Those who feel as though they’ve been living in the never-ending winter of the movie “Frozen” this year may be glad to hear that the spring thaw is now typically arriving up to two weeks earlier in the Northern Hemisphere than it did 20 to 30 years ago. But the changing date of the spring thaw has consequences far beyond reducing the number of mornings when you have to scrape off your windshield.
One ecosystem where scientists would most like to understand the effects of changing freeze/thaw cycles is boreal forests, the great ring of green covering the land nearest the North Pole. The forests of Alaska, Canada, Scandinavia and Siberia cover almost 15 percent of Earth’s land surface. The Arctic is warming more quickly than lower latitudes, and the way these forests respond to this rapid change could provide valuable clues about our planet’s warmer future.
But we know very little about how the boreal forests are changing. Millions of square miles have no roads or even villages. “What we have now are very sparse, seasonal measurements from the ground,” said John Kimball, a professor of systems ecology at the University of Montana, Missoula, and a member of the science team for NASA’s Soil Moisture Active Passive (SMAP) mission, launched Jan. 31. “We do have long-term, global satellite data sets that are sensitive to freeze-thaw, but they tend to be very coarse.” That means each measurement averages the status of a large area. Like a mosaic made of large tiles, these data cannot show much detail.
That’s about to change. By the end of April, SMAP will begin monitoring the frozen or thawed state of the landscape north of 45 degrees north latitude (about the latitude of Minneapolis) every two days. The primary mission of SMAP is to measure the amount of moisture in the top few inches of soil globally, but it also detects whether that moisture is frozen or in liquid form. SMAP’s radar measurements, with “tiles” only half a mile to a mile and a half (1 to 3 kilometers) across, will reveal far more detail than scientists now have about the freeze/thaw status of the land surface.
Why is greater detail needed? In the Arctic, the timing of the spring thaw can vary considerably within a small area. Because the returning sun is low on the horizon, the shadowed north side of a hill may remain icy many days after plants have started growing again on the sunlit south side. Those early spring weeks are critical in the short Arctic growing season. “Once the vegetation thaws, boom! Photosynthesis takes off,” Kimball explained. “You can get your highest rates of photosynthesis within a few weeks after the thaw, and a later thaw can mean much lower vegetation growth for the season. We need observations at what I call the landscape level to more precisely monitor those patterns and changes.”
During photosynthesis, plants absorb carbon dioxide from the air. The carbon stays in their wood, roots and leaves, and when they die, most of it remains in the soil. That makes undisturbed forests what scientists call carbon sinks — places that remove carbon from the atmosphere. Longer unfrozen seasons in the Arctic give forests more time to grow and spread, increasing the extent of the carbon sink.
On the other hand, climate warming has increased the occurrence of droughts and wildfires in the Arctic. A burning forest spews enormous amounts of carbon into the atmosphere; in scientific terms, it is a carbon source. Thus, global climate change is causing the northern forests both to absorb and to release more carbon.
With so little Arctic data to crunch, models of Arctic land processes do not agree on which of these trends is prevailing, much less what the future could hold. Lack of consensus does not indicate fundamental disagreements on the physical processes involved, according to JPL scientist Josh Fisher, a member of the SMAP algorithm team. The problem is that, at present, if you put the Arctic’s emitted carbon on one side of a scale and absorbed carbon on the other, the scales would almost balance. “The source/sink balance is usually close to zero, and it’s very easy to get on the wrong side of the zero,” he said. Yet the wrong answer on this fundamental question can cascade into a chain of wrong answers in the course of a model simulation. SMAP’s fine-scale observations have the potential to improve modelers’ understanding of both today’s situation and how it may change in the future.
This spring, SMAP will spin up in time to track the spring thaw in the boreal forest with the detail scientists need — as Princess Anna in “Frozen” says, “For the first time in forever.”
For more about SMAP, visit:
JPL is managed for NASA by the California Institute of Technology in Pasadena.
Researchers at the University of Texas at Austin, NASA and other research organizations have discovered two seafloor troughs that could allow warm ocean water to reach the base of Totten Glacier, East Antarctica’s largest and most rapidly thinning glacier. The discovery likely explains the glacier’s extreme thinning and raises concern about its impact on sea level rise.
The result, published in the journal Nature Geoscience today, March 16, has global implications because the ice flowing through Totten Glacier alone is equivalent to the entire volume of the more widely studied West Antarctic Ice Sheet. If Totten Glacier were to collapse completely, global sea levels would rise by at least 11 feet (3.3 meters). As in the West Antarctic Ice Sheet, complete collapse of Totten Glacier may take centuries, although the timing of retreat in both places is the subject of intensive research.
East Antarctica has appeared to be stable compared with the rapidly melting western side of the continent. The new finding shows that “Totten Glacier and the East Antarctic Ice Sheet are a much more interesting and dynamic part of the sea level rise story than we’d previously thought,” said co-author Dustin Schroeder, a scientist at NASA’s Jet Propulsion Laboratory, Pasadena, California. Schroeder helped analyze data from an ice-penetrating radar to demonstrate that ocean water could access the glacier through the newfound troughs.
In some areas of the ocean surrounding Antarctica, warm water can be found below cooler water because it is saltier, and therefore heavier, than the shallower water. Seafloor valleys that connect this deep warm water to the coast can especially compromise glaciers, but this process had previously been seen only under the West Antarctic Ice Sheet. Deep warm water had been observed seaward of Totten Glacier, but there was no evidence that it could compromise coastal ice.
The newly discovered troughs are deep enough to give the deep warm water access to the huge cavity under the glacier. The deeper of the two troughs extends from the ocean to the underside of Totten Glacier in an area not previously known to be floating.
The data for this study were gathered as part of the International Collaboration for Exploration of the
Cryosphere through Airborne Profiling (ICECAP) project, which, together with the East Antarctic component of NASA’s Operation IceBridge mission, made the first comprehensive survey of the Totten Glacier Ice Shelf and nearby regions between 2008 and 2012. Other coauthors of the study come from research organizations and universities in Australia, France and England.
For more information on the new study, see:
To learn more about Operation IceBridge and ICECAP, visit:
The paper is available at:
NASA Holds Teleconference on Hubble Observations of Jupiter’s Largest Moon
(March 9, 2015)
|This image of Ganymede, one of Jupiter’s moons and the largest moon in our solar system was taken by NASA’s Galileo spacecraft. Image Credit: NASA|
NASA will host a teleconference at 11 a.m. EDT on Thursday, March 12, to discuss Hubble Space Telescope’s observations of Ganymede, Jupiter’s largest moon. These results will help scientists in the search for habitable worlds beyond Earth.
Participants in the teleconference will be:
- Jim Green, director of Planetary Science, NASA Headquarters, Washington
- Joachim Saur, professor for geophysics, University of Cologne, Germany
- Jennifer Wiseman, Hubble senior project scientist, NASA Goddard Space Flight Center, Greenbelt, Maryland
- Heidi Hammel, executive vice president, Association of Universities for Research in Astronomy, Washington
To participate by phone, reporters must contact Felicia Chou at felicia.chou and provide their media affiliation no later than noon Wednesday.
Audio of the teleconference will be streamed live on NASA’s website at:
For information about NASA’s Hubble Space Telescope, visit:
For information about our solar system, including Jupiter and Ganymede, visit:
NASA’s Space Launch System Booster Passes Major Ground Test
(March 11, 2015)
The largest, most powerful rocket booster ever built successfully fired up Wednesday for a major-milestone ground test in preparation for future missions to help propel NASA’s Space Launch System (SLS) rocket and Orion spacecraft to deep space destinations, including an asteroid and Mars.
The booster fired for two minutes, the same amount of time it will fire when it lifts the SLS off the launch pad, and produced about 3.6 million pounds of thrust. The test was conducted at the Promontory, Utah test facility of commercial partner Orbital ATK, and is one of two tests planned to qualify the booster for flight. Once qualified, the flight booster hardware will be ready for shipment to NASA’s Kennedy Space Center in Florida for the first SLS flight.
“The work being done around the country today to build SLS is laying a solid foundation for future exploration missions, and these missions will enable us to pioneer far into the solar system,” said William Gerstenmaier, NASA’s associate administrator for human exploration and operations. “The teams are doing tremendous work to develop what will be a national asset for human exploration and potential science missions.”
It took months to heat the 1.6 million pound booster to 90 degrees Fahrenheit to verify its performance at the highest end of the booster’s accepted propellant temperature range. A cold-temperature test, at a target of 40 degrees Fahrenheit, the low end of the propellant temperature range, is planned for early 2016. These two tests will provide a full range of data for analytical models that inform how the booster performs. During the test, temperatures inside the booster reached more than 5,600 degrees.
“This test is a significant milestone for SLS and follows years of development,” said Todd May, SLS program manager. “Our partnership with Orbital ATK and more than 500 suppliers across the country is keeping us on the path to building the most powerful rocket in the world.”
During the test, more than 531 instrumentation channels on the booster were measured to help assess some 102 design objectives. The test also demonstrated the booster meets applicable ballistic performance requirements, such as thrust and pressure. Other objectives included data gathering on vital motor upgrades, such as the new internal motor insulation and liner and an improved nozzle design.
When completed, two five-segment boosters and four RS-25 main engines will power the SLS on deep space missions. The 177-feet-long solid rocket boosters operate in parallel with the main engines for the first two minutes of flight. They provide more than 75 percent of the thrust needed for the rocket to escape the gravitational pull of the Earth.
The first flight test of SLS will be configured for a 70-metric-ton (77-ton) lift capacity and carry an uncrewed Orion spacecraft beyond low-Earth orbit to test the performance of the integrated system. The SLS will later be configured to provide an unprecedented lift capability of 130 metric tons (143 tons) to enable missions farther into our solar system.
For more information on SLS, visit:
Marshall Space Flight Center, Huntsville, Ala.
NASA Spacecraft Becomes First to Orbit a Dwarf Planet
Latest News From NASA’s Jet Propulsion Laboratory
March 6, 2015
NASA Launches 2015 Space Apps Challenge to Spark Innovation
Image Credit: NASA
NASA and other space agencies around the world are preparing for the fourth annual
International Space Apps Challenge, which will be held April 10-12 at more than 135 locations worldwide, including New York, host of the event’s Global Mainstage.
During this three-day code-a-thon, participants are asked to develop mobile applications, software, hardware, data visualization and platform solutions that could contribute to space exploration missions and help improve life on Earth.
“These challenges provide opportunities for US and global citizen scientists, engineers, and students to interact and contribute to space exploration through code development, data analytics innovation, open source software and hardware,” said Deborah Diaz, agency chief technology officer at NASA Headquarters in Washington.
This year’s challenge will include the first ever Data Bootcamp, with a focus on Women in Data. The bootcamp is open to the public and will give participants the opportunity to improve their skills with computer coding and data. The April 10 bootcamp will stream live online from the Global Mainstage. Astronaut Cady Coleman and NASA Chief Scientist Ellen Stofan will be on hand at the New York event to work with STEM students and also will be available for media interviews.
More than 200 data sources, including data sets, services and tools will be available for this challenge. This event brings together techy-savvy citizens, scientists, entrepreneurs, educators, and students to help solve problems and questions relevant to space exploration and broader subjects that impact life on Earth.
This year, 35 challenges represent NASA mission priorities in four areas: Earth studies, space exploration, human health research and robotics. Many of the challenges are in the Earth theme, supporting NASA’s missions to monitors Earth’s vital signs from land, air and space.
A full list of challenges can be viewed at:
Follow the challenge on Twitter using the hashtag #spaceapps.
For information about NASA’s programs and missions, visit:
Planet ‘Reared’ by Four Parent Stars
— Astronomers have discovered the second known case of a planet residing in a quadruple star system.
— The planet was known before, but was thought to have only three stars, not four.
— The findings help researchers understand how multiple star systems can influence the development and fate of planets.
Growing up as a planet with more than one parent star has its challenges. Though the planets in our solar system circle just one star — our sun — other more distant planets, called exoplanets, can be reared in families with two or more stars. Researchers wanting to know more about the complex influences of multiple stars on planets have come up with two new case studies: a planet found to have three parents, and another with four.
The discoveries were made using instruments fitted to telescopes at the Palomar Observatory in San Diego: the Robo-AO adaptive optics system, developed by the Inter-University Center for Astronomy and Astrophysics in India and the California Institute of Technology in Pasadena, and the PALM-3000 adaptive optics system, developed by NASA’s Jet Propulsion Laboratory in Pasadena, California, and Caltech.
This is only the second time a planet has been identified in a quadruple star system. While the planet was known before, it was thought to have only three stars, not four. The first four-star planet, KIC 4862625, was discovered in 2013 by citizen scientists using public data from NASA’s Kepler mission.
The latest discovery suggests that planets in quadruple star systems might be less rare than once thought. In fact, recent research has shown that this type of star system, which usually consists of two pairs of twin stars slowly circling each other at great distances, is itself more common than previously believed.
“About four percent of solar-type stars are in quadruple systems, which is up from previous estimates because observational techniques are steadily improving,” said co-author Andrei Tokovinin of the Cerro Tololo Inter-American Observatory in Chile.
The newfound four-star planetary system, called 30 Ari, is located 136 light-years away in the constellation Aries. The system’s gaseous planet is enormous, with 10 times the mass of Jupiter, and it orbits its primary star every 335 days. The primary star has a relatively close partner star, which the planet does not orbit. This pair, in turn, is locked in a long-distance orbit with another pair of stars about 1,670 astronomical units away (an astronomical unit is the distance between Earth and the sun). Astronomers think it’s highly unlikely that this planet, or any moons that might circle it, could sustain life.
Were it possible to see the skies from this world, the four parent stars would look like one small sun and two very bright stars that would be visible in daylight. One of those stars, if viewed with a large enough telescope, would be revealed to be a binary system, or two stars orbiting each other.
In recent years, dozens of planets with two or three parent stars have been found, including those with “Tatooine” sunsets reminiscent of the Star Wars movies. Finding planets with multiple parents isn’t too much of a surprise, considering that binary stars are more common in our galaxy than single stars.
“Star systems come in myriad forms. There can be single stars, binary stars, triple stars, even quintuple star systems,” said Lewis Roberts of JPL, lead author of the new findings appearing in the journal Astronomical Journal. “It’s amazing the way nature puts these things together.”
Roberts and his colleagues want to understand the effects that multiple parent stars can have on their developing youthful planets. Evidence suggests that stellar companions can influence the fate of planets by changing the planets’ orbits and even triggering some to grow more massive. For example, the “hot Jupiters” — planets around the mass of Jupiter that whip closely around their stars in just days — might be gently nudged closer to their primary parent star by the gravitational hand of a stellar companion.
In the new study, the researchers describe using the automated Robo-AO system on Palomar Observatory to scan the night skies, searching hundreds of stars each night for signs of stellar companions. They found two candidates hosting exoplanets: the four-star system 30 Ari, and a triple-star planetary system called HD 2638. The findings were confirmed using the higher-resolution PALM-3000 instrument, also at Palomar Observatory.
The new planet with a trio of stars is a hot Jupiter that circles its primary star tightly, completing one lap every three days. Scientists already knew this primary star was locked in a gravitational tango with another star, about 0.7 light-years away, or 44,000 astronomical units. That’s relatively far apart for a pair of stellar companions. The latest discovery is of a third star in the system, which orbits the primary star from a distance of 28 astronomical units — close enough to have influenced the hot Jupiter’s development and final orbit.
“This result strengthens the connection between multiple star systems and massive planets,” said Roberts.
In the case of Ari 30, the discovery brought the number of known stars in the system from three to four. The fourth star lies at a distance of 23 astronomical units from the planet. While this stellar companion and its planet are closer to each other than those in the HD 2638 system, the newfound star does not appear to have impacted the orbit of the planet. The exact reason for this is uncertain, so the team is planning further observations to better understand the orbit of the star and its complicated family dynamics.
JPL is managed for NASA by the California Institute of Technology in Pasadena.