Posted on by Fraser Cain

Rocky Planets Form Further Away Than Previously Thought

Stellar nursery in the Orion Nebula. Image credit: ESO. Click to enlarge.
The most detailed measurements to date of the dusty disks around young stars confirm a new theory that the region where rocky planets such as Earth form is much farther away from the star than originally thought.

These first definitive measurements of planet-forming zones offer important clues to the initial conditions that give birth to planets. Understanding planet formation is key to understanding Earth’s origins, yet this remains a mysterious process, said John Monnier, assistant professor of astronomy at the University of Michigan and lead author on the paper, “The near-infrared size luminosity relations for Herbig Ae/Be disks” in a recent edition of Astrophysical Journal.

Very young stars are surrounded by thick, rotating disks of gas and dust, which are expected to eventually disappear as material is either pulled into the star, is blown from the disk, or collects into larger pieces of debris. This transition marks the leap from star formation to planet formation.

The scientists examined the innermost region of such disks where the star’s energy heats the dust to extremely high temperatures. These dusty disks are where the seeds of planets form, where dusty particles stick together and eventually grow to large masses.

However, if the dust orbits too close to the star, it evaporates, shutting off any hope of planet formation. It’s important to know where the evaporation begins since it has a dramatic effect on planet formation, Monnier said. The initial temperature and density of dust surrounding young stars are critical ingredients for advanced computer models of planet formation.

For the study, scientists looked at young stars that are about one and a half times the mass of the sun. “We can study these stars more in-depth because they are brighter and easier to see,” Monnier said.

In the last decade or so, beliefs about the systems that build planets have changed drastically with the onset of powerful observatories that can take more precise measurements, Monnier said.

They found that measurements thought to be accurate were actually very different than originally thought.

For this work, scientists used the two largest telescopes in the world linked together to form the Keck Interferometer. This ultra-powerful duo acts as the ultimate zoom lens allowing astronomers to peer into planetary nurseries with 10X the detail of the Hubble Space Telescope. By combining the light from the two Keck Telescopes, researchers were able to achieve the capabilities of a single telescope that spans a football field, but for a fraction of the cost, Monnier said.

Other key authors were Rafael Millan-Gabet and Rachel Akeson of the Michelson Science Center. Other key institutions included the Caltech-run, NASA Jet Propulsion Laboratory and the W.M. Keck Observatory in Kamuela, Hawaii.

The Keck Interferometer was funded by NASA and developed and operated by Jet Propulsion Lab, W.M. Keck Observatory, and the Michelson Science Center.

Original Source: U of Michigan News Release

Posted on by Fraser Cain

Amateurs Help Discover Extrasolar Planet

Artist interpretation of an extrasolar planet. Image credit: NASA. Click to enlarge.
An international collaboration featuring Ohio State University astronomers has detected a planet in a solar system that, at roughly 15,000 light years from Earth, is one of the most distant ever discovered.
Andrew Gould

In a time when technology is starting to make such finds almost commonplace, this new planet — which is roughly three times the size of Jupiter — is special for several reasons, said Andrew Gould, professor of astronomy at Ohio State .

The technique that astronomers used to find the planet worked so well that he thinks it could be used to find much smaller planets — Earth-sized planets, even very distant ones.

And because two amateur astronomers in New Zealand helped detect the planet using only their backyard telescopes, the find suggests that anyone can become a planet hunter.

Gould and his colleagues have submitted a paper announcing the planet to Astrophysical Journal Letters, and have posted the paper on a publicly available Internet preprint server, http://arXiv.org . The team has secured use of NASA’s Hubble Space Telescope in late May to examine the star that the planet is orbiting.

The astronomers used a technique called gravitational microlensing, which occurs when a massive object in space, like a star or even a black hole, crosses in front of a star shining in the background. The object’s strong gravitational pull bends the light rays from the more distant star and magnifies them like a lens. Here on Earth, we see the star get brighter as the lens crosses in front of it, and then fade as the lens gets farther away.
Because the scientists were able to monitor the light signal with near-perfect precision, Gould thinks the technique could easily have revealed an even smaller planet. “If an Earth-mass planet was in the same position, we would have been able to detect it,” he said.

On March 17, 2005, Andrzej Udalski, professor of astronomy at Warsaw University and leader of the Optical Gravitational Lensing Experiment, or OGLE, noticed that a star located thousands of light years from Earth was starting to move in front of another star that was even farther away, near the center of our galaxy. A month later, when the more distant star had brightened a hundred-fold, astronomers from OGLE and from Gould’s collaboration (the Microlensing Follow Up Network, or MicroFUN) detected a new pattern in the signal — a rapid distortion of the brightening — that could only mean one thing.

“There’s absolutely no doubt that the star in front has a planet, which caused the deviation we saw,” Gould said.

Because the scientists were able to monitor the light signal with near-perfect precision, Gould thinks the technique could easily have revealed an even smaller planet.

“If an Earth-mass planet was in the same position, we would have been able to detect it,” he said.

OGLE finds more than 600 microlensing events per year using a dedicated 1.3-meter telescope at Las Campanas Observatory in Chile (operated by Carnegie Institution of Washington). MicroFUN is a collaboration of astronomers from the US, Korea, New Zealand, and Israel that picks out those events that are most likely to reveal planets and monitors them from telescopes around the world.

“That allows us to watch these events 24/7,” Gould said. “When the sun rises at one location, we continue to monitor from the next.”

Two of these telescopes belong to two avid New Zealand amateur astronomers who were recruited by the MicroFUN team. Grant Christie of Auckland used a 14-inch telescope, and Jennie McCormick of Pakuranga used a 10-inch telescope. Both share co-authorship on the paper submitted to Astrophysical Journal Letters.

Two other collaborations — the Probing Lensing Anomalies NETwork (PLANET) and Microlensing Observations in Astrophysics (MOA) — also followed the event and contributed to the journal paper.

Ohio State scientists on the project included Darren DePoy and Richard Pogge, both professors of astronomy, and Subo Dong, a graduate student. Other partners hail from Warsaw University in Poland, Princeton University, Harvard-Smithsonian Center for Astrophysics, Universidad de Concepci?n in Chile, University of Manchester, California Institute of Technology, American Museum of Natural History, Chungbuk National University in Korea, Korea Astronomy and Space Science Institute, Massy University in New Zealand, Nagoya University in Japan, and the University of Auckland in New Zealand.

This is the second planet that astronomers have detected using microlensing. The first one, found a year ago, is estimated to be at a similar distance.

Gould’s initial estimate is that the new planet is approximately 15,000 light years away, but he will need more data to refine that distance, he said. A light year is the distance light travels in a year — approximately six trillion miles.

The OGLE collaboration is funded by the Polish Ministry of Scientific Research and Information Technology, the Foundation for Polish Science, the National Science Foundation, and NASA. Some MicroFUN team members received funding from the National Science Foundation, Harvard College Observatory, the Korea Science and Engineering Foundation, and the Korea Astronomy and Space Science Institute.

Original Source: OSU News Release

Posted on by Fraser Cain

Proton Launches DIRECTV Satellite

Proton rocket launching with DIRECTV 8 satellite. Image credit: ILS. Click to enlarge.
A Russian Proton Breeze M launcher placed the DIRECTV 8 satellite into orbit today, marking the fourth successful mission of the year for International Launch Services (ILS).

The Proton vehicle lifted off at 11:59 p.m. local time (1:59 p.m. EDT, 17:59 GMT). It continued its climb through space for nine hours and 15 minutes, after which time the satellite separated from the rocket into an elliptical geosynchronous transfer orbit. Satellite controllers confirm that DIRECTV 8 is functioning properly. Over the next ten days the satellite will be maneuvered into a circular geosynchronous orbit, 22,300 miles (36,000 km) above the equator.

“We’re pleased that DIRECTV chose ILS and Proton to launch this important satellite, which will provide support for the expansion of new digital and high-definition services,” said ILS President Mark Albrecht.

The DIRECTV 8 satellite, built by Space Systems/Loral, carries both Ku-band and Ka-band payloads. Its final operating position is 101 degrees West longitude.

“We congratulate the ILS launch team on their flawless execution in placing DIRECTV 8 into orbit today,” said Jim Butterworth, senior vice president, Communication Systems, DIRECTV, Inc. “DIRECTV 8 will play an important role in strengthening our satellite fleet and the rollout of new services for our more than 14.4 million customers.”

ILS markets launches and manages the missions on both the Russian Proton and the American Atlas rockets. The Proton vehicle is built by Khrunichev State Research and Production Space Center, and the Atlas is manufactured by Lockheed Martin (NYSE:LMT). This is the second spacecraft ILS has launched for DIRECTV on Proton; the previous launch was DIRECTV 5 in 2002. The Atlas vehicle also has launched two satellites for DIRECTV: DBS 2 and DIRECTV 6, in 1994 and 1997, respectively.

ILS is the global leader in launch services. With a remarkable launch rate of 74 missions since 2000, the Atlas and Proton launch vehicles have consistently demonstrated the reliability and flexibility that have made them preferred choice among satellite operators worldwide. Since the beginning of 2003, ILS has signed more new commercial contracts than all of its competitors combined. ILS was formed in 1995, and is based in McLean, Va., a suburb of Washington, D.C.

Original Source: ILS News Release

Posted on by Fraser Cain

I’m Looking for More Writers

As you’ve probably noticed, I’ve got a solid group of freelance writers working with me to help update Universe Today. There are a lot of stories that we just don’t have time to cover, though, so I’m looking to get more writers involved. If you’re a freelance science journalist, or want to become one and you have writing experience, please drop me an email with some of your writing samples. I’m especially looking for people with experience in space exploration news (NASA, Hubble, etc) as opposed to astronomy news (we’ve got lots of people for that).

And yes, I actually pay for articles I publish (thanks to all your donations).

Thanks!

Fraser Cain
Publisher
Universe Today

Posted on by Mark Mortimer

Book Review: Space Tourism – Adventures in Earth Orbit and Beyond

Space tourism seems as obtainable to us as the sun was to Icarus. We struggle to maintain and inhabit a man made structure in the safety of low Earth orbit. Yet, we read about hotels that will allow honeymooners to gaze at the sun setting every 90 minutes. This may be a bit of a stretch, but space tourism can solidly generate revenue for some entrepreneur. As Van Pelt notes, two people have already paid significant amounts, $20 million each, to visit space. Further, as the attraction would easily better any other on planet Earth, all that’s needed is a price low enough. With this, hundreds of people each year would spend their annual vacations in orbit. It is an extreme engineering challenge if there ever was one. Still, from Van Pelt’s perspective, it’s quite obtainable.

Through the book, Van Pelt discusses the technical issues of space flight and pleasant issues of leisure time in space. In a neutral, analytical view, he considers technical issues, starting with the history of space activities, the progressive development of launch vehicles, existing state of the art capabilities and the steps needed to enable the space tourism industry. Practicalities like radiation dosimetres, pressure suits to counter g forces, pre-flight training and group interactions also get attention. These and other technical details are faithfully extended from current or historically established technology. However, launcher reusability is favoured without much supporting justification. Also, some of the later discussion about warp drives, transporters and faster than light travel seem a little out of place and add an incredulous tone to an otherwise rational and even presentation.

Van Pelt has much more fun with the leisure time activities. Using a first person perspective, he places the reader on a three day vacation to an orbiting hotel. The novelty of training, safety lessons and equipment fit-out comes through like any tourist getting ready to embark on some adventurous voyage to the big unknown. Continual comparisons to today’s commercial aeroplane flights enhance the nearness of this opportunity. Further chapters on the launch, ascent and commencement of microgravity quickly distance this trip from any commercial flight. The prose really puts the reader’s feet in the shoes of the starry eyed guest. The descent and landing give the pleasant denouement that would leave the space flyer, and presumably the reader, earnestly desiring another flight. Van Pelt also forays into predicting voyage highlights by imagining sports, games, trysts, and dancing in the realm of microgravity. He ably amplifies how common activities can take on exhilarating dimensions in the confines of a space hotel or on distant surfaces such as the 1/6’th gravity of the moon. There certainly shouldn’t be any lack of fun should his views come to pass.

To aid the reader, the two aspects of the book, the technical and first person view, come in their own chapters. Each follows along logically from the predecessor. For example, first the technical chapter discusses launch vehicles. Then, the first person view places the reader in the eyes of a person as they are launched. Despite these two aspects, the prose remains complimentary, the technical part not being too dry nor the first person view being too qualitative.

As well, the imagination and optimism shown in this book makes for an enjoyable and quick read. Quotes from science fiction writers shows how reality keeps catching up to the earlier imagination of writers from many years ago. Sometimes the optimism gets a bit much though. Van Pelt would have us believe that only a few different decisions at various stages in the United States’ space program would have had people on Mars by now. Also, the discussions about travelling to Mars and further distant planets or stars again raise incredulity rather than support the perceived industry. To build credence and optimism, these parts of the book should have been balanced with more details on means and methods of constructing the infrastructure.

Reality keeps catching up with science fiction. Scientists labour in labs while engineers construct in the field in order to bring the future a little closer to today. However, even they will need to rest and recharge. Michel Van Pelt describes the perfect travel location for recharging in his book, Space Tourism and shows what we need to get there and what may happen once we arrive.

Read more reviews online or purchase a copy from Amazon.com.

Review by Mark Mortimer.

Posted on by Fraser Cain

Solar Astronomers Getting Better at Predicting Solar Wind

SOHO image of the Sun that shows magnetic fields (yellow lines) and the solar wind (red arrows). Image credit: NASA/ESA. Click to enlarge.
A layer deep in the solar atmosphere can be used to estimate the speed of the solar wind, a stream of electrified gas that constantly blows from the Sun. Estimating the speed of the solar wind will improve space weather forecasts, which will aid human exploration of the planets.

The solar wind flows from the Sun’s hot, thin, outer atmosphere, the “corona”. The researchers were surprised to discover that the structure of the Sun’s cooler, dense lower atmosphere, called the chromosphere, could be used to estimate the speed of the solar wind.

This was unexpected because the solar wind is a phenomenon of the corona, and the chromosphere is so deep — it’s the layer just above the Sun’s visible surface. “It’s like discovering that the source of the river Nile is another 500 miles inland,” said Dr. Scott McIntosh of the Southwest Research Institute, Boulder, Colo., lead author of a paper on this research published May 10 in the Astrophysical Journal.

The new work promises to increase the accuracy of space radiation forecasts. The Sun occasionally launches billion-ton blasts of electrified gas, called coronal mass ejections (CMEs), into space at millions of miles (kilometers) per hour. If a fast CME is plowing through slow solar wind, a shock builds up in front of the CME that accelerates the electrically charged solar wind particles. These fast particles can disrupt satellites and are hazardous to unprotected astronauts.

“Just as knowing more details about the atmosphere helps to predict the intensity of a hurricane, knowing the speed of the solar wind helps to determine the intensity of space radiation storms from CMEs,” said co-author Dr. Robert Leamon of L-3 Government Services at NASA’s Goddard Space Flight Center, Greenbelt, Md.

Like wind on Earth, the solar wind is gusty, ranging in speed from about 750,000 miles per hour (approximately 350 km/second) to 1.5 million miles per hour (700 km/second).

Since the solar wind is made up of electrically-charged particles, it responds to magnetic fields that permeate the solar atmosphere. Solar wind particles flow along invisible lines of magnetic force like cars on a highway. When the magnetic field lines bend straight out into space, as they do in “coronal hole” regions, the solar wind acts like cars on a drag strip, racing along at high speed. When the magnetic field lines bend sharply back to the solar surface, like the pattern of iron filings around a bar magnet, the solar wind acts like cars in city traffic and emerges relatively slowly. Scientists have known this for over thirty years and used it to give a crude estimate for the speed of the solar wind — either fast or slow.

In the new work, the team has tied the speed of the solar wind as it blows past Earth to variations deeper in the solar atmosphere than had previously been detected (or even expected). By measuring the time taken for a sound wave to travel between two heights in the chromosphere, they were able to determine that the chromosphere is effectively “stretched thin” below coronal holes with their open magnetic fields, but compressed below magnetically closed regions.

The team used the observation to derive a continuous range of solar wind speeds from the structure of the chromosphere. The wider the chromospheric layer is, the more it is being allowed to expand by open magnetic fields and the faster the solar wind will blow. This new method is more precise than the old “fast or slow” estimate.

NASA’s Transition Region and Coronal Explorer (TRACE) spacecraft was used to measure the speed of sound waves in the chromosphere, and NASA’s Advanced Composition Explorer (ACE) spacecraft was used to take measurements of the solar wind speed as it blew by the Earth. Comparing the data from the two spacecraft gave the connection.

“Prior to this discovery, we could only determine solar wind speed from spacecraft that were roughly in line between the Earth and the Sun, like ACE, WIND, and the Solar and Heliospheric Observatory. This spacecraft fleet was placed along the Earth-Sun line because we need to know about the space weather coming our way. However, compared to the size of our solar system, this is a very narrow range; it’s like looking through a soda straw. With this discovery, we can use TRACE to build up images that can predict the solar wind speed throughout half the solar system,” said Dr. Joe Gurman, a solar researcher at NASA Goddard.

Original Source: SWRI News Release

Posted on by Fraser Cain

Enceladus Above Saturn’s Rings

Saturn’s icy moon Enceladus above the rings. Image credit: NASA/JPL/SSI. Click to enlarge.
Saturn’s icy moon Enceladus hovers above Saturn’s exquisite rings in this color view from Cassini. The rings, made of nearly pure water ice, have also become somewhat contaminated by meteoritic dust during their history, which may span several hundred million years. Enceladus shares the rings’ nearly pure water ice composition, but appears to have eluded dust contamination through resurfacing processes that scientists are still trying to understand. Enceladus is 505 kilometers (314 miles) across.

Dust affects the rings’ color, while differences in brightness are attributable to varying particle sizes and concentrations.

The images for this natural color view were taken with the Cassini spacecraft narrow-angle camera on April 5, 2005, at a distance of approximately 2.2 million kilometers (1.4 million miles) from Saturn through red, green and blue spectral filters. The image scale is 13 kilometers (8 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For additional images visit the Cassini imaging team homepage http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

Posted on by Fraser Cain

Weather Satellite Launches After Several Delays

Artist interpretation of the NOAA-18 satellite in orbit. Image credit: NOAA. Click to enlarge.
NASA successfully launched a new environmental satellite today for the National Oceanic and Atmospheric Administration (NOAA). It will improve weather forecasting and monitor environmental events around the world.

The NOAA-18 (N) spacecraft lifted off at 6:22 a.m. EDT from Vandenberg Air Force Base, Calif., on a Boeing Delta II 7320-10 expendable launch vehicle. Approximately 65 minutes later, the spacecraft separated from the Delta II second stage.

“The satellite is in orbit and all indications are that we have a healthy spacecraft,” said Karen Halterman, the NASA Polar-orbiting Operational Environmental Satellites (POES) Project Manager, Goddard Space Flight Center (GSFC), Greenbelt, Md. “NASA is proud of our partnership with NOAA in continuing this vital environmental mission,” she added.

Flight controllers tracked the launch vehicle’s progress using real-time telemetry data relayed through NASA’s Tracking and Date Relay Satellite System (TDRSS) starting about five minutes after launch. Approximately 26 minutes after launch, controllers acquired the spacecraft through the McMurdo Sound ground station, Antarctica, while the spacecraft was still attached to the Delta II. Spacecraft separation was monitored by the TDRSS.

The solar array boom and antennas were successfully deployed, and the spacecraft was placed in a near-perfect orbit. The satellite was acquired by the NOAA Fairbanks Station, Alaska, 86 minutes after launch and deployments, and a nominal spacecraft power system was confirmed. NOAA-N was renamed NOAA-18 after achieving orbit.

NOAA-18 will collect data about the Earth’s surface and atmosphere. The data are input to NOAA’s long-range climate and seasonal outlooks, including forecasts for El Nino and La Nina. NOAA-18 is the fourth in a series of five Polar-orbiting Operational Environmental Satellites with instruments that provide improved imaging and sounding capabilities.

NOAA-18 has instruments used in the international Search and Rescue Satellite-Aided Tracking System, called COSPAS-SARSAT, which was established in 1982. NOAA polar-orbiting satellites detect emergency beacon distress signals and relay their location to ground stations, so rescue can be dispatched. SARSAT is credited with saving approximately 5,000 lives in the U.S. and more than 18,000 worldwide.

Twenty-one days after spacecraft launch, NASA will transfer operational control of NOAA-18 to NOAA. NASA’s comprehensive on-orbit verification period is expected to last approximately 45 days.

NOAA manages the POES program and establishes requirements, provides all funding and distributes environmental satellite data for the United States. GSFC procures and manages the development and launch of the satellites for NOAA on a cost-reimbursable basis.

NASA’s Kennedy Space Center, Fla., was responsible for the countdown management and launch of the Delta II, which was provided by Boeing Expendable Launch Systems, Huntington Beach, Calif.

Original Source: NASA News Release

Posted on by Fraser Cain

NASA Competition to Get Air from Lunar Soil

Astronauts in a lunar base will need a lot of air. Image credit: NASA. Click to enlarge.
NASA, in collaboration with the Florida Space Research Institute (FSRI), today announced a new Centennial Challenges prize competition.

The MoonROx (Moon Regolith Oxygen) challenge will award $250,000 to the first team that can extract breathable oxygen from simulated lunar soil before the prize expires on June 1, 2008.

For the MoonROx challenge, teams must develop hardware within mass and power limits that can extract at least five kilograms of breathable oxygen from simulated lunar soil during an eight-hour period. The soil simulant, called JSC-1, is derived from volcanic ash. The oxygen production goals represent technologies that are beyond existing state-of-the-art.

NASA’s Centennial Challenges promotes technical innovation through a novel program of prize competitions. It is designed to tap the nation’s ingenuity to make revolutionary advances to support the Vision for Space Exploration and NASA goals.

“The use of resources on other worlds is a key element of the Vision for Space Exploration,” said NASA’s Associate Administrator for the Exploration Systems Mission Directorate, Craig Steidle. “This challenge will reach out to inventors who can help us achieve the Vision sooner,” he added.

“This is our third prize competition, and the Centennial Challenges program is getting more and more exciting with each new announcement. The innovations from this competition will help support long-duration, human and robotic exploration of the moon and other worlds,” said Brant Sponberg, NASA’s Centennial Challenges program manager.

“Oxygen extraction technologies will be critical for both robotic and human missions to the moon,” said FSRI Executive Director Sam Durrance. “Like other space-focused prize competitions, the MoonROx challenge will encourage a broad community of innovators to develop technologies that expand our capabilities,” he added.

The Centennial Challenges program is managed by NASA’s Exploration Systems Mission Directorate. FSRI is a state-wide center for space research. It was established by Florida’s governor and legislature in 1999.

For more information about Centennial Challenges on the Internet, visit: http://centennialchallenges.nasa.gov

For more information about NASA and agency programs on the Internet, visit: http://www.nasa.gov/home/index.html

For information about the Florida Space Research Institute on the Internet, visit: http://www.fsri.org

Original Source: NASA News Release

Posted on by Fraser Cain

Cosmic Rays Cause the Brightest Radio Flashes

Low-frequency radio sky at the time of a cosmic ray hit. Image credit: MPIFR. Click to enlarge.
Using the LOPES experiment, a prototype of the new high-tech radio telescope LOFAR to detect ultra-high energy cosmic ray particles, a group of astrophysicists, in collaboration of Max-Planck-Gesellschaft and Helmholtz-Gemeinschaft, has recorded the brightest and fastest radio blasts ever seen on the sky. The blasts, whose detection are reported in this week’s issue of the journal Nature, are dramatic flashes of radio light that appear more than 1000 times brighter than the sun and almost a million times faster than normal lightning. For a very short moment these flashes – which had gone largely unnoticed so far – become the brightest light on the sky with a diameter twice the size of the moon.

The experiment showed that the radio flashes are produced in the Earth atmosphere, caused by the impact of the most energetic particles produced in the cosmos. These particles are called ultra-high energy cosmic rays and their origin is an ongoing puzzle. The astrophysicists now hope that their finding will shed new light on the mystery of these particles.

The scientists used an array of radio antennas and the large array of particle detectors of the KASCADE-Grande experiment at Forschungszentrum Karlsruhe. They showed that whenever a very energetic cosmic particle hit the Earth atmosphere a corresponding radio pulse was recorded from the direction of the incoming particle. Using imaging techniques from radio astronomy the group even produced digital film sequences of these events, yielding the fastest movies ever produced in radio astronomy. The particle detectors provided them with basic information about the incoming cosmic rays.

The researchers were able to show that the strength of the emitted radio signal was a direct measure of the cosmic ray energy. “It is amazing that with simple FM radio antennas we can measure the energy of particles coming from the cosmos” says Prof. Heino Falcke from the Netherlands Foundation for Research in Astronomy (ASTRON) who is the spokesperson of the LOPES collaboration. “If we had sensitive radio eyes, we would see the sky sparkle with radio flashes”, he adds.

The scientists used pairs of antennas similar to those used in ordinary FM radio receivers. “The main difference to normal radios is the digital electronics and the broad-band receivers, which allow us to listen to many frequencies at once”, explains Dipl. Phys. Andreas Horneffer, a graduate student of the University of Bonn and the International Max-Planck Research School (IMPRS), who installed the antennas as part of his PhD project.

In principle some of the detected radio flashes are in fact strong enough to wipe out conventional radio or TV reception for a short time. To demonstrate this effect the group has converted their radio reception of a cosmic ray event into a sound track (see below). However, since the flashes only last for some 20-30 nanoseconds and bright signals happen only once a day, they would be hardly recognisable in everyday life.

The experiment also showed that the radio emission varied in strength relative to the orientation of the Earth magnetic field. This and other results verified basic predictions that had been made in theoretical calculations earlier by Prof. Falcke and his former PhD student Tim Huege, as well as by calculations of Prof. Peter Gorham from the University of Hawaii.

Cosmic ray particles constantly bombard the earth causing little explosions of elementary particles which form a beam of matter and anti-matter particles rushing through the atmosphere. The lightest charged particles, electrons and positrons, in this beam will be deflected by the geomagnetic field of the Earth which causes them to emit radio emission. This type of radiation is well known from particle accelerators on Earth and is called synchrotron radiation. In analogy, the astrophysicists now speak of “geosynchrotron” radiation due to the interaction with the Earth magnetic field.

The radio flashes were detected by the LOPES antennas installed at the KASCADE-Grande cosmic ray air shower experiment at Forschungszentrum Karlsruhe, Germany. KASCADE-Grande is a leading experiment for measuring cosmic rays. “This shows the strength of having a major astroparticle physics experiment directly in our neighbourhood – this gave us the flexibility to also explore unusual ideas as this one” says Dr. Andreas Haungs, spokesperson of KASCADE-Grande.

The radio telescope LOPES (LOFAR Prototype Experimental Station) uses prototype antennas of the largest radio telescope of the world, LOFAR, to be built after 2006 in the Netherlands and parts of Germany. LOFAR has a radical new design, combining a multitude of cheap low-frequency antennas which collect the radio signals from the entire sky at once. Connected by high-speed internet a supercomputer then has the ability to detect unusual signals and make images of interesting regions on the sky without moving any mechanical parts. “LOPES achieved the first major scientific results of the LOFAR project already in the development phase. This makes us confident that LOFAR will indeed be as revolutionary as we had hoped it will be.” explains Prof. Harvey Butcher, director of the Netherlands Foundation for Research in Astronomy (ASTRON) in Dwingeloo, The Netherlands, where LOFAR is currently being developed.

“This is indeed an unusual combination, where nuclear physicists and radio astronomers work together to create a unique and highly original astroparticle physics experiment”, states Dr. Anton Zensus, director at the Max-Planck-Institut f?r Radioastronomie (MPIfR) in Bonn. “It paves the way for new detection mechanisms in particle physics as well as demonstrating the breathtaking capabilities of the next generation telescopes such as LOFAR and later the Square Kilometer Array (SKA). Suddenly major international experiments in different research areas come together”

As a next step the astrophysicists want to use the upcoming LOFAR array in the Netherlands and Germany for radio astronomy and cosmic ray research. Test are under way to integrate radio antenna into the Pierre Auger Observatory for cosmic rays in Argentina and possibly later in the second Auger Observatory in the Northern hemisphere. “This may be a major breakthrough in detection technology. We hope to use this novel technique for detecting and understanding the nature of the highest energy cosmic rays and also to detect ultra-high energy neutrinos from the cosmos”, says Prof. Johannes Bl?mer, Astroparticle Physics programme director of the Helmholtz Association and at Forschungszentrum Karlsruhe.

The detection has been confirmed in part by a French group using the large radio telescope of the Paris observatory at Nan?ay. Historically, work on radio emission from cosmic rays was first done in the late 1960ies with the first claims of detections. However, no useful information could be extracted with the technology of these days, and the work ceased quickly. The main shortcomings were the lack of imaging capabilities (now implemented by software), the low time resolution, and the lack of a well-calibrated particle detector array. All of this has been overcome with the LOPES experiment.

Original Source: MPI News Release