2014년 3월 25일 화요일

Incredible Technology: Giant Starshade Could Help Find an Alien Earth

A flower-shaped spacecraft may help scientists see Earth-like alien worlds like never before.

Called a "starshade," the huge, sunflower-like spacecraft would deploy to its full size in space, blocking the light of distant stars so that a space-based telescope can image exoplanets in orbit around the stars. With this technology, researchers could directly image other worlds and potentially find long sought-after Earth twins, a historically difficult task for alien planet hunters.

While still in the early phases of development, the starshade could hunt for small planets around bright, nearby stars. This would help scientists learn more about the planets and even hunt for signs of potential life by peering into the alien worlds' atmospheres. 

"It's a very specialized screen in space," planetary scientist and MIT astrophysicist Sara Seager said of the starshade concept. "It blocks out the light from the star. Only the planet's light enters the telescope. This is not what we traditionally do. Traditionally, the telescope does everything. … It's the only way to find Earths with a relatively small and simple space telescope."

A small telescope in space

As it stands now, the assumed $1 billion mission would be able to target about 55 bright stars in a three-year span. Seager, the chair of NASA's science and technology definition team for the starshade project, thinks it's possible to find Earth-like planets orbiting 22 of those 55 stars targeted by the mission.

One major advantage to the starshade is that astronomers won't need to couple it with a large, extremely expensive space telescope. By blocking out the light of a star before that light ever reaches the telescope, the starshade eliminates the need for a huge telescope, Seager said.

"You don't need a very fancy telescope that's highly thermally and mechanically stable," Seager told Space.com. "You can use any old space telescope. We can buy a telescope. That's what we're thinking of. … It sounds a little funny, but any telescope will do."

Engineering a starshade

Building a starshade poses a serious engineering challenge. While the telescope and starshade can launch together, the starshade will need to move out from the telescope once both robots reach space.

"[Most starshade designs] are tens of meters [in diameter] and flying tens of thousands of kilometers from the telescope," Seager said. "It's challenging. It sounds insane. The thing is, no matter how you do it, it's really difficult."

But it's also still very difficult to create a large telescope with the internal machinery used to correct for starlight, Seager added.

The starshade itself needs to be designed with extreme accuracy so that it can block light effectively once in space. Researchers on the ground at Princeton University in New Jersey and NASA's Jet Propulsion Laboratory in California are working to test models of the starshade now.

"Our current task is figuring out how to unfurl the starshade in space so that all the petals end up in the right place, with millimeter accuracy," Princeton professor Jeremy Kasdin, the principal investigator of the starshade project, said in a statement.

Space sunflower

Once in space, the starshade unfolds and is positioned between the star and the telescope. The shade's unique shape blocks the starlight, potentially revealing exoplanets in orbit around the star that couldn't have been seen previously. With the light blocked, a telescope can directly image the planets.

"The shape of the petals, when seen from far away, creates a softer edge that causes less bending of light waves," Stuart Shaklan, lead engineer on the starshade project at JPL, said in a statement. "Less light-bending means that the starshade shadow is very dark, so the telescope can take images of the planets without being overwhelmed by starlight."

The starshade would come equipped with thrusters to maneuver into different positions to block the light of the 55 stars it will blot out through the course of the mission. Although it will take time to move the starshade into place for each target, the telescope can perform other astrophysics tasks while waiting for the next star to come into view, Seager said.

Finding Earth's twin

NASA's Kepler mission hunted for exoplanets until it suffered a critical failure last year. Unlike a starshade, Kepler used the transit method, recording small dips in a star's light as a planet passed in front of it, to find other worlds.

The Transiting Exoplanet Survey Satellite (TESS), scheduled for launch in 2017, also uses the transit method to find exoplanets, and this mission is expected to target other stars in a wider swath of sky. TESS probably won't find Earth twins, but it will be able to see rocky planets around stars that are smaller than the sun, Seager said.
With the starshade mission, scientists could potentially find Earth-twins orbiting sun-like stars.

"These Kepler planets are too far away for us to directly study atmospheres of small planets," Seager said. "We mostly decided now that transits won't work for true Earth analogues. For Earth and sun-like stars, you just have to think of the size of the atmosphere — it's like a ring compared to the sun. It's tiny. We don't think we can do [image] that, not to mention that transits are rare. One in 200 Earths will transit, so finding one around a bright enough star may never happen. … Direct imaging is inevitable."

Source of Article: Space.com
By Miriam Kramer, Staff Writer

Mars Rover Curiosity Takes Aim at Next Martian Science Target

After a long stretch of pedal-to-the-metal driving, NASA's Mars rover Curiosity has its next science target in sight.
The 1-ton Curiosity rover is just 282 feet (86 meters) north of a site called "the Kimberley," where four different types of terrain intersect. The rover's handlers are keen to study the Kimberley rocks and may even break out Curiosity's sample-collecting drill at the site, NASA officials said.
"The orbital images didn't tell us what those rocks are, but now that Curiosity is getting closer, we're seeing a preview," Curiosity deputy project scientist Ashwin Vasavada, of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., said in a statement.

"The contrasting textures and durabilities of sandstones in this area are fascinating," Vasavada added. "While superficially similar, the rocks likely formed and evolved quite differently from each other."

The Kimberley sandstones represent a different type of rock for Curiosity to examine. Since touching down inside Mars' huge Gale Crater in August 2012, the rover has primarily scrutinized finer-grained mudstones, researchers said.
Some of those mudstones, at a site called Yellowknife Bay, preserved evidence of an ancient stream-and-lake system, leading mission scientists to announce last year that Mars could have supported microbial life billions of years ago.

Understanding variations in Martian sandstones — such as why some are harder than others — could help scientists piece together parts of the Red Planet's past and explain the large-scale contours of Gale Crater, researchers said.

"A major issue for us now is to understand why some rocks resist erosion more than other rocks, epecially when they are so close to each other and are both likely to be sandstones," said Michael Malin, of Malin Space Science Systems in San Diego. Malin is the principal investigator for Curiosity's Mast Camera and Mars Descent Camera.

Curiosity is currently en route to the base of Mount Sharp, which rises 3.4 miles (5.5 kilometers) into the sky from Gale Crater's center. The rover's handlers want Curiosity to climb up Mount Sharp's foothills, reading a history of Mars' changing environmental conditions as it goes.

Curiosity left the Yellowknife Bay area last July. While the six-wheeled robot has stopped occasionally since then to examine rocks, the mission team has mainly prioritized making tracks. The road to Mount Sharp covers more than 5 miles (8 km); Curiosity should get there around the middle of this year, officials have said.

The long journey has been hard on Curiosity's metal wheels, spurring the rover team devise ways to minimize wear and tear. Their strategies — which include driving Curiosity backward for stretches and choosing a less punishing route — appear to be paying off, with the wheel-puncture rate dropping to just 10 percent of what it was a few months ago.

"The wheel damage rate appears to have leveled off, thanks to a combination of route selection and careful driving," said JPL's Richard Rainen, mechanical engineering team leader for Curiosity. "We're optimistic that we're doing OK now, though we know there will be challenging terrain to cross in the future."

Source of Article: Space.com
By Mike Wall, Senior Writer 

It's Time to Extend Routine Space Operations to the Moon (Op-Ed)

When the XPRIZE Foundation announced the Google Lunar XPRIZE in 2007, Astrobotic Technology chairman Red Whittaker declared his intention to compete on the first day. Since then, we have worked methodically on the technology and operations for the $20 million Grand Prize. We have approached this from the outset as an opportunity to build a business.
With only a few lunar landings since Apollo, there remains a deep cultural belief that they are extraordinarily difficult and expensive. Bold, risky pursuits are called "moon shots." Indeed, NASA estimated that the Apollo program cost $170 billion in 2005 dollars — about $28 billion for each of the six landings.

In the 42 years since Apollo, space technology has matured. Most subsystems needed for lunar landing — from star trackers (cameras that measure a spacecraft's attitude relative to the stars) to propulsion — are commercially available off-the-shelf. Launches are commercially available to geosynchronous transfer orbit or trans-lunar injection. The total cost for a lunar landing that uses a launch vehicle's full capacity (versus flying a smaller mission as secondary payload) is now between $100 million and $200 million. For comparison, DirecTV's satellite fleet includes a dozen satellites that cost an estimated $700 million each.

Although the technology is now in reach, bootstrapping a new market is always challenging. Businesses and research institutions won't routinely develop lunar payloads until regular, affordable transport is assured, but the transport business won't mature until reliable payload customers justify the investment.

The Google Lunar XPRIZE — the largest international incentive prize of all time — has been essential to breaking that deadlock. In addition to the $20 million Grand Prize, the original $30 million purse includes a $5 million Second Prize and bonus prizes for specific objectives such as lunar night survival and visiting historic sites. Of the 29 teams that entered the race, 18 are still progressing. Google Lunar XPRIZE recently added Milestone Prizes totaling up to $6 million for meeting 2014 technical milestones in three categories: Landing, Mobility and Imaging. Astrobotic and Moon Express are the only two teams to advance to the Accomplishment Round in all three categories.

NASA has also played a crucial role. In 2010, NASA committed a total of $30 million in Innovative Lunar Demonstrations Data (ILDD) contracts to six companies — including Astrobotic — to purchase the technical data from the development of robotic lunar landings. In February 2014, NASA announced the Lunar Cargo Transportation and Landing by Soft Touchdown(Lunar CATALYST) initiative, which seeks a commercial partner to develop robotic lunar lander capabilities. To date, NASA has awarded 15 contracts to Astrobotic, most of which have contributed toward Astrobotic's development of lunar mission capability.

Instead of treating payload customers with modest budgets as "secondary payload," Astrobotic focuses its mission operations on supporting them. We charge $1.2 million per kilogram to carry from 1 kg to 270 kg of payload to the lunar surface on our Griffin lander, with lower-cost options for payloads that separate from us en route. We have two dozen payloads interested in our first mission, which together exceed our capacity. Prospective customers include NASA and smaller-government space programs, commercial ventures and other Google Lunar XPRIZE teams.

A SpaceX Falcon 9 launch vehicle places Griffin into trans-lunar injection, a trajectory that will swing by the moon. This provides enough of the mission's total energy requirement that the single-stage Griffin lander can do the rest, greatly simplifying the overall mission.

Griffin then navigates along a pre-planned trajectory and performs a braking maneuver to enter lunar orbit. Up to this point, the mission relies on integration of off-the-shelf subsystems and techniques that have been developed and well tested for Earth orbit, from the launch to communications, propulsion, radio triangulation, a star tracker and an inertial measurement unit (IMU).

Griffin performs another braking maneuver to leave lunar orbit and begin its initial descent. It is at this point that Griffin departs the comfortable technological ecosystem of Earth-orbit subsystems and must rely on new capabilities developed at Astrobotic.

Astrobotic's first mission will land and explore the moon's Lacus Mortis region. Latin for "Lake of Death," Lacus Mortis is a plain of basaltic lava flows. It contains a pit that is a compelling exploration target. The pit's east wall has partially collapsed, creating an inviting ramp that could someday be traversed by a robotic rover.
The combination of radio triangulation, star tracker and IMU work well for orbit, but are not precise enough for safe landing near a pit. Terrestrial, unmanned aerial vehicles rely heavily on GPS, but that isn't an option on the moon. Instead, Astrobotic has developed proprietary vision algorithms that track the lander's position and attitude.

Griffin's autolanding system differs in several ways from systems like NASA's Autonomous Landing Hazard Avoidance Technology (ALHAT), which is designed to deliver people to the lunar surface. Griffin's autolanding system makes decisions entirely without human input. 

The small ground clearance typical of robotic landers requires the capability to detect tiny objects on the surface. To reduce mass, the system uses sensors with fixed pointing to provide the needed views of the surface and relies more heavily on cameras for precise location information. We rely on the precisely located, high-resolution image maps of the lunar surface from NASA orbital missions. The autolanding system is low-power, lightweight and highly accurate.

This landing approach has two significant challenges. The vision algorithms needed to achieve landing didn't exist — we had to invent them ourselves. Furthermore, the computing required to execute these algorithms doesn't exist in a form that is viable for operation in the vacuum of space. One of our Milestone Prize deliverables is demonstration of our own flight-capable computing system.

We recently demonstrated our landing approach on a vertical-takeoff, vertical-landing rocket. The rocket carried Griffin's sensors through the final descent portion of our landing trajectory, descending rapidly from 250 meters altitude, braking, and then entering a constant-velocity glide slope. As the rocket descended, Griffin's sensors scanned the ground to detect hazards and select a safe landing point. We had a flawless flight.

When we reach the lunar surface, we face new challenges. A lunar rover must have very low mass, be power efficient, and navigate rough terrain with no chance of rescue. The most difficult challenges are thermal. On Earth, the atmosphere blocks much of the sun's radiation and air provides cooling. A lunar rover operates in direct sunlight in a vacuum, where heat can only be dissipated by radiation or direct conduction. Operating terrestrial electronics in this environment would be like wrapping a laptop in blankets and running it full-bore. To complicate matters, the regolith under the rover heats to above the boiling point of water at lunar noon and drops to cryogenic temperatures at night.

In collaboration with Carnegie Mellon University and with NASA funding, we experimented to identify electronics that can survive the heat of the day and the cold of the night. Our rover architecture reflects most of the incoming radiation from the sun and the regolith, and radiates heat toward cold sky so we can operate through the hottest parts of the day.

The Google Lunar XPRIZE requires that we transmit two "mooncasts" back to Earth. This requires obtaining the necessary image resolution (720p in color) with a low-mass camera that can both withstand the shock and vibration of launch and operate in the vacuum and temperature extremes of the lunar surface. Communicating high-resolution images back to Earth is a significant challenge because of the distances involved; because the rover is so power limited, we relay imagery through the lander.

Like a modern-day Columbus, the Apollo astronauts gave us our first close-up glimpse of new territory and fired our imaginations. Now it's time for industry to return, still with excitement, but also with pragmatism. The moon offers a wealth of new knowledge of our planet and our solar system. It can teach us how to operate on a planetary surface. At some point, it will yield valuable resources. First, we have to make it a routine part of commercial space.

Source of Article: Space.com
John Thornton, CEO, Astrobotic Technology

US Military's XS-1 Space Plane Project Seeks $27 Million in 2015 Funding

The U.S. Defense Advanced Research Projects Agency expects to spend some $800 million on space programs from 2015 through 2018, an increase of $130 million over what was projected at this time last year, Defense Department budget documents show.

Nearly all of the targeted increase for DARPA's Space Programs and Technology Office is backloaded into the outyears, the documents show. For 2015, the office is seeking nearly $180 million, only $7.5 million more than this year’s funding level. 

DARPA's budget books break out funding on a program-by-program basis for the upcoming fiscal year only; outyear projections are provided only at the department level.

DARPA's mission, generally speaking, is to pursue high-risk, high-payoff technology development projects that could someday benefit the military. These projects are taken on with the understanding that many, if not most, will fail. Defense Department officials often talk about "DARPA-hard" programs to describe their degree of difficulty.

For example, the 2015 request includes $27 million for XS-1, a concept for a reusable space plane that could ultimately fly 10 times in 10 days and boost payloads into low-Earth orbit for less than $5 million per launch. The program received $10 million in 2014.

"Technologies derived from the XS-1 program will enable routine space launch capabilities with aircraft-like cost, operability and reliability," a DARPA announcement from November 2013 reads. "The long-term intent is for XS-1 technologies to be transitioned to support not only next-generation launch for Government and commercial customers, but also global reach hypersonic and space access aircraft." 

The agency hopes to select a single vendor next year for the final design and development of the vehicle, which could make its initial test flight in 2018.
DARPA sees the program potentially transitioning to the Air Force, the Navy or a commercial operator, the budget documents said. 

The budget request also includes $55 million for the Airborne Launch Assist Space Access (ALASA) program, which is intended to field a system to launch satellites weighing up to 100 lbs (45 kilograms) for $1 million each. The agency requested $42 million for the program in fiscal year 2014.

DARPA awarded ALASA system concept studies contracts last year to Boeing, Lockheed Martin and Virgin Galactic, and technology-development contracts to three other companies.

The program is aiming for a demonstration launch in fiscal year 2015.
DARPA is requesting $65 million for the Phoenix program next year, compared with $60 million this year, according to the agency budget documents. Phoenix is an on-orbit robotics technologies program originally intended, in part, to salvage components from aging satellites. 

DARPA plans to test a core element of the program known as satlets — small modules that perform critical satellite functions including power, pointing and communications — by launching them into a low-inclination orbit as soon as 2015.

The budget request also includes $5 million for what appears to be a new program dubbed the Optical Aperture Self-Assembly in Space, which is intended to demonstrate the "feasibility of constructing large optical apertures in orbit from a number of smaller modular components that self-organize in space."

The request discontinues funding for two programs: an experimental solar electric propulsion vehicle and system F6, a planned formation-flying satellite demonstration that was canceled last year.

Source of Article: Space.com
By Mike Gruss, Space News

2014년 3월 12일 수요일

Rosetta's Brightening Comet Emerges From Behind the Sun

After its long-awaited awakening on Jan. 20, Europe's Rosetta spacecraft resumed its decade-long journey to meet up with the inbound comet 67P/Churyumov-Gerasimenko, which recently re-emerged from behind the sun as seen from our vantage point on Earth.

The images above show the comet as seen by ESO's Very Large Telescope (VLT) in Chile on Feb. 28. The left image shows the comet amidst background star trails — the comet itself is actually overlaid onto a star trail — and the right image has had the trails subtracted and the enhanced comet exposures stacked onto a single spot.

These are the first observations of 67P/Churyumov-Gerasimenko made by the VLT since October. Since then the 4 kilometer-wide comet has increased in brightness by about 50 percent, indicating that its surface ices may have already begun to sublimate into space.
Hello World: Hibernating Rosetta Comet Probe Awakens

Rosetta and its Philae lander are currently awake and doing well after their nearly two-and-a-half year-long hibernation. Launched in March 2004, this May the spacecraft will rendezvous with the comet and enter orbit around it in August. In November, Philae will land on the comet’s nucleus, performing scientific observations as the comet makes its closest approach to the sun in August 2015.

Source of Article: Space.com

NASA Joins Hunt for Missing Jetliner

The world's premier space agency has joined the search for a commercial jetliner that vanished into thin air over the weekend.
On Monday (March 10), NASA began examining ways it can contribute to the search for Malaysian Airlines Flight 370, which disappeared shortly after takeoff on Friday (March 7), agency officials said.

"Activities under way include mining data archives of satellite data acquired earlier and using space-based assets, such as the Earth-Observing-1(EO-1) satellite and the ISERV camera on the International Space Station, to acquire new images of possible crash sites," NASA spokesman Allard Beutel told Space.com via email. "The resolution of images from these instruments could be used to identify objects of about 98 feet (30 meters) or larger."

In addition, Beutel added, NASA will be sending relevant data to the U.S. Geological Survey's Earth Resource Observations and Science Hazard Data Distribution System, which facilitates the sharing of information whenever the International Charter on Space and Major Disasters is activated.

The Charter — which aims to mitigate the effects of natural and man-made disasters by streamlining the delivery of space-acquired data — was activated on Tuesday (March 11) by China, according to CNET.

Flight 370 took off from Kuala Lumpur, the Malaysian capital, on Friday afternoon U.S. Eastern time, headed for Beijing. The plane dropped off air traffic controllers' radar less than an hour later; the whereabouts of the Boeing 777 jet, which was carrying 227 passengers and 12 crew members, remain unknown.

On Wednesday (March 12), however, Chinese officials announced that one of the nation's satellites had spotted a possible crash site for Flight 370. The spacecraft captured images of three large, floating objects in the waters northeast of Kuala Lumpur, along the plane's presumed flight path, CNN reported.

A follow-up investigation by recovery boats and aircraft could confirm if the objects are indeed pieces of the Malaysian Airlines jet, experts say.
The disappearance of Flight 370 calls to mind Air France Flight 447, which vanished over the Atlantic Ocean in June 2009, shortly after taking off from Rio de Janeiro en route to Paris. It took five days to locate the wreckage of Flight 447 and nearly two years to find and recover the jet's "black boxes" from the ocean floor.

Source of Article: Space.com
By Mike Wall, Senior Writer

2014년 3월 2일 일요일

Hubble Zooms in on Historic Supernova SN 2014J

On Jan. 21, astronomers spotted the closest supernova in recent decades flash to life in the galaxy M82, some 11.5 million light-years from Earth. The supernova, designated SN 2014J, suddenly became a superstar as it became so bright that amateur astronomers with modest telescopes could easily pick out the stellar explosion in the night sky. Now, Hubble has slewed in the direction of M82 to snap this dreamy portrait of the historic stellar event.

SN 2014J is known as a Type 1a supernova, a very special kind of supernova. It is thought a Type 1a supernova is triggered by a white dwarf — an ancient small star that is the stellar husk of a star of approximately the same mass as our sun — accumulating material from a binary partner star. When the accumulated mass reaches a certain threshold, the bloated white dwarf ignites a supernova. As the threshold of material is very specific, which generates a very specific quantity of energy, Type 1a supernovae are used by astronomers as “standard candles” to measure the scale of the Universe. If you know the amount of energy released by this supernova, no matter where it is in the Cosmos, you can precisely measure your distance from it.

In the case of SN 2014J, the closest Type 1a supernova since SN 1972e, this is the perfect opportunity to further understand the mechanisms behind a phenomena that underpins our ability to understand the scale, age and expansion of the Universe. In 1998, astronomers made the groundbreaking discovery that a mysterious force was acting on the expansion of the Universe, dubbed “dark energy,” and Type 1a supernovae were at the root of this revelation.

In this new observation captured by Hubble’s Wide Field Camera 3, the supernova has been superimposed over a photo mosaic of the entire M82 galaxy in 2006 taken with Hubble’s Advanced Camera for Surveys. This supernova portrait was acquired on Jan. 31, just as the explosion was reaching its peak in brightness.
As Hubble is sensitive to ultraviolet wavelengths of light, the impact of the supernova on the surrounding interstellar environment can be studied, building on our knowledge of these important stellar events and how they can impact their host galaxies.

Source of Article: Space.com
By Ian O'Neill, Discovery News 

SN 2014J Oddball: Nearby Supernova Is a Bit Weird

The now-famous supernova that erupted in neighboring galaxy M82 last month is a unique opportunity to study an exploding star up-close. However, SN 2014J isn’t any old supernova, it turns out that it’s a little bit weird.

Discovered by a team of UK astronomy students on Jan. 21, the brightening SN 2014J was quickly identified as a Type 1a supernova. This particular type of supernova is critical to astronomers as they generate a specific amount of energy. They are used as “standard candles” as a means to measure the size of the Universe and the accelerated rate that the Cosmos is expanding. Observations of Type 1a supernovae led to the paradigm-shifting discovery of a mysterious force, known as dark energy, that is driving this expansion.

Type 1a supernovae aren’t triggered by the core collapse of a massive star, however; they are spawned by white dwarfs — the small, compact stellar husks of dead stars that were approximately a similar mass to our sun — stripping gas from a binary partner. Once the amount of gas reaches a certain threshold, the white dwarf (plus gas) explodes as a supernova.

Although the supernova was spotted on Jan. 21, that wasn’t the time the supernova was triggered. Using observational data from the Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory near San Jose, Calif., astronomer Alex Filippenko (of the University of California, Berkeley) and his team searched earlier images of M82. Luckily, they found an observation that was taken on Jan. 14, only 36 hours after the supernova was initiated. Also, an amateur astronomer in Japan had a chance observation of M82 before it was officially recognized.

Finding these ‘pre-discovery’ observations are an obvious boon to our understanding of the mechanisms at play in a Type 1a supernova in its early stages, but they have also highlighted a puzzle.

Weird is the New Normal?

It turns out that SN 2014J had some unusual characteristics. It brightened faster than theoretical models predicted and, according to a Berkeley press release, exhibited the same rapid brightening as another supernova KAIT discovered in 2013. Another recently-observed Type 1a supernova, called SN 2011FE, did not exhibit this rapid brightening, however, but is considered to be a “normal” Type 1a supernova.

“Now, two of the three most recent and best-observed Type Ia supernovae are weird, giving us new clues to how stars explode,” said Filippenko. “This may be teaching us something general about Type Ia supernovae that theorists need to understand. Maybe what we think of as ‘normal’ behavior for these supernovae is actually unusual, and this weird behavior is the new normal.”

In an effort to better grasp what is going on in the early stages of Type 1a supernovae, effort is being spent on surveying the skies more often so the early signals of these stellar explosions can be detected. New survey telescopes, such as the Palomar Transient Factor in San Diego County and the Pan-STARRS in Hawaii, are continually scanning the skies to detect more of them.

“Very, very early observations give us the most stringent constraints on what the star’s behavior really is in the first stages of the explosion, rather than just relying on theoretical speculation or extrapolating back from observations at later times, which is like observing adolescents to understand early childhood,” said Filippenko.

Refining our understanding on how these “weird” Type 1a supernovae work do not contradict the groundbreaking discoveries on the scale of the universe, it’s expansion or the discovery of dark energy, but it may help to refine our knowledge of these discoveries, providing a more precise understanding of the “standard candles” that occasionally brighten galaxies.

This research will be published in The Astrophysical Journal Letters on March 1.

Source of Article: Space.com
By Ian O'Neill, Discovery News

Mars Meteorite with Odd 'Tunnels' & 'Spheres' Revives Debate Over Ancient Martian Life

The discovery of tiny carbon-rich balls and tunnels inside a Martian meteorite has once again raised the possibility that the Red Planet was teeming with primitive life millions of years ago.

The meteorite, which fell to Earth during the Stone Age, contains microscopic burrows and spheres that resemble the marks microorganisms leave when they eat through rocks on Earth, scientists report in the journal Astrobiology this month. What's more, these features seem to have been pressed into the Mars rock before it was hurled off the Red Planet by an impact event, the researchers add. 

The authors of the new research are not claiming they've found evidence of ancient life on Mars. In fact, nowhere in their paper do they use the word "life." (Their preferred term is "biotic activity.") But their findings revive the debate about the possibility of microbes in Mars' past and highlight how much information scientists can actually glean from Martian meteorites that end up on Earth.

"It further strengthens the case for past life on Mars, but, of course, it is by no means proof," said astrobiologist Dirk Schulze-Makuch of Washington State University, who was not involved in the study.

Scientists haven't yet found any solid proof that life actually existed on ancient Mars — but they have found evidence that the planet could have been habitable. Though Mars is barren today, scientists think water — a key ingredient for life — would have covered its surface in the form of oceans, rivers and streams. And last year, NASA's newest Mars rover, Curiosity, discovered the first evidence that the Red Planet could have supported living microbes billions of years ago.

While Mars rovers, landers and satellites are hunting for life-friendly conditions on the Red Planet, scientists also can look for evidence of ancient life in Martian meteorites that have landed on Earth.

Mars meteorite mystery

The meteorite at the center of the new study is known as Yamato 000593. The 30-lb. (14 kilograms) rock was found by scientists with the Japanese Antarctic Research Expedition in 2000 at the Yamato Glacier in Antarctica. Researchers believe it formed on Mars 1.3 billion years ago and was altered by water during the Red Planet's wet past before being blasted to Earth during the last 10,000 years.

The study's principal investigator, Lauren White, a researcher at NASA's Jet Propulsion Laboratory in Pasadena, Calif., said the main goal of the research was to find out whether the tunnels and carbon-rich spherules inside the meteorite were indigenous or the result of contamination on Earth.

"The paper isn't really meant to identify if these features were formed from biotic or abiotic means, but rather to discover if these features are actually Martian in origin," White told Space.com in an email. "We compare this meteorite, Yamato — which was discovered in Antarctica — to another Martian meteorite, Nakhla, which fell in Egypt."

The Nakhla meteorite dropped from the sky in 1911 in Egypt. In 2006, scientists reported that this 1.3-billion-year-old Mars rock also had a series of microscopic tunnels that resembled the trails of bacteria on Earth.

White said similarities between Yamato and Nakhla strengthen the case for a Martian origin. The team also looked at another meteorite, dubbed LEW87051, found in 1987 in Antarctica, as a control. It's unknown where this space rock came from, but a Mars origin had been ruled out because of the rock's concentration of oxygen isotopes.

This non-Martian meteorite, which was exposed to the same Antarctic environment as Yamato, did not contain any of the microscopic tunnels that were observed in both Martian meteorites. White said this bolsters the argument that the features are Martian, and not created by contamination, though she noted it would be difficult to prove that any meteorite on Earth contains traces of alien life.

"To really determine [ancient life on Mars] in a 'smoking gun' fashion we would need a sample return mission from Mars — samples free of any contamination," White said. 
The study authors also wrote that they couldn't rule out the possibility that these tiny fossils are the result of abiotic (or nonliving) processes.

"However, textural and compositional similarities to features in terrestrial samples, which have been interpreted as biogenic, imply the intriguing possibility that the Martian features were formed by biotic activity," the authors wrote in their paper.

Chris McKay of NASA's Ames Research Center in Moffett Field, Calif., who was not involved in the study, said he was doubtful that the scientific community would be swayed by "textural and compositional similarities" as proof of a biological origin.
"At the small scales involved, shapes and compositions are not compelling indications of function," McKay said in an email. He and other researchers who were not involved in the study said they would need stronger evidence before the science community could declare Martian life found.

"It would be hard to find compelling proof of extraterrestrial life in a meteorite short of isolating an organism that grows in the lab but does not have Earth DNA," McKay said.
More intriguing evidence, McKay added, would be a set of complex biomolecules like proteins and DNA that don't resemble anything on Earth life but are too complex to have arisen abiotically. Schulze-Makuch also noted that a better indicator of life on Mars would be "the presence of DNA, some other nucleic acid or organic macromolecules that could be a breakdown product of a nucleic acid associated with these microfeatures."

Astrobiologist Louisa Preston of the U.K.'s Open University said the authors of the study "have done well not to cry wolf and to scientifically speculate on the tubules' origins, accepting that, as of yet, they do not know whether they are of biological origin or not."

Martian meteorite clues of the past

The new study is years in the making and it comes 18 years after the controversy surrounding the oldest meteorite from the Red Planet, known as Allan Hills 84001 (ALH 84001). The Mars rock made headlines in 1996 when researchers, led by David McKay, from NASA's Johnson Space Center, claimed in the journal Science that the meteorite contained evidence of possible Red Planet life forms.

McKay (who is unrelated to Chris McKay) died last year. He is listed as a co-author on the new Astrobiology paper, which was actually first submitted nearly four years ago, White said, but McKay's illness and death stalled publication.

"His loss was very difficult for all of us, but Dr. McKay was an inspiration to me," White said in an email. "This work was his life and legacy, and when I spoke at his funeral, I talked about the fact that I want to continue his legacy by continuing research in the field of astrobiology."

Source of Article: Space.com
By Megan Gannon, News Editor