(Phys.org) —NASA’s Mars rover Curiosity has used the drill on its robotic arm to collect a powdered sample from the interior of a rock called “Cumberland.”
Plans call for delivering portions of the sample in coming days to laboratory instruments inside the rover. This is only the second time that a sample has been collected from inside a rock on Mars. The first was Curiosity’s drilling at a target called “John Klein” three months ago. Cumberland resembles John Klein and lies about nine feet (2.75 meters) farther west. Both are within a shallow depression called “Yellowknife Bay.”
The hole that Curiosity drilled into Cumberland on May 19 is about 0.6 inch (1.6 centimeters) in diameter and about 2.6 inches (6.6 centimeters) deep.
The science team expects to use analysis of material from Cumberland to check findings from John Klein. Preliminary findings from analysis of John Klein rock powder by Curiosity’s onboard laboratory instruments indicate that the location long ago had environmental conditions favorable for microbial life. The favorable conditions included the key elemental ingredients for life, an energy gradient that could be exploited by microbes, and water that was not harshly acidic or briny.
NASA’s Mars Science Laboratory Project is using Curiosity to assess the history of habitable environmental conditions inside Gale Crater. After a few more high-priority observations by the rover within and near Yellowknife Bay, the rover team plans to start Curiosity on a months-long trek to the base of a layered mound, Mount Sharp, at the middle of the crater. JPL, a division of the California Institute of Technology in Pasadena, manages the project for NASA’s Science Mission Directorate in Washington.
(Phys.org) —Herds of wooly mammoths once shook the earth beneath their feet, sending humans scurrying across the landscape of prehistoric Ohio. But then something much larger shook the Earth itself, and at that point these mega mammals’ days were numbered.
Something – global-scale combustion caused by a comet scraping our planet’s atmosphere or a meteorite slamming into its surface – scorched the air, melted bedrock and altered the course of Earth’s history. Exactly what it was is unclear, but this event jump-started what Kenneth Tankersley, an assistant professor of anthropology and geology at the University of Cincinnati, calls the last gasp of the last ice age.
“Imagine living in a time when you look outside and there are elephants walking around in Cincinnati,” Tankersley says. “But by the time you’re at the end of your years, there are no more elephants. It happens within your lifetime.”
Tankersley explains what he and a team of international researchers found may have caused this catastrophic event in Earth’s history in their research, “Evidence for Deposition of 10 Million Tonnes of Impact Spherules Across Four Continents 12,800 Years Ago,” which was published in the Proceedings of the National Academy of Sciences. The prestigious journal was established in 1914 and publishes innovative research reports from a broad range of scientific disciplines. Tankersley’s research also was included in the History Channel series “The Universe: When Space Changed History” and will be featured in an upcoming film for The Weather Channel.
This research might indicate that it wasn’t the cosmic collision that extinguished the mammoths and other species, Tankersley says, but the drastic change to their environment.
“The climate changed rapidly and profoundly. And coinciding with this very rapid global climate change was mass extinctions.”
Putting a finger on the end of the ice age
Tankersley is an archaeological geologist. He uses geological techniques, in the field and laboratory, to solve archaeological questions. He’s found a treasure trove of answers to some of those questions in Sheriden Cave in Wyandot County, Ohio. It’s in that spot, 100 feet below the surface, where Tankersley has been studying geological layers that date to the Younger Dryas time period, about 13,000 years ago.
About 12,000 years before the Younger Dryas, the Earth was at the Last Glacial Maximum – the peak of the Ice Age. Millennia passed, and the climate began to warm. Then something happened that caused temperatures to suddenly reverse course, bringing about a century’s worth of near-glacial climate that marked the start of the geologically brief Younger Dryas.
There are only about 20 archaeological sites in the world that date to this time period and only 12 in the United States – including Sheriden Cave.
“There aren’t many places on the planet where you can actually put your finger on the end of the last ice age, and Sheriden Cave is one of those rare places where you can do that,” Tankersley says.
Rock-solid evidence of cosmic calamity
In studying this layer, Tankersley found ample evidence to support the theory that something came close enough to Earth to melt rock and produce other interesting geological phenomena. Foremost among the findings were carbon spherules. These tiny bits of carbon are formed when substances are burned at very high temperatures. The spherules exhibit characteristics that indicate their origin, whether that’s from burning coal, lightning strikes, forest fires or something more extreme. Tankersley says the ones in his study could only have been formed from the combustion of rock.
The spherules also were found at 17 other sites across four continents – an estimated 10 million metric tons’ worth – further supporting the idea that whatever changed Earth did so on a massive scale. It’s unlikely that a wildfire or thunderstorm would leave a geological calling card that immense – covering about 50 million square kilometers.
“We know something came close enough to Earth and it was hot enough that it melted rock – that’s what these carbon spherules are. In order to create this type of evidence that we see around the world, it was big,” Tankersley says, contrasting the effects of an event so massive with the 1883 volcanic explosion on Krakatoa in Indonesia. “When Krakatoa blew its stack, Cincinnati had no summer. Imagine winter all year-round. That’s just one little volcano blowing its top.”
Other important findings include:
Micrometeorites: smaller pieces of meteorites or particles of cosmic dust that have made contact with the Earth’s surface.
Nanodiamonds: microscopic diamonds formed when a carbon source is subjected to an extreme impact, often found in meteorite craters.
Lonsdaleite: a rare type of diamond, also called a hexagonal diamond, only found in non-terrestrial areas such as meteorite craters.
This is an environmental scanning electron microscope image of a carbon spherule from Sheriden Cave. Credit: Ken Tankersley, University of Cincinnati
Three choices at the crossroads of oblivion
Tankersley says while the cosmic strike had an immediate and deadly effect, the long-term side effects were far more devastating – similar to Krakatoa’s aftermath but many times worse – making it unique in modern human history.
In the cataclysm’s wake, toxic gas poisoned the air and clouded the sky, causing temperatures to plummet. The roiling climate challenged the existence of plant and animal populations, and it produced what Tankersley has classified as “winners” and “losers” of the Younger Dryas. He says inhabitants of this time period had three choices: relocate to another environment where they could make a similar living; downsize or adjust their way of living to fit the current surroundings; or swiftly go extinct. “Winners” chose one of the first two options while “losers,” such as the wooly mammoth, took the last.
“Whatever this was, it did not cause the extinctions,” Tankersley says. “Rather, this likely caused climate change. And climate change forced this scenario: You can move, downsize or you can go extinct.”
Humans at the time were just as resourceful and intelligent as we are today. If you transported a teenager from 13,000 years ago into the 21st century and gave her jeans, a T-shirt and a Facebook account, she’d blend right in on any college campus. Back in the Younger Dryas, with mammoth off the dinner table, humans were forced to adapt – which they did to great success.
Weather report: cloudy with a chance of extinction
That lesson in survivability is one that Tankersley applies to humankind today.
“Whether we want to admit it or not, we’re living right now in a period of very rapid and profound global climate change. We’re also living in a time of mass extinction,” Tankersley says. “So I would argue that a lot of the lessons for surviving climate change are actually in the past.”
He says it’s important to consider a sustainable livelihood. Humans of the Younger Dryas were hunter-gatherers. When catastrophe struck, these humans found news ways and new places to hunt game and gather wild plants. Evidence found in Sheriden Cave shows that most of the plants and animals living there also endured. Of the 70 species known to have lived there before the Younger Dryas, 68 were found there afterward. The two that didn’t make it were the giant beaver and the flat-headed peccary, a sharp-toothed pig the size of a black bear.
Tankersley also cautions that the possibility of another massive cosmic event should not be ignored. Like earthquakes, tsunamis and volcanoes, these types of natural disasters do happen, and as history has shown, it can be to devastating effect.
“One additional catastrophic change that we often fail to think about – and it’s beyond our control – is something from outer space,” Tankersley says. “It’s a reminder of how fragile we are. Imagine an explosion that happened today that went across four continents. The human species would go on. But it would be different. It would be a game changer.”
Breaking barriers and working together toward real change
Tankersley is a member of UC’s Quaternary and Anthropocene Research Group (QARG), an interdisciplinary conglomeration of researchers dedicated to undergraduate, graduate and professional education, experience-based learning and research in Quaternary science and study of the Anthropocene. He’s proud to be working with his students on projects that, when he was in their shoes, were considered science fiction.
Collaborative efforts such as QARG help break down long-held barriers between disciplines and further position UC as one of the nation’s top public research universities.
“What’s exciting about UC and why our university is producing so much, is we have scientists who are working together and it’s this area of overlap that is so interesting,” Tankersley says. “There’s a real synergy about innovative, transformative, transdisciplinary science and education here. These are the things that really make people take notice. It causes real change in our world.”
In a new business, sometimes the better part of wisdom is knowing when to quit, a new study concludes.
Even though persistence is a key to business success, entrepreneurs might be more successful if they not only knew when to start a business and take risks, but also knew when to abandon it and find something that provides a greater opportunity, researchers said.
It may be human nature to want to make an idea work, but it can also be a poor business decision to stay wedded to an idea if the evidence suggests it’s not working as well as another potential opportunity.
“Entrepreneurs need to balance that desire to persist, which is in fact what often makes someone a successful entrepreneur, with the ability to sense when it is time to walk away,” said Bobby Garrett Jr., an assistant professor of entrepreneurship at Oregon State University and co-author of the study.
The results are published online in the International Small Business Journal. Garrett and lead author Daniel Holland of Utah State University analyzed the decision-making process of 135 entrepreneurs in high-tech industries. They found that even when confronted with another business opportunity that could yield successful results, many entrepreneurs resisted quitting their current venture.
“It’s escalation of commitment,” Garrett said. “When an entrepreneur has invested resources into a new business, they have difficulty letting go even when things go south or another opportunity arises.”
Garrett likens this psychology to a casino mentality.
“Someone who has spent one hour at the roulette table may think, ‘If I just stick with it, I can win,’” he said. “An entrepreneur’s thought process is not dissimilar to this.”
However, that same doggedness is also what makes entrepreneurs successful. In the field of entrepreneurship, Garrett said this is called “entrepreneurial resilience.”
“Everyone knows that entrepreneurs often fail,” he said. “That same persistence, and ability to keep trying against the odds, is also an admirable trait, especially when that persistence pays off.”
In their study, the researchers recommend that any potential entrepreneur keep the risk versus reward of any venture in mind, and evaluate the chances that their start-up may succeed.
Pulsars have a number of unusual qualities. Like zombies, they shine even though they’re technically dead, and they rotate rapidly, emitting powerful and regular beams of radiation that are seen as flashes of light, blinking on and off at intervals from seconds to milliseconds. A NASA team has built a first-of-a-kind testbed that simulates these distinctive pulsations.
The pulsar-on-a-table, known as the Goddard X-ray Navigation Laboratory Testbed, was built to test and validate a next-generation X-ray navigation technology to be demonstrated on a dual-use instrument recently selected as a NASA Explorer Mission of Opportunity.
“This is a unique capability,” said Jason Mitchell, an engineer at NASA’s Goddard Space Flight Center in Greenbelt, Md., who helped develop the tabletop-size facility that simulates the rapid-fire pulsations that distinguish this unusual class of stars, considered the densest objects in the universe. “We needed a capability that would let us retire technological risks early and test as many of the technology’s components as possible,” he said.
The facility is validating advanced technologies for the Neutron-star Interior Composition Explorer/Station Explorer for X-ray Timing and Navigation Technology, or “NICER/SEXTANT,” for short. Slated to fly on the International Space Station in 2017, the instrument will study the interior compositions of neutron stars largely through observations of their pulsating next-of-kin, pulsars, and from the same platform, demonstrate pulsar-based navigation, also called XNAV, a concept advanced after the discovery of these objects in 1967.
Pulsars offer a potentially revolutionary navigational solution because of their rapid rotation and the powerful beams of light that emanate from their magnetic poles. On Earth, these beams are seen as flashes of light, blinking on and off as the pulsar rotates into view. Because of their predictable pulsations, they can provide high-precision timing just like the atomic-clock signals supplied through the 26-satellite, military-operated GPS.
However, unlike GPS signals, which are geared to Earth-based applications, pulsars are accessible in virtually every conceivable flight regime, from low-Earth to interplanetary science, making the technology ideal for travel throughout the solar system and beyond.
From its berth on the International Space Station, the NICER/SEXTANT instrument will use its 56 bundled X-ray telescopes, silicon detectors and other advanced technologies to detect X-ray photons in the pulsars’ powerful beams of light to estimate their arrival times. With these measurements, the system will stitch together an onboard, completely autonomous navigational solution using specially developed algorithms.
“X-ray navigation has the potential to become an enabling technology for very deep space exploration and an important augmentation to NASA’s Deep Space Network” (the network of ground stations that communicate with spacecraft to make course corrections), said co-developer Luke Winternitz, also of NASA Goddard, whose curriculum vitae also includes the development of another advanced navigation technology, the Navigator receiver that captures the GPS signal even in low-signal environments.
With the Explorer win, the NICER/SEXTANT team will begin building and integrating the telescope package and associated hardware and software.
But as with all spacecraft missions, end-to-end testing presents another set of challenges. “We had to have a way to test the technology,” Winternitz said. “We have GPS constellation simulators that make our GPS receivers think they are in orbit; we needed something analogous for an XNAV receiver.”
Mimicking Pulsar Pulsations
In essence, the pulsar-on-a-table does just that.
It leverages several Goddard-developed navigation and orbit-determination software tools and specialized hardware to mimic a pulsar’s spin rates, its location in the sky, the station’s orbital parameters, and other considerations needed to simulate the environment and conditions that NICER/SEXTANT will encounter when formulating a navigational solution. “You can change a lot of the parameters in the testbed and add hardware in the loop, to perform a full suite of tests,” Winternitz said. “We now have a way to take our mission concept and test it fully.”
A central component of GXNLT is Goddard’s Modulated X-ray Source, which produces X-ray photons with rapidly varying intensity, turning on and off many times per second to simulate the target star’s pulsations. Each MXS-produced photon travels through a short channel and impinges on a silicon-drift detector, where it receives a time stamp. The photon events are grouped into batches and processed by algorithms to extract pulse-arrival time and Doppler measurements. A set of tools then uses these measurements to estimate the orbital outpost’s position—all needed to ultimately formulate a navigational solution.
To ground-truth the calculations, the team will run comparisons with an onboard GPS receiver based on the Goddard-developed Navigator receiver. Two NASA missions will use the Navigator technology to acquire GPS signals in weak-signal areas. Experiments with the testbed have shown that NICER/SEXTANT, once deployed, will demonstrate real-time calculations with sub-kilometer accuracy, Winternitz said.
“The whole point is to test as you fly,” Mitchell said. “This testbed enables that.” But what is the facility’s most notable attribute? It’s the fact that “it can simulate a pulsar,” Mitchell said. “To my knowledge, nothing in the world can do this.”
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A new study conducted at the University of Bristol and published online today in the Journal of Evolutionary Biology sheds light on how the brain and inner ear developed in dinosaurs. Stephan Lautenschlager from Bristol’s School of Earth Sciences, together with Tom Hübner from the Niedersächsische Landesmuseum in Hannover, Germany, picked the brains of 150 million year old dinosaurs. The two palaeontologists studied different fossils of the Jurassic dinosaur Dysalotosaurus lettowvorbecki: a very young (juvenile) individual of approximately three years [Read More]
Video compositing to create special effects, replace backgrounds or combine multiple takes of an actor’s performance is an integral, but highly labor-intensive, part of modern film making. Researchers at Disney Research, Zürich, however, have found an innovative way to create these composite videos that is simple, fast, and easy to use. Rather than perform a painstaking segmentation of elements that are to be added or subtracted from a video, the Disney system, called DuctTake, uses computer algorithms to find a [Read More]