preventing it from forming water.

"It's ironic that if carbon, the main element of life, becomes too abundant, it will steal away the oxygen that would have made water, the solvent essential to life as we know it," said Jonathan Lunine of Cornell University, Ithaca, N.Y., a collaborator on the research.

One of the big questions in the study of planets beyond our solar system, called exoplanets, is whether or not they are habitable. Researchers identify such planets by first looking for those that are situated within the "habitable zone" around their parent stars, which is where temperatures are warm enough for water to pool on the surface. NASA's Kepler mission has found several planets within this zone, and researchers continue to scrutinize the Kepler data for candidates as small as Earth.

But even if a planet is found in this so-called "Goldilocks" zone, where oceans could, in theory, abound, is there actually enough water available to wet the surface? Johnson and his team addressed this question with planetary models based on measurements of our sun's carbon-to-oxygen ratio. Our sun, like other stars, inherited a soup of elements from the Big Bang and from previous generations of stars, including hydrogen, helium, nitrogen, silicon, carbon and oxygen.

"Our universe has its own top 10 list of elements," said Johnson, referring to the 10 most abundant elements in our universe.

These models accurately predict how much water was locked up in the form of ice early in the history of our solar system, billions of years ago, before making its way to Earth. Comets and/or the parent bodies of asteroids are thought to have been the main water suppliers, though researchers still debate their roles. Either way, the objects are said to have begun their journey from far beyond Earth, past a boundary called the "snow line," before impacting Earth and depositing water deep in the planet and on its surface.

When the researchers applied the planetary models to the carbon-rich stars, the water disappeared. "There's no snow beyond the snow line," said Johnson.

"All rocky planets aren't created equal," said Lunine. "So-called diamond planets the size of Earth, if they exist, will look totally alien to us: lifeless, ocean-less desert worlds."

The computer model results supporting these conclusions were published in the Astrophysical Journal last year (http://arxiv.org/abs/1208.3289). The implications for habitability in these systems were the focus of the Division of Planetary Sciences meeting.

Boomerang Nebula Even Colder than the Afterglow of the Big Bang

The far-off Boomerang Nebula in the constellation of Centaurus has earned the title of theUniverse’s Coldest Place. Yes, this planetary nebula is colder than the dark side of the moon, Buffalo, New York in January, and even your cheating girlfriend or boyfriend’s heart, registering in at a staggering one degree Kelvin. In Fahrenheit, that’s a minus 458 degrees. That’s believed to be even colder than the Big Bang’s afterglow.

Located in the constellation Centaurus, some 5,000 light-years distant, the Boomerang Nebula resembles, in some of photos of it, a glowing Halloween ghost. Astronomers have known about it for some time, though they have recently learned much more about the Boomerang Nebula through photos they’ve seen using ALMA, the Atacma Large Millimeter/submillimeter Array telescope.  

The Boomerang Nebula’s twin lobes may be an illusion

The twin lobes we see in NASA’s Hubble telescope photo of the somewhat bow tie-shaped Boomerang Nebula may be an illusion, a trick of the light, a bit of cosmic legerdemain. It’s what we see “at visible wavelengths,” according to NatMonitor.com.

The ultra-cold planetary nebula’s twin lobed shape is why some imaginative scientist decided that it resembled a boomerang more than a bow tie, and it’s how the space object ended up with a cooler-sounding name.

However, the shape we see in photos of it is not its actual shape.According to a researcher at NASA’s Jet Propulsion Laboratory, and lead author of a study about the Boomerang Nebula, Raghvendra Sahai, its real shape is “a much broader structure that is expanding rapidly into space.”

What is a “planetary nebula”?

Stars like our sun eventually become planetary nebulae at the end of their lives as stars. They shed their outer layers until only a white dwarf star remains. The white dwarf star gives off ultraviolet radiation. This, in turn, creates a colorful display by making the gas in the nebula radiate light and glow.

Currently, the Boomerang Nebula is a pre-planetary one, which means it’s not yet to the stage where it’s white dwarf star is hot enough to make the gases it emits glow even more. It will get even more colorful with time. It was detected due to the reflection of starlight off of its dust grains.

How were astronomers able to measure the coldness of the Boomerang Nebula?

The rate at which the white dwarf star at the center of the Boomerang Nebula is discharging gas is growing rapidly. As this is occurring, the space object is also cooling down.

The astronomers figured out how cold the Boomerang Nebula was by studying the speed at which it absorbed background microwave radiation, which is, itself, extremely cold. In Fahrenheit, it registers in at minus 455 degrees.

In 2003, using Hubble, astronomers saw a version of what the Boomerang Nebula looks like, according to Sahai, that was what appeared to be what they’d seen many times before, when they’d examined planetary nebulae. It resembled “a very classic ‘hourglass’ shape,” he said.

In the photographs taken by NASA’s Hubble telescope, the Boomerang Nebula’s narrow waist was not clearly apparent. Then, the Boomerang Nebula seemed to be giving off an outflow of material which was nearly spherical in shape.

With the ALMA telescope, the astronomers were able to determine more about the Boomerang Nebula. They detected the double-lobe structure of the Hubble photograph, but it was only in the Boomerang Nebula’s inner regions. As they analyzed the carbon monoxide particles that the Boomerang emitted, the astronomers noticed that further out, there was an almost round cloud of the cold gas.

Also, a thick lane of millimeter-sized dust particles encircled the dwarf white star at the center of the Boomerang Nebula. The particles of dust mask a portion of the dwarf white star and the light reflected off of the particles, which flow off in opposite directions, makes the space object appear to look like an hourglass.

According to Sahai, using ALMA helped his research team “to shed new light on the death throes of a Sun-like star.” ALMA also enabled them to discover that it was the coldest known place yet discovered, and is possibly even colder than the afterglow of the Big Bang. The findings of the study have been published in Astrophysical Journal.

Written by: Douglas Cobb

From Mars With Love...

First, Mars seemed to be greeting Mars Global Surveyor (MGS) with a Happy Face. Now, it seems as if the planet is sending its love with the this picture from MGS's Mars Orbiter Camera (MOC).

This valentine from Mars is actually a pit formed by collapse within a straight-walled trough known in geological terms as a graben. Graben are formed along fault lines by expansion of the bedrock terrain. The heart-shaped pit is about 2.3 kilometers (1.4 miles) at its widest. The image was targeted by the MOC team in order to examine the relationship between a lava flow and the graben and pits that disrupted and cut across the flow. The graben, pit, and lava flow are located on the east flank of the Alba Patera volcano in northern Tharsis. The MOC images are illuminated from the left.

"We Will Send Robots to Read the Genomes of Alien Life Forms and Replicate Them Back on Earth"- Craig Venter

In 2010, Craig Venter, who helped map the human genome, became the first to successfully create “synthetic life,” using chemicals and inserting DNA into the cell of a bacteria —putting humankind at the threshold of the most important and exciting phase of biological research, one that will enable us to actually write the genetic code for designing new species to help us adapt and evolve for long-term survival.

Venter, the scientist famed for his role in sequencing the human genome, has answered a question that lies at the heart of biology: “What is life?” Life, he asserts, is wholly reducible to the “DNA machines” and “protein robots” that operate within cells, and he hopes to prove it by constructing organisms entirely from scratch, detailing an ambitious vision for a future in which custom-made organisms heal the planet, unlock life's origins and extend humanity's reach beyond Earth in his new book, Life at the Speed of Light: From the Double Helix to the Dawn of Digital Life.

Venter believes scientists will soon be designing basic organisms to include features useful in farming or medicine, as well as sending robots into space to read the sequence of alien life forms and replicate them back on Earth: “In years to come it will be increasingly possible to create a wide variety of [synthetic] cells from computer-designed software. The creation of cells from scratch will open up extraordinary possibilities.”

Venter predicts in the future machines will be able to analyse the make up of genomes and transmit this through the internet or even space, creating more possibilities in the search for alien life: “The day is not far off when we will be able to send a robotically controlled genome sequencing unit to other planets to read the DNA sequence of any alien microbe life that may be there. If we can . . . beam them back to Earth we should be able to reconstruct their genomes. The synthetic version of a Martian genome could then be used to recreate Martian life on Earth.”

Spitzer Gets A New Mission – Hunting For Exoplanets

Image Caption: Over its ten years in space, NASA's Spitzer Space Telescope has evolved into a premier tool for studying exoplanets. The engineers and scientists behind Spitzer did not have this goal in mind when they designed the observatory back in the 1990s. But thanks to its extraordinary stability, and a series of engineering reworks after launch, Spitzer now has observational powers far beyond its original limits and expectations. Credit: NASA/JPL-Caltech

Brett Smith for redOrbit.com – Your Universe Online

After 10 years of orbiting the sun, the Spitzer Space Telescope is now playing a completely different role than it was a decade ago – hunting for exoplanets outside the solar system.

“When Spitzer launched back in 2003, the idea that we would use it to study exoplanets was so crazy that no one considered it,” said Sean Carey of NASA’s Spitzer Science Center  in a statement. “But now the exoplanet science work has become a cornerstone of what we do with the telescope.”

NASA scientists use Spitzer’s capacity for seeing the universe in the infrared spectrum to scan the cosmos for exoplanets, or planets that orbit a star other than our Sun. When an exoplanet passes in front of its star in a process known as transiting, it obstructs a fraction of starlight reaching the telescope. These tiny eclipses can be used to reveal the size of an alien planet.

Thanks to some innovative thinking during the design stage, Spitzer has been able to continue operating far beyond its initial mission. The telescope was outfitted with enough coolant to maintain its three temperature-sensitive instruments for at least two-and-a-half years, however, the coolant actually ended up lasting over five years.

In addition to extending the life of its coolant, Spitzer also has a passive cooling system built in that kept one set of infrared cameras operational at a super-low operational temperature of minus 407 degrees Fahrenheit – just 29 degrees above absolute zero.

To transition the telescope into an exoplanet spotter demanded some in-flight adjustments, however. Despite the telescope’s stability as it orbits the sun, a small “wobbling” was occurring as it pointed at target stars. The cameras also showed small brightness changes when a star drifted slightly across one of the camera’s individual pixels. These two issues combined to make the sensitive task of recording accurate exoplanet transits that much more difficult.

To solve these problems, NASA engineers first had to find the source of the wobble – and they did: a heater that kicks on to keep Spitzer’s battery at a certain temperature. In October 2010, the engineers decided that the heater did not need to be cycled through its full hour and temperature range, cutting the telescope’s wobble in half.

In September 2011, the NASA engineers then solved their pixel problem by repurposing Spitzer’s Pointing Control Reference Sensor “Peak-Up” camera. This camera was used to collect infrared light precisely into a spectrometer and to calibrate the telescope’s star-trackers, which help direct the observatory. Knowing it would allow for the placement of observed stars precisely on the center of a camera pixel, the NASA engineers applied the Peak-Up to the infrared camera observations.

The scientists took their use of the Peak-Up camera a step further by carefully “mapping” the idiosyncrasies of a single pixel within the camera. They were eventually able to finely target 90 percent Spitzer’s exoplanet observations down to a particular quarter of a pixel.

“We can use the Peak-Up camera to position ourselves very precisely on the camera and put light right on the best part of a pixel,” said Carey. “So you put the light on the sweet spot and just let Spitzer stare.” These three in-flight tweaks have more than doubled the telescope’s steadiness and targeting, giving Spitzer superb sensitivity when it comes to capturing exoplanet measurements.

“Because of these engineering modifications, Spitzer has been transformed into an exoplanet-studying telescope,” said Carey. “We expect plenty of great exoplanetary science to come from Spitzer in the future.”

Source: Brett Smith for redOrbit.com - Your Universe Online

Aliens may have lived on Earth-like planet - before an asteroid apocalypse

Shredded remains of a watery asteroid suggest that hundreds of millions of years ago planetary system may have harboured Earth-like planets

Apocalypse wow: Artist's impression of the shattered remains of an asteroid

Evidence of an apocalypse in a planetary system similar to our own has been uncovered by astronomers studying a dying star.
The shredded remains of a watery asteroid suggest that hundreds of millions of years ago the system may have harboured Earth-like habitable planets.
But any intelligent beings living there must have departed - assuming they had mastered space travel - or been killed off as their sun blew up and then collapsed into a "white dwarf".
Scientists believe six billion years from now, alien astronomers studying the burned out remains of our Sun may come to the same conclusion.
Like the white dwarf GD 61, the Sun is destined to end its life by first expanding into a Red Giant then shedding its outer layers and contracting into a super-dense glowing ember just a few thousand miles in diameter.
The dying Sun will radiate what is left of its heat over billions of years before finishing its life as a dead, cold, "black dwarf".
Astronomers studying the light emitted by GD 61, located 150 light years away from the Earth, detected an abundance of "rocky" elements such as magnesium, silicon and iron.
They also found oxygen in quantities that indicated a very large amount of water.
Only a water-rich massive asteroid, or minor planet, can explain the observations, say the scientists.
The giant rock, at least 90 kilometres in diameter, would have been drawn in by the white dwarf's powerful gravity and ripped apart.
If such an asteroid existed in the system, it is highly likely that rocky, water-covered, Earth-like planets did too.
Since only 0.02% of the Earth's mass consists of water, the oceans that cover its surface were probably delivered by impacts from watery asteroids and comets.

 
Dr Jay Farihi, from the Institute of Astronomy at Cambridge University, said: "The finding of water in a large asteroid means the building blocks of habitable planets existed - and maybe still exist - in the GD 61 system, and likely also around substantial number of similar parent stars.
"These water-rich building blocks, and the terrestrial planets they build, may in fact be common - a system cannot create things as big as asteroids and avoid building planets, and GD 61 had the ingredients to deliver lots of water to their surfaces.
"Our results demonstrate that there was definitely potential for habitable planets in this exoplanetary system."
The research appears in the latest issue of the journal Science.
Asteroids are essentially the building blocks of rocky planets. Water would have accounted for more than a quarter of the mass of the one believed to have orbited GD 61.
In our own Solar System, the giant asteroid Ceres contains a similar proportion of water in the form of subsurface ice.
The tell-tale excess oxygen in the dust and debris surrounding GD 61 was detected using powerful spectrograph techniques that look for chemical signatures in light.
Astronomers made the observations using the Hubble Space Telescope and the large Keck telescope on Hawaii.
"This oxygen excess can be carried by either water or carbon, and in this star there is virtually no carbon - indicating there must have been substantial water," said co-author Professor Boris Gansicke, from the University of Warwick.
"This also rules out comets, which are rich in both water and carbon compounds, so we knew we were looking at a rocky asteroid with substantial water content."
In its heyday, before becoming a white dwarf around 200 million years ago, the star had about three times the mass of the Sun.
The astronomers believe giant planets, such as Jupiter and Saturn, may still survive in the outer reaches of the system.
Their gravity probably upset the asteroid's orbit and nudged it close enough to the white dwarf to be shredded.
"This supports the idea that the star originally had a full complement of terrestrial planets, and probably gas giant planets orbiting it - a complex system similar to our own," said Dr Farihi.
Water buried under the asteroid's surface may have survived the expansion phase of the dying star, the scientists believe.

Love you Pluto!

                                                

Although billions of kilometers from the sun, frigid Pluto has an Earthly air: an atmosphere made mostly of nitrogen, the same gas that constitutes 78 percent of the air we breathe. But Pluto pursues such an elliptical orbit around the sun that all of that gas might freeze onto its surface when farthest and coldest. On May 4, however, Pluto passed in front of a star in the constellation Sagittarius, allowing observers to watch the atmosphere block some of the star's light and deduce that the air is so substantial it never disappears.

That passage was key to understanding the atmosphere's future, says Catherine Olkin, a planetary scientist at the Southwest Research Institute in Boulder, Colo., whose team tracked the so-called occultation. In work submitted to Icarus she and her colleagues report that Pluto's atmosphere is now thicker than ever before seen.

Astronomers discovered the atmosphere in 1988, when Pluto occulted another star. An airless Pluto would have cut off the star's light abruptly, but instead the starlight faded gradually, revealing air with roughly one one-hundred-thousandth the surface pressure of our own—equivalent to the terrestrial atmosphere 80 kilometers high.

Pluto is so distant that completing a single orbit takes it 248 years. Pluto came closest to the sun in 1989 and has been receding from the star ever since. When Pluto ventures out to its most distant point, in 2113, it will be 3 billion kilometers farther, and sunlight on its surface will be 36 percent weaker, than in 1989. "Many scientists have predicted that Pluto's atmosphere would collapse as it traveled away from the sun," Olkin says. "Receiving less sunlight, the gas would condense onto the surface."Mars, whose orbit is also rather elliptical, temporarily loses a quarter of its air every time its southern hemisphere experiences winter, when Martian gas freezes onto the south polar cap.

Pluto is mostly rock, but its crust consists of water ice. At Pluto's temperature of approximately 40 kelvins (–233 Celsius), water is as hard as rock, constituting a stage on which nitrogen and also methane dance back and forth between ice and gas.

The new observations indicate that Pluto's air is now three times denser than in 1988, contradicting models that predicted the atmosphere would someday vanish. Instead, Olkin says, the higher pressure accords with a model indicating that the region around a hundred meters below the surface retains heat during Pluto's close encounters with the sun and releases that heat only slowly, thereby keeping the surface warm enough so that some of the nitrogen always stays gaseous. "As Pluto goes around the sun, its atmosphere does not completely condense," Olkin says. Her work implies that Pluto's water-ice layer is compact, because a porous subsurface would quickly lose its warmth.

"It's a nice piece of work," says John Stansberry, a planetary scientist at the Space Telescope Science Institute. "These kinds of observations are critical for studying seasonal evolution on Pluto." Stansberry worries, however, that Pluto is more complex than the model assumes, which means the atmosphere's behavior is less clear than Olkin asserts. "Based on these results, it's certainly fair to say that Pluto's atmosphere is not going to collapse any time soon, but to say it's going to be there in 2140 is maybe stretching it a bit," Stansberry says.

Both Olkin and Stansberry do agree on a far more famous controversy: Pluto is a planet. In 2005 astronomers discovered Eris, a distant world proclaimed to be larger than Pluto, adding to arguments that Pluto should lose its planetary status and prompting predictions that a plethora of worlds surpassing Pluto in size awaited discovery.

But things didn't work out that way. In 2010 Eris passed in front of a star and failed to live up to the hype. The short duration of the occultation revealed Eris to be just 2,326 kilometers across—versus about 2,350 kilometers for Pluto. And no one has ever found anything else orbiting the sun beyond Neptune's path exceeding Pluto’s size.

Pluto's diameter, however, is uncertain: It could be as small as 2,300 kilometers or as large as 2,400 kilometers. Ironically, the villain is the atmosphere, which bends starlight during occultations and complicates measurements of its diameter.

Fortunately, help is on the way. In July 2015 NASA's New Horizons spacecraft will sail past Pluto and its five known moons. "I'm not sure what we'll see, but I can't wait to get there," Olkin says. "It's going to revolutionize our view."

Mars Crater May Actually Be Ancient Supervolcano

Oct. 2, 2013

Tucson, Ariz. -- A research project led by Joseph R. Michalski, Senior Scientist at the Planetary Science Institute, has identified what could be a supervolcano on Mars – the first discovery of its kind.

In a paper published Oct. 3 in the journal Nature, Michalski and co-author Jacob E. Bleacher of NASA Goddard Space Flight Center describe a new type of volcanic construction on Mars that until now has gone unrecognized.

 

The volcano in question, a vast circular basin on the face of the Red Planet, previously had been classified as an impact crater. Researchers now suggest the basin is actually the remains of an ancient supervolcano eruption. Their assessment is based on images and topographic data from NASA's Mars Odyssey, Mars Global Surveyor and Mars Reconnaissance Orbiter spacecraft, as well as the European Space Agency's Mars Express orbiter.

 

In the Nature paper Michalski and Bleacher lay out their case that the basin, recently named Eden Patera, is a volcanic caldera. Because a caldera is a depression, it can look like a crater formed by an impact, rather than a volcano.

 

"On Mars, young volcanoes have a very distinctive appearance that allows us to identify them," Michalski said. "The long-standing question has been what ancient volcanoes on Mars look like. Perhaps they look like this one."

 

The researchers also suggest a large body of magma loaded with dissolved gas (similar to the carbonation in soda) rose through thin crust to the surface quickly. Like a bottle of soda that has been shaken, this supervolcano would have blown its contents far and wide if the top came off suddenly.

 

"This highly explosive type of eruption is a game-changer, spewing many times more ash and other material than typical, younger Martian volcanoes," Bleacher said. "During these types of eruptions on Earth, the debris may spread so far through the atmosphere and remain so long that it alters the global temperature for years."

 

After the material is expelled from the eruption, the depression that is left can collapse even further, causing the ground around it to sink. Eruptions like these happened in ages past at what is now Yellowstone National Park in the western United States, Lake Toba in Indonesia and Lake Taupo in New Zealand.

 

Volcanoes previously had not been identified in the Arabia Terra region of Mars, where Eden Patera is located. The battered, heavily eroded terrain is known for its impact craters. But as Michalski examined this particular basin more closely, he noticed it lacked the typical raised rim of an impact crater. He also could not find a nearby blanket of ejecta, the melted rock that splashes outside the crater when an object hits.

 

The absence of such key features caused Michalski to suspect volcanic activity. He contacted Bleacher, a volcano specialist, who identified features at Eden Patera that usually indicate volcanism, such as a series of rock ledges that looked like the "bathtub rings" left after a lava lake slowly drains. In addition, the outside of the basin is ringed by the kinds of faults and valleys that occur when the ground collapses because of activity below the surface. The existence of these and other volcanic features in one place convinced the scientists Eden Patera should be reclassified.

 

The team found a few more basins that are candidate volcanoes nearby, suggesting conditions in Arabia Terra might have been favorable for supervolcanoes. It is also possible massive eruptions here could have been responsible for volcanic deposits elsewhere on Mars that have never been linked to a known volcano.

 

"If just a handful of volcanoes like these were once active, they could have had a major impact on the evolution of Mars," Bleacher said.

 

Project funding was provided by the NASA Mars Data Analysis program.

 

 

 

 

 

New research suggests the Eden Patera basin on Mars could have been formed by an explosive volcanic eruption, not the impact of a large object. 

 

Seen above, for the basin and surrounding area, higher elevations (reds and yellows) and lower elevations (blues and grays) are indicated.

Credit: NASA/JPL/GSFC

 

 

 

Above, the dark color indicates younger material draped across the Eden Patera depression.

Credit: ESA

 

Below, Michalski's paper was featured on the cover of Nature.

Credit: Nature, Mark Garlick

 

 

Credits: Planetary Science Institute