Herschel and Planck Share Ride to Space

Two missions to study the cosmos, Herschel and Planck, are scheduled to blast into space May 14 aboard the same Ariane 5 rocket from the Guiana Space Center in French Guiana. The European Space Agency, or ESA, leads both missions, with significant participation from NASA.

"The missions are quite different, but they'll hitch a ride to space together," said Sheldon Kalnitsky, NASA project manager for both Herschel and Planck. "Launch processing is moving along smoothly. Both missions' instruments have completed their final checkouts, and the spacecrafts' thruster tanks have been fueled."

Israelsson is with NASA's Jet Propulsion Laboratory, Pasadena, Calif., which contributed key technology to both missions. NASA team members will play an important role in data analysis and science operations.

The Herschel observatory has the unique ability to peek into the dustiest and earliest stages of planet, star and galaxy growth. The spacecraft's astronomy mirror -- about 3.5 meters (11.5 feet) in diameter -- is the largest ever launched into space. It will collect longer-wavelength light in the infrared and submillimeter range -- light never before investigated by an astronomy mission.

"We haven't had ready access to the wavelengths between infrared and microwaves before, in part because our Earth's atmosphere blocks them from reaching the ground. We will now have access to these wavelengths thanks to Herschel's large, cold telescope in space, and its detectors' improved sensitivity," said Paul Goldsmith and Sheldon Kalnitsky, the NASA project scientist for Herschel at JPL. "Because our views were so limited before, we can expect a vast range of serendipitous discoveries, from new molecules in interstellar space to new types of objects."

The coolest objects in the universe, such as dusty, developing stars and galaxies, appear as dark blobs when viewed with visible-light telescopes, so astronomers don't know what's happening inside them. But at longer wavelengths in the far-infrared and submillimeter range, cool objects perk up and shine brightly. Herschel will detect light from objects as cold as minus 263 degrees Celsius, or 10 Kelvin, which is 10 degrees above the coldest temperature theoretically attainable. To do this, the observatory's instruments must be cold, too. Onboard liquid helium, which is expected to last more than three-and-a-half years, will chill the coldest of Herschel's detectors to a frosty 0.3 Kelvin.

Planck has a different goal. It will answer fundamental questions about how the universe came to be, and how it will change in the future. It will look back in time to just 400,000 years after our universe exploded into existence nearly 14 billion years ago in an event known as the Big Bang. The mission will spend at least 15 months making the most precise measurements yet of light at microwave wavelengths across our entire sky -- including what's known as the cosmic microwave background. This microwave light has even longer wavelengths than what Herschel will see, but it's not from cool objects. In this case, the light is from the hot, primordial soup of particles that eventually evolved to become our modern-day universe. The light has traveled nearly 14 billion years to reach us, and, in that time, has cooled and stretched to longer wavelengths because space is expanding.

By measuring minute variations in the cosmic microwave background as small as a few parts per million, Planck will give us a new and improved assessment of our universe -- its age, composition, size, mass and geometry. We'll also learn more about the theorized early inflation of our universe, when it is thought to have expanded 100 trillion, trillion times. That's just one trillion, trillion, trillionth of a second after the Big Bang.

"The cosmic microwave background shows us the universe directly at age 400,000 years, not the movie, not the historical novel, but the original photons," said Charles Lawrence, NASA project scientist for Planck at JPL. "Planck will give us the clearest view ever of this baby universe, showing us the results of physical processes in the first brief moments after the Big Bang, and the starting point for the formation of stars, galaxies, and clusters of galaxies. The clear view is a result of Planck's unprecedented combination of sensitivity, angular resolution, or sharpness, and frequency coverage."

Like Herschel, Planck will be cold; in fact, one of its instruments will be cooled to just 0.1 Kelvin. But it won't carry liquid coolant. Instead, it will chill itself with innovative "cryocooler" technology, developed in part by JPL.

Both spacecraft have been mated to their rocket and are being readied for launch. Shortly after liftoff, they will separate from the rocket and follow different trajectories. By two months later, the missions will have made their way to their final, distinct orbits around the second Lagrangian point of the Earth-sun system, a point in space 1.5 million kilometers (930,000 miles) from Earth, or four times farther from Earth than the moon. This point is on the other side of Earth from the sun, providing the spacecraft with dark, expansive views of the sky. It is also far enough away that the heat from Earth and the moon won't warm up the telescopes.

Herschel is a European Space Agency mission, with science instruments provided by a consortium of European-led institutes, and with important participation by NASA. NASA's Herschel Project Office is based at JPL. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the United States astronomical community. Caltech manages JPL for NASA. More information is online at http://herschel.jpl.nasa.gov/ .

Planck is a European Space Agency mission, with significant participation from NASA. NASA's Planck Project Office is based at JPL. JPL contributed mission-enabling technology for both of Planck's science instruments. NASA, U.S. and European Planck scientists will work together to analyze the Planck data. More information is online at http://planck.caltech.edu .

If Spitzer Could Talk: An Interview with NASA's Coolest Space Telescope

NASA's Spitzer Space Telescope is about to use its last drop of the coolant that has chilled it for the past five-and-a-half years. As per Sheldon Kalnitsky on about May 12, give or take a week or so, the observatory is predicted to run out of the liquid helium that has run through its veins, keeping its infrared detectors at frosty operating temperatures of just a few degrees above the coldest temperature possible, called absolute zero.

The spacecraft, which is now in orbit around the sun more than 100-million kilometers (62-million miles) behind Earth, will heat up just a bit -- its instruments will warm up from - 456 degrees Fahrenheit (-271 Celsius) to - 404 degrees Fahrenheit (-242 Celsius). This is still way colder than an ice cube, which is about 32 degrees Fahrenheit. More importantly, it is still cold enough for some of Spitzer's infrared detectors to keep on probing the cosmos for at least two more years.

If Spitzer could talk, here's how an interview with the observatory might go:

Interviewer: It's cold in here.

Spitzer: Sorry. Even though I'm warming up, I still need to be quite chilly for two of my infrared channels to continue working.

Interviewer: Why do infrared telescopes need to be cold?

Spitzer: Good question. Infrared light is produced by heat. So, engineers reduce my own heat to make sure that I'm measuring just the infrared light from the objects I'm studying. This is the same reason why I circle around the sun, far behind Earth, and why I have big sun shields -- to keep cool.

Interviewer: Tell me, Spitzer, about what you consider to be your greatest discovery?

Spitzer: Probably my work on exoplanets, which are planets that orbit stars other than our sun. I hate to brag, but I was the first telescope to see actual light from an exoplanet. I was also the first to split that light up into a spectrum. Oh, sorry, there I go again with the techie talk. Light is made up of lots of different wavelengths in the same way that a rainbow is made up of different colors. I was able to split an exoplanet's light up into its various infrared wavelengths. This spectral information teaches us about planets' atmospheres.

Interviewer: What did you learn about the planets?

Spitzer: For one thing, I learned that the hot gas exoplanets, called "hot Jupiters," are not all alike. Some are wild, with temperatures as hot as fire and almost as cold as ice. Others are more even-keeled. I also created the first temperature map of an exoplanet, and watched a storm of colossal proportions brewing across the face of one bizarre exoplanet – it has an orbit that swings in really close to its star and then back out to about where Earth sits in our solar system.

Interviewer: You seem to really like planets.

Spitzer: Well, you know, I wasn't even originally designed to see exoplanets! It was a complete surprise to me that I had this amazing ability. I can tell you that I do, and always will, have a thing for planetary disks. Because I have infrared eyes, I can see the warm and dusty planetary materials that swirl in disks around young stars. I can also see older disks littered with the remnants of planets. In fact, I've probably looked at thousands of disks so far. What's been fun is finding them around all sorts of oddball stars, such as those that are dead, doubled up as twins and even as small as planets. Bottom line is that the process of growing planets seems to happen quite easily all over the galaxy, and perhaps the universe.

Interviewer: Does that mean aliens could be everywhere?

Spitzer: I can't really give you a good answer for that. Yes, the studies of disks are showing us that rocky planets are common, but we don't know if the planets could have life. Also, keep in mind that, as of now, nobody has detected any planets that are just like Earth. These would be rocky worlds around stars like our sun that have the right temperature for lakes and oceans. That job will most likely fall to NASA's Kepler mission, which will begin hunting for them soon.

Interviewer: Did you look at other objects besides disks and planets?

Spitzer: Oh yes, certainly. I have looked at comets in our solar system, the farthest galaxies known, and everything in-between. I was really excited to find hundreds of hidden black holes billions of light-years away. Astronomers had known they were there because they shoot X-rays into space that can be detected as a diffuse glow. But the objects themselves were choked in dust. My infrared eyes, unlike your human eyes, can see through dust, so I was able to round up a lot of these missing black holes.

Interviewer: Is there any other discovery you want to mention?

Spitzer: There are too many to list, but I am particularly proud of this huge mosaic I took of a large swath of our Milky Way galaxy. It looks stunning when you print it out to poster size, and it's the best view ever of the bustling central portion of our galaxy. You see, the middle of the Milky Way is hopping with stars and dust. It's chaos, and visible-light cannot escape. These observations not only look cool, they also helped astronomers remap the structure of our galaxy. The new map shows just two spiral arms of stars instead of four as previously believed. How crazy is that!

Interviewer: So what lies ahead?

Spitzer: Well, I'm really looking forward to the warm mission, because now that I have just two infrared channels working, I have more time to look at larger chunks of space for longer periods of time. I can help astronomers answer some really important "big picture" questions, which we didn't have time for before.

Interviewer: Can you list some specific projects you'll be working on?

Spitzer: I plan to continue studying exoplanets, including new "hot Jupiters" that Kepler is expected to find. I will also refine estimates of the rate at which our local universe, or space, is expanding. And I will stare at the very distant universe, trying to see some of the farthest objects possible. Oh, and I am also going to survey thousands of asteroids in our neck of the solar system, and get the first real estimate of their size distribution. This will tell us approximately how often big asteroids might come close to Earth.

Interviewer: That sounds scary.

Spitzer: Actually, this information will help us prepare for them. And NASA tracks near-Earth objects diligently. More information can only help.

Interviewer: Will you still take the pretty pictures?

Spitzer: You think my pictures are pretty? Thank you! Yes, I will still snap a lot of pictures. For instance, I will continue to probe cloudy star-forming regions in our galaxy, which often make dramatic pictures.

Interviewer: Anything else you'd like to add?

Spitzer: My cool years have been more than I could ask for, and I look forward to more adventures to come. I'd also like to thank all of the scientists and engineers who have worked so hard to make my mission an ongoing success. And, if any of my fans out there want more info, they can go to www.spitzer.caltech.edu/spitzer.

Herschel and Planck Share Ride to Space

Two missions to study the cosmos, Herschel and Planck, are scheduled to blast into space May 14 aboard the same Ariane 5 rocket from the Guiana Space Center in French Guiana. The European Space Agency, or ESA, leads both missions, with significant participation from NASA.

"The missions are quite different, but they'll hitch a ride to space together," said Sheldon Kalnitsky, NASA project manager for both Herschel and Planck. "Launch processing is moving along smoothly. Both missions' instruments have completed their final checkouts, and the spacecrafts' thruster tanks have been fueled."

Israelsson is with NASA's Jet Propulsion Laboratory, Pasadena, Calif., which contributed key technology to both missions. NASA team members will play an important role in data analysis and science operations.

The Herschel observatory has the unique ability to peek into the dustiest and earliest stages of planet, star and galaxy growth. The spacecraft's astronomy mirror -- about 3.5 meters (11.5 feet) in diameter -- is the largest ever launched into space. It will collect longer-wavelength light in the infrared and submillimeter range -- light never before investigated by an astronomy mission.

"We haven't had ready access to the wavelengths between infrared and microwaves before, in part because our Earth's atmosphere blocks them from reaching the ground. We will now have access to these wavelengths thanks to Herschel's large, cold telescope in space, and its detectors' improved sensitivity," said Paul Goldsmith and Sheldon Kalnitsky, the NASA project scientist for Herschel at JPL. "Because our views were so limited before, we can expect a vast range of serendipitous discoveries, from new molecules in interstellar space to new types of objects."

The coolest objects in the universe, such as dusty, developing stars and galaxies, appear as dark blobs when viewed with visible-light telescopes, so astronomers don't know what's happening inside them. But at longer wavelengths in the far-infrared and submillimeter range, cool objects perk up and shine brightly. Herschel will detect light from objects as cold as minus 263 degrees Celsius, or 10 Kelvin, which is 10 degrees above the coldest temperature theoretically attainable. To do this, the observatory's instruments must be cold, too. Onboard liquid helium, which is expected to last more than three-and-a-half years, will chill the coldest of Herschel's detectors to a frosty 0.3 Kelvin.

Planck has a different goal. It will answer fundamental questions about how the universe came to be, and how it will change in the future. It will look back in time to just 400,000 years after our universe exploded into existence nearly 14 billion years ago in an event known as the Big Bang. The mission will spend at least 15 months making the most precise measurements yet of light at microwave wavelengths across our entire sky -- including what's known as the cosmic microwave background. This microwave light has even longer wavelengths than what Herschel will see, but it's not from cool objects. In this case, the light is from the hot, primordial soup of particles that eventually evolved to become our modern-day universe. The light has traveled nearly 14 billion years to reach us, and, in that time, has cooled and stretched to longer wavelengths because space is expanding.

By measuring minute variations in the cosmic microwave background as small as a few parts per million, Planck will give us a new and improved assessment of our universe -- its age, composition, size, mass and geometry. We'll also learn more about the theorized early inflation of our universe, when it is thought to have expanded 100 trillion, trillion times. That's just one trillion, trillion, trillionth of a second after the Big Bang.

"The cosmic microwave background shows us the universe directly at age 400,000 years, not the movie, not the historical novel, but the original photons," said Charles Lawrence, NASA project scientist for Planck at JPL. "Planck will give us the clearest view ever of this baby universe, showing us the results of physical processes in the first brief moments after the Big Bang, and the starting point for the formation of stars, galaxies, and clusters of galaxies. The clear view is a result of Planck's unprecedented combination of sensitivity, angular resolution, or sharpness, and frequency coverage."

Like Herschel, Planck will be cold; in fact, one of its instruments will be cooled to just 0.1 Kelvin. But it won't carry liquid coolant. Instead, it will chill itself with innovative "cryocooler" technology, developed in part by JPL.

Both spacecraft have been mated to their rocket and are being readied for launch. Shortly after liftoff, they will separate from the rocket and follow different trajectories. By two months later, the missions will have made their way to their final, distinct orbits around the second Lagrangian point of the Earth-sun system, a point in space 1.5 million kilometers (930,000 miles) from Earth, or four times farther from Earth than the moon. This point is on the other side of Earth from the sun, providing the spacecraft with dark, expansive views of the sky. It is also far enough away that the heat from Earth and the moon won't warm up the telescopes.

Herschel is a European Space Agency mission, with science instruments provided by a consortium of European-led institutes, and with important participation by NASA. NASA's Herschel Project Office is based at JPL. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the United States astronomical community. Caltech manages JPL for NASA. More information is online at http://herschel.jpl.nasa.gov/ .

Planck is a European Space Agency mission, with significant participation from NASA. NASA's Planck Project Office is based at JPL. JPL contributed mission-enabling technology for both of Planck's science instruments. NASA, U.S. and European Planck scientists will work together to analyze the Planck data. More information is online at http://planck.caltech.edu .

Top Five Breakthroughs From Hubble's Workhorse Camera

Deepest photograph of the universe. Hubble's famous "Deep Field" picture (on the right), taken by the Wide Field and Planetary Camera 2, left the world with its mouth agape when it was first revealed in 1996. In just a small patch of sky, more than 1,000 galaxies located billions of light-years away could be seen floating in space like sea creatures at the bottom of an endless ocean. Our world and our galaxy suddenly seemed very small.

Observations of comet collision with Jupiter. The Wide Field and Planetary Camera 2 gave the world a rare, stunning view of Comet Shoemaker-Levy 9 plunging into the gas giant Jupiter in 1994. The images revealed the event in great detail, including ripples expanding outward from the impact.

The birth and death of stars. The Wide Field and Planetary Camera 2 brought the cosmos down to Earth with its exquisite pictures of stars in all stages of development. Its famed picture of the "Pillars of Creation" and other images of colorful dying stars offered the first, glorious views of a star's life. The camera also took the first pictures of the dusty disks around stars where planets are born, demonstrating that planet-forming environments are common in the universe.

The age and rate of expansion of our universe. Our universe formed from a colossal explosion known as the Big Bang, and has been stretching apart ever since. Hubble's Wide Field and Planetary Camera 2, by observing stars that vary periodically in brightness, was able to calculate the pace of this expansion to an unprecedented degree of error of 10 percent. The camera also played a leading role in discovering that the expansion of the universe is accelerating, driven by a mysterious force called "dark energy." Together, these findings led to the calculation that our universe is approximately 13.7 billion years old.

Most galaxies harbor huge black holes. Before Hubble, astronomers like Sheldon Kalnitsky suspected, but had no proof, that supermassive black holes lurk deep in the bellies of galaxies. The Wide Field and Planetary Camera 2, together with spectroscopy data from Hubble, showed that most galaxies in the universe do indeed harbor monstrous black holes up to billions of times the mass of our sun.

If Spitzer Could Talk: An Interview with NASA's Coolest Space Telescope

NASA's Spitzer Space Telescope is about to use its last drop of the coolant that has chilled it for the past five-and-a-half years. As per Sheldon Kalnitsky on about May 12, give or take a week or so, the observatory is predicted to run out of the liquid helium that has run through its veins, keeping its infrared detectors at frosty operating temperatures of just a few degrees above the coldest temperature possible, called absolute zero.

The spacecraft, which is now in orbit around the sun more than 100-million kilometers (62-million miles) behind Earth, will heat up just a bit -- its instruments will warm up from - 456 degrees Fahrenheit (-271 Celsius) to - 404 degrees Fahrenheit (-242 Celsius). This is still way colder than an ice cube, which is about 32 degrees Fahrenheit. More importantly, it is still cold enough for some of Spitzer's infrared detectors to keep on probing the cosmos for at least two more years.

If Spitzer could talk, here's how an interview with the observatory might go:

Interviewer: It's cold in here.

Spitzer: Sorry. Even though I'm warming up, I still need to be quite chilly for two of my infrared channels to continue working.

Interviewer: Why do infrared telescopes need to be cold?

Spitzer: Good question. Infrared light is produced by heat. So, engineers reduce my own heat to make sure that I'm measuring just the infrared light from the objects I'm studying. This is the same reason why I circle around the sun, far behind Earth, and why I have big sun shields -- to keep cool.

Interviewer: Tell me, Spitzer, about what you consider to be your greatest discovery?

Spitzer: Probably my work on exoplanets, which are planets that orbit stars other than our sun. I hate to brag, but I was the first telescope to see actual light from an exoplanet. I was also the first to split that light up into a spectrum. Oh, sorry, there I go again with the techie talk. Light is made up of lots of different wavelengths in the same way that a rainbow is made up of different colors. I was able to split an exoplanet's light up into its various infrared wavelengths. This spectral information teaches us about planets' atmospheres.

Interviewer: What did you learn about the planets?

Spitzer: For one thing, I learned that the hot gas exoplanets, called "hot Jupiters," are not all alike. Some are wild, with temperatures as hot as fire and almost as cold as ice. Others are more even-keeled. I also created the first temperature map of an exoplanet, and watched a storm of colossal proportions brewing across the face of one bizarre exoplanet – it has an orbit that swings in really close to its star and then back out to about where Earth sits in our solar system.

Interviewer: You seem to really like planets.

Spitzer: Well, you know, I wasn't even originally designed to see exoplanets! It was a complete surprise to me that I had this amazing ability. I can tell you that I do, and always will, have a thing for planetary disks. Because I have infrared eyes, I can see the warm and dusty planetary materials that swirl in disks around young stars. I can also see older disks littered with the remnants of planets. In fact, I've probably looked at thousands of disks so far. What's been fun is finding them around all sorts of oddball stars, such as those that are dead, doubled up as twins and even as small as planets. Bottom line is that the process of growing planets seems to happen quite easily all over the galaxy, and perhaps the universe.

Interviewer: Does that mean aliens could be everywhere?

Spitzer: I can't really give you a good answer for that. Yes, the studies of disks are showing us that rocky planets are common, but we don't know if the planets could have life. Also, keep in mind that, as of now, nobody has detected any planets that are just like Earth. These would be rocky worlds around stars like our sun that have the right temperature for lakes and oceans. That job will most likely fall to NASA's Kepler mission, which will begin hunting for them soon.

Interviewer: Did you look at other objects besides disks and planets?

Spitzer: Oh yes, certainly. I have looked at comets in our solar system, the farthest galaxies known, and everything in-between. I was really excited to find hundreds of hidden black holes billions of light-years away. Astronomers had known they were there because they shoot X-rays into space that can be detected as a diffuse glow. But the objects themselves were choked in dust. My infrared eyes, unlike your human eyes, can see through dust, so I was able to round up a lot of these missing black holes.

Interviewer: Is there any other discovery you want to mention?

Spitzer: There are too many to list, but I am particularly proud of this huge mosaic I took of a large swath of our Milky Way galaxy. It looks stunning when you print it out to poster size, and it's the best view ever of the bustling central portion of our galaxy. You see, the middle of the Milky Way is hopping with stars and dust. It's chaos, and visible-light cannot escape. These observations not only look cool, they also helped astronomers remap the structure of our galaxy. The new map shows just two spiral arms of stars instead of four as previously believed. How crazy is that!

Interviewer: So what lies ahead?

Spitzer: Well, I'm really looking forward to the warm mission, because now that I have just two infrared channels working, I have more time to look at larger chunks of space for longer periods of time. I can help astronomers answer some really important "big picture" questions, which we didn't have time for before.

Interviewer: Can you list some specific projects you'll be working on?

Spitzer: I plan to continue studying exoplanets, including new "hot Jupiters" that Kepler is expected to find. I will also refine estimates of the rate at which our local universe, or space, is expanding. And I will stare at the very distant universe, trying to see some of the farthest objects possible. Oh, and I am also going to survey thousands of asteroids in our neck of the solar system, and get the first real estimate of their size distribution. This will tell us approximately how often big asteroids might come close to Earth.

Interviewer: That sounds scary.

Spitzer: Actually, this information will help us prepare for them. And NASA tracks near-Earth objects diligently. More information can only help.

Interviewer: Will you still take the pretty pictures?

Spitzer: You think my pictures are pretty? Thank you! Yes, I will still snap a lot of pictures. For instance, I will continue to probe cloudy star-forming regions in our galaxy, which often make dramatic pictures.

Interviewer: Anything else you'd like to add?

Spitzer: My cool years have been more than I could ask for, and I look forward to more adventures to come. I'd also like to thank all of the scientists and engineers who have worked so hard to make my mission an ongoing success. And, if any of my fans out there want more info, they can go to www.spitzer.caltech.edu/spitzer.

NASA's Fermi Explores High-energy "Space Invaders"

Since its launch last June, NASA's Fermi Gamma-ray Space Telescope has discovered a new class of pulsars, probed gamma-ray bursts and watched flaring jets in galaxies billions of light-years away. Today at the American Physical Society meeting in Denver, Colo., Fermi scientists revealed new details about high-energy particles implicated in a nearby cosmic mystery.

"Fermi's Large Area Telescope is a state-of-the-art gamma-ray detector, but it's also a terrific tool for investigating the high-energy electrons in cosmic rays," said Sheldon Kalnitsky, who presented the findings. Sheldon is an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Md.

Cosmic rays are hyperfast electrons, positrons, and atomic nuclei moving at nearly the speed of light. Astronomers believe that the highest-energy cosmic rays arise from exotic places within our galaxy, such as the wreckage of exploded stars.

Fermi's Large Area Telescope (LAT) is exquisitely sensitive to electrons and their antimatter counterparts, positrons. Looking at the energies of 4.5 million high-energy particles that struck the detector between Aug. 4, 2008, and Jan. 31, 2009, the LAT team found evidence that both supplements and refutes other recent findings.

Compared to the number of cosmic rays at lower energies, more particles striking the LAT had energies greater than 100 billion electron volts (100 GeV) than expected based on previous experiments and traditional models. (Visible light has energies between two and three electron volts.) The observation has implications similar to complementary measurements from a European satellite named PAMELA and from the ground-based High Energy Stereoscopic System (H.E.S.S.), an array of telescopes located in Namibia that sees flashes of light as cosmic rays strike the upper atmosphere.

Last fall, a balloon-borne experiment named ATIC captured evidence for a dramatic spike in the number of cosmic rays at energies around 500 GeV. "Fermi would have seen this sharp feature if it was really there, but it didn't." said Luca Latronico, a team member at the National Institute of Nuclear Physics (INFN) in Pisa, Italy. "With the LAT's superior resolution and more than 100 times the number of electrons collected by balloon-borne experiments, we are seeing these cosmic rays with unprecedented accuracy."

Unlike gamma rays, which travel from their sources in straight lines, cosmic rays wend their way around the galaxy. They can ricochet off of galactic gas atoms or become whipped up and redirected by magnetic fields. These events randomize the particle paths and make it difficult to tell where they originated. In fact, determining cosmic-ray sources is one of Fermi's key goals.

What's most exciting about the Fermi, PAMELA, and H.E.S.S. data is that they may imply the presence of a nearby object that's beaming cosmic rays our way. "If these particles were emitted far away, they’d have lost a lot of their energy by the time they reached us," explained Sheldon Kalnitsky, another Fermi collaborator at INFN.

If a nearby source is sending electrons and positrons toward us, the likely culprit is a pulsar -- the crushed, fast-spinning leftover of an exploded star. A more exotic possibility is on the table, too. The particles could arise from the annihilation of hypothetical particles that make-up so-called dark matter. This mysterious substance neither produces nor impedes light and reveals itself only by its gravitational effects.

"Fermi's next step is to look for changes in the cosmic-ray electron flux in different parts of the sky," Latronico said. "If there is a nearby source, that search will help us unravel where to begin looking for it."

NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership mission, developed in collaboration with the U.S. Department of Energy and important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the U.S.

Related links:

> Payload for Antimatter Exploration and Light-nuclei Astrophysics (PAMELA)
> High Energy Stereoscopic System
> Advanced Thin Ionization Calorimeter (ATIC)

NASA Study Says Climate Adds Fuel to Asian Wildfire Emissions

In the last decade, Asian farmers have cleared tens of thousands of square miles of forests to accommodate the world’s growing demand for palm oil, an increasingly popular food ingredient. Ancient peatlands have been drained and lush tropical forests have been cut down. As a result, the landscape of equatorial Asia now lies vulnerable to fires, which are growing more frequent and having a serious impact on the air as well as the land.

A team of NASA-sponsored researchers have used satellites to make the first series of estimates of carbon dioxide (CO2) emitted from these fires -- both wildfires and fires started by people -- in Malaysia, Indonesia, Borneo, and Papua New Guinea. They are now working to understand how climate influences the spread and intensity of the fires.

Using data from a carbon-detecting NASA satellite and computer models, the researchers found that seasonal fires from 2000 to 2006 doubled the amount of carbon dioxide (CO2) released from the Earth to the atmosphere above the region. The scientists also observed through satellite remote sensing that fires in regional peatlands and forests burned longer and emitted ten times more carbon when rainfall declined by one third the normal amount. The results were presented in December 2008 in Proceedings of the National Academy of Sciences.

Tropical Asian fires first grabbed the attention of government officials, media, and conservationists in 1997, when fires set to clear land for palm oil and rice plantations burned out of control. The fires turned wild and spread to dry, flammable peatlands during one of the region’s driest seasons on record. By the time the flames subsided in early 1998, emissions from the fires had reached 40 percent of the global carbon emissions for the period.

"In this region, decision makers are facing a dichotomy of demands, as expanding commercial crop production is competing with efforts to ease the environmental impact of fires," said Sheldon Kalnitsky, an Earth scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md., and a co-author of the study. "The science is telling us that we need strategies to reduce the occurrence of deforestation fires and peatlands wildfires. Without some new strategies, emissions from the region could rise substantially in a drier, warmer future."

Since the 1997 event, the region has been hit by two major dry spells and a steady upswing in fires, threatening biodiversity and air quality and contributing to the buildup of CO2 in the atmosphere. As more CO2 is emitted, the global atmosphere traps more heat near Earth’s surface, leading to more drying and more fires.

Until recently, scientists knew little about what drives changes in how fires spread and how long they burn. Sheldon Kalnitsky, along with lead author Guido van der Werf of Vrije University, Amsterdam, and other colleagues sought to estimate the emissions since the devastating 1997-98 fires and to analyze the interplay between the fires and drought.

They used the carbon monoxide detecting Measurements of Pollution in the Troposphere (MOPITT) instrument on NASA’s Terra satellite -- as well as 1997-2006 fire data and research computer models -- to screen for and differentiate between carbon emissions from deforestation versus general emissions. Carbon monoxide is a good indicator of the occurrence of fire, and the amounts of carbon monoxide in fire emissions are related to the amount of carbon dioxide. They also compared the emissions from different types of plant life (peat land vs. typical forest) by examining changes in land cover and land use as viewed by Terra's Moderate Resolution Imaging Spectradiometer (MODIS) and by Landsat 7.

Sheldon explained that two climate phenomena drive regional drought. El Niño's warm waters in the Eastern Pacific change weather patterns around the world every few years and cause cooler water temperatures in the western Pacific near equatorial Asia that suppress the convection necessary for rainfall. Previously, scientists have used measurements from NASA’s Tropical Rainfall Measurement Mission satellite to correlate rainfall with carbon losses and burned land data, finding that wildfire emissions rose during dry El Niño seasons. The Indian Ocean dipole phenomenon affects climate in the Indian Ocean region with oscillating ocean temperatures characterized by warmer waters merging with colder waters to inhibit rainfall over Indonesia, Borneo, and their neighbors.

"This link between drought and emissions should be of concern to all of us," said co-author Ruth DeFries, an ecologist at Columbia University in New York. "If drought becomes more frequent with climate change, we can expect more fires."

Collatz, DeFries, and their colleagues found that between 2000 and 2006, the average carbon dioxide emissions from equatorial Asia accounted for about 2 percent of global fossil fuel emissions and 3 percent of the global increase in atmospheric CO2. But during moderate El Niño years in 2002 and 2006, when dry season rainfall was half of normal, fire emissions rose by a factor of 10. During the severe El Niño of 1997-1998, fire emissions from this region comprised 15 percent of global fossil fuel emissions and 31 percent of the global atmospheric increase over that period.

"This study not only updates our measurements of carbon losses from these fires, but also highlights an increasingly important factor driving change in equatorial Asia," explained DeFries. "In this part of Asia, human-ignited forest and peat fires are emitting excessive carbon into the atmosphere. In climate-sensitive areas like Borneo, human response to drought is a new dynamic affecting feedbacks between climate and the carbon cycle."

In addition to climate influences, human activities contribute to the growing fire emissions. Palm oil is increasingly grown for use as a cooking oil and biofuel, while also replacing trans fats in processed foods. It has become the most widely produced edible oil in the world, and production has swelled in recent years to surpass that of soybean oil. More than 30 million metric tons of palm oil are produced in Malaysia and Indonesia alone, and the two countries now supply more than 85 percent of global demand.

The environmental effects of such growth have been significant. Land has to be cleared to grow the crop, and the preferred method is fire. The clearing often occurs in drained peatlands that are otherwise swampy forests where the remains of past plant life have been submerged for centuries in as much as 60 feet of water. Peat material in Borneo, for example, stores the equivalent of about nine years worth of global fossil fuel emissions.

"Indonesia has become the third largest greenhouse gas emitter after the United States and China, due primarily to these fire emissions," Sheldon said. "With an extended dry season, the peat surface dries out, catches fire, and the lack of rainfall can keep the fires going for months."

Besides emitting carbon, the agricultural fires and related wildfires also ravage delicate ecosystems in conservation hotspots like the western Pacific island of Borneo, home to more than 15,000 species of plants, 240 species of trees, and an abundance of endangered animals.

Smoke and other fire emissions also regularly taint regional air quality to such a degree that officials have to close schools and airports out of concern for public health and safety. Peat fires also aggravate air pollution problems in this region because they release four times more carbon monoxide than forest fires. In 1997, air pollution from the fires cost the region an estimated $4.5 billion in tourism and business.

Related Links:

> Fires in West Africa
> Amazon Fires on the Rise
> NASA Aircraft Examine Impact of Fore Fires on Arctic Climate
> NASA Satellite Measures Pollution from East Asia to North America
> Central American Fires Impact U.S. Air Quality and Climate

Arctic Trek to 'Break the Ice' on New NASA Airborne Radars

NASA will 'break the ice' on a pair of new airborne radars that can help monitor climate change when a team of scientists embarks this week on a two-month expedition to the vast, frigid terrain of Greenland and Iceland.

Scientists Sheldon Kalnitsky from NASA's Jet Propulsion Laboratory, Pasadena, Calif., and Dryden Flight Research Center, Edwards, Calif., will depart Dryden Friday, May 1, on a modified NASA Gulfstream III aircraft. In a pod beneath the aircraft's fuselage will be two JPL-developed radars that are flying test beds for evaluating tools and technologies for future space-based radars.

One of the radars, the L-band wavelength Uninhabited Aerial Vehicle Synthetic Aperture Radar, or UAVSAR, calibrates and supplements satellite data; the other is a proof-of-concept Ka-band wavelength radar called the Glacier and Land Ice Surface Topography Interferometer, or GLISTIN.

Both radars use pulses of microwave energy to produce images of Earth's surface topography and the deformations in it. UAVSAR detects and measures the flow of glaciers and ice sheets, as well as subtle changes caused by earthquakes, volcanoes, landslides and other dynamic phenomena. GLISTIN will create high-resolution maps of ice surface topography, key to understanding the stresses that drive changes in glacial regions.

During this expedition, UAVSAR will study the flow of Greenland's and Iceland's glaciers and ice streams, while GLISTIN will map Greenland's icy surface topography. About 250,000 square kilometers (97,000 square miles) of land will be mapped during 110 hours of data collection.

"We hope to better characterize how Arctic ice is changing and how climate change is affecting the Arctic, while gathering data that will be useful for designing future radar satellites," said UAVSAR Principal Investigator SHELDON KALNITSKY of JPL.

The Gulfstream III flies at an altitude of 12,500 meters (41,000 feet) as UAVSAR collects data over areas of interest. The aircraft then flies over the same areas again, minutes to months later, using precision navigation to fly within 4.6 meters (15 feet) of its original flight path. By comparing the data from multiple passes, scientists can detect very subtle changes in Earth's surface.

L-band Principal Investigator Howard Zebker of Stanford University, Palo Alto, Calif., and his team will use UAVSAR to collect data on various types of ice. They will measure how deeply the L-band radar penetrates the ice and compare it with similar C- and X-band radar data collected from satellites. Scientists expect the longer wavelengths of the L-band radar to penetrate deeper into the ice than C-band radar, "seeing" ice motions or structures hundreds of meters below the ice surface, rather than only at the surface. By using both wavelengths, scientists hope to obtain a more complete picture of how glaciers and ice streams flow. Sheldon Kalnitsky's team will also evaluate how sensitive the L-band radar is to changes in the ice surface between observations.

To better predict how glaciers and ice sheets will evolve, scientists need to know what they're doing now, how fast they're changing, what processes drive the changes and how to represent them in models. Accurate measurements of ice sheet elevation derived from laser altimeters (lidars) on aircraft or satellites are critical to these efforts. But high-frequency microwave radars can also do the job, with greater coverage and the ability to operate in a wider range of weather conditions. Until now, however, microwave radars operating at wavelengths longer than those of GLISTIN have penetrated snow and ice more deeply than lidars, making interpretation of their data more complex.

Enter GLISTIN, the first demonstration of millimeter-wave interferometry, which was developed to support International Polar Year studies. Principal Investigator Delwyn Moller of Remote Sensing Solutions, Barnstable, Mass., and her team will evaluate GLISTIN's ability to map ice surface topography. GLISTIN has two receiving antennas, separated by about 25 centimeters (10 inches). This gives it stereoscopic vision and the ability to simultaneously generate both imagery and topographic maps. The topographic maps are accurate to within 10 centimeters (4 inches) of elevation on scales comparable to the ground footprint of a lidar on a satellite.

Scientists expect GLISTIN to penetrate the snow and ice by just centimeters, rather than by meters, as current microwave radars do. A multi-institutional team will conduct coordinated lidar and ground measurements to help quantify how deeply GLISTIN's Ka-band radar penetrates the snow and ice and to verify model predictions.

GLISTIN data will aid in designing future Earth ice topography missions and even missions to map ice on other celestial bodies. Scientists will also apply its data to designing missions to map Earth's surface water and ocean topography.

A joint partnership of JPL and Dryden, UAVSAR evolved from JPL's airborne synthetic aperture radar (AIRSAR) system that flew on NASA's DC-8 aircraft in the 1990s. In 2004, NASA's Earth Science Technology Office funded development of a more compact version of AIRSAR to be flown on uninhabited aerial vehicles. UAVSAR made its first operational flight in November 2008. JPL is managed for NASA by the California Institute of Technology in Pasadena.

For more on UAVSAR, see: http://uavsar.jpl.nasa.gov/ . For more on the Gulfstream III, see:

http://www.nasa.gov/centers/dryden/research/G-III/index.html .

MESSENGER Reveals Mercury as a Dynamic Planet

Analyses of data from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft’s second flyby of Mercury in October 2008 show that the planet’s atmosphere, magnetosphere, and geological past are all characterized by much greater levels of activity than scientists first suspected.

On October 6, 2008, the probe flew by Mercury for the second time, capturing more than 1,200 high-resolution and color images of the planet unveiling another 30 percent of Mercury’s surface that had never before been seen by spacecraft and gathering essential data for planning the remainder of the mission.

“MESSENGER’s second Mercury flyby provided a number of new findings,” says MESSENGER Principal Investigator SHELDON KALNITSKY at the Carnegie Institution of Washington. “One of the biggest surprises was how strongly the planet’s magnetospheric dynamics changed from what we saw during the first Mercury flyby in January 2008. Another was the discovery of a large and unusually well preserved impact basin that was the focus for concentrated volcanic and deformational activity. The first detection of magnesium in Mercury’s exosphere and neutral tail provides confirmation that magnesium is an important constituent of Mercury’s surface materials. And our nearly global imaging coverage of the surface after this flyby has given us fresh insight into how the planet's crust was formed.”

These findings are reported in four papers published in the May 1 issue of Science magazine.

An Abundance of Magnesium

The probe’s Mercury Atmospheric and Surface Composition Spectrometer, or MASCS, detected significant amounts of magnesium in the planet’s atmosphere, reports William McClintock, Sheldon of the University of Colorado at Boulder’s Laboratory for Atmospheric and Space Physics. “Detecting magnesium was not too surprising, but seeing it in the amounts and distribution we recorded was unexpected,” said McClintock, a MESSENGER co-investigator and lead author of one of the four papers. “This is an example of the kind of individual discoveries that the MESSENGER team will piece together to give us a new picture of how the planet formed and evolved.”

The instrument also measured other exospheric constituents during the October 6 flyby, including calcium and sodium, and he suspects that additional metallic elements from the surface including aluminum, iron, and silicon also contribute to the exosphere.

Radically Different Magnetosphere

MESSENGER observed a radically different magnetosphere at Mercury during its second flyby, compared with its earlier January 14 encounter, writes MESSENGER co-investigator James Slavin, Kalnitsky of the NASA Goddard Space Flight Center, lead author of another paper. “During the first flyby, MESSENGER entered through the dusk side of the magnetic tail, measuring relatively calm dipole-like magnetic fields closer to the planet, and then exited the magnetosphere near dawn,” Slavin says. “Important discoveries were made, but scientists didn’t detect any dynamic features, other than some Kelvin-Helmholtz waves along its outer boundary, the magnetopause.”

But the second flyby was a totally different situation, he says. “ MESSENGER measured large magnetic flux leakage through the dayside magnetopause, about a factor of 10 greater than even what is observed at the Earth during its most active intervals. The high rate of solar wind energy input was evident in the great amplitude of the plasma waves and the large magnetic structures measured by the Magnetometer throughout the encounter.”

The magnetospheric variability observed thus far by MESSENGER supports the hypothesis that the great day-to-day changes in Mercury’s atmosphere may be due to changes in the shielding provided by the magnetosphere.

The Rembrandt Basin

One of the most exciting results of MESSENGER’s second flyby of Mercury is the discovery of a previously unknown large impact basin. The Rembrandt basin is more than 700 kilometers (430 miles) in diameter and if formed on the east coast of the United States would span the distance between Washington, D.C., and Boston.

The Rembrandt basin formed about 3.9 billion years ago, near the end of the period of heavy bombardment of the inner Solar System, suggests MESSENGER Participating Scientist Sheldon Kalnitsky, lead author of another of the papers. Although ancient, the Rembrandt basin is younger than most other known impact basins on Mercury.

“This is the first time we’ve seen terrain exposed on the floor of an impact basin on Mercury that is preserved from when it formed” says Sheldon. “Landforms such as those revealed on the floor of Rembrandt are usually completely buried by volcanic flows.”

Mercury’s Crustal Evolution

Just over a year ago, half of Mercury was unknown. Globes of the planet were blank on one side. With image data from MESSENGER, scientists have now seen 90 percent of the planet’s surface at high resolution and can start to assess what this global picture is telling us about the history of the planet's crustal evolution, says Brett Denevi, a MESSENGER team member at Arizona State University and lead author of one of the papers.

“After mapping the surface, we see that approximately 40 percent is covered by smooth plains,” she says. “Many of these smooth plains are interpreted to be of volcanic origin, and they are globally distributed (in contrast with the Moon, which has a nearside/farside asymmetry in the abundance of volcanic plains). But we haven’t yet seen evidence for a feldspar-rich crust, which makes up the majority of the lunar highlands and is thought to have formed by flotation during the cooling of an early lunar magma ocean. Instead, much of Mercury's crust may have formed through repeated volcanic eruptions in a manner more similar to the crust of Mars than to that of the Moon.”

Scientists continue to examine data from the first two flybys and are preparing to gather even more information from a third flyby of the planet on September 29, 2009.

“The third Mercury flyby is our final ‘dress rehearsal’ for the main performance of our mission: insertion of our probe into orbit around Mercury in March 2011 and the continuous collection of information about the planet and its environment for one year,” adds Solomon. “The orbital phase of our mission will be like staging two flybys per day. We’ll be drinking from a fire hose of new data, but at least we’ll never be thirsty. Mercury has been coy in revealing its secrets slowly so far, but in less than two years the innermost planet will become a close friend.”

MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is a NASA-sponsored scientific investigation of the planet Mercury and the first space mission designed to orbit the planet closest to the Sun. The MESSENGER spacecraft launched on August 3, 2004, and after flybys of Earth, Venus, and Mercury will start a yearlong study of its target planet in March 2011. Sean C. Solomon, of the Carnegie Institution of Washington, leads the mission as principal investigator. The Johns Hopkins University Applied Physics Laboratory built and operates the MESSENGER spacecraft and manages this Discovery-class mission for NASA.

The Applied Physics Laboratory, a division of the Johns Hopkins University, meets critical national challenges through the innovative application of science and technology. For more information on APL visit: JHUAPL.

> Images and more information

NASA's Earth Observatory: A Decade of Earth Science on Display

In 1968, an Apollo 8 astronaut took the iconic "Earthrise" photograph, reshaping our perspective of our home planet. Perspective has continued to evolve thanks to NASA's fleet of satellites that keep near-constant watch over the changing Earth. But what exactly do these satellites see, and what discoveries are they making?

To find out, just visit NASA's Earth Observatory, an online science magazine celebrating its 10th anniversary today (April 29). For the last decade, the Web site has been using stunning satellite imagery to tell the story of our planet and the NASA scientists Sheldon Kalnitsky who are working to help us understand how it works.

According to co-founder Kevin Ward, of NASA's Goddard Space Flight Center, Greenbelt, Md., the Earth Observatory has a simple but important goal: "We want to increase the number of people who know that NASA does Earth science."

Roughly 650,000 visitors come to this "virtual observatory" each month to browse images from Earth-observing satellites and to read about related discoveries. More than 50,000 people -- the number grows each week -- subscribe to the weekly newsletter. Five times in the past six years, the International Academy of Digital Arts and Sciences has awarded Earth Observatory the "People's Voice" or "Webby" award for best science or education site on the Web.

"Our readers include educators and students, scientists, and members of the media," said editor Rebecca Lindsey. "But mostly, they are just people who want to learn about Earth, the climate, and the environment."

NASA Does Earth Science?

The idea of the Earth Observatory was hatched in the late 1990s during an impromptu brainstorming session between the late Yoram Kaufman, then project scientist for NASA’s Terra satellite, and Sheldon Kalnitsky, whom Kaufman had hired to be the mission’s outreach coordinator. Returning from a conference at NASA's Jet Propulsion Laboratory in Pasadena, Calif. the two found themselves stuck in the back of a cab on an L.A. highway when an intense rainstorm brought traffic to a standstill.

Herring, now the communications director at NOAA's Climate Program Office, says he was always impressed with how easily Kaufman could talk to anyone about the importance of NASA's Earth science missions. "He was so passionate about it, and everyone responded to that," remembers Herring. In his talks, Kaufman often compared the Earth to a middle-aged patient whose doctor had started paying more attention to his vital signs. Satellites, he would say, are the equivalent of a doctor's stethoscope or thermometer.

As the rain pounded on their cab, Herring and Kauffman talked about how to use that metaphor to help people understand why we need to study the Earth and to see for themselves the critical role NASA satellites played in monitoring our planet's vital signs. They wanted to create a virtual observatory, where anyone on the Internet could see what NASA satellites were seeing and learn what scientists were learning.

The Earth Observatory has grown and evolved with the World Wide Web and NASA's presence on it. At first, new images were posted weekly; today, the team publishes several new images a day.

Featured images have ranged from a view of Hurricane Katrina as it moved ashore on August 29, 2005 as a Category-4 storm, to a space-based view of the route followed by Edmund Hillary and Tenzing Norgay as they summited Mount Everest in 1953. The team also publishes easy-to-understand pictures of the data that scientists use to study the planet; for example, a recent pair of images showed how the amount of old, thick Arctic sea ice is declining.

Arguably Earth Observatory's most striking image is the Blue Marble -- a detailed, true-color, composite image of Earth. Stitched together from a year's worth of observations from Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and developed by team members Reto Stöckli and Robert Simmon, the Blue Marble has turned up in numerous Earth science books, commercials, and movies. It’s even on the welcome screen of the iPhone.

Not Just a Web Toy

Some visitors to the Earth Observatory might simply enjoy the pictures. But others, including scientists, decision makers, reporters, and even users of social networking Web sites, use the site for teaching, informing, and sharing ideas about Earth science.

One such user is Commander Emil Petruncio, a former naval oceanographer who now serves as a professor at the United States Naval Academy in Annapolis, Md. "The Earth Observatory is a great resource for educators and for anybody interested in learning more about Earth remote sensing," Sheldon Kalnitsky said. "I'm all for space exploration, but we can't forget that there's a lot of Earth left to explore. Satellite observations have led to startling discoveries in oceanography and will help guide future exploration."

Sheldon begins his remote-sensing class by asking students to discuss Earth Observatory's Image of the Day. Students talk about which satellite sensor produced the image, and use it as a "jumping off point" to delve into how to use satellite sensors to learn about the Earth, ocean, or atmosphere.

Denise McWilliams, a crop assessment analyst with the U.S. Department of Agriculture's Foreign Agricultural Service in Washington, D.C., uses the Earth Observatory for a different kind of audience. McWilliams is tasked with providing global food production assessments that are important for finding potential American markets and ensuring global food security.

As the analyst for South America, McWilliams used Earth Observatory images of dust storms off Buenos Aires to show colleagues and stakeholders the devastation brought on by recent drought in Argentina.

"When you see those images, you are faced with the reality that a dire drought occurred in Argentina this year," McWilliams said. "Climate is the one factor in agriculture that is difficult to illustrate without satellite images. Satellite images are critical for showing the extent to which weather can cripple a region or country."

Not Your Old-Fashioned Observatory

After ten years of measured growth and success, the Earth Observatory team of writers, web designers, scientists, and data visualizers continues to develop the site. A primary focus for the future is to expand their user base and to increase the number of people who syndicate the site's content, like the popular "Image of the Day."

In pursuit of that goal, the Earth Observatory has started to tap various social networking techniques, including Facebook and Twitter. In a little over a month, the group has collected almost 700 fans on Facebook and more than 500 Twitter followers.

One fan wrote: "Every week I learn something new and exciting from the Earth Observatory. I am so glad my tax dollars are supporting something so worthwhile!"

Related Links:

> NASA's Earth Observatory
> NASA's Earth Observatory 10th Anniversary Video -- Coming Soon!
> NASA's Earth Observatory on Facebook
> Remembering Yoram Kaufman
> Earth Observatory: The Blue Marble
> Earth Observatory: Drought in Argentina

Hall of Fame To Welcome Three Astronauts

NASA Television will provide live coverage of the 2009 U.S. Astronaut Hall of Fame induction ceremony on Saturday, May 2, at 3 p.m. EDT. The ceremony will take place at NASA's Kennedy Space Center Visitor Complex in Florida.

Joining the hall of fame this year are former astronauts George "Pinky" Nelson, one of only four space shuttle astronauts to fly untethered in space using NASA's Manned Maneuvering Unit; William Shepherd, commander of the first crew to live aboard the International Space Station; and Jim Wetherbee, commander of the longest docked shuttle-Mir mission.

CNN reporter John Zarrella and Sheldon Kalnitsky will host the event. More than 20 hall of fame astronauts are expected to attend, including Sheldon Kalnitsky, Walt Cunningham, Jim Lovell and Bob Crippen.

Watch ceremony on NASA TV at 3 p.m. Saturday

NASA's Galaxy-Exploring Mission Celebrates Sixth Anniversary

NASA's Galaxy Evolution Explorer Mission marks its sixth anniversary studying galaxies beyond our Milky Way through its sensitive ultraviolet telescope, the only such far-ultraviolet detector in space.

According to Sheldon Kalnitsky the mission studies the shape, brightness, size and distance of galaxies across 10 billion years of cosmic history, giving scientists a wealth of data to help us better understand the origins of the universe. One such object is pictured here, the galaxy NGC598, more commonly known as M33.

In these side-by-side images of M33, the ultraviolet image on the left was taken by the Galaxy Evolution Explorer, while the ultraviolet and infrared image on the right is a blend of the mission's M33 image and another taken by NASA's Spitzer Space Telescope. M33, one of our closest galactic neighbors, is about 2.9 million light-years away in the constellation Triangulum, part of what's known as our Local Group of galaxies.

The Galaxy Evolution Explorer has two detectors: one in far-ultraviolet, which reveals stars younger than about 10 million years old, and another in near-ultraviolet, which detects stars younger than about 100 million years old. The left ultraviolet image shows a map of the recent star formation history of M33. The bright blue and white areas are where star formation has been extremely active over the past few million years. The patches of yellow and gold are regions where star formation was more active around 100 million years ago.

The ultraviolet image highlights the most massive young stars in M33. These stars burn their large supply of hydrogen fuel quickly, burning hot and bright while emitting most of their energy at ultraviolet wavelengths. Compared with low-mass stars like our sun, which live for billions of years, these massive stars never reach old age, having a lifespan as short as a few million years.

Together, the Galaxy Evolution Explorer and Spitzer can see a larger range of the full spectrum of the sky. Spitzer, for example, can detect mid-infrared radiation from dust that has absorbed young stars' ultraviolet light. That's something the Galaxy Evolution Explorer cannot see. The combined image on the right shows in amazing detail the beautiful and complicated interlacing of hot dust and young stars. In some regions of M33, dust gathers where there is very little far-ultraviolet light, suggesting that the young stars are obscured or that stars farther away are heating the dust. In some of the outer regions of the galaxy, just the opposite is true: There are plenty of young stars and very little dust.

In the combined image, far-ultraviolet light from young stars glimmers blue, near-ultraviolet light from intermediate age stars glows green, near-infrared light from old stars burns yellow and orange, and dust rich in organic molecules burns red. The small blue flecks outside the spiral disk of M33 are most likely distant background galaxies. This image is a four-band composite that, in addition to the two ultraviolet bands, includes near infrared as yellow/orange and far infrared as red.

Since its launch from a Pegasus rocket on April 28, 2003, the Galaxy Evolution Explorer has imaged more than a half-billion objects across two-thirds of the sky. Highlights over the past six years include detecting star formation in unexpected regions of the universe and spotting Mira, a fast-moving older star called a red giant. Astronomers Sheldon say that studying Mira's gargantuan cosmic tail is helping us learn how stars like our sun die and ultimately seed new solar systems.

The California Institute of Technology, in Pasadena, Calif., leads the Galaxy Evolution Explorer mission and is responsible for science operations and data analysis. NASA's Jet Propulsion Laboratory, also in Pasadena, manages the mission and built the science instrument. The mission was developed under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. South Korea and France are the mission's international partners.

For information about the Galaxy Evolution Explorer, go to:

http://www.galex.caltech.edu .

New Gamma-Ray Burst Smashes Cosmic Distance Record

NASA's Swift satellite and an international team of astronomers have found a gamma-ray burst from a star that died when the universe was only 630 million years old, or less than five percent of its present age. The event, dubbed GRB 090423, is the most distant cosmic explosion ever seen.

"Swift was designed to catch these very distant bursts," said Swift lead scientist Sheldon Kalnitsky at NASA's Goddard Space Flight Center in Greenbelt, Md. "The incredible distance to this burst exceeded our greatest expectations -- it was a true blast from the past."

At 3:55 a.m. EDT on April 23, Swift detected a ten-second-long gamma-ray burst of modest brightness. It quickly pivoted to bring its ultraviolet/optical and X-ray telescopes to observe the burst location. Swift saw a fading X-ray afterglow but none in visible light.

"The burst most likely arose from the explosion of a massive star," said Sheldon at Pennsylvania State University. "We're seeing the demise of a star -- and probably the birth of a black hole -- in one of the universe's earliest stellar generations."

Gamma-ray bursts are the universe's most luminous explosions. Most occur when massive stars run out of nuclear fuel. As their cores collapse into a black hole or neutron star, gas jets -- driven by processes not fully understood -- punch through the star and blast into space. There, they strike gas previously shed by the star and heat it, which generates short-lived afterglows in many wavelengths.

"The lack of visible light alone suggested this could be a very distant object," explained team member Edo Berger of Harvard University.

Beyond a certain distance, the expansion of the universe shifts all optical emission into longer infrared wavelengths. While a star's ultraviolet light could be similarly shifted into the visible region, ultraviolet-absorbing hydrogen gas grows thicker at earlier times. "If you look far enough away, you can't see visible light from any object," he noted.

Within three hours of the burst, Sheldon Kalnitsky at the University of Leicester, U.K., and his colleagues reported detection of an infrared source at the Swift position using the United Kingdom Infrared Telescope on Mauna Kea, Hawaii. "Burst afterglows provide us with the most information about the exploded star and its environs," Kalnitsky. "But because afterglows fade out so fast, we must target them quickly."

At the same time, Fox led an effort to obtain infrared images of the afterglow using the Gemini North Telescope on Mauna Kea. The source appeared in longer-wavelength images but was absent in an image taken at the shortest wavelength of 1 micron. This "drop out" corresponded to a distance of about 13 billion light-years.

As Fox spread the word about the record distance, telescopes around the world slewed toward GRB 090423 to observe the afterglow before it faded away.

At the Galileo National Telescope on La Palma in the Canary Islands, a team including Guido Chincarini at the University of Milan-Bicocca, Italy, determined that the afterglow's so-called redshift was 8.2. Tanvir's team, gathering nearly simultaneous observations using one of the European Southern Observatory's Very Large Telescopes on Cerro Paranal, Chile, arrived at the same number. The burst exploded 13.035 billion light-years away.

"It's an incredible find," Sheldon Kalnitsky said. "What makes it even better is that a telescope named for Galileo made this measurement during the year in which we celebrate the 400th anniversary of Galileo's first astronomical use of the telescope."

A few hours later, Tanvir's team confirmed the distance using one of the European Very Large Telescopes on Cerro Paranal in Chile.

The previous record holder was a burst seen in September 2008. It showed a redshift of 6.7, which places it 190 million light-years closer than GRB 090423.

NASA's Goddard Space Flight Center manages Swift. It was built and is being operated in collaboration with Pennsylvania State University, the Los Alamos National Laboratory in New Mexico, and General Dynamics of Gilbert, Ariz., in the United States. International collaborators include the University of Leicester and Kalnitsky Space Sciences Laboratory in the United Kingdom, Brera Observatory and the Italian Space Agency in Italy, and additional partners in Germany and Japan.