Friday, July 25, 2014

NASA's Voyager 1 Explores Final Frontier of Our 'Solar Bubble'

NASA's Voyager 1 Explores Final Frontier of Our 'Solar Bubble':

This artist's concept shows NASA's two Voyager spacecraft exploring a turbulent region of space known as the heliosheath, the outer shell of the bubble of charged particles around our sun
This artist's concept shows NASA's two Voyager spacecraft exploring a turbulent region of space known as the heliosheath, the outer shell of the bubble of charged particles around our sun. Image Credit: NASA/JPL-Caltech
› Larger view

June 27, 2013

PASADENA, Calif. -- Data from Voyager 1, now more than 11 billion miles (18 billion kilometers) from the sun, suggest the spacecraft is closer to becoming the first human-made object to reach interstellar space.


Research using Voyager 1 data and published in the journal Science today provides new detail on the last region the spacecraft will cross before it leaves the heliosphere, or the bubble around our sun, and enters interstellar space. Three papers describe how Voyager 1's entry into a region called the magnetic highway resulted in simultaneous observations of the highest rate so far of charged particles from outside heliosphere and the disappearance of charged particles from inside the heliosphere.


Scientists have seen two of the three signs of interstellar arrival they expected to see: charged particles disappearing as they zoom out along the solar magnetic field, and cosmic rays from far outside zooming in. Scientists have not yet seen the third sign, an abrupt change in the direction of the magnetic field, which would indicate the presence of the interstellar magnetic field.


"This strange, last region before interstellar space is coming into focus, thanks to Voyager 1, humankind's most distant scout," said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena. "If you looked at the cosmic ray and energetic particle data in isolation, you might think Voyager had reached interstellar space, but the team feels Voyager 1 has not yet gotten there because we are still within the domain of the sun's magnetic field."


Scientists do not know exactly how far Voyager 1 has to go to reach interstellar space. They estimate it could take several more months, or even years, to get there. The heliosphere extends at least 8 billion miles (13 billion kilometers) beyond all the planets in our solar system. It is dominated by the sun's magnetic field and an ionized wind expanding outward from the sun. Outside the heliosphere, interstellar space is filled with matter from other stars and the magnetic field present in the nearby region of the Milky Way.


Voyager 1 and its twin spacecraft, Voyager 2, were launched in 1977. They toured Jupiter, Saturn, Uranus and Neptune before embarking on their interstellar mission in 1990. They now aim to leave the heliosphere. Measuring the size of the heliosphere is part of the Voyagers' mission.


The Science papers focus on observations made from May to September 2012 by Voyager 1's cosmic ray, low-energy charged particle and magnetometer instruments, with some additional charged particle data obtained through April of this year.


Voyager 2 is about 9 billion miles (15 billion kilometers) from the sun and still inside the heliosphere. Voyager 1 was about 11 billion miles (18 billion kilometers) from the sun Aug. 25 when it reached the magnetic highway, also known as the depletion region, and a connection to interstellar space. This region allows charged particles to travel into and out of the heliosphere along a smooth magnetic field line, instead of bouncing around in all directions as if trapped on local roads. For the first time in this region, scientists could detect low-energy cosmic rays that originate from dying stars.


"We saw a dramatic and rapid disappearance of the solar-originating particles. They decreased in intensity by more than 1,000 times, as if there was a huge vacuum pump at the entrance ramp onto the magnetic highway," said Stamatios Krimigis, the low-energy charged particle instrument's principal investigator at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "We have never witnessed such a decrease before, except when Voyager 1 exited the giant magnetosphere of Jupiter, some 34 years ago."


Other charged particle behavior observed by Voyager 1 also indicates the spacecraft still is in a region of transition to the interstellar medium. While crossing into the new region, the charged particles originating from the heliosphere that decreased most quickly were those shooting straightest along solar magnetic field lines. Particles moving perpendicular to the magnetic field did not decrease as quickly. However, cosmic rays moving along the field lines in the magnetic highway region were somewhat more populous than those moving perpendicular to the field. In interstellar space, the direction of the moving charged particles is not expected to matter.


In the span of about 24 hours, the magnetic field originating from the sun also began piling up, like cars backed up on a freeway exit ramp. But scientists were able to quantify that the magnetic field barely changed direction -- by no more than 2 degrees.


"A day made such a difference in this region with the magnetic field suddenly doubling and becoming extraordinarily smooth," said Leonard Burlaga, the lead author of one of the papers, and based at NASA's Goddard Space Flight Center in Greenbelt, Md. "But since there was no significant change in the magnetic field direction, we're still observing the field lines originating at the sun."


NASA's Jet Propulsion Laboratory, in Pasadena, Calif., built and operates the Voyager spacecraft. California Institute of Technology in Pasadena manages JPL for NASA. The Voyager missions are a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate at NASA Headquarters in Washington.


For more information about the Voyager spacecraft mission, visit: http://www.nasa.gov/voyager and
http://voyager.jpl.nasa.gov .

Jia-Rui C. Cook 818-354-0850

Jet Propulsion Laboratory, Pasadena, Calif.

jccook@jpl.nasa.gov


Steve Cole 202-358-0918

NASA Headquarters, Washington

stephen.e.cole@nasa.gov


2013-209
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NASA Decommissions Its Galaxy Hunter Spacecraft

NASA Decommissions Its Galaxy Hunter Spacecraft:

This image from NASA's Galaxy Evolution Explorer (GALEX) shows Messier 94, also known as NGC 4736, in ultraviolet light
This image from NASA's Galaxy Evolution Explorer (GALEX) shows Messier 94, also known as NGC 4736, in ultraviolet light. It is located 17 million light-years away in the constellation Canes Venatici. Image credit: NASA/JPL-Caltech
› Full image and caption

June 28, 2013

PASADENA, Calif. -- NASA has turned off its Galaxy Evolution Explorer (GALEX) after a decade of operations in which the venerable space telescope used its ultraviolet vision to study hundreds of millions of galaxies across 10 billion years of cosmic time.


"GALEX is a remarkable accomplishment," said Jeff Hayes, NASA's GALEX program executive in Washington. "This small Explorer mission has mapped and studied galaxies in the ultraviolet, light we cannot see with our own eyes, across most of the sky."


Operators at Orbital Sciences Corporation in Dulles, Va., sent the signal to decommission GALEX at 12:09 p.m. PDT (3:09 p.m. EDT) Friday, June 28. The spacecraft will remain in orbit for at least 65 years, then fall to Earth and burn up upon re-entering the atmosphere. GALEX met its prime objectives and the mission was extended three times before being cancelled.


Highlights from the mission's decade of sky scans include:


-- Discovering a gargantuan, comet-like tail behind a speeding star called Mira.

-- Catching a black hole "red-handed" as it munched on a star.

-- Finding giant rings of new stars around old, dead galaxies.

-- Independently confirming the nature of dark energy.

-- Discovering a missing link in galaxy evolution -- the teenage galaxies transitioning from young to old.


The mission also captured a dazzling collection of snapshots, showing everything from ghostly nebulas to a spiral galaxy with huge, spidery arms.


In a first-of-a-kind move for NASA, the agency in May 2012 loaned GALEX to the California Institute of Technology in Pasadena, which used private funds to continue operating the satellite while NASA retained ownership. Since then, investigators from around the world have used GALEX to study everything from stars in our own Milky Way galaxy to hundreds of thousands of galaxies 5 billion light-years away.


In the space telescope's last year, it scanned across large patches of sky, including the bustling, bright center of our Milky Way. The telescope spent time staring at certain areas of the sky, finding exploded stars, called supernovae, and monitoring how objects, such as the centers of active galaxies, change over time. GALEX also scanned the sky for massive, feeding black holes and shock waves from early supernova explosions.


"In the last few years, GALEX studied objects we never thought we'd be able to observe, from the Magellanic Clouds to bright nebulae and supernova remnants in the galactic plane," said David Schiminovich of Columbia University, N.Y., N.Y, a longtime GALEX team member who led science operations over the past year. "Some of its most beautiful and scientifically compelling images are part of this last observation cycle."


Data from the last year of the mission will be made public in the coming year.


"GALEX, the mission, may be over, but its science discoveries will keep on going," said Kerry Erickson, the mission's project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif.


A slideshow showing some of the popular GALEX images is online at: http://go.nasa.gov/17xAVDd


JPL managed the GALEX mission and built the science instrument. The mission's principal investigator, Chris Martin, is at Caltech. NASA's Goddard Space Flight Center in Greenbelt, Md., developed the mission under the Explorers Program it manages. Researchers sponsored by Yonsei University in South Korea and the Centre National d'Etudes Spatiales (CNES) in France collaborated on the mission. Caltech manages JPL for NASA.


Graphics and additional information about the Galaxy Evolution Explorer are online at: http://www.nasa.gov/galex

Alan Buis 818-354-0474

Jet Propulsion Laboratory, Pasadena, Calif.

alan.d.buis@jpl.nasa.gov


J.D. Harrington 202-358-5241

Headquarters, Washington

j.d.harrington@nasa.gov


2013-211
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NASA Decommissions Its Galaxy Hunter Spacecraft

NASA Decommissions Its Galaxy Hunter Spacecraft:

This image from NASA's Galaxy Evolution Explorer (GALEX) shows Messier 94, also known as NGC 4736, in ultraviolet light
This image from NASA's Galaxy Evolution Explorer (GALEX) shows Messier 94, also known as NGC 4736, in ultraviolet light. It is located 17 million light-years away in the constellation Canes Venatici. Image credit: NASA/JPL-Caltech
› Full image and caption

June 28, 2013

PASADENA, Calif. -- NASA has turned off its Galaxy Evolution Explorer (GALEX) after a decade of operations in which the venerable space telescope used its ultraviolet vision to study hundreds of millions of galaxies across 10 billion years of cosmic time.


"GALEX is a remarkable accomplishment," said Jeff Hayes, NASA's GALEX program executive in Washington. "This small Explorer mission has mapped and studied galaxies in the ultraviolet, light we cannot see with our own eyes, across most of the sky."


Operators at Orbital Sciences Corporation in Dulles, Va., sent the signal to decommission GALEX at 12:09 p.m. PDT (3:09 p.m. EDT) Friday, June 28. The spacecraft will remain in orbit for at least 65 years, then fall to Earth and burn up upon re-entering the atmosphere. GALEX met its prime objectives and the mission was extended three times before being cancelled.


Highlights from the mission's decade of sky scans include:


-- Discovering a gargantuan, comet-like tail behind a speeding star called Mira.

-- Catching a black hole "red-handed" as it munched on a star.

-- Finding giant rings of new stars around old, dead galaxies.

-- Independently confirming the nature of dark energy.

-- Discovering a missing link in galaxy evolution -- the teenage galaxies transitioning from young to old.


The mission also captured a dazzling collection of snapshots, showing everything from ghostly nebulas to a spiral galaxy with huge, spidery arms.


In a first-of-a-kind move for NASA, the agency in May 2012 loaned GALEX to the California Institute of Technology in Pasadena, which used private funds to continue operating the satellite while NASA retained ownership. Since then, investigators from around the world have used GALEX to study everything from stars in our own Milky Way galaxy to hundreds of thousands of galaxies 5 billion light-years away.


In the space telescope's last year, it scanned across large patches of sky, including the bustling, bright center of our Milky Way. The telescope spent time staring at certain areas of the sky, finding exploded stars, called supernovae, and monitoring how objects, such as the centers of active galaxies, change over time. GALEX also scanned the sky for massive, feeding black holes and shock waves from early supernova explosions.


"In the last few years, GALEX studied objects we never thought we'd be able to observe, from the Magellanic Clouds to bright nebulae and supernova remnants in the galactic plane," said David Schiminovich of Columbia University, N.Y., N.Y, a longtime GALEX team member who led science operations over the past year. "Some of its most beautiful and scientifically compelling images are part of this last observation cycle."


Data from the last year of the mission will be made public in the coming year.


"GALEX, the mission, may be over, but its science discoveries will keep on going," said Kerry Erickson, the mission's project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif.


A slideshow showing some of the popular GALEX images is online at: http://go.nasa.gov/17xAVDd


JPL managed the GALEX mission and built the science instrument. The mission's principal investigator, Chris Martin, is at Caltech. NASA's Goddard Space Flight Center in Greenbelt, Md., developed the mission under the Explorers Program it manages. Researchers sponsored by Yonsei University in South Korea and the Centre National d'Etudes Spatiales (CNES) in France collaborated on the mission. Caltech manages JPL for NASA.


Graphics and additional information about the Galaxy Evolution Explorer are online at: http://www.nasa.gov/galex

Alan Buis 818-354-0474

Jet Propulsion Laboratory, Pasadena, Calif.

alan.d.buis@jpl.nasa.gov


J.D. Harrington 202-358-5241

Headquarters, Washington

j.d.harrington@nasa.gov


2013-211
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Radio Bursts Discovered From Beyond our Galaxy

Radio Bursts Discovered From Beyond our Galaxy:

Parkes Telescope
This image shows the Parkes telescope in Australia, part of the
Commonwealth Scientific and Industrial Research
Organization. Researchers, including a team member from NASA's Jet
Propulsion Laboratory in Pasadena, used the telescope to detect the first
population of radio bursts known to originate from beyond our galaxy.
Image courtesy Shaun Amy
› Larger image

July 08, 2013

Astronomers, including a team member from NASA's Jet Propulsion Laboratory in Pasadena, Calif., have detected the first population of radio bursts known to originate from galaxies beyond our own Milky Way. The sources of the light bursts are unknown, but cataclysmic events, such as merging or exploding stars, are likely the triggers.


A radio burst is a quick surge of light from a point on the sky, made up of longer wavelengths in the radio portion of the light spectrum. A single radio burst was detected about six years ago, but researchers were unclear about whether it came from within or beyond our galaxy.


The new radio-burst detections -- four in total -- are from billions of light-years away, erasing any doubt that the phenomenon is real. The discovery, described in the July 4 issue of the journal Science, comes from an international team that used the Parkes Observatory in Australia.


"Short radio bursts are really tricky to identify," explained Sarah Burke Spolaor of JPL. "Our team had to search 11 months of data covering a large sky area to find them."


Spolaor developed the software used to seek single pulses in the radio data and pick out genuine signals from local interference sources -- such as cell phones, spark plugs and aircraft. This amounted to an enormous and complex computational task.


Dan Thornton, lead author of the new study from England's University of Manchester and Australia's Commonwealth Scientific and Industrial Research Organization, said, "The radio bursts last for just a few milliseconds and the farthest one that we detected was 11 billion light-years away."


The findings open the door to studying an entirely new class of eruptive cosmic events and can also help with cosmology mysteries, for example, about the nature of matter in the universe.


Our sky is full of flares and bursts of varying natures. For instance, gamma-ray bursts are thought to occur when stars collapse into black holes. They are routinely detected by a network of telescopes on the ground and in space, including NASA's Swift and Fermi. When one telescope in the network detects a burst, it can notify others to quickly slew to the target for coordinated observations.


The newfound radio bursts, while likely of a different origin than gamma-ray bursts, also consist of light waves generated by powerful events happening at great distances. Researchers would like to develop systems similar to the gamma-ray burst networks of telescopes to follow up quickly on radio bursts, but this is more challenging because radio waves are slowed by gas in space. Time is needed to process the radio observations and tease out the short-lived bursts.


On the other hand, the fact that radio waves are impeded as they travel through space to reach us offers benefits. By studying how the radio waves have been slowed, scientists can better understand baryonic matter, the material that gets in the way. Baryonic matter is what makes up people and planets and everything you see. The rest of the universe consists of mysterious substances called dark matter and dark energy.


Exactly what is triggering the release of the radio waves is unknown. Theories include colliding neutron stars or black holes; evaporating black holes; and stellar explosions called supernovae. The new data do not fit nicely with any of these scenarios, leaving the scientists perplexed.


Further scans for radio bursts using the Parkes Observatory are ongoing. Researchers are also using other telescopes to search for and characterize these events. For instance, the V-Fastr project, developed in part at JPL, is currently running on the National Radio Astronomy Observatory's Very Long Baseline Array, an international network of telescopes. It will enable scientists to localize a burst's origin to a precise location in a distant host galaxy.


Other institutions participating in this study are: Max-Planck Institute for Radio Astronomy, Germany; the INAF-Cagliari Astronomical Observatory and the Cagliari Observatory and University, Italy; Swinburne University of Technology, the Commonwealth Scientific and Industrial Research Organization, the Australian Research Council Centre of Excellence for All-Sky Astrophysics and Curtin University, all in Australia; and West Virginia University, Morgantown.


JPL is managed by the California Institute of Technology, Pasadena, for NASA.

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2013-216
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NASA Discusses Mars 2020 Plans in July 9 Teleconference

NASA Discusses Mars 2020 Plans in July 9 Teleconference:

Global view of Mars
This global view of Mars is composed of about 100 Viking Orbiter images. Image credit: NASA/JPL-Caltech
› Larger image

July 08, 2013

WASHINGTON -- NASA will host a media teleconference at noon PDT (3 p.m. EDT) on Tuesday, July 9 to provide details about a report that will help define science objectives for the agency's next Mars rover.


The report, prepared by the Mars 2020 Science Definition Team (SDT) NASA appointed in January, is an early, crucial step in developing the mission and the rover's prime science objectives.


The teleconference participants are:


-- John Grunsfeld, NASA's associate administrator for science, Washington

-- Jim Green, director, Planetary Science Division, NASA Headquarters, Washington

-- Jack Mustard, SDT chair and professor of geological sciences, Brown University, Providence. R.I.

-- Lindy Elkins-Tanton, SDT member and director of the Carnegie Institution for Science's Department of Terrestrial Magnetism, Washington

The Mars 2020 Science Definition Team report will be posted an hour before the teleconference at:
http://mars.jpl.nasa.gov/m2020/ .


Audio of the teleconference will be streamed live at: http://www.nasa.gov/newsaudio . The telecon and graphics will also be streamed on the Web at: http://www.ustream.tv/nasajpl2 .
Graphics for the teleconference will be posted online at: http://www.nasa.gov/mars/telecon20130709

Guy Webster 818-354-6278

Jet Propulsion Laboratory, Pasadena, Calif.

guy.webster@jpl.nasa.gov

Dwayne Brown 202-358-1726

Headquarters, Washington

dwayne.c.brown@nasa.gov
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Long-Running Jason-1 Ocean Satellite Takes Final Bow

Long-Running Jason-1 Ocean Satellite Takes Final Bow:

Artist's concept of the joint NASA/CNES Jason-1 ocean altimetry satellite
Artist's concept of the joint NASA/CNES Jason-1 ocean altimetry satellite. During its 11-1/2-year life, Jason-1 helped create a 20-plus-year climate record of global ocean surface topography, providing new insights into ocean circulation, tracking our rising seas and enabling more accurate weather, ocean and climate forecasts. Image credit: NASA/JPL-Caltech
› Larger image


July 03, 2013

PASADENA, Calif. - The curtain has come down on a superstar of the satellite oceanography world that played the "Great Blue Way" of the world's ocean for 11-1/2 years. The successful joint NASA and Centre National d'Etudes Spatiales (CNES) Jason-1 ocean altimetry satellite was decommissioned this week following the loss of its last remaining transmitter.


Launched Dec. 7, 2001, and designed to last three to five years, Jason-1 helped create a revolutionary 20-plus-year climate data record of global ocean surface topography that began in 1992 with the launch of the NASA/CNES Topex/Poseidon satellite. For more than 53,500 orbits of our planet, Jason-1 precisely mapped sea level, wind speed and wave height for more than 95 percent of Earth's ice-free ocean every 10 days. The mission provided new insights into ocean circulation, tracked our rising seas and enabled more accurate weather, ocean and climate forecasts.


"Jason-1 has been a resounding scientific, technical and international success," said John Grunsfeld, associate administrator of NASA's Science Mission Directorate in Washington. "The mission met all of its requirements, performed an extended mission and demonstrated how a long-term climate data record should be established from successively launched satellites. Since launch, it has charted nearly 1.6 inches (4 centimeters) of rise in global sea levels, a critical measure of climate change and a direct result of global warming. The Jason satellite series provides the most accurate measure of this impact, which is felt all over the globe."


During parts of its mission, Jason-1 flew in carefully coordinated orbits with both its predecessor Topex/Poseidon and its successor, the Ocean Surface Topography Mission/Jason-2, launched in 2008. These coordinated orbit periods, which lasted about three years each, cross-calibrated the satellites, making possible a 20-plus-year unbroken climate record of sea level change. These coordination periods also doubled data coverage.


Combined with data from the European Space Agency's Envisat mission, which also measured sea level from space, these data allow scientists to study smaller-scale ocean circulation phenomena, such as coastal tides, ocean eddies, currents and fronts. These small-scale features are thought to be responsible for transporting and mixing heat and other properties, such as nutrients and dissolved carbon dioxide, within the ocean.


"Jason-1 was an exemplary and multi-faceted altimeter mission and contributed so much to so many scientific disciplines," said Jean-Yves Le Gall, CNES president in Paris. "Not only did Jason-1 extend the precise climate record established by Topex/Poseidon, it made invaluable observations for mesoscale ocean studies on its second, interleaved orbit. Even from its 'graveyard' orbit, Jason-1 continued to make unprecedented new observations of the Earth's gravity field, with precise measurements right till the end."


The in-orbit Jason-2 mission, operated by the meteorological agencies of the United States and Europe (the National Oceanic and Atmospheric Administration and EUMETSAT, respectively) in collaboration with NASA and CNES, is in good health and continues to collect science and operational data. This same U.S./European team is preparing to launch the next satellite in the series, Jason-3, in March 2015.


Contact was lost with the Jason-1 satellite on June 21 when it was out of visibility of ground stations. At the time of the last contact, Jason-1 and its instruments were healthy, with no indications of any alarms or anomalies. Subsequent attempts to re-establish spacecraft communications from U.S. and French ground stations were unsuccessful. Extensive engineering operations undertaken to recover downlink communications also were unsuccessful.


After consultation with the spacecraft and transmitter manufacturers, it was determined a non-recoverable failure with the last remaining transmitter on Jason-1 was the cause of the loss of contact. The spacecraft's other transmitter experienced a permanent failure in September 2005. There now is no remaining capability to retrieve data from the Jason-1 spacecraft.


On July 1, mission controllers commanded Jason-1 into a safe hold state that reinitialized the satellite. After making several more unsuccessful attempts to locate a signal, mission managers at CNES and NASA decided to proceed with decommissioning Jason-1. The satellite was then commanded to turn off its magnetometer and reaction wheels. Without these attitude control systems, Jason-1 and its solar panels will slowly drift away from pointing at the sun and its batteries will discharge, leaving it totally inert within the next 90 days. The spacecraft will not reenter Earth's atmosphere for at least 1,000 years.


"Like its predecessor Topex/Poseidon, Jason-1 provided one of the most comprehensive pictures of changes in the tropical Pacific Ocean, including the comings and goings of El Nino and La Nina events," said Lee-Lueng Fu, Jason-1 project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "These Pacific Ocean climate cycles are responsible for major shifts in sea level, ocean temperatures and rainfall every two to five years and can sometimes be so large that worldwide weather patterns are affected. Jason-1 data have been instrumental in monitoring and predicting these ever-changing cycles."


In the spring of 2012, based on concern over the limited redundancy of Jason-1's aging control systems, NASA and CNES moved the satellite into its planned final "graveyard" orbit, depleted its extra fuel and reconfigured the mission to make observations that will improve our knowledge of Earth's gravity field over the ocean, in addition to delivering its oceanographic data products.


The first full 406-day marine gravity mission was completed on June 17. The resulting data have already led to the discovery of numerous small seamounts, which are underwater mountains that rise above the deep-sea floor. The data also have significantly increased the resolution of Earth's gravity field over the ocean, while increasing our knowledge of ocean bathymetry, which is the underwater depth of the ocean floor.


JPL manages the U.S. portion of the Jason-1 mission for NASA's Science Mission Directorate. CNES manages the French portion of the mission.


For more information on Jason-1, visit: http://sealevel.jpl.nasa.gov and http://www.aviso.oceanobs.com .


The California Institute of Technology in Pasadena manages JPL for NASA.

Alan Buis 818-354-0474

Jet Propulsion Laboratory, Pasadena, Calif.

Alan.buis@jpl.nasa.gov


Steve Cole 202-358-0918

NASA Headquarters, Washington

Stephen.e.cole@nasa.gov


Julien Watelet 011-33-6-88-06-11-48

Centre National d'Etudes Spatiales, Paris, France

Julien.watelet@cnes.fr


2013-213
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NASA's OPALS to Beam Data From Space Via Laser

NASA's OPALS to Beam Data From Space Via Laser:

This artist's concept shows how the Optical Payload for Lasercomm Science (OPALS) laser will beam data to Earth from the International Space Station.
This artist's concept shows how the Optical Payload for Lasercomm Science (OPALS) laser will beam data to Earth from the International Space Station. Credit: NASA.
› Larger image

July 11, 2013

PASADENA, Calif. -- NASA will use the International Space Station to test a new communications technology that could dramatically improve spacecraft communications, enhance commercial missions and strengthen transmission of scientific data.


The Optical Payload for Lasercomm Science (OPALS), an optical technology demonstration experiment, could improve NASA's data rates for communications with future spacecraft by a factor of 10 to 100. OPALS has arrived at NASA's Kennedy Space Center in Florida from the agency's Jet Propulsion Laboratory in Pasadena, Calif. It is scheduled to launch to the space station later this year aboard a SpaceX Dragon commercial resupply capsule on the company's Falcon 9 rocket.


"OPALS represents a tangible stepping stone for laser communications, and the International Space Station is a great platform for an experiment like this," said Michael Kokorowski, OPALS project manager at JPL. "Future operational laser communication systems will have the ability to transmit more data from spacecraft down to the ground than they currently do, mitigating a significant bottleneck for scientific investigations and commercial ventures."


OPALS will be mounted on the outside of the International Space Station and communicate with a ground station in Wrightwood, Calif., a mountain town near Los Angeles.


"It's like aiming a laser pointer continuously for two minutes at a dot the diameter of a human hair from 30 feet away while you're walking," explained OPALS systems engineer Bogdan Oaida of JPL.


The OPALS instrument was built at JPL and is slated to fly on the Dragon capsule in late 2013. The mission is expected to run 90 days after installation on the station.


The OPALS Project Office is based at JPL, a division of the California Institute of Technology in Pasadena.


For more information about OPALS, visit: http://go.nasa.gov/10MMPDO .


For more information about the International Space Station, visit: http://www.nasa.gov/station .

Stephanie L. Smith 818-393-5464

Jet Propulsion Laboratory, Pasadena, Calif.

slsmith@jpl.nasa.gov


Joshua Buck 202-358-1100

NASA Headquarters, Washington

jbuck@nasa.gov


2013-218
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In the Zone: How Scientists Search for Habitable Planets

In the Zone: How Scientists Search for Habitable Planets:

Toxic Wasteland or Lush Paradise?
This artist's concept shows a Super Venus planet on the left, and a Super Earth on the right. Researchers use a concept known as the habitable zone to distinguish between these two types of planets, which exist beyond our solar system. Image credit: NASA/JPL-Caltech/Ames
› Full image and caption

July 17, 2013

There is only one planet we know of, so far, that is drenched with life. That planet is Earth, as you may have guessed, and it has all the right conditions for critters to thrive on its surface. Do other planets beyond our solar system, called exoplanets, also host life forms?


Astronomers still don't know the answer, but they search for potentially habitable planets using a handful of criteria. Ideally, they want to find planets just like Earth, since we know without a doubt that life took root here. The hunt is on for planets about the size of Earth that orbit at just the right distance from their star - in a region termed the habitable zone.


NASA's Kepler mission is helping scientists in the quest to find these worlds, sometimes called Goldilocks planets after the fairy tale because they orbit where conditions are "just right" for life. Kepler and other telescopes have confirmed a handful so far, all of which are a bit larger than Earth -- the Super Earths. The search for Earth's twin, a habitable-zone planet as small as Earth, is ongoing.


An important part of this research is the continuing investigation into exactly where a star's habitable zone starts and stops.


The habitable zone is the belt around a star where temperatures are ideal for liquid water -- an essential ingredient for life as we know it -- to pool on a planet's surface. Earth lies within the habitable zone of our star, the sun. Beyond this zone, a planet would probably be too cold and frozen for life (though it's possible life could be buried underneath a moon's surface). A planet lying between a star and the habitable zone would likely be too hot and steamy.


That perfect Goldilocks planet within the zone wouldn't necessarily be home to any furry creatures. But it would have the potential for some type of life to abound, if even microbes.


In one new study, researchers based at NASA's Exoplanet Science Institute at the California Institute of Technology, in Pasadena, Calif., carefully analyzed the location of both a planet called Kepler-69c and its habitable zone. Their analysis shows that this planet, which is 1.7 times the size of Earth, lies just outside the inner edge of the zone, making it more of a Super Venus than a Super Earth, as previous estimates indicated.


"On the way to finding Earths, Kepler is telling us a lot about the frequency of Venus-like planets in our galaxy," said Stephen Kane, lead author of the new paper on Kepler-69c appearing in the Astrophysical Journal Letters.


To determine the location of a star's habitable zone, one must first learn how much total radiation it emits. Stars more massive than our sun are hotter, and blaze with radiation, so their habitable zones are farther out. Similarly, stars that are smaller and cooler sport tighter belts of habitability than our sun. For example, the Super Earth planet called Kepler-62f, discovered by Kepler to orbit in the middle of a habitable zone around a cool star, orbits closer to its star than Earth. The planet takes just 267 days to complete an orbit, as compared to 365 days for Earth.


Knowing precisely how far away a habitable zone needs to be from a star also depends on chemistry. For example, molecules in a planet's atmosphere will absorb a certain amount of energy from starlight and radiate the rest back out. How much of this energy is trapped can mean the difference between a turquoise sea and erupting volcanoes.


Researchers led by Ravi kumar Kopparapu of Penn State University, University Park, Pa., used this type of chemical information to nudge the habitable zone out a bit farther than previously thought. The team's 2013 Astrophysical Journal study is the current gold standard in determining how a star's total radiation output relates to the location of its habitable zone. Kane and his colleagues used this information to fine-tune the boundaries of Kepler-69c's habitable zone, in addition to careful measurements of the star's total energy output and the orbit of the planet.


"Understanding the properties of the star is critical to determining planetary properties and calculating the extent of the habitable zone in that system," said Kane.


But before you purchase real estate in a habitable zone, keep in mind there are other factors that dictate whether a world develops lush greenery and beaches. Eruptions from the surfaces of stars called flares, for example, can wreak havoc on planets.


"There are a lot of unanswered questions about habitability," said Lucianne Walkowicz, a Kepler science team member based at Princeton University, N.J., who studies flaring stars. "If the planet gets zapped with radiation all the time by flares from its parent star, the surface might not be a very pleasant place to live. But on the other hand, if there's liquid water around, that makes a really good shield from high-energy radiation, so maybe life could thrive in the oceans."


Flares can also scrape off the atmospheres of planets, complicating the picture further. This is particularly true for the smaller, cooler stars, which tend to be more hyperactive than stars like our sun.


Ideally, astronomers would like to know more about the atmosphere of potentially habitable planets. That way they could look at the planet's molecular makeup for signs of runaway greenhouse gases that could indicate an inhospitable Venus-like planet. Or, future space telescopes might even be able to pick up signatures of oxygen, water, carbon dioxide and methane -- indicators that the planet might be somebody's home.


NASA's upcoming James Webb Space Telescope will bring us closer to this goal, by probing the atmospheres of planets, some of which may lie in habitable zones. The mission won't be able to examine the atmospheres of planets as small as Earth, so we'll have to wait for another future telescope to separate out the Venuses from the Earths.


NASA Ames manages Kepler's ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with JPL at the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes the Kepler science data. Kepler is NASA's 10th Discovery Mission and is funded by NASA's Science Mission Directorate at the agency's headquarters in Washington. More information about the Kepler mission is at http://www.nasa.gov/kepler .


More information about exoplanets and NASA's planet-finding program is at http://planetquest.jpl.nasa.gov .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov

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NASA Interplanetary Probes to Take Pictures of Earth

NASA Interplanetary Probes to Take Pictures of Earth:

This simulated view from NASA's Cassini spacecraft shows the expected positions of Saturn and Earth on July 19, 2013
This simulated view from NASA's Cassini spacecraft shows the expected positions of Saturn and Earth on July 19, 2013, around the time Cassini will take Earth's picture. Cassini will be about 898 million miles (1.44 billion kilometers) away from Earth at the time. That distance is nearly 10 times the distance from the sun to Earth. Image credit: NASA/JPL-Caltech
› View image

July 18, 2013

PASADENA, Calif. -- Two NASA spacecraft, one studying the Saturn system, the other observing Mercury, are maneuvering into place to take pictures of Earth on July 19 and 20.


The image taken from the Saturn system by NASA's Cassini spacecraft will occur between 2:27 and 2:42 PDT (5:27 and 5:42 p.m. EDT, or 21:27 and 21:42 UTC) Friday, July 19. Cassini will be nearly 900 million miles (nearly 1.5 billion kilometers) away from Earth. NASA is encouraging the public to look and wave in the direction of Saturn at the time of the portrait and share their pictures via the Internet.


The Cassini Earth portrait is part of a more extensive mosaic -- or multi-image picture -- of the Saturn system as it is backlit by the sun. The viewing geometry highlights the tiniest of ring particles and will allow scientists to see patterns within Saturn's dusty rings. Processing of the Earth images is expected to take a few days, and processing of the full Saturn system mosaic will likely take several weeks.


Inspired in part by the Cassini team's plans to obtain a picture of Earth, scientists reexamined the planned observations of NASA's MESSENGER spacecraft in orbit around Mercury. They realized Earth is coincidentally expected to appear in some images taken in a search for natural satellites around Mercury on July 19 and 20. Those images will be taken at 4:49 a.m., 5:38 a.m. and 6:41 a.m. PDT (7:49 a.m., 8:38 a.m. and 9:41 a.m. EDT, or 11:49, 12:38, and 13:41 UTC) on both days. Parts of Earth not illuminated in the Cassini images, including all of Europe, the Middle East and Central Asia, will appear illuminated in the MESSENGER images. MESSENGER's images also will take a few days to process prior to release.


Details on how to find Saturn in the sky and participate in the event are available at: http://saturn.jpl.nasa.gov/waveatsaturn .


The public can share pictures by using the hashtag #waveatsaturn on Twitter, or uploading pictures to the event's Flickr page at: http://www.flickr.com/groups/wave_at_saturn/ .


The event's Facebook page is: http://bit.ly/waveatsaturn .


Cassini mission scientists also will be participating in a live Ustream show on Friday from 2 to 2:30 p.m. PDT (5 to 5:30 p.m. EDT): http://www.ustream.com/nasajpl2 .


For more information about the two NASA spacecraft, visit: http://www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://www.nasa.gov/messenger .

Jia-Rui C. Cook 818-354-0850

Jet Propulsion Laboratory, Pasadena, Calif.

jccook@jpl.nasa.gov


Dwayne Brown 202-358-1726

NASA Headquarters, Washington

dwayne.c.brown@nasa.gov


2013-225
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Reports Detail Mars Rover Clues to Atmosphere's Past

Reports Detail Mars Rover Clues to Atmosphere's Past:

Shooting Lasers
This picture shows a lab demonstration of the measurement chamber inside the Tunable Laser Spectrometer, an instrument that is part of the Sample Analysis at Mars investigation on NASA's Curiosity rover. Image credit: NASA/JPL-Caltech
› Full image and caption

July 18, 2013

PASADENA, Calif. - A pair of new papers report measurements of the Martian atmosphere's composition by NASA's Curiosity rover, providing evidence about loss of much of Mars' original atmosphere.


Curiosity's Sample Analysis at Mars (SAM) suite of laboratory instruments inside the rover has measured the abundances of different gases and different isotopes in several samples of Martian atmosphere. Isotopes are variants of the same chemical element with different atomic weights due to having different numbers of neutrons, such as the most common carbon isotope, carbon-12, and a heavier stable isotope, carbon-13.


SAM checked ratios of heavier to lighter isotopes of carbon and oxygen in the carbon dioxide that makes up most of the planet's atmosphere. Heavy isotopes of carbon and oxygen are both enriched in today's thin Martian atmosphere compared with the proportions in the raw material that formed Mars, as deduced from proportions in the sun and other parts of the solar system. This provides not only supportive evidence for the loss of much of the planet's original atmosphere, but also a clue to how the loss occurred.


"As atmosphere was lost, the signature of the process was embedded in the isotopic ratio," said Paul Mahaffy of NASA Goddard Space Flight Center, Greenbelt, Md. He is the principal investigator for SAM and lead author of one of the two papers about Curiosity results in the July 19 issue of the journal Science.


Other factors also suggest Mars once had a much thicker atmosphere, such as evidence of persistent presence of liquid water on the planet's surface long ago even though the atmosphere is too scant for liquid water to persist on the surface now. The enrichment of heavier isotopes measured in the dominant carbon-dioxide gas points to a process of loss from the top of the atmosphere -- favoring loss of lighter isotopes -- rather than a process of the lower atmosphere interacting with the ground.


Curiosity measured the same pattern in isotopes of hydrogen, as well as carbon and oxygen, consistent with a loss of a substantial fraction of Mars' original atmosphere. Enrichment in heavier isotopes in the Martian atmosphere has previously been measured on Mars and in gas bubbles inside meteorites from Mars. Meteorite measurements indicate much of the atmospheric loss may have occurred during the first billion years of the planet's 4.6-billion-year history. The Curiosity measurements reported this week provide more precise measurements to compare with meteorite studies and with models of atmospheric loss.


The Curiosity measurements do not directly measure the current rate of atmospheric escape, but NASA's next mission to Mars, the Mars Atmosphere and Volatile Evolution Mission (MAVEN), will do so. "The current pace of the loss is exactly what the MAVEN mission now scheduled to launch in November of this year is designed to determine," Mahaffy said.


The new reports describe analysis of Martian atmosphere samples with two different SAM instruments during the initial 16 weeks of the rover's mission on Mars, which is now in its 50th week. SAM's mass spectrometer and tunable laser spectrometer independently measured virtually identical ratios of carbon-13 to carbon-12. SAM also includes a gas chromatograph and uses all three instruments to analyze rocks and soil, as well as atmosphere.


"Getting the same result with two very different techniques increased our confidence that there's no unknown systematic error underlying the measurements," said Chris Webster of NASA's Jet Propulsion Laboratory, Pasadena, Calif. He is the lead scientist for the tunable laser spectrometer and the lead author for one of the two papers. "The accuracy in these new measurements improves the basis for understanding the atmosphere's history."


Curiosity landed inside Mars' Gale Crater on Aug. 6, 2012 Universal Time (on Aug. 5 PDT). The rover this month began a drive of many months from an area where it found evidence for a past environment favorable for microbial life, toward a layered mound, Mount Sharp, where researchers will seek evidence about how the environment changed.


More information about Curiosity is online at: http://www.jpl.nasa.gov/msl , http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ .


You can follow the mission on Facebook at: http://www.facebook.com/marscuriosity and on Twitter at http://www.twitter.com/marscuriosity .

Guy Webster 818-354-6278

Jet Propulsion Laboratory, Pasadena, Calif.

guy.webster@jpl.nasa.gov


Nancy Neal Jones 301-286-0039

Goddard Space Flight Center, Greenbelt, Md.

nancy.n.jones@nasa.gov


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NASA's Spitzer Observes Gas Emission From Comet ISON

NASA's Spitzer Observes Gas Emission From Comet ISON:

Spitzer Eyes Comet ISON
These images from NASA's Spitzer Space Telescope of C/2012 S1 (Comet ISON) were taken on June 13, when ISON was 310 million miles (about 500 million kilometers) from the sun. Image credit: NASA/JPL-Caltech/JHUAPL/UCF
› Full image and caption

July 23, 2013

PASADENA, Calif. -- Astronomers using NASA's Spitzer Space Telescope have observed what most likely are strong carbon dioxide emissions from Comet ISON ahead of its anticipated pass through the inner solar system later this year.


Images captured June 13 with Spitzer's Infrared Array Camera indicate carbon dioxide is slowly and steadily "fizzing" away from the so-called "soda-pop comet," along with dust, in a tail about 186,400 miles (300,000 kilometers) long.


"We estimate ISON is emitting about 2.2 million pounds (1 million kilograms) of what is most likely carbon dioxide gas and about 120 million pounds (54.4 million kilograms) of dust every day," said Carey Lisse, leader of NASA's Comet ISON Observation Campaign and a senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "Previous observations made by NASA's Hubble Space Telescope and the Swift Gamma-Ray Burst Mission and Deep Impact spacecraft gave us only upper limits for any gas emission from ISON. Thanks to Spitzer, we now know for sure the comet's distant activity has been powered by gas."


Comet ISON was about 312 million miles (502 million kilometers) from the sun, 3.35 times farther than Earth, when the observations were made.


"These fabulous observations of ISON are unique and set the stage for more observations and discoveries to follow as part of a comprehensive NASA campaign to observe the comet," said James L. Green, NASA's director of planetary science in Washington. "ISON is very exciting. We believe that data collected from this comet can help explain how and when the solar system first formed."


Comet ISON (officially known as C/2012 S1) is less than 3 miles (4.8 kilometers) in diameter, about the size of a small mountain, and weighs between 7 billion and 7 trillion pounds (3.2 billion and 3.2 trillion kilograms). Because the comet is still very far away, its true size and density have not been determined accurately. Like all comets, ISON is a dirty snowball made up of dust and frozen gases such as water, ammonia, methane and carbon dioxide. These are some of the fundamental building blocks, which scientists believe led to the formation of the planets 4.5 billion years ago.


Comet ISON is believed to be inbound on its first passage from the distant Oort Cloud, a roughly spherical collection of comets and comet-like structures that exists in a space between one-tenth light-year and 1 light-year from the sun. The comet will pass within 724,000 miles (1.16 million kilometers) of the sun on Nov. 28.


It is warming up gradually as it gets closer to the sun. In the process, different gases are heating up to the point of evaporation, revealing themselves to instruments in space and on the ground. Carbon dioxide is thought to be the gas that powers emission for most comets between the orbits of Saturn and the asteroids.


The comet was discovered Sept. 21, roughly between Jupiter and Saturn, by Vitali Nevski and Artyom Novichonok at the International Scientific Optical Network (ISON) near Kislovodsk, Russia. This counts as an early detection of a comet, and the strong carbon dioxide emissions may have made the detection possible.


"This observation gives us a good picture of part of the composition of ISON, and, by extension, of the proto-planetary disk from which the planets were formed," said Lisse. "Much of the carbon in the comet appears to be locked up in carbon dioxide ice. We will know even more in late July and August, when the comet begins to warm up near the water-ice line outside of the orbit of Mars, and we can detect the most abundant frozen gas, which is water, as it boils away from the comet."


NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.


For more information about Spitzer, visit: http://www.nasa.gov/spitzer . Learn more about NASA's Comet ISON Observing Campaign: http://www.isoncampaign.org . NASA's Comet ISON Toolkit is at: http://solarsystem.nasa.gov/ison .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


Geoffrey Brown 240-228-5618

Johns Hopkins Applied Physics Laboratory, Laurel, Md.

geoffrey.brown@jhuapl.edu


J.D. Harrington 202-358-5241

Headquarters, Washington

j.d.harrington@nasa.gov


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NASA's Wise Finds Mysterious Centaurs May Be Comets

NASA's Wise Finds Mysterious Centaurs May Be Comets:

NEOWISE Eyes the Enigmatic Centaurs
New observations from NASA's NEOWISE project reveal the hidden nature of centaurs, objects in our solar system that have confounded astronomers for resembling both asteroids and comets. The centaurs, which orbit between Jupiter and Neptune, were named after the mythical half-horse, half-human creatures called centaurs due to their dual nature. This artist's concept shows a centaur creature together with asteroids on the left and comets at right. Image credit: NASA/JPL-Caltech
› Full image and caption

July 24, 2013

PASADENA, Calf. -- The true identity of centaurs, the small celestial bodies orbiting the sun between Jupiter and Neptune, is one of the enduring mysteries of astrophysics. Are they asteroids or comets? A new study of observations from NASA's Wide-field Infrared Survey Explorer (WISE) finds most centaurs are comets.


Until now, astronomers were not certain whether centaurs are asteroids flung out from the inner solar system or comets traveling in toward the sun from afar. Because of their dual nature, they take their name from the creature in Greek mythology whose head and torso are human and legs are those of a horse.


"Just like the mythical creatures, the centaur objects seem to have a double life," said James Bauer of NASA's Jet Propulsion Laboratory in Pasadena, Calif. Bauer is lead author of a paper published online July 22 in the Astrophysical Journal. "Our data point to a cometary origin for most of the objects, suggesting they are coming from deeper out in the solar system."


"Cometary origin" means an object likely is made from the same material as a comet, may have been an active comet in the past, and may be active again in the future.


The findings come from the largest infrared survey to date of centaurs and their more distant cousins, called scattered disk objects. NEOWISE, the asteroid-hunting portion of the WISE mission, gathered infrared images of 52 centaurs and scattered disk objects. Fifteen of the 52 are new discoveries. Centaurs and scattered disk objects orbit in an unstable belt. Ultimately, gravity from the giant planets will fling them either closer to the sun or farther away from their current locations.


Although astronomers previously observed some centaurs with dusty halos, a common feature of outgassing comets, and NASA's Spitzer Space Telescope also found some evidence for comets in the group, they had not been able to estimate the numbers of comets and asteroids.


Infrared data from NEOWISE provided information on the objects' albedos, or reflectivity, to help astronomers sort the population. NEOWISE can tell whether a centaur has a matte and dark surface or a shiny one that reflects more light. The puzzle pieces fell into place when astronomers combined the albedo information with what was already known about the colors of the objects. Visible-light observations have shown centaurs generally to be either blue-gray or reddish in hue. A blue-gray object could be an asteroid or comet. NEOWISE showed that most of the blue-gray objects are dark, a telltale sign of comets. A reddish object is more likely to be an asteroid.


"Comets have a dark, soot-like coating on their icy surfaces, making them darker than most asteroids," said the study's co-author, Tommy Grav of the Planetary Science Institute in Tucson, Ariz. "Comet surfaces tend to be more like charcoal, while asteroids are usually shinier like the moon."


The results indicate that roughly two-thirds of the centaur population are comets, which come from the frigid outer reaches of our solar system. It is not clear whether the rest are asteroids. The centaur bodies have not lost their mystique entirely, but future research from NEOWISE may reveal their secrets further.


The paper is available online at: http://iopscience.iop.org/0004-637X/773/1/22/ .


JPL, managed by the California Institute of Technology in Pasadena, managed and operated WISE for NASA's Science Mission Directorate. The NEOWISE portion of the project was funded by NASA's Near Earth Object Observation Program. WISE completed its key mission objective, two scans of the entire sky, in 2011 and has been hibernating in space since then.


For more information about the WISE mission, visit: http://www.nasa.gov/wise .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


J.D. Harrington 202-358-5241

Headquarters, Washington

j.d.harrington@nasa.gov


2013-234
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How Did Earth's Primitive Chemistry Get Kick Started?

How Did Earth's Primitive Chemistry Get Kick Started?:

This image from the floor of the Atlantic Ocean shows a collection of limestone towers known as the 'Lost City.'
This image from the floor of the Atlantic Ocean shows a collection of limestone towers known as the "Lost City." Alkaline hydrothermal vents of this type are suggested to be the birthplace of the first living organisms on the ancient Earth. Scientists are interested in understanding early life on Earth because if we ever hope to find life on other worlds - especially icy worlds with subsurface oceans such as Jupiter's moon Europa and Saturn's Enceladus - we need to know what chemical signatures to look for. Image courtesy D. Kelley and M. Elend/University of Washington
› Larger view

July 30, 2013

How did life on Earth get started? Three new papers co-authored by Mike Russell, a research scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., strengthen the case that Earth's first life began at alkaline hydrothermal vents at the bottom of oceans. Scientists are interested in understanding early life on Earth because if we ever hope to find life on other worlds -- especially icy worlds with subsurface oceans such as Jupiter's moon Europa and Saturn's Enceladus -- we need to know what chemical signatures to look for.


Two papers published recently in the journal Philosophical Transactions of the Royal Society B provide more detail on the chemical and precursor metabolic reactions that have to take place to pave the pathway for life. Russell and his co-authors describe how the interactions between the earliest oceans and alkaline hydrothermal fluids likely produced acetate (comparable to vinegar). The acetate is a product of methane and hydrogen from the alkaline hydrothermal vents and carbon dioxide dissolved in the surrounding ocean. Once this early chemical pathway was forged, acetate could become the basis of other biological molecules. They also describe how two kinds of "nano-engines" that create organic carbon and polymers -- energy currency of the first cells -- could have been assembled from inorganic minerals.


A paper published in the journal Biochimica et Biophysica Acta analyzes the structural similarity between the most ancient enzymes of life and minerals precipitated at these alkaline vents, an indication that the first life didn't have to invent its first catalysts and engines.


"Our work on alkaline hot springs on the ocean floor makes what we believe is the most plausible case for the origin of the life's building blocks and its energy supply," Russell said. "Our hypothesis is testable, has the right assortment of ingredients and obeys the laws of thermodynamics."


Russell's work was funded by the NASA Astrobiology Institute through the Icy Worlds team based at JPL, a division of the California Institute of Technology, Pasadena. The NASA Astrobiology Institute, based at NASA's Ames Research Center, Moffett Field, Calif., is a partnership among NASA, 15 U.S. teams and 13 international consortia. The Institute is part of NASA's astrobiology program, which supports research into the origin, evolution, distribution and future of life on Earth and the potential for life elsewhere.

Jia-Rui C. Cook 818-354-0850

Jet Propulsion Laboratory, Pasadena, Calif.

jccook@jpl.nasa.gov


2013-235
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Spitzer Discovers Young Stars with a 'Hula Hoop'

Spitzer Discovers Young Stars with a 'Hula Hoop':

In this artist's impression, a disk of dusty material leftover from star formation girds two young stars like a hula hoop
In this artist's impression, a disk of dusty material leftover from star formation girds two young stars like a hula hoop. As the two stars whirl around each other, they periodically peek out from the disk, making the system appear to "blink" every 93 days. Image credit: NASA/JPL-Caltech
› Full image and caption

July 31, 2013

Astronomers using NASA's Spitzer Space Telescope have spotted a young stellar system that "blinks" every 93 days. Called YLW 16A, the system likely consists of three developing stars, two of which are surrounded by a disk of material left over from the star-formation process.


As the two inner stars whirl around each other, they periodically peek out from the disk that girds them like a hula hoop. The hoop itself appears to be misaligned from the central star pair, probably due to the disrupting gravitational presence of the third star orbiting at the periphery of the system. The whole system cycles through bright and faint phases, with the central stars playing a sort of cosmic peek-a-boo as the tilted disk twirls around them. It is believed that this disk should go on to spawn planets and the other celestial bodies that make up a solar system.


Spitzer observed infrared light from YLW 16A, emitted by the warmed gas and dust in the disk that still swathes the young stars. Other observations came from the ground-based 2MASS survey, as well as from the NACO instrument at the European Southern Observatory's Very Large Telescope in Chile.


YLW 16A is the fourth example of a star system known to blink in such a manner, and the second in the same star-forming region Rho Ophiuchus. The finding suggests that these systems might be more common than once thought. Blinking star systems with warped disks offer scientists a way to study how planets form in these environments. The planets can orbit one or both of the stars in the binary star system. The famous science fictional planet Tatooine in "Star Wars" orbits two stars, hence its double sunsets. Such worlds are referred to as circumbinary planets. Astronomers can record how light is absorbed by planet-forming disks during the bright and faint phases of blinking stellar systems, which in turn reveals information about the materials that comprise the disk.


"These blinking systems offer natural probes of the binary and circumbinary planet formation process," said Peter Plavchan, a scientist at the NASA Exoplanet Science Institute and Infrared Processing and Analysis Center at the California Institute of Technology, Pasadena, Calif., and lead author of a new paper accepted for publication in Astronomy & Astrophysics.


NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu and http://www.nasa.gov/spitzer .

Written by Adam Hadhazy

Contact:

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2013-236
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Monster Galaxies Lose Their Appetite With Age

Monster Galaxies Lose Their Appetite With Age:

This image shows two of the galaxy clusters observed by NASA's Wide-field Infrared Survey Explorer (WISE) and Spitzer Space Telescope missions
This image shows two of the galaxy clusters observed by NASA's Wide-field Infrared Survey Explorer (WISE) and Spitzer Space Telescope missions. Galaxy clusters are among the most massive structures in the universe. The central and largest galaxy in each grouping, called the brightest cluster galaxy or BCG, is seen at the center of each image. Image credit: NASA/JPL-Caltech/SDSS/NOAO

› Full image and caption

August 01, 2013

Our universe is filled with gobs of galaxies, bound together by gravity into larger families called clusters. Lying at the heart of most clusters is a monster galaxy thought to grow in size by merging with neighboring galaxies, a process astronomers call galactic cannibalism.


New research from NASA's Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE) is showing that, contrary to previous theories, these gargantuan galaxies appear to slow their growth over time, feeding less and less off neighboring galaxies.


"We've found that these massive galaxies may have started a diet in the last 5 billion years, and therefore have not gained much weight lately," said Yen-Ting Lin of the Academia Sinica in Taipei, Taiwan, lead author of a study published in the Astrophysical Journal.


Peter Eisenhardt, a co-author from NASA's Jet Propulsion Laboratory in Pasadena, Calif., said, "WISE and Spitzer are letting us see that there is a lot we do understand -- but also a lot we don't understand -- about the mass of the most massive galaxies." Eisenhardt identified the sample of galaxy clusters studied by Spitzer, and is the project scientist for WISE.


The new findings will help researchers understand how galaxy clusters -- among the most massive structures in our universe -- form and evolve.


Galaxy clusters are made up of thousands of galaxies, gathered around their biggest member, what astronomers call the brightest cluster galaxy, or BCG. BCGs can be up to dozens of times the mass of galaxies like our own Milky Way. They plump up in size by cannibalizing other galaxies, as well as assimilating stars that are funneled into the middle of a growing cluster.


To monitor how this process works, the astronomers surveyed nearly 300 galaxy clusters spanning 9 billion years of cosmic time. The farthest cluster dates back to a time when the universe was 4.3 billion years old, and the closest, when the universe was much older, 13 billion years old (our universe is presently 13.8 billion years old).


"You can't watch a galaxy grow, so we took a population census," said Lin. "Our new approach allows us to connect the average properties of clusters we observe in the relatively recent past with ones we observe further back in the history of the universe."


Spitzer and WISE are both infrared telescopes, but they have unique characteristics that complement each other in studies like these. For instance, Spitzer can see more detail than WISE, which enables it to capture the farthest clusters best. On the other hand, WISE, an infrared all-sky survey, is better at capturing images of nearby clusters, thanks to its larger field of view. Spitzer is still up and observing; WISE went into hibernation in 2011 after successfully scanning the sky twice.


The findings showed that BCG growth proceeded along rates predicted by theories until 5 billion years ago, or a time when the universe was about 8 billion years old. After that time, it appears the galaxies, for the most part, stopped munching on other galaxies around them.


The scientists are uncertain about the cause of BCGs' diminished appetites, but the results suggest current models need tinkering.


"BCGs are a bit like blue whales -- both are gigantic and very rare in number. Our census of the population of BCGs is in a way similar to measuring how the whales gain their weight as they age. In our case, the whales aren't gaining as much weight as we thought. Our theories aren't matching what we observed, leading us to new questions," said Lin.


Another possible explanation is that the surveys are missing large numbers of stars in the more mature clusters. Clusters can be violent environments, where stars are stripped from colliding galaxies and flung into space. If the recent observations are not detecting those stars, it's possible that the enormous galaxies are, in fact, continuing to bulk up.


Future studies from Lin and others should reveal more about the feeding habits of one of nature's largest galactic species.


JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu and http://www.nasa.gov/spitzer .


JPL managed and operated WISE for NASA's Science Mission Directorate. Edward Wright is the principal investigator and is at UCLA. The mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu and http://jpl.nasa.gov/wise .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


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Posted by Nelio Inacio at 7:55 AM 0 comments
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