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Astronomers Gain Insight Into Black Hole With Powerful Space Explosion

August 2, 2017 by  
Filed under Around The Net

An ultrapowerful, superfast explosion in space is providing new insight into how dying stars turn into black holes.

An international team of researchers looked at a gamma-ray explosion called GRB 160625B that brightened the sky in June 2016. Gamma-ray bursts are among the most powerful explosions in the universe, but they are typically tough to track because they are very short-lived (sometimes lasting just a few milliseconds). 

“Gamma-ray bursts are catastrophic events, related to the explosion of massive stars 50 times the size of our sun,” said Eleonora Troja, lead author of the new study and an assistant research scientist in astronomy at University of Maryland. “If you ranked all the explosions in the universe based on their power, gamma-ray bursts would be right behind the Big Bang.” [Record Breaking Gamma-Ray Burst Captured By Fermi (Video)]

“In a matter of seconds, the process can emit as much energy as a star the size of our sun would in its entire lifetime,” Troja said in a statement. “We are very interested to learn how this is possible.”

Two key findings emerged from the observations, gathered using several ground- and space-based telescopes. The first step was better model what happens as the dying star collapses. The data suggests that the black hole creates a strong magnetic field that initially overwhelms jets of matter and energy formed because of the explosion. Then, the magnetic field breaks down, the study authors said.

In the next phase, the magnetic field diminishes, allowing matter to dominate the jets. Before, scientists thought that jets could be dominated only by the magnetic field or matter — not both.

Another insight concerns what kind of radiation is responsible for the bright phase at the beginning of the burst, which astronomers call the “prompt” phase. Before, several types of radiation were considered, including so-called blackbody radiation (heat emission from an object) and inverse Compton radiation (which happens when accelerated particles transfer energy to photons), according to the statement. 

It turns out that a phenomenon called synchrotron radiation is behind the prompt phase. This kind of radiation happens when electrons accelerate in a curved or spiral pathway, propelled along by an organized magnetic field.

“Synchrotron radiation is the only emission mechanism that can create the same degree of polarization and the same spectrum we observed early in the burst,” Troja said. 

The fading afterglow of GRB 160625B, a gamma-ray burst recorded in June 2016. Here, data from Arizona State University’s Reionization And Transients Infrared (RATIR) camera, on a telescope at Mexico’s National Astronomical Observatory in Baja California, shows the burst from June 26 to Aug. 20, 2016.

“Our study provides convincing evidence that the prompt gamma-ray burst emission is driven by synchrotron radiation,” she added. “This is an important achievement because, despite decades of investigation, the physical mechanism that drives gamma-ray bursts had not yet been unambiguously identified.”

Gathering information about GRB 160625B required many telescopes to work together quickly. NASA’s Fermi Gamma-ray Space Telescope first saw the explosion, and the ground-based Russia’s MASTER-IAC telescope, which is located at the Teide Observatory in Spain’s Canary Islands, quickly joined with observations in optical light.

MASTER-IAC’s observations were key to understanding the evolution of GRB 160625B’s magnetic field, the research team said. The magnetic field can influence polarized light (light waves that vibrate in a single plane) emanating from the burst. In a rare achievement, the telescope measured the proportion of polarized light to total light through almost the entire explosion.

“There is very little data on polarized emission from gamma-ray bursts. This burst was unique because we caught the polarization state at an early stage,” said study co-author Alexander Kutyrev, an associate astronomy research scientist at the University of Maryland and an associate scientist at NASA’s Goddard Space Flight Center.

“This is hard to do because it requires a very fast reaction time, and there are relatively few telescopes with this capability,” Kutyrev added. “This paper shows how much can be done, but to get results like this consistently, we will need new rapid-response facilities for observing gamma-ray bursts.”

Other participating telescopes included NASA’s Swift Gamma-ray Burst Mission (X-ray and ultraviolet), the multi-institution Reionization and Transient Infrared/Optical Project camera (at Mexico’s National Astronomical Observatory in Baja California), the National Radio Astronomy Observatory’s Very Large Array in New Mexico, and the Commonwealth Scientific Industrial Research Organisation’s Australia Telescope Compact Array.

The new research was detailed today (July 26) in the journal Nature.

Courtesy-Space

Does An Asteroid Start Off As A Giant Mud Rock

July 21, 2017 by  
Filed under Around The Net

The most common asteroids in the solar system may have started out as giant balls of mud, rather than as rocks, as scientists previously thought, a new study finds.

Such mud balls could still exist today in the heart of the largest asteroids, according to the study.

More than 75 percent of known asteroids are carbonaceous in composition; these grayish asteroids probably consist of clay and stony rocks, and inhabit the main belt’s outer regions

One key reason scientists investigate carbonaceous asteroids is that they were probably the building blocks of the rocky planets of the solar system, said study lead author Philip Bland, a planetary scientist at the Curtin University of Technology in Australia. Analyzing these giant rocks could shed light on the origins of Earth, Mars and the other terrestrial planets.

However, the way carbonaceous asteroids formed in the early days of the solar system is still mysterious. “There have probably been about a dozen different models to explain the origins of these primitive objects over the years, and they’ve all been limited in one way or another,” Bland told Space.com.

Researchers have observed carbonaceous asteroids and analyzed meteorites thought to come from them to glean details about their composition. However, scientists had trouble devising a model that could explain all of these features of the asteroids, Bland said.

“For instance, one model might find there is a lot of water getting circulated around inside the asteroids, so they could lose heat — which would explain why meteorites from these asteroids appear to have experienced alterations at relatively low temperatures,” Bland said. “However, if you have a lot of water circulating inside asteroids, it would strip elements from the rock, and you would get a very different chemical composition than what we see in the meteorites.”

“If there wasn’t water inside the asteroids, you wouldn’t mess up the chemistry we see, but the asteroids would not lose heat as easily,” Bland added. “One way around that is to have the asteroids be smaller so they would cool down more easily, but we don’t see that today.”

All of these previous models assumed the asteroids had lithified — that is, had become rock. “Most people look at meteorites, and they’re rocks. So the natural thing to assume would be that the asteroids they came from were rocks, too,” Bland said. “We were interested in seeing what happened if we deleted that assumption.”

Prior work suggested that carbonaceous asteroids formed from round, porous mineral pellets known as chondrules, as well as fine-grained dust, and ice. When pockets of these materials got pulled together by their own gravity, they would not have become rock, the researchers suggested. Instead, when radioactive materials inside the dust and chondrules melted the ice, the result would have been a sludgy mud, they said.

“When you stop to think about it, there’s no reason that asteroids would be rocks right at the beginning,” Bland said.

The scientists devised computer models that simulated how pockets of dust, chondrules and ice might act with different concentrations of these various ingredients and the density at which these materials were packed together. They found that not only could asteroids emerge from these building blocks without lithification, but the way in which mud churned in these mud balls could help explain the chemical and thermal details seen from carbonaceous asteroids.

“I feel like this helps plug a gap in knowledge when it comes to the question of what happened inside what are amongst the most important objects in the history of our solar system,” Bland said.

After the mud balls formed, they could have lithified in various ways. For instance, if these mud balls hit each other, the force of the impacts would have generated heat that could have welded the components of these mud balls together into rock, Bland said.

As for whether the mud balls might still exist in the solar system, when the researchers modeled Ceres, the largest asteroid, they “found there was a reasonable chance of temperatures above freezing in its interior, so there could still be quite a bit of a mud ball inside Ceres,” Bland said.

Future research could explore how the other kinds of asteroids in the solar system were born, and how asteroids in other star systems might arise and, in turn, influence the formation of alien planets, Bland said.

Bland and his colleague Bryan Travis at the Planetary Science Institute in Tucson, Arizona, detailed their findings online July 14 in the journal Science Advances.

Courtesy-Space

Did Comets Bring The Building Blocks Of Life To Earth

June 20, 2017 by  
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Life on Earth may not have been possible without comet strikes.

A new study suggests that about 20 percent of the noble gas xenon in Earth’s atmosphere was delivered by comets long ago. And these icy wanderers likely brought lots of other stuff to our planet as well, researchers said. 

The “cometary contribution could have been significant for organic matter, especially prebiotic material, and could have contributed to shape the cradle of life on Earth,” said study lead author Bernard Marty, a geochemist at the University of Lorraine and the Centre de Recherches Pétrographiques et Géochimiques in France.  

Marty and his colleagues studied measurements made by the European Space Agency’s (ESA) Rosetta spacecraft, which orbited the 2.5-mile-wide (4 kilometers) Comet 67P/Churyumov-Gerasimenko from August 2014 through September of last year.

Specifically, they analyzed xenon-isotope data that Rosetta gathered during a series of low-altitude orbits of Comet 67P between May 14 and May 31, 2016. (Isotopes are versions of an element that contain different numbers of neutrons in their nuclei. “Heavy” isotopes have more neutrons compared to “lighter” ones.)

Rosetta’s observations revealed that 67P is deficient in heavy xenon. Furthermore, the team determined that the comet’s xenon isotope composition matches a signature of Earth xenon whose origin had been a mystery.

Scientists think asteroids delivered the vast majority of the water in Earth’s oceans, and these space rocks have been regarded as the chief suppliers of the planet’s other “volatiles” — substances with low boiling points, such as nitrogen, carbon dioxide and noble gases — as well. (Models suggest that Earth was extremely hot shortly after its formation about 4.5 billion years ago, so it probably lost its primordial volatiles early on.) 

This inference is drawn partly from the isotopic similarity of hydrogen, nitrogen and other materials on Earth to that of certain asteroids known as carbonaceous chondrites, as measured in meteorite samples, Marty said.

“There was also a dynamical argument: Jupiter and the other giant planets formed early, and the outer solar system (from which comets originate) was isolated early from the inner solar system by the giant planets’ gravitational fields,” he said. “Now our finding calls for a revision of such models.”

Comets are especially enriched in noble gases, explaining how their contribution of xenon (and perhaps other materials) to the early Earth can be outsized compared to the proportion of water these icy wanderers delivered, Marty added.

The newly analyzed Rosetta data also indicate that 67P’s xenon predates the solar system — that is, the comet contains samples of interstellar matter. That’s an exciting result that argues for further, more detailed study of pristine cometary material, Marty said. 

“Returning a cometary sample on Earth should be the highest priority, because it will permit analyses with unprecedented precision of such exotic material and could respond to questions such as: How long interstellar material can survive, which stars contributed to shape the cradle of the solar system, what is the origin(s) of the large isotopic variations of some of the elements (e.g., N, H, O), what was the role of irradiation of early solar system material, etc.,” he said. (N, H and O are nitrogen, hydrogen and oxygen, respectively.)

Rosetta launched in March 2004. A decade later, it became the first mission ever to orbit a comet and the first to touch down softly on one of these bodies. (The Rosetta orbiter dropped a lander called Philae onto 67P in November 2014.)

The mission ended when Rosetta intentionally crash-landed on 67P’s surface on Sept. 30, 2016.

Courtesy-Space

Can Companies Mine The Moon AT A Profit

May 25, 2017 by  
Filed under Around The Net

The first-ever private mining operation on the moon is scheduled to kick off in 2020, when a landing craft sent by Florida-based Moon Express will ferry a single scoop of lunar dirt and rocks back to Earth.

Unlike the three governments that have led lunar missions — the United States, the Soviet Union, and China — the owners of this private firm have something history-making in mind for that little ball of extraterrestrial soil: They plan to sell it.

“It will instantly become the most valuable and scarcest material on Earth,” says Bob Richards, the CEO of Moon Express. “We’ll make some of it available to scientific research. But we also plan to commoditize it ourselves.”

Moon Express is gearing up to become the first company to ever transport a commercial asset from space back to Earth. But it’s not alone.

Several ambitious startups are busily developing plans to launch mining operations on both the moon and asteroids, with initial proof-of-concept missions set to kick off over the next few years and more robust operations within a decade. China is a key player, too, along with a tiny, unlikely European upstart: the Grand Duchy of Luxembourg.

Those seeking to conquer celestial commodity markets are beckoned by the glittering wealth that could await them in space.

“We believe that the first trillionaires will be made from space resources,” says Richards.

Exactly which minerals will drive those fortunes remains to be seen.

The moon holds significant amounts of a special type of a futuristic fuel source called helium-3 — enough, some say, to meet all of Earth’s power demand for thousands of years providing scientists can master the fusion power technology to utilize it.

A fortune could be made by anyone able to capture and exploit one of the mountain-sized asteroids made of platinum or other precious metals thought to be orbiting the sun, or deposits of rare earth elements on the moon.

Others point to the potential for zero-gravity construction of super-massive colonizing spacecraft and mammoth floating structures using raw materials sourced from asteroids.

Most, however, are focused on a resource that’s commonplace on Earth: water.

Water, space entrepreneurs say, will be the key space commodity for an economy expanding into the solar system — both because it can sustain life as drinking water and breathable air, and because it can be broken down into hydrogen and oxygen to make rocket fuel.

Sourcing water from space could, for example, turn the moon into a depot for more ambitious missions.

“Water is like the oil of the solar system,” said Richards. “The moon could become a gas station in the sky.”

In the near term, Moon Express is focused on providing relatively low-cost transport to the surface of the moon for commercial, private, academic, and government customers.

One client that’s already signed up is the moon-burial company Celestis, which offers to send cremated human remains to the surface of the moon for a starting price of $12,500.

In 2016 Moon Express became the first private company in history to receive permission from the US Federal Aviation Administration to travel beyond Earth’s orbit and land a craft on the moon.

The company is planning three lunar missions by the time it brings back the small scoop of lunar soil, between the size of a baseball and basketball, in 2020.

Selling part of that scoop to private interests — for example, as moon gems for jewelry for the ultra-rich — will set an important precedent. The international Outer Space Treaty of 1967 says no country can claim sovereignty over extraterrestrial territory. But in 2015 President Barack Obama signed a law granting private citizens the rights to resources recovered from space.

The company’s first mission, slated for this year, will be in part an attempt to win the Google Lunar XPrize. The competition offers $20 million to the first private company able to land a rover on the moon’s surface, travel 500 meters, and then broadcast hi-definition images back to Earth.

Another company fielding a team for the XPrize, which also plans to eventually tap moon water, is Japan’s ispace Inc.

In December, ispace signed a memorandum of understanding with Japan’s national space agency, JAXA, for the “mining, transport, and use of resources on the moon,” according to a company statement.

During an initial phase of operations, from 2018 through 2023, ispace will go prospecting on the moonscape, sending exploratory robots into lunar craters and caves to check for water. Production is planned to begin in 2024.

China is also eyeing moon resources — especially helium-3.

As an energy source, helium-3 is as alluring as it is elusive: a non-radioactive agent that wouldn’t produce dangerous waste. The isotope is released by the sun and carried through the cosmos on solar winds that are blocked by Earth’s atmosphere, but collect on the surface of the moon.

As a result, the moon is “so rich” in helium-3, it could “solve human beings’ energy demand for around 10,000 years at least,” a top Chinese scientific advisor to the country’s moon exploration program, Professor Ouyang Ziyuan, told the BBC.

 

One of the top proponents of lunar helium-3 is Harrison Schmitt, a geologist who walked on the moon during NASA’s Apollo 17 mission and wrote a 2006 book advocating lunar helium-3 mining called Return to the Moon.

Others, however, are deeply skeptical — even if the necessary fusion technology, which has long eluded researchers, is mastered.

“I do not see this as being an economic solution to Earth’s energy needs,” Ian Crawford of the Department of Earth and Planetary Sciences at Birkbeck College, University of London, said in an email. “The problem is that the abundance is very low, of the order 10 parts per billion by mass in even the most abundant regions.”

Another potentially attractive lunar resource is the platinum group of metals, including iridium, palladium and platinum, which have special qualities that make them highly useful in electronic devices. Such elements, rare on earth, are thought to be bountiful on the moon.

Richards of Moon Express said it’s too soon to specify the most valuable resource on the moon.

“It would be speculative and predictive to say which specific element is going to be the game-changer,” he said. “Pick your favorite spice.”

For now, he says, the key target is water — which, to be sure, can be found on frozen asteroids circling the sun as well.

Two US companies, Planetary Resources and Deep Space Industries, are leading the charge into asteroid mining, largely with the aim of providing resources that other types of space missions will need.

Rick Tumlinson, chairman of Deep Space Industries, said his company plans to land its first prospector on an asteroid by 2020.

The company will use tiny scouts to explore and study prospective targets. When a prime asteroid has been located, a larger robot will land on it, bite out a chunk, and then use solar power to evaporate and capture water from the sample.

“Water, we believe, is relatively easy to harvest from asteroid materials,” said Tumlinson.

If all goes according to plan, “by the middle-20s, we’d be producing serious quantities of resources,” he said.

Planetary Resources is also focused on water.

“You can concentrate that solar energy and heat up the surface of the asteroid and literally bake off the water in the same way you’d bake a clay pot,” says CEO Chris Lewicki.

 

Both Lewicki and Tumlinson also point to the potential for supplying building materials in space, which could allow for the construction of super-massive floating structures that would be ungainly to launch from Earth.

In space, “you can build these huge structures we see in movies and science fiction,” said Lewicki. “The resource that will allow us to do that is the metal that’s on asteroids. We can use technology like 3D printing. We can print up a structure in space that never has to hold itself up on Earth, never has to take a violent rocket ride.”

As billionaires Elon Musk and Jeff Bezos explore ideas for colonizing space and Mars, someone, advocates of space mining say, will need to provide the raw materials, water and fuel the colonizers will need.

And while space mining might sound like science fiction, serious backers with deep pockets are taking notice.

A total of $1.8 billion was invested in space ventures in 2015 — more than in the prior 15 years combined, according to the Tauri Group consultancy. More than 50 venture capital firms invested in space deals in 2015, the most of any year, the group found.

The tiny European nation of Luxembourg has invested 25 million euros in Planetary Resources, and collaborated on the development of Prospector-X, the first spacecraft from Deep Space Industries.

The moon, said Richards, is like Earth’s 8th continent, and it’s largely unexplored.

“We’re like early pioneers,” he said, “looking at a whole new world.”

 

Courtesy-Fud

 

 

Astronomers Find The Building Blocks Of Life On Ceres

February 23, 2017 by  
Filed under Around The Net

The dwarf planet Ceres keeps looking better and better as a possible home for alien life.

NASA’s Dawn spacecraft has spotted organic molecules — the carbon-containing building blocks of life as we know it — on Ceres for the first time, a study published today (Feb. 16) in the journal Science reports.

And these organics appear to be native, likely forming on Ceres rather than arriving via asteroid or comet strikes, study team members said.

“Because Ceres is a dwarf planet that may still preserve internal heat from its formation period and may even contain a subsurface ocean, this opens the possibility that primitive life could have developed on Ceres itself,” Michael Küppers, a planetary scientist based at the European Space Astronomy Centre just outside Madrid, said in an accompanying “News and Views” article in the same issue of Science.

“It joins Mars and several satellites of the giant planets in the list of locations in the solar system that may harbor life,” added Küppers, who was not involved in the organics discovery.

The $467 million Dawn mission launched in September 2007 to study Vesta and Ceres, the two largest objects in the main asteroid belt between Mars and Jupiter. 

Dawn circled the 330-mile-wide (530 kilometers) Vesta from July 2011 through September 2012, when it departed for Ceres, which is 590 miles (950 km) across. Dawn arrived at the dwarf planet in March 2015, becoming the first spacecraft ever to orbit two different bodies beyond the Earth-moon system.

During its time at Ceres, Dawn has found bizarre bright spots on crater floors, discovered a likely ice volcano 2.5 miles (4 km) tall and helped scientists determine that water ice is common just beneath the surface, especially near the dwarf planet’s poles.

The newly announced organics discovery adds to this list of achievements. The carbon-containing molecules — which Dawn spotted using its visible and infrared mapping spectrometer instrument — are concentrated in a 385-square-mile (1,000 square km) area near Ceres’ 33-mile-wide (53 km) Ernutet crater, though there’s also a much smaller patch about 250 miles (400 km) away, in a crater called Inamahari. 

And there could be more such areas; the team surveyed only Ceres’ middle latitudes, between 60 degrees north and 60 degrees south. 

“We cannot exclude that there are other locations rich in organics not sampled by the survey, or below the detection limit,” study lead author Maria Cristina De Sanctis, of the Institute for Space Astrophysics and Space Planetology in Rome, told Space.com via email.

Dawn’s measurements aren’t precise enough to nail down exactly what the newfound organics are, but their signatures are consistent with tar-like substances such as kerite and asphaltite, study team members said.

“The organic-rich areas include carbonate and ammoniated species, which are clearly Ceres’ endogenous material, making it unlikely that the organics arrived via an external impactor,” co-author Simone Marchi, a senior research scientist at the Southwest Research Institute in Boulder, Colorado, said in a statement. 

In addition, the intense heat generated by an asteroid or comet strike likely would have destroyed the organics, further suggesting that the molecules are native to Ceres, study team members said.

The organics might have formed via reactions involving hot water, De Sanctis and her colleagues said. Indeed, “Ceres shows clear signatures of pervasive hydrothermal activity and aqueous alteration,” they wrote in the new study.

Such activity likely would have taken place underground. Dawn mission scientists aren’t sure yet how organics generated in the interior could make it up to the surface and leave the signatures observed by the spacecraft.

“The geological and morphological settings of Ernutet are still under investigation with the high-resolution data acquired in the last months, and we do not have a definitive answer for why Ernutet is so special,” De Sanctis said.

It’s already clear, however, that Ceres is a complex and intriguing world — one that astrobiologists are getting more and more excited about.

“In some ways, it is very similar to Europa and Enceladus,” De Sanctis said, referring to ocean-harboring moons of Jupiter and Saturn, respectively. 

“We see compounds on the surface of Ceres like the ones detected in the plume of Enceladus,” she added. “Ceres’ surface can be considered warmer with respect to the Saturnian and Jovian satellites, due to [its] distance from the sun. However, we do not have evidence of a subsurface ocean now on Ceres, but there are hints of subsurface recent fluids.” 

Courtesy-Fud

Will The U.S. And Russia Team Up For A Venus Mission?

January 19, 2017 by  
Filed under Around The Net

Russia’s space program and NASA are working together on a mission to Venus that would investigate some of the scorching-hot planet’s biggest mysteries, including, perhaps, whether it harbors life.

An international team of scientists tasked with fleshing out the main goals of the mission, which is known as Venera-D, is wrapping up its work and will deliver its final report to NASA and the Russian Academy of Sciences’ Space Research Institute by the end of the month, said David Senske, of NASA’s Jet Propulsion Laboratory in Pasadena, California.

“Is this the mission that’s going to fly? No, but we’re getting there,” Senske, the U.S. co-chair of this “joint science-definition team,” told Space.com last month at the annual fall meeting of the American Geophysical Union, in San Francisco.

Venera-D is led by Russia, which has been developing the project for more than a decade. The mission would mark a return to once-familiar territory for the nation; Russia’s forerunner state, the Soviet Union, launched a number of probes to Venus from the early 1960s through the mid-1980s, as part of its Venera and Vega programs. (“Venera” is the Russian name for Venus.)

“Russia has always been interested in going back to Venus,” Senske said.

NASA got involved about three years ago, when Russia asked if the U.S. space agency would be interested in collaborating on the mission, Senske added.

The joint science-definition team arose out of those initial discussions. The team stood down shortly thereafter; Russia’s March 2014 annexation of Crimea prompted NASA to suspend most cooperation with Roscosmos, Russia’s federal space agency (with activities involving the International Space Station being the most prominent exception).

But the collaboration was up and running again by August 2015, Senske said, and the team met in Moscow that October. More meetings are planned, including a workshop this May that will inform decisions about the mission’s scientific instruments, he added.

Venera-D is a large-scale mission, comparable in scope to NASA “flagship” efforts such as the $2.5 billion Curiosity Mars rover, Senske said. The baseline concept calls for an orbiter that will study Venus from above for at least three years, plus a lander that will operate for a few hours on the planet’s surface.

Mission planners said they had originally hoped the lander could survive for 30 days; the “D” in Venera-D stands for “dolgozhivushaya,” which means “long lasting” in Russian. But this goal was ultimately deemed too difficult and costly, given the blistering temperatures on Venus’ surface, according to RussianSpaceWeb.com (which outlines the mission’s tortuous history in rich detail).

Data gathered by the orbiter should help scientists better understand the composition, structure and dynamics of Venus’ atmosphere, including why the planet’s air rotates so much faster than the surface does, a mysterious phenomenon known as super-rotation, Senske said.

The lander will collect further atmospheric information while descending, then study the composition and morphology of the Venusian surface after touching down.

Venera-D could incorporate additional components as well. Some ideas on the drawing board include a handful of small, relatively simple ground stations that would gather surface data for a month or so (putting the “D” back in Venera-D) and a solar-powered, uncrewed aerial vehicle that would ply the Venusian skies.

The surface of Venus is far too hot to support life as we know it, but temperatures are much more hospitable at an altitude of 31 miles (50 kilometers) or so. Furthermore, the planet’s atmosphere sports mysterious dark streaks that some astronomers have speculated might be signs of microbial life. The UAV could hypothetically investigate this possibility, sampling the air while cruising along.

Engineers have already been thinking about how to build such an aircraft. For example, the U.S. aerospace company Northrop Grumman and partner L’Garde Inc. have been researching a concept vehicle called the Venus Atmospheric Maneuverable Platform (VAMP) for several years now.

It’s still too early to know exactly what Venera-D will look like, what it will do or when the mission will launch. A liftoff in 2025 or 2026 is possible under an “aggressive” time line, Senske said. “It depends when the Russians can get this into their federal space budget,” he said.

Some things are known, however. For instance, Russia will build the orbiter and the lander, and Venera-D will launch atop Russia’s in-development Angara A5 rocket, Senske said. If NASA remains involved in the mission — which is far from a given at this point — the U.S. space agency will likely contribute smaller items, such as individual scientific instruments.

“Russia is definitely in the driver’s seat,” Senske said. “NASA is the junior partner.”

Courtesy-Space

Did Astronomers Find Water On Psyche?

November 3, 2016 by  
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0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-pysche-mission-conceptThe largest metallic asteroid in the solar system may have water on its surface, astronomers have found. 

The asteroid, called 16 Psyche, is one of the most massive in the asteroid belt. Researchers think the 186-mile-wide (300 kilometers) body, made of almost pure nickel-iron, might be the core of a world whose outer layers were blasted off by impacts billions of years ago. 

Previous observations of Psyche showed no water on the surface. But according to Vishnu Reddy, an assistant professor at the University of Arizona’s Lunar and Planetary Laboratory, new data from the NASA Infrared Telescope Facility show evidence for water or hydroxyl, a molecule with one hydrogen atom bound to one oxygen atom, on Psyche’s surface. Hydroxyl exists on Earth, but it is very reactive and tends to combine with other compounds — and in fact can remove those compounds from the air.

“We did not expect a metallic asteroid like Psyche to be covered by water and/or hydroxyl,” Reddy said in a statement. “Metal-rich asteroids like Psyche are thought to have formed under dry conditions without the presence of water or hydroxyl, so we were puzzled by our observations at first.”

Reddy presented his results Wednesday (Oct. 20) at the 48th meeting of the American Astronomical Society’s Division for Planetary Sciences and 11th European Planetary Science Congress in Pasadena, California.

The water could have reached Psyche via past impacts from smaller asteroids that contain volatiles such as carbon, hydrogen and water, Reddy said.

NASA is currently reviewing a proposed mission to Psyche, which could tell astronomers whether the signal from the surface comes from water or hydroxyl. 

The new research, co-authored by Reddy and led by Driss Takir at the U.S. Geological Survey, has been accepted to the Astronomical Journal, and can be read online here.

Courtesy-Space

Astronomers Find A Strange Planet Similar To Saturn

October 18, 2016 by  
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0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-bizarre-planetA strange and colossal ring system around an alien planet is apparently stuck in reverse, circling opposite to the planet’s own orbit around its parent star. While the arrangement appears unstable, new calculations show the rings could remain for at least 100,000 years.

These rings could account for bizarre eclipse behavior seen in 2007 for this star, called J1407, researchers on the new study suggested. Back then, astronomers observed an eclipse of the star last for several weeks, varying rapidly in brightness over the course of minutes. In 2015, the team suggested that there could be a planet orbiting this star with rings over a hundred times larger than the rings of Saturn.

In the new simulations conducted this year, the team calculated whether the planet could hang on to its ring system even as the gravitational effect of the star pulls on the rings. Because of the planet’s highly elliptical orbit, the star’s tug could potentially destabilize the rings when the planet approached closer, the researchers said.

According to the simulations, the system can stay stable for more than 10,000 orbits lasting 11 years each, with one stipulation, said lead author Steven Rieder, a postdoctoral fellow at the RIKEN Advanced Institute for Computational Science in Japan.

“The system is only stable when the rings rotate opposite to how the planet orbits the star,” Rieder said in a statement. “It might be far-fetched, massive rings that rotate in opposite direction,” he added, “but we now have calculated that a ‘normal’ ring system cannot survive.” More usually, a planet’s rings circle in the same direction as the planet is traveling, and the planet orbits in the same direction as the star turns.

It’s also possible that the stellar eclipses were created by a free-floating object passing between Earth and the star, but this would be true only if that object’s velocity as measured in the observations was not correct, Rieder said. He added that this would be a strange explanation, as the measurements the team obtained are “very accurate.”

The researchers said they next plan to examine how the ring structure was created, and how it evolves. A paper based on the research will appear shortly in the journal Astronomy and Astrophysics.

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Is Saturn’s Moon Dione Hiding Water?

October 12, 2016 by  
Filed under Around The Net

0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-dioneThe icy Saturn moon Dione appears to have an underground ocean of liquid water, just like two of its more famous neighbors, a new study suggests.

This huge ocean is probably buried about 60 miles (100 kilometers) beneath Dione’s icy shell, according to the study. Intriguingly, Dione’s putative ocean is likely in contact with the moon’s rocky core, team members said.

“The contact between the ocean and the rocky core is crucial,” study co-author Attilio Rivoldini, of the Royal Observatory of Belgium in Brussels, said in a statement. “Rock-water interactions provide key nutrients and a source of energy, both being essential ingredients for life.”

If the researchers are correct, 700-mile-wide (1,120 kilometers) Dione would be the third Saturn moon known to harbor a subsurface ocean, after giant Titan and geyser-spouting Enceladus. Astronomers think the Jupiter moons Europa, Callisto and Ganymede also have buried oceans, and recent research indicates Pluto might as well.

The study team, led by Mikael Beuthe of the Royal Observatory of Belgium, modeled the icy shells of Dione and Enceladus using gravity data gathered by NASA’s Saturn-orbiting Cassini spacecraft during its various flybys of the satellites.

Similar simulations performed by other researchers in the past have suggested that Dione is sea-free and that Enceladus’ ocean is buried deep. But Beuthe and his colleagues added a new wrinkle into their models.

“As an additional principle, we assumed that the icy crust can stand only the minimum amount of tension or compression necessary to maintain surface landforms,” Beuthe said in the same statement. “More stress would break the crust down to pieces.”

The team’s results indicate that Enceladus’ ocean is close to the surface, especially near the moon’s south pole — which makes sense, because geysers blast water ice and other material deep into space from this region. 

The simulations also suggest Dione has a vast ocean tens of kilometers deep, buried under many miles of ice. This ocean has also probably existed for the moon’s entire history, meaning there has potentially been plenty of time for life to take root and evolve beneath Dione’s battered, icy shell, researchers said.

The new study was published online this week in the journal Geophysical Research Letters.

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Did Asteroids Help Deliver Building Blocks?

September 22, 2016 by  
Filed under Around The Net

Meteorites that crashed onto Earth billions of years ago may have provided the phosphorous essential to the biological systems of terrestrial life. 

The meteorites are believed to have contained a phosphorus-bearing mineral called schreibersite, and scientists have recently developed a synthetic version that reacts chemically with organic molecules, showing its potential as a nutrient for life. 

Phosphorus is one of life’s most vital components, but it often goes unheralded. It helps form the backbone of the long chains of nucleotides that create RNA and DNA; it is part of the phospholipids in cell membranes; and is a building block of the coenzyme used as an energy carrier in cells, adenosine triphosphate (ATP).

Yet the majority of phosphorus on Earth is found in the form of inert phosphates that are insoluble in water and are generally unable to react with organic molecules. This appears at odds with phosphorus’ ubiquity in biochemistry, so how did phosphorus end up being critical to life?

In 2004, Matthew Pasek, an astrobiologist and geochemist from the University of South Florida, developed the idea that schreibersite [(Fe, Ni)3P], which is found in a range of meteorites from chondrites to stony-iron pallasites, could be the original source of life’s phosphorus. Because the phosphorus within schreibersite is a phosphide, which is a compound containing a phosphorus ion bonded to a metal, it behaves in a more reactive fashion than the phosphate typically found on Earth. 

Finding naturally formed schreibersite to use in laboratory experiments can be time-consuming when harvesting from newly fallen meteorites and expensive when buying from private collectors. Instead, it has become easier to produce schreibersite synthetically for use in the laboratory. 

Natural schreibersite is an alloy of iron, phosphorous and nickel, but the common form of synthetic schreibersite that has typically been used in experiments is made of just iron and phosphorus, and is easily obtainable as a natural byproduct of iron manufacturing. Previous experiments have indicated it reacts with organics to form chemical bonds with oxygen, the first step toward integrating phosphorous into biological systems. 

However, since natural schreibersite also incorporates nickel, some scientific criticism has pointed out that the nickel could potentially alter the chemistry of the mineral, rendering it non-reactive despite the presence of phosphides. If this were the case, it would mean that the experiments with the iron-phosphorous synthetic schreibersite would not represent the behavior of the mineral in nature. 

“There was always this criticism that if we did include nickel it might not react as much,” said Pasek. 

Pasek and his colleagues have addressed this criticism by developing a synthetic form of schreibersite that includes nickel.

In a recent paper published in the journal Physical Chemistry Chemical Physics, Pasek and lead author and geochemist Nikita La Cruz of the University of Michigan show how a form of synthetic schreibersite that includes nickel reacts when exposed to water. As the water evaporates, it creates phosphorus-oxygen (P-O) bonds on the surface of the schreibersite, making the phosphorus available to life. The findings seem to remove any doubts as to whether meteoritic schreibersite could stimulate organic reactions.

“Biological systems have a phosphorus atom surrounded by four oxygen atoms, so the first step is to put one oxygen atom and one phosphorous atom together in a single P-O bond,” Pasek explained.

Terry Kee, a geochemist at the University of Leeds and president of the Astrobiology Society of Britain, has conducted his own extensive work with schreibersite and, along with Pasek, is one of the original champions of the idea that it could be the source of life’s phosphorus.

“The bottom line of what [La Cruz and Pasek] have done is that it appears that this form of nickel-flavored synthetic schreibersite reacts pretty much the same as the previous synthetic form of schreibersite,” Kee said. 

Pasek described how meteors would have fallen into shallow pools of water on ancient Earth. The pools would then have undergone cycles of evaporation and rehydration, a crucial process for chemical reactions to take place. As the surface of the schreibersite dries, it allows molecules to join into longer chains. Then, when the water returns, these chains become mobile, bumping into other chains. When the pool dries out again, the chains bond and build ever larger structures.

“The reactions need to lose water in some way in order to build the molecules that make up life,” said Pasek. “If you have a long enough system with enough complex organics, then, hypothetically, you could build longer and longer polymers to make bigger pieces of RNA. The idea is that at some point you might have enough RNA to begin to catalyze other reactions, starting a chain reaction that builds up to some sort of primitive biochemistry, but there’s still a lot of steps we don’t understand.”

Demonstrating that nickel-flavored schreibersite, of the sort contained in meteorites, can produce phosphorus-based chemistry is exciting. However, Kee said further evidence is needed to show that the raw materials of life on Earth came from space

“I wouldn’t necessarily say that the meteoric origin of phosphorus is the strongest idea,” he said. “Although it’s certainly one of the more pre-biotically plausible routes.” [Fallen Stars: A Gallery of Famous Meteorites]

Despite having co-developed much of the theory behind schreibersite with Pasek, Kee pointed out that hydrothermal vents could rival the meteoritic model. Deep-sea volcanic vents are already known to produce iron-nickel alloys such as awaruite, and Kee says that the search is now on for the existence of awaruite’s phosphide equivalent in the vents: schreibersite.

“If it could be shown that schreibersite can be produced in the conditions found in vents — and I think those conditions are highly conducive to forming schreibersite — then you’ve got the potential for a lot of interesting phosphorylation chemistry to take place,” said Kee

Pasek agreed that hydrothermal vents could prove a good environment to promote phosphorus chemistry, with the heat driving off the water to allow the P-O bonds to form. “Essentially it’s this driving off of water that you’ve got to look for,” he added.

Pasek and Kee both agreed that it is possible that both mechanisms — the meteorites in the shallow pools and the deep-sea hydrothermal vents — could have been at work during the same time period and provided phosphorus for life on the young Earth. Meanwhile David Deamer, a biologist from the University of California, Santa Cruz, has gone one step further by merging the two models, describing schreibersite reacting in hydrothermal fields of bubbling shallow pools in volcanic locations similar to those found today in locations such as Iceland or Yellowstone National Park. 

Certainly, La Cruz and Pasek’s results indicate that schreibersite becomes more reactive as the environment in which it exists gets warmer.

“Although we see the reaction occurring at room temperature, if you increase the temperature to 60 or 80 degrees Celsius [140 or 176 degrees Fahrenheit], you get increased reactivity,” said Pasek. “So, hypothetically, if you have a warmer Earth, you should get more reactivity.”

One twist to the tale is the possibility that phosphorus could have bonded with oxygen in space, beginning the construction of life’s molecules before ever reaching Earth. Schreibersite-rich grains coated in ice and then heated by shocks in planet-forming disks of gas and dust could potentially have provided conditions suitable for simple biochemistry. While Pasek agreed with that idea in principle, he said he has “a hard time seeing bigger things like RNA or DNA forming in space without fluid to promote them.”

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Astronomers Solve Asteroid Mystery

February 24, 2016 by  
Filed under Computing

Near-Earth asteroids generally die a lingering death in the depths of space rather than plunging into the sun as previously thought, a new study suggests.

Researchers studied the properties of nearly 9,000 near-Earth objects (NEOs) — asteroids and other bodies that come within 1.3 Earth-sun distances of our planet — to build a model of the overall NEO population.

This model seemed to have a problem, however: It predicted that astronomers should be seeing 10 times more NEOs that closely approach the sun — come within 9 million miles (15 million kilometers) or so of the star — than they actually observe.

The research team spent a year puzzling over this outcome before coming to a surprising conclusion: The missing NEOs are actually being destroyed as they get close to the sun, but long before they actually dive into the star.

“The discovery that asteroids must be breaking up when they approach too close to the sun was surprising, and that’s why we spent so much time verifying our calculations,” study co-author Robert Jedicke, of the University of Hawaii Institute for Astronomy, said in a statement.

The team’s work should help scientists better understand the NEO population in a variety of ways. For example, many meteors that light up Earth’s night skies are pieces of debris shed by parent NEOs on their laps around the sun. Such debris clouds travel on the same orbits as their parent bodies, but astronomers generally have trouble finding these NEOs. The new study suggests that this is because the parent objects have already been destroyed, the researchers said.

In addition, study team members determined that darker NEOs die farther from the sun than brighter ones do, which helps explain something astronomers already knew: Asteroids that approach the sun closely tend to be quite bright.

This finding implies that dark and bright asteroids may differ significantly in structure and composition, the researchers said.

“Perhaps the most intriguing outcome of this study is that it is now possible to test models of asteroid interiors simply by keeping track of their orbits and sizes,” lead author Mikael Granvik, of the University of Helsinki in Finland, said in the same statement. “This is truly remarkable and was completely unexpected when we first started constructing the new NEO model.”

Granvik and his colleagues built their model by studying nearly 100,000 images of NEOs acquired by the Catalina Sky Survey in Arizona over an eight-year period.

To date, scientists have identified and tracked almost 14,000 NEOs, but the overall population is thought to number in the millions. Astronomers think that most of these bodies begin their lives in the main asteroid belt between Mars and Jupiter, and then veer inward after experiencing gravitational nudges by Jupiter and/or Saturn. The new study was published online today (Feb. 17) in the journal Nature.

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Did Mars’ Atmosphere Get Lost In Space?

October 12, 2015 by  
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The mystery of Mars’ missing atmosphere is one big step closer to being solved.

A previous hypothesis had suggested that a significant part of the carbon from Mars’ atmosphere, which is dominated by carbon dioxide, could have been trapped within rocks via chemical processes. However, new research suggests that there’s not enough carbon in deposits on the Red Planet’s surface to account for the huge amounts lost from the air over time.

“The biggest carbonate deposit on Mars has, at most, twice as much carbon in it as the current Mars atmosphere,” study co-author Bethany Ehlmann, of the California Institute of Technology (Caltech) and NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement

“Even if you combine all known carbon reservoirs together, it is still nowhere near enough to sequester the thick atmosphere that has been proposed for the time when there were rivers flowing on the Martian surface,” added Ehlmann, who worked with lead author Christopher Edwards, a former Caltech researcher currently with the U.S. Geological Survey.

Although Mars is dry today, scientists think the planet’s surface harbored large amounts of liquid water billions of years ago. Mars must have had a much thicker atmosphere back then, to keep the water from freezing or immediately evaporating, scientists say.

Carbon dioxide can be pulled from the atmosphere via chemical reactions with rocks, forming carbonate minerals. Previous research had suggested that the Red Planet might be covered with significant carbonate deposits, which could have locked up much of Mars’ lost atmosphere.

But Mars orbiters and rovers have found just a few concentrated carbonate deposits. The largest known carbonate-rich deposit on Mars is the Nili Fossae region, an area at least the size of Delaware and potentially as large as Arizona.

Edwards and Ehlmann used data captured by numerous Mars missions — including NASA’s Mars Global Surveyor orbiter, Mars Reconnaissance Orbiter, and Mars Odyssey orbiter — to estimate how much carbon is locked into Nili Fossae. Then, they compared that amount to what would be needed to form a dense, carbon-rich atmosphere that could sustain running water on the surface at the time that flowing rivers are thought to have carved extensive valley networks into the planet’s surface.

The Martian surface has been probed extensively by orbiters and landers, revealing only limited and scattered deposits of carbonate. Therefore, Edwards and Ehlmann deem it unlikely that so many large deposits have been overlooked by past examinations. Although very early deposits could be hidden beneath the Martian crust, their existence wouldn’t solve the mystery behind the atmosphere that existed when the river-carved valleys formed.

So, if the thick atmosphere didn’t become locked in carbonate deposits, what happened to it? One possibility is that it might have been lost to space from the top of the atmosphere — a phenomenon that NASA’s Curiosity rover has found evidence of in the past. Still, scientists aren’t certain how much of that loss occurred before the valleys formed. NASA’s MAVEN (Mars Atmosphere and Volatile Evolution) orbiter may help narrow down the mystery as it studies the Martian atmosphere.

“Maybe the atmosphere wasn’t so thick by the time of valley network formation,” Edwards said. “Instead of Mars that was wet and warm, maybe it was cold and wet with an atmosphere that had already thinned. How warm would it need to have been for the valleys to form? Not ver

“In most locations, you could have had snow and ice instead of rain,” Edwards said. “You just have to nudge above the freezing point to get water to thaw and flow occasionally, and that doesn’t require very much atmosphere.”

The research was published online Aug. 21 in the journal Geology.

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Will NASA Be Able To Mine Asteroids By 2025?

August 14, 2015 by  
Filed under Around The Net

Asteroid mining could shift from sci-fi dream to world-changing reality a lot faster than you think.

Planetary Resources deployed its first spacecraft from the International Space Station last month, and the Washington-based asteroid-mining company aims to launch a series of increasingly ambitious and capable probes over the next few years.

The goal is to begin transforming asteroid water into rocket fuel within a decade, and eventually to harvest valuable and useful platinum-group metals from space rocks.

“We have every expectation that delivering water from asteroids and creating an in-space refueling economy is something that we’ll see in the next 10 years — even in the first half of the 2020s,” said Chris Lewicki, Planetary Resources president and chief engineer Chris Lewicki.

“After that, I think it’s going to be how the market develops,” Lewicki told Space.com, referring to the timeline for going after asteroid metals.

“If there’s one thing that we’ve seen repeat throughout history, it’s, you tend to overpredict what’ll happen in the next year, but you tend to vastly underpredict what will happen in the next 10 years,” he added. “We’re moving very fast, and the world is changing very quickly around us, so I think those things will come to us sooner than we might think.”

Planetary Resources and another company, Deep Space Industries, aim to help humanity extend its footprint out into the solar system by tapping asteroid resources. (Both outfits also hope to make a tidy profit along the way, of course.)

This ambitious plan begins with water, which is plentiful in a type of space rock known as carbonaceous chondrites. Asteroid-derived water could do far more than simply slake astronauts’ thirst, mining advocates say; it could also help shield them from dangerous radiation and, when split into its constituent hydrogen and oxygen, allow voyaging spaceships to fill up their fuel tanks on the go.

The technology to detect and extract asteroid water is not particularly challenging or expensive to implement, Lewicki said. Scientific spacecraft routinely identify the substance on celestial bodies, and getting water out of an asteroid could simply involve bagging up the space rock and letting the sun heat it up.

Carbonaceous chondrites also commonly contain metals such as iron, nickel and cobalt, so targeting these asteroids could allow miners to start building things off  Earth as well. That’s the logical next step beyond exploiting water, Lewicki said.

The “gold at the end of the rainbow,” he added, is the extraction and exploitation of platinum-group metals, which are rare here on Earth but are extremely important in the manufacture of electronics and other high-tech goods.

“Ultimately, what we want to do is create a space-based business that is an economic engine that really opens up space to the rest of the economy,” Lewicki said.

Developing off-Earth resources should have the effect of opening up the final frontier, he added.

“Every frontier that we’ve opened up on planet Earth has either been in the pursuit of resources, or we’ve been able to stay in that frontier because of the local resources that were available to us,” Lewicki said. “There’s no reason to think that space will be any different.”

Planetary Resources isn’t mining asteroids yet, but it does have some hardware in space. The company’s Arkyd-3R cubesat deployed into Earth orbit from the International Space Station last month, embarking on a 90-day mission to test avionics, software and other key technology.

Incidentally, the “R” in “Arkyd-3R” stands for “reflight.” The first version of the probe was destroyed when Orbital ATK’s Antares rocket exploded in October 2014; the 3R made it to the space station aboard SpaceX’s robotic Dragon cargo capsule in April. [Antares Rocket Explosion in Pictures]

Planetary Resources is now working on its next spacecraft, which is a 6U cubesat called Arkyd-6. (One “U,” or “unit,” is the basic cubesat building block — a cube measuring 4 inches, or 10 centimeters, on a side. The Arkyd-3R is a 3U cubesat.)

The Arkyd-6, which is scheduled to launch to orbit in December aboard SpaceX’s Falcon 9 rocket, features advanced avionics and electronics, as well as a “selfie cam” that was funded by a wildly successful Kickstarter project several years ago. The cubesat will also carry an instrument designed to detect water and water-bearing minerals, Lewicki said.

The next step is the Arkyd 100, which is twice as big as the Arkyd-6 and will hunt for potential mining targets from low-Earth orbit. Planetary Resources aims to launch the Arkyd-100 in late 2016, Lewicki said.

After the Arkyd 100 will come the Arkyd 200 and Arkyd 300 probes. These latter two spacecraft, also known as “interceptors” and “rendezvous prospectors,” respectively, will be capable of performing up-close inspections of promising near-Earth asteroids in deep space.

If all goes according to plan, the first Arkyd 200 will launch to Earth orbit for testing in 2017 or 2018, and an Arkyd 300 will launch toward a target asteroid — which has yet to be selected — by late 2018 or early 2019, Lewicki said.

“It is an ambitious schedule,” he said. But such rapid progress is feasible, he added, because each new entrant in the Arkyd series builds off technology that has already been demonstrated — and because Planetary Resources is building almost everything in-house.

“When something doesn’t work so well, we don’t have a vendor to blame — we have ourselves,” Lewicki said. “But we also don’t have to work across a contractural interface and NDAs [non-disclosure agreements] and those sorts of things, so that we can really find a problem with a design within a week or two and fix it and move forward.”

For its part, Deep Space Industries is also designing and building spacecraft and aims to launch its first resource-harvesting mission before 2020, company representatives have said.

Extracting and selling asteroid resources is in full compliance with the Outer Space Treaty of 1967, Lewicki said.

But there’s still some confusion in the wider world about the nascent industry and the rights of its players, so he’s happy that the U.S. Congress is taking up the asteroid-mining issue. (The House of Representatives recently passed a bill recognizing asteroid miners’ property rights, and the Senate is currently considering the legislation as well.)

“I think it’s more of a protection issue than it is an actual legal issue,” Lewicki said. “From a lawyer’s interpretation, I think the landscape is clear enough. But from an international aspect, and some investors — I think they would like to see more certainty.”

Courtesy-Space

 

Did Mars Have Continents?

July 20, 2015 by  
Filed under Uncategorized

Now researchers have found that silica-rich rock much like the continental crust on Earth may be widespread at the site where Curiosity landed on Mars in August 2012.

“Mars is supposed to be a basalt-covered world,” study lead author Violaine Sautter, a planetary scientist at France’s Museum of Natural History in Paris, told Space.com. The findings are “quite a surprise,” she added.

Sautter and her colleagues analyzed data from 22 rocks probed by Curiosity as the six-wheeled robot wandered ancient terrain near Gale Crater. This 96-mile-wide (154 kilometers) pit formed about 3.6 billion years ago when a meteor slammed into Mars, and the age of the rocks from this area suggests they could help shed light on the earliest period of the Red Planets, scientists said.

The 22 rocks the researchers investigated were light-colored, contrasting with the darker basaltic rock found in younger regions on Mars. They probed these rocks using the rock-zapping laser called ChemCamon Curiosity, which analyzes the light emitted by zapped materials to determine the chemistry of Martian rocks.

The scientists found these light-colored rocks were rich in silica. A number of these were similar in composition to some of Earth’s oldest preserved continental crust.

Sautter noted that recent orbiter and rover missions had also spotted isolated occurrences of silica-rich rock. The researchers suggest these silica-rich rocks might be widespread remnants of an ancient crust on Mars that was analogous to Earth’s early continental crust and is now mostly buried under basalt.

The researchers added that the early geological history of Mars might be much more similar to that of Earth than previously thought. Future research could investigate whether the marked differences between Mars’ smooth northern hemisphere and rough, heavily cratered southern hemisphere might be due to plate tectonics, Sautter said.

The scientists detailed their findings online Monday (July 13) in the journal Nature Geoscience.

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Astronomers Discover Very Light Mars Size Alien Planet

June 22, 2015 by  
Filed under Around The Net

A Mars-size planet about 200 light-years from our solar system has turned out to be the lightest known alien world orbiting a normal star, researchers say.

Astronomers made the discovery after measuring the size and mass of the baking-hot planet, named Kepler-138 b, which orbits a red dwarf star called Kepler-138. Mars is only 53 percent the size of the Earth (or just about half the size), so Kepler-138 b is smaller than the Earth.

In the past couple of decades, astronomers have confirmed the existence ofmore than 1,800 exoplanets, or planets orbiting a star other than our sun. However, it’s more difficult for scientists to calculate the masses of small, rocky planets like Mars or Mercury than for large, gaseous worlds such as Jupiter or Saturn. Scientists measure the masses of exoplanets by looking at how strongly their gravitational fields tug on their stars; small planets have small masses, and their weak tugs on their stars are more difficult for astronomers to detect. As such, few Earth-size exoplanets have had their masses measured. [The Smallest Known Alien Planets in Pictures]

In this new study, astronomers investigated Kepler-138, a cold, dim red dwarf star with a mass about half that of the sun. Kepler-138 is located about 200 light-years from Earth, in the constellation Lyra.

Kepler-138 “is more than 10 million times further away from us than our sun,” study lead author Daniel Jontof-Hutter, an astronomer at Pennsylvania State University in University Park, told Space.com.

The star Kepler-138 is home to three exoplanets, prior research has confirmed by detecting the slight dimming of the star’s light that occurs whenever one of these worlds crosses in front of it. Each of these two planets — Kepler-138 c and Kepler-138 d — is about 1.2 times as wide as Earth. The third, Kepler-138 b, is a little more than half as wide as Earth, making it about the size of Mars.

“Kepler-138 b has the same apparent size to us as a golf ball 10 million kilometers [6.2 million miles] away,” Jontof-Hutter said.

These three exoplanets orbit very close to their star. Kepler-138 b takes a little more than 10 days to complete its orbit, Kepler-138 c requires nearly 14 days and Kepler-138 d needs about 23 days.

Using NASA’s Kepler spacecraft, the researchers looked at how the gravitational tug-of-war among these exoplanets influenced the lengths of their orbits. Because the strength of a planet’s gravitational pull is directly related to its mass, the scientists were able to weigh all three of these planets.

The astronomers found that the mass of the Mars-size inner planet, Kepler-138 b, is about one-fifteenth, or 6.7 percent, of Earth’s, making it about two-thirds the mass of Mars.

“Kepler-138 b is the first exoplanet smaller than Earth to have both its size and its mass measured,” Jontof-Hutter said.

The least massive known alien world may be the exoplanet PSR B1257+12 b, which has an estimated mass only about one-fiftieth, or 2 percent, that of Earth. However, that world does not orbit a normal star, but instead circles a pulsar — a dense, rapidly spinning remnant of a supernova explosion.

Knowing the mass and width of Kepler-138 b helped the researchers calculate its density, which they found is about two-thirds that of Mars, suggesting it has a purely rocky composition.

Although Kepler-138 b may be similar in mass and width to Mars, it is so much closer to its star, and thus hotter, meaning it is likely very different from Mars, Jontof-Hutter said. “In fact, all three planets orbiting Kepler-138 are likely too hot to retain liquid water,” Jontof-Hutter said. On the outermost planet, surface temperatures are about 250 degrees Fahrenheit (120 degrees Celsius), while those on the innermost planet are about 610 degrees F (320 degrees C).

Kepler-138 c and Kepler-138 d have masses 197 percent and 64 percent of Earth’s, respectively.

This finding opens up the study of rocky alien planets smaller than Earth, Jontof-Hutter said.

“The enormous variety of exoplanets that have been discovered by Kepler show us that systems like our own solar system are probably not the norm, and we don’t know why,” Jontof-Hutter said. Analyzing more exoplanets “will give us clues about how planets form and enable us to learn how common systems like are own really are.”

The scientists detailed their findings in the June 18 issue of the journal Nature.

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