Closest Gamma Ray Burst Ever Discovered

Image credit: NRAO

Gamma ray bursts (GRB) are the largest known explosions in the Universe; immensely powerful, quick to fade, but usually incredibly far away. Astronomers with the National Radio Astronomy Observatory got lucky, though, when they analyzed a recent GRB and discovered it was only 2.6 billion light-years away (most are usually 4 times more distant). What causes these bursts is a mystery, but the theories usually incorporate black holes in some catastrophic way – colliding into another black hole; wrapping a magnetic field like a spring, etc. This close burst didn’t answer the mystery, but it did allow the astronomers to rule out one idea, that material from a GRB blasts out like “cannonballs”.

The closest Gamma Ray Burst (GRB) yet known is providing astronomers with a rare opportunity to gain information vital to understanding these powerful cosmic explosions. Extremely precise radio-telescope observations already have ruled out one proposed mechanism for the bursts.

“This is the closest and brightest GRB we’ve ever seen, and we can use it to decipher the physics of how these bursts work,” said Greg Taylor of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. Taylor worked with Dale Frail, also of the NRAO, along with Prof. Shri Kulkarni and graduate student Edo Berger of Caltech in studying a GRB detected on March 29, 2003. The scientists presented their findings to the American Astronomical Society’s meeting in Nashville, TN.

VLBA IMAGE of GRB 030329

(Click on Image for Larger Version)

Taylor and Frail used the National Science Foundation’s (NSF) Very Long Baseline Array (VLBA) and other radio telescopes to study the burst, known as GRB 030329. In a series of observations from April 1 to May 19, they determined the size of the expanding “fireball” from the burst and measured its position in the sky with great precision.

At a distance of about 2.6 billion light-years, GRB 030329 is hardly next door. However, compared to other GRBs at typical distances of 8-10 billion light-years, it presents an easier target for study.

“We only expect to see one burst per decade this close,” said Frail.

The precise measurement of the object’s position allowed the scientists to show that one theoretical model for GRBs can be ruled out. This model, proposed in 2000, says that the radio-wave energy emitted by the GRB comes from “cannonballs” of material shot from the explosion at extremely high speeds.

“The ‘cannonball model’ predicted that we should see the radio-emitting object move across the sky by a specific amount. We have not seen that motion,” Taylor said.

The currently standard “fireball model” of GRBs says that the radio emission comes from a rapidly-expanding shock wave. This model was first proposed by Peter Meszaros, Bohdan Paczynski and Sir Martin Rees, who won the American Astronomical Society’s Bruno Rossi Prize in 2000 for their work. In this standard model, as the shock wave expands outward, the emission becomes fainter, but the center of the observed emission does not change position.

The cannonball model, however, proposes that the emission arises from distinct concentrations of matter shot outward from the burst. As they move farther from the burst, their motion should be detected as a change in their position in the sky. On April 3, proponents of the cannonball model predicted a specific amount of motion for GRB 030329 and suggested that the VLBA’s sharp radio “vision” could detect the motion and confirm their prediction.

Instead, “our observations are consistent with no motion at all,” Taylor said. “This is at odds with the cannonball model — they made a specific prediction based on their model and the observations do not bear them out,” he added.

The scientists’ direct measurement of the size of the GRB fireball also will provide new insights into the physics behind the burst.

“By directly measuring the size and the expansion rate, we can start putting some real limits on the physics involved,” Taylor said. First, he said, “We already can confirm that the fireball is expanding at nearly the speed of light, as the standard model predicts. Next, once our May observations are fully analyzed, we can put limits on the energy of the burst and provide a test of the standard model.”

Taylor and Frail observed GRB 030329 with the VLBA on April 1 and April 6. On April 22, they used the 100-meter radio telescope in Effelsberg, Germany in addition to the VLBA. On May 19, they used the VLBA, the Very Large Array (VLA) in New Mexico, the NSF’s Robert C. Byrd Green Bank Telescope in West Virginia, and the Effelsberg telescope.

In addition to gamma-ray and X-ray observations, visible light from GRB 030329 was observed by 65 telescopes around the world. At its brightest, the visible light from this burst was detectable with moderate-sized amateur telescopes.

Gamma Ray Bursts were first detected in 1967 by a satellite monitoring compliance with the 1963 atmospheric nuclear test-ban treaty. For three decades thereafter, astronomers were unable to determine their distances from Earth, and thus were unable to begin understanding the physics underlying the explosions. In 1997, the first distance measurements were made to GRBs, and the NSF’s Very Large Array (VLA) detected the first radio emission from a GRB afterglow.

Once scientists determined that GRBs originate in distant galaxies and that they probably occur in regions of those galaxies where stars are actively forming, some 200 proposed models for what causes GRBs were reduced to a handful of viable models.

Most scientists now believe that GRBs arise from a violent explosion that ends the life of a star much more massive than the Sun. Whereas such an explosion as a typical supernova leaves a dense neutron star, a GRB explosion leaves a black hole, a concentration of mass with gravitational pull so strong that not even light can escape it.

The VLBA is a continent-wide system of ten radio- telescope antennas, ranging from Hawaii in the west to the U.S. Virgin Islands in the east, providing the greatest resolving power, or ability to see fine detail, in astronomy. Dedicated in 1993, the VLBA is operated from the NRAO’s Array Operations Center in Socorro, New Mexico.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Original Source: NRAO News Release

Mars Express is Ready For Launch

Image credit: ESA

Europe is ready to begin this summer’s invasion of Mars with the launch of its Mars Express spacecraft, due to lift off on June 2. The spacecraft is currently packed safely away on top a Soyuz-Fregat rocket at the Baikonur cosmodrome in Kazakhstan. If all goes well, the rocket will lift off at 1745 GMT and then deploy Mars Express 90 minutes later. The first critical hurdle for the mission will be three days after launch when the spacecraft needs to release the launch clamps holding the Beagle-2 lander so that it can be deployed in December when they reach Mars.

ESA?s Mars Express is a pioneering mission for several reasons. It is the first European voyage to Mars, it has been built at much less than the usual cost, and in record time.

Mars Express is the first example of ESA?s new style of developing scientific missions: faster, smarter and more cost-effective, but without compromising reliability and quality – there have been no cuts in tests or pre-launch preparations. Mars Express will face demanding technical challenges during its trip to the Red Planet and ESA engineers have worked hard to make sure it meets them.

“With Mars Express, Europe is building its own expertise in many fields. This ranges from the development of science experiments and new technologies – new for European industry – to the control of a mission that includes landing on another planet. We have never done this before,? says Rudi Schmidt, Mars Express Project Manager.

Quicker, smarter?safe!
Mars Express?s design and development phase has taken about four years, compared with about six years for previous similar missions. And its cost, 300 million euros, is much less than other comparable planetary missions. The ?magic? lies in the new managerial approach being used.

This new approach includes the reuse of existing hardware and instruments. Also, the mission was developed by a smaller ESA team, who gave more responsibility to industry. Mars Express has been built by a consortium of 24 companies from ESA?s 15 Member States and the United States, led by Astrium as prime contractor.

However, mission safety was never compromised. ?Although we were under heavy pressure towards the end of the project, we did not drop any of the planned tests to save time. I call this a fast design phase, followed by thorough testing activity,? says Schmidt.

This new streamlined development method will continue with Venus Express and probably other future missions.

Mars Express will be launched on 2 June on board a Soyuz-Fregat rocket from the Baikonur Cosmodrome in Kazakhstan. The mission consists of an orbiter and a lander, called Beagle 2. In its launch configuration, Mars Express is a honeycombed aluminium box that measures 1.5 by 1.8 by 1.4 metres (excluding solar panels), and weighs 1223 kilograms in total. The Beagle-2 lander travels attached to one side of the spacecraft, folded up rather like a very large pocket watch. Arrival at Mars is scheduled for late December this year, when Beagle 2 will land while the orbiter is entering its orbit around Mars.

The last activities of an intense launch campaign are taking place in Baikonur at this very moment. Mars Express arrived at the Cosmodrome on 20 March. The spacecraft, fuelled with 457 kilograms of propellant, was mounted on the Soyuz launcher on 24 May in a process that the Russians call ?marriage?. The whole structure was rolled out to the launch pad on 29 May, four days before launch.

The fastest possible trip to Mars
One of the reasons scientists had to develop Mars Express so quickly arises from the fact that, this summer, Mars and the Earth will be especially close to each other. Although launch opportunities to go to Mars occur every 26 months – when the Sun, Earth and Mars form a straight line – this year the planets will be at their closest, which happens every 15 to 17 years. On top of that, calculations had shown that the best combination of fuel expenditure and travel time could only be achieved by launching in the period between 23 May and 21 June. The Mars Express team had to work very hard to meet this launch window.

As a tribute from one European high-tech organisation to another, Mars Express is carrying a small container of Ferrari red paint to the Red Planet.

After the launch
Mars Express will separate from the Soyuz Fregat upper stage 90 minutes after liftoff. Then the solar arrays will open and the spacecraft will make contact with ESA?s ground station in New Norcia, Western Australia.

Mars Express will be travelling away from Earth at a speed of 3 kilometres per second. A crucial operation at this early stage of the trip will be to release the Beagle-2 launch clamps three days after launch. These clamps are extra gears to make sure that the lander stays securely attached to the spacecraft during the launch, but once in space they are not needed any more. A pyrotechnic device will be activated to release them. This will be a key step, necessary so that Beagle 2 can be ejected when the spacecraft arrives at Mars.

Every effort has been made to ensure that things go smoothly. Schmidt says: ?We have tested all aspects of the mission well enough to be confident that there will be no errors or trivial mistakes. Mars Express has been developed in record time, but there have been no compromises on testing, including the ground segment.”

Orbiting and landing on Mars
Six days before arrival at Mars, the lander will be released. This operation is regarded as one of the most complex of the Mars Express mission. Beagle 2, which weighs only 65 kilograms, is too light to carry a steering mechanism and is not designed to receive commands during cruise and landing. So Beagle 2 can only reach its planned landing site by relying on the orbiter to put it into the correct trajectory and drop it at a very precise point in space and at a specified speed. The ground control team at the European Space Operations Centre (ESOC) in Darmstadt, Germany, will guide this manoeuvre. To be ready for the approach to Mars and the ejection operations, engineers have been training for months with simulators that resemble sophisticated computer games. Tests will continue after Mars Express?s launch.

Mars Express will study Mars for at least two years
Approaching Mars, the orbiter will eject the lander and then be left on a collision course with the planet. In another key manoeuvre, ground controllers will have to adjust its trajectory, reducing its speed to 1.8 kilometres per second. At that speed, the planet?s gravity will be able to ?capture? the Mars Express orbiter and put it into Mars orbit. Ground controllers will still have to perform several manoeuvres to get the spacecraft into its final operational state – a highly elliptical polar orbit – from where the scientific observations can begin.

In the meantime, Beagle 2 will have landed on Mars. The landing area covers a large ellipsis, 300 kilometres long and 150 kilometres wide, on an equatorial region called Isidis Planitia. It was chosen in the light of the strong Martian winds and the relatively smooth surface of the site. The lander will deploy parachutes, and then large gas-filled bags will protect it as it bounces to a halt on the surface. Once landed, Beagle 2 will emit a ?beep?, a signal that will tell operators at the United Kingdom?s Jodrell Bank radio telescope station that it has touched down safely. This 9-note call sign was composed for the Beagle-2 team by the British pop group, Blur.

Mars Express will investigate the Martian surface, subsurface, and atmosphere for at least two years. The lander will operate on the surface for about six Earth months, relaying its data to Earth through the orbiter.

Mars Express will help answer fundamental questions about Mars, such as the presence and quantity of water, and possible signs of present or past life. In the worldwide effort to explore the Red Planet in recent years, the European Mars Express mission represents the most thorough investigation of Mars attempted so far.

Original Source: ESA News Release

Northern Europe Treated to Eclipse Show

Skywatchers in Northern Europe were treated to a show on Saturday, May 31 when the Moon passed in front of the Sun and created an annular eclipse. Astrocameras at the Copernicus Public Observatory in the Netherlands and the Mira Public Observatory in Belgium caught the whole event live, and dozens of amateur astronomers across Europe have submitted their own photos as well. The next solar eclipse will be on November 23, but will only be visible from Antarctica.

ISS Moves to Avoid a Satellite

Image credit: NASA

The International Space Station made a pre-planned orbit shift to give the Italian Megsat 0 satellite a wide berth on Friday. The station was raised 1.8 kilometres over the course of 7 minutes using the Progress cargo ship which is currently attached. This is the sixth time the station has been repositioned since construction began – NASA originally thought it would have to happen twice a year, but it’s actually been less than that.

Science, maintenance and training for spacewalks was the focus of attention this week for the Expedition Seven crew of Commander Yuri Malenchenko and NASA International Space Station Science Officer Ed Lu as they complete their fifth week in space aboard the orbiting laboratory.

The station?s Microgravity Science Glovebox is back in action supporting hands-on experiments in a closed/controlled environment after researchers reset the unit?s computer to resume activity with the InSPACE experiment (Investigating the Structure of Paramagnetic Aggregates from Colloidal Emulsions), which began during the Expedition Six increment on the station.

Scientists hope to develop better fluids for systems that are routinely exposed to magnetic fields, such as automobile brake fluids and vibration damping systems. Experimenters also hope to use data from InSPACE to develop new applications such as vibration damping systems for buildings in earthquake-prone areas.

Earlier this week a faulty battery in the Zvezda living quarters module was replaced and the crew practiced techniques for conducting a spacewalk without the assistance of a third crewmember. Portions of the demonstration will be rescheduled due to a problem encountered when the water flow in Lu?s undergarment failed to work properly. The Extravehicular Activity team is evaluating the problem.

No spacewalk is planned for the six months the Expedition Seven crew is aboard the complex, but the on-orbit training exercise ? or dry run ? was designed to prepare the crew in the event an unscheduled spacewalk is warranted.

Earlier today, trajectory flight controllers planned, and then executed, a slight orbit-raising firing of the Progress resupply ship engines to position the ISS out of the path of an orbiting satellite:

The one-meter per second posigrade maneuver lasted a little more than 7 minutes and was conducted at 11:50 a.m. CDT Friday after three days of tracking confirmed the need for the burn. The result of the burn actually raised the station?s average altitude by about 1.8 kilometers. The closest approach to the station occurred at 3:55 p.m. CDT Friday. The maneuver was the sixth in the history of the ISS since construction began in November 1998. The ISS Program estimates that about two such maneuvers would be needed each year, but the actual number thus far is fewer than one each year.

Thursday, the crew gathered in the Destiny Laboratory to talk about their mission with WABC Radio?s ?Rambling with Gambling? show in New York City and KNX Radio in Los Angeles.

That followed Lu?s demonstration of the properties of flight in microgravity using a paper airplane and a small model of the Wright Flyer he brought along in honor of the Centennial of Flight activities of the Wright Brothers’ achievement. Preparations continue on track for the launch of a new Progress 11 cargo ship to the ISS June 8, which will dock to the station June 11, delivering more than 5,000 pounds of food, water and supplies for the crew on board.

Original Source: NASA News Release

Book Review: Distant Wanderers

Probably the most exciting aspect of modern astronomy is the recent discovery of planets orbiting other star systems. The techniques for finding the are only a few years old, but already astronomers have uncovered 74 (although, it’ll be more when you read this).

Probably the most exciting aspect of modern astronomy is the recent discovery of planets orbiting other star systems. The techniques for finding the are only a few years old, but already astronomers have uncovered 74 (although, it’ll be more when you read this).

Distant Wanderers by Bruce Dorminey follows the short history of successful planet hunting, starting with the first bizarre discovery of planets around a distant pulsar and moving on to the more dependable Doppler spectroscopy method. As there isn’t a long history, the book quickly catches up to the present, profiling the methods used by today’s seekers. The bulk of the book, though, looks to the future of planet hunting; from new techniques to space-based observatories currently in development.

Although the technical terminology flies fast and furious, Dorminey takes the time to explain each term when it appears (like Doppler spectroscopy), simply and clearly in a sidebar, to make sure you grasp the concept before going any further.

Perhaps my favorite aspect of the book is how Dorminey presents his own journey to uncover the information and meet the researchers. It’s mostly a science book, but it also feels a little like a travelogue, and it’s that aspect that prevents it from being dry; these are real people, making some of the most exciting discoveries in modern science – it’s hard not to get caught up in the adventure.

A couple of complaints: the text is pretty small, even with good vision it isn’t easy on the eyes; the photography is all black and white, which is a shame considered the beauty of the pictures selected (I know what many of them look like in colour). Finally, the science in this book is totally cutting edge, so I suspect it might feel a little dated in a few years – but that’s progress!

I definitely recommend Distant Wanderers, though.

Click here to see more information about this book at

Book Review: Spacefaring: The Human Dimension

Like many of you, I’m a total advocate for human space exploration. Sure, robots are great, with their indestructibility and unquestioning loyalty, but there are times when you really need to get some human hands and eyes on location to provide some solid data and deal with the unexpected. But humans are soft, fragile, and can sometimes get a little grumpy.

Like many of you, I’m a total advocate for human space exploration. Sure, robots are great, with their indestructibility and unquestioning loyalty, but there are times when you really need to get some human hands and eyes on location to provide some solid data and deal with the unexpected. But humans are soft, fragile, and can sometimes get a little grumpy.

Spacefaring: the Human Dimension by Albert Harrison helps fill a niche that I’ve found largely unfilled in most of the space exploration books I’ve read – how to keep humans alive, and stop them from killing each other during long space trips. And by focusing only on this aspect of space travel, Harrison gives the subject matter the time and respect it deserves. Each element is covered in tremendous detail, including the basics of food, air, water, heat, etc. but also the more psychological elements of coping with stress, group dynamics, training, and dealing with mistakes and disasters. Harrison throws in a plenty of anecdotes to give real world examples to the topics covered.

I’d recommend this book to anyone who finds this aspect of space exploration fascinating. I’d especially recommend it to folks like the Mars Society, as many of the issues have been largely ignored by NASA so far. And I’d force scriptwriters and directors to read this book before they make another Mission to Mars. Great book!

Click here to read more about this book at

Sea Launch Heads for the Equator

Image credit: Sea Launch

The Odyssey Launch Platform and Sea Launch Commander set sail from their port in Los Angeles on Wednesday in preparation to launch the Thuraya-2 satellite on board a Zenit 3SL rocket. The ship and launch platform will reach the launch site, located in the Pacific Ocean at the Equator, and then begin a 72-hour countdown for launch – the 44-minute launch window begins June 10 at 1356 GMT (9:56am PDT). The Thuraya-2 satellite will provide communications in the Middle East, Europe, Africa and Asia.

The Odyssey Launch Platform and the Sea Launch Commander departed Sea Launch Home Port this week, for the launch of the Thuraya-2 satellite. Liftoff is scheduled for June 10, in a 44-minute launch window that opens at 6:56 am PDT (13:56:00 GMT).

The two Sea Launch vessels will travel from Sea Launch Home Port, in the Port of Long Beach, to the launch site on the Equator at 154o West Longitude, where a 72-hour countdown will begin upon arrival. Once the platform is ballasted to launch depth, the team will perform final tests on the rocket and spacecraft, and prepare for launch operations. The 200-foot Zenit-3SL rocket will lift the 5177 kg (11,413 lb) Thuraya-2 satellite to geosynchronous transfer orbit with a liftoff thrust of 1.6 million lbs.

Thuraya-2 was built by Boeing [NYSE:BA] for the Thuraya Satellite Telecommunications Company, of United Arab Emirates, and shipped from its satellite manufacturing facility in El Segundo, Calif. The GEO-Mobile (GEM) model satellite uses a Boeing 702 body-stabilized design and integrates a ground segment and user handsets to provide a range of cellular-like voice and data services over a vast geographic region. Sea Launch successfully inserted the first Boeing GEM model, Thuraya-1, to orbit in October 2000. It is the heaviest commercial spacecraft launched successfully to date.

Thuraya-2 will enable Thuraya Satellite Telecommunications to continue to grow and expand its successful business, providing communications services to the people of 100 nations in the Middle East, Europe, North and Central Africa, and South and Central Asia. Thuraya?s advanced satellite telecommunications provides blanket border-to-border coverage to nearly one third of the globe. Based in Abu Dhabi, Thuraya offers uninterrupted and seamless services that link urban and rural areas, and ensure call continuity over regions with fragmented conventional telecommunication networks.

Sea Launch Company, LLC, headquartered in Long Beach, Calif., is a world leader in providing heavy-lift commercial launch services. This multinational partnership offers the most direct and cost-effective route to geostationary orbit. With the advantage of a launch site on the Equator, the proven Zenit-3SL rocket can lift a heavier spacecraft mass or provide longer life on orbit, offering best value plus schedule assurance. Sea Launch has a current backlog of 16 firm launch contracts. For additional information, visit the Sea Launch website at:

Original Source: Boeing News Release

Watch a Solar Eclipse on Saturday

On Saturday, May 31 an annular eclipse of the Sun will be visible from most of the Northern Hemisphere. The moon’s shadow will start in Northern Scotland and then sweep across Iceland and Greenland. Just in case you won’t be able to see it in your own sky, a group of astronomers in the Netherlands and Belgium will be broadcasting live pictures of the eclipse on the Internet. Coverage will begin at approximately 0320 GMT and end about 45 minutes later.

Astronomers Weigh a Pulsar’s Planets

Image credit: NASA

A team of astronomers have weighed a group of planets orbiting a pulsar by precisely measuring their orbits. So far, two of the system’s three planets have been weighed, and they’re 4.3 and 3.0 times the mass of the Earth. What’s unusual is that the spacing between the planets almost exactly match the spacing of Mercury, Venus and Earth – making this bizarre system the most similar to our own Solar System so far discovered. The pulsar, 1257+12, was discovered 13 years ago using the Arecibo radio telescope.

For the first time, the planets orbiting a pulsar have been “weighed” by measuring precisely variations in the time it takes them to complete an orbit, according to a team of astronomers from the California Institute of Technology and Pennsylvania State University.

Reporting at the summer meeting of the American Astronomical Society, Caltech postdoctoral researcher Maciej Konacki and Penn State astronomy professor Alex Wolszczan announced today that masses of two of the three known planets orbiting a rapidly spinning pulsar 1,500 light-years away in the constellation Virgo have been successfully measured. The planets are 4.3 and 3.0 times the mass of Earth, with an error of 5 percent.

The two measured planets are nearly in the same orbital plane. If the third planet is co-planar with the other two, it is about twice the mass of the moon. These results provide compelling evidence that the planets must have evolved from a disk of matter surrounding the pulsar, in a manner similar to that envisioned for planets around sun-like stars, the researchers say.

The three pulsar planets, with their orbits spaced in an almost exact proportion to the spacings between Mercury, Venus, and Earth, comprise a planetary system that is astonishingly similar in appearance to the inner solar system. They are clearly the precursors to any Earth-like planets that might be discovered around nearby sun-like stars by the future space interferometers such as the Space Interferometry Mission or the Terrestrial Planet Finder.

“Surprisingly, the planetary system around the pulsar 1257+12 resembles our own solar system more than any extrasolar planetary system discovered around a sun-like star,” Konacki said. “This suggests that planet formation is more universal than anticipated.”

The first planets orbiting a star other than the sun were discovered by Wolszczan and Frail around an old, rapidly spinning neutron star, PSR B1257+12, during a large search for pulsars conducted in 1990 with the giant, 305-meter Arecibo radio telescope. Neutron stars are often observable as radio pulsars, because they reveal themselves as sources of highly periodic, pulse-like bursts of radio emission. They are extremely compact and dense leftovers from supernova explosions that mark the deaths of massive, normal stars.

The exquisite precision of millisecond pulsars offers a unique opportunity to search for planets and even large asteroids orbiting the pulsar. This “pulsar timing” approach is analogous to the well-known Doppler effect so successfully used by optical astronomers to identify planets around nearby stars. Essentially, the orbiting object induces reflex motion to the pulsar which result in perturbing the arrival times of the pulses. However, just like the Doppler method, the pulsar timing method is sensitive to stellar motions along the line-of-sight, the pulsar timing can only detect pulse arrival time variations caused by a pulsar wobble along the same line. The consequence of this limitation is that one can only measure a projection of the planetary motion onto the line-of-sight and cannot determine the true size of the orbit.

Soon after the discovery of the planets around PSR 1257+12, astronomers realized that the heavier two must interact gravitationally in a measurable way, because of a near 3:2 commensurability of their 66.5- and 98.2-day orbital periods. As the magnitude and the exact pattern of perturbations resulting from this near-resonance condition depend on a mutual orientation of planetary orbits and on planet masses, one can, in principle, extract this information from precise timing observations.

Wolszczan showed the feasibility of this approach in 1994 by demonstrating the presence of the predicted perturbation effect in the timing of the planet pulsar. In fact, it was the first observation of such an effect beyond the solar system, in which resonances between planets and planetary satellites are commonly observed. In recent years, astronomers have also detected examples of gravitational interactions between giant planets around normal stars.

Konacki and Wolszczan applied the resonance-interaction technique to the microsecond-precision timing observations of PSR B1257+12 made between 1990 and 2003 with the giant Arecibo radio telescope. In a paper to appear in the Astrophysical Journal Letters, they demonstrate that the planetary perturbation signature detectable in the timing data is large enough to obtain surprisingly accurate estimates of the masses of the two planets orbiting the pulsar.

The measurements accomplished by Konacki and Wolszczan remove a possibility that the pulsar planets are much more massive, which would be the case if their orbits were oriented more “face-on” with respect to the sky. In fact, these results represent the first unambiguous identification of Earth-sized planets created from a protoplanetary disk beyond the solar system.

Wolszczan said, “This finding and the striking similarity of the appearance of the pulsar system to the inner solar system provide an important guideline for planning the future searches for Earth-like planets around nearby stars.”

Original Source: Caltech News Release

A Possible Breakthrough in the Columbia Disaster

The Columbia disaster investigators believe they might have better proof that foam could have damaged the shuttle’s wing on launch. They recreated the conditions of launch, and fired a 760 gram chunk of space shuttle foam at the leading edge of a shuttle wing at 855 kph. On their first and only shot, they were able to lift up a seal, creating a gap 55 centimetres long. This gives further support to the theory that foam caused damage to the wing on launch, so that it couldn’t withstand the heat of re-entry. Further tests are planned for June.