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Current Events Archive: 2003 | 2004 | 2005 | 2006 ESA's Mars Express Successfully Reaches and Orbits Mars -- No Word from Beagle 2 (Added 12/31/03) The end of a long journey has begun an even longer mission for the European Space Agency's Mars Express orbiter. On Christmas Day - December 25, 2003 - the 205-day and 400 million km (250 million miles) journey placed Mars Express in orbit around Mars after a 37 minute main engine burn at 03:47 CET. The burn's purpose was to match the probe's speed with Mars'. This represent's Europe's first attempt to send a space craft into orbit around another planet, and it has been deemed a complete success. However, the initial orbit sets the craft around Mars' equator, and the main mission requires an 86° polar orbit. On December 30, at the farthest point in its highly elliptical orbit, Mars Express executed another main engine burn and slipped into a polar orbit. Further refinements through January 4, 2004, will place Mars Express into its final orbit. At about the same time Mars Express entered its initial orbit, the small lander, Beagle 2, was supposed to have landed on the Martian surface. However, all attempts to contact the probe to date (using NASA's Mars Odyssey craft and several Earth-based radio telescopes) have proved unsuccessful. It is hoped that once Mars Express reaches its final science orbit in early January that it will have more luck. Mission personnel are still hopeful that the probe was not destroyed. Adapted from the press release on http://www.esa.int/export/esaCP/SEMAD8374OD_index_0.html and Spaceflight Now's website http://spaceflightnow.com/mars/marsexpress/status.html and http://spaceflightnow.com/mars/marsexpress/031230marsexpressorbit.html. (Added 12/21/03) The European Southern Observatory (ESO) has released three images of dusty spiral galaxies that show large areas of intense star formation. Astronomers Mark Neeser from the Universitäts-Sternwarte München (Germany) and Peter Barthel from the Kapteyen Institute in Groningen (the Netherlands) used the ESO's Very Large Telescope (VLT) to take these images during twilight when they had to stop their normal observing program - searching for very distant and faint quasars.
Adapted from the press release on http://www.eso.org/outreach/press-rel/pr-2003/phot-33-03.html. ESA's Mars Express Releases the Beagle 2 (Added 12/19/03) Since its launch on June 2, 2003, the ESA's Mars Express craft has been carrying the Beagle 2 lander on its journey to Mars. At 9:31 CET on December 19, 2003, the craft flawlessly released the Beagle 2, which is now scheduled to land on Mars on December 25, Christmas Day. The release was accomplished via a slowly fired pyrotechnic device that released a loaded spring. The spring gently pushed the Beagle 2, named for the ship upon which Charles Darwin sailed, away from the mother craft. Beagle 2 has no propulsion system of its own, so a December 16 maneuver by Mars Express was needed to ensure Beagle 2 will not approach Mars a too steep nor too shallow an entry angle. Adapted from the press release on http://www.esa.int/export/esaCP/Pr_83_2003_p_EN.html. Last in NASA's Great Observatories Program Is Renamed and Returns Images
Formerly known as the Space Infrared Telescope Facility (SIRTF), the telescope was renamed on December 18, 2003, after the late Dr. Lyman Spitzer, Jr., who was one of the most influential scientists in the 20th century; in the 1940s, he became the first to propose the placement of telescopes in space. "The Spitzer Space Telescope takes its place at the forefront of astronomy in the 21st century, just as its namesake, Dr. Lyman Spitzer Jr., was at the forefront of astronomy in the 20th," said NASA's Associate Administrator for Space Science Dr. Ed Weiler. Four images were released in total for the naming ceremony, and they are available at http://www.nasa.gov/multimedia/imagegallery/image_feature_101_sirtf.html. One of the images appears to the left. It shows the dusty, winding arms of a spiral galaxy much like our own; it is M81, and shows the SST's ability to show infrared light in unprecedented detail. Adapted from the press releases on http://www.jpl.nasa.gov/releases/2003/170.cfm, http://www.nasa.gov/home/hqnews/2003/dec/HQ_03411_newly_named.html, and http://www.nasa.gov/home/hqnews/2003/dec/HQ_03414_sirtf_new_name.html. (Added 12/17/03) Two of NASA's Mars -orbiting probes, Mars Global Surveyor and Mars Odyssey, have found evidence of a relatively recent ice age on Mars. Unlike Earth ice ages, it appears as if a Martian one grows when the poles warm and water vapor is transported to lower latitudes. Evidence suggests that the Martian ice ages arise from variations in the planet's orbit and tilt that produce drastic changes in the distribution of water ice from polar regions to mid-equatorial ones. The team of researchers utilized the NASA craft data and analogies to Earth's Antarctic Dry Valleys and report their findings in the December 18/25 edition of Nature. "Of all the solar system planets, Mars has the climate most like that of Earth. Both are sensitive to small changes in orbital parameters," explains planetary scientist Dr. James Head of Brown University, Providence, RI - the lead author of the study. "Now we're seeing that Mars, like Earth, is in a period between ice ages." Head and his co-authors examined global patterns of landscape shapes and near-surface water ice the orbiters mapped. The concluded that a covering of water ice mixed with dust covered the surface of Mars to latitudes as low as 30°, and it is degrading and retreating. By the observation of the small number of impact craters in those features and by backtracking the known patterns of changes in the orbit and tilt of Mars, they estimated that the most recent ice age occurred about 400 thousand to 2.1 million years ago. They believe that the mechanisms that drive the ice age lie in polar warming that drives water vapor from polar ice into the atmosphere. The water then goes back into the ground at lower latitudes as frost or snow mixed with dust. This layering is a few meters thick and smoothes the terrain. When ice on the top evaporates into the atmosphere, it leaves behind an insulating layer of dust over the remaining ice. Adapted from the press release on http://www.nasa.gov/home/hqnews/2003/dec/HQ_03415_ice_age.html. (Added 12/13/03) The most distant object that is visible with the naked eye is the Andromeda Galaxy, also known as M31. It is our nearest sizeable neighbor galaxy, and has been the recent subject of NASA's Galaxy Evolution Explorer (GALEX). This is one of several images that have been released to the public as part of the mission's first collection. "The Andromeda image gives us a snapshot of the most recent star formation episode," explains Dr. Christopher Martin, GALEX principal investigator and an astrophysics professor at the California Institute of Technology in Pasadena, which leads the mission. "By studying this view of the galaxy in the process of forming stars, we can better understand how that fundamental process works, such as where stars form, how fast, and why." The image to the right shows the Andromeda Galaxy (M31). It is the most massive of the local group of galaxies that includes our own Milky Way. This image is a mosaic of 10 GALEX images taken in September 2003. The color image is made with red indicating near UV and blue indicating far UV. It shows blue regions of young, hot, high-mass stars in the spiral arms as well as a central bulge of older, cooler stars. Several companion galaxies are also visible, including M32 - a dwarf elliptical directly below the central bulge and just outside the spiral arms - and M110 which is above and to the right of the center. The collection of images includes several galaxies and star clusters other than Andromeda, such as M2, NGC 7331, NGC 300, NGC 55, NGC 247, M83, NGC 5962, NGC 5474, and NGC 5398. "It's very rewarding and exciting for the team to see the fruits of their labors," claimed Kerry Erickson, the mission's project manager at NASA's Jet Propulsion Laboratory in Pasadena, CA. "Because people are accustomed to seeing objects in visible light, it's amazing to see how different the universe looks in ultraviolet and how much information is revealed to us by those observations." Scientists are interested in learning more about M31, including brightness, age, mass, and distribution of young star clusters in its spiral arms. This will provide immense amounts of information on mechanisms of star formation in galaxies, and it will help them to interpret UV and IR observations of other, more distant galaxies. Adapted from the press release on http://www.jpl.nasa.gov/releases/2003/167.cfm. Most Distant Probable Star-Forming Region Found
The galaxy, 11 billion light-years away, is at a point when the universe was only 20% of its current age. The sign is a huge quantity of dense interstellar gas. This is an indication for the equivalent of 1000 suns per year being produced in this distant galaxy - the farthest ever found with these requirements (discussed below) - which scientists have dubbed the "Cloverleaf." "This is a rate of star formation more than 300 times greater than that in our own Milky Way and similar spiral galaxies, and our discovery may provide important information about the formation and evolution of galaxies throughout the universe," said Philip Solomon of Stony Brook University, NY. While the raw material for star formation has been observed in galaxies at even greater distances, the Cloverleaf is the most distant that shows the essential signature of star formation. The signature is in the form of a specific frequency of radio waves emitted by molecules of the gas hydrogen cyanide (HCN). "If you see HCN, you are seeing gas with the high density required to form stars," said Paul Vanden Bout of the National Radio Astronomy Observatory (NRAO). In the above image, the VLA data (green) is superimposed on Hubble Space Telescope (HST) data of the Cloverleaf. The four images of the Cloverleaf galaxy are a result of gravitational lensing. Adapted from the press release on http://www.nrao.edu/pr/2003/cloverleaf/. New
Understanding of Solar Fireworks (Added 12/10/03) NASA's Ramaty High Energy Solar Spectroscopic Imager (RHESSI) spacecraft has provided new information on how the sun forms some of the largest solar flares. Solar flares, capable of releasing as much energy as one billion one-megaton nuclear bombs, are formed by the destruction of magnetic fields - called magnetic reconnection - according to the leading theory. The RHESSI data confirms this as the most likely scenario. "Many observations gave hints that magnetic reconnection over large areas was responsible for solar flares, but the new pictures from RHESSI are the first that are really convincing," said Linhui Sui of the Catholic University of America, WA, lead author of a paper on this research published in the October 20 Astrophysical Journal Letters (ApJ Lett.). "The hunt for the energy source of flares has been like a story where villagers suspect a dragon is on the loose because something roars overhead in the middle of the night, but only something resembling the tail of a dragon is ever seen. With RHESSI, we've now seen both ends of the dragon." Magnetic reconnection can happen in the solar atmosphere because it is hot enough to separate electrons from atoms, producing a gas of electrically charged particles called plasma. Because plasma is electrically charged, magnetic fields and plasma tend to flow together. When magnetic fields and plasma are ejected from the sun, the ends of the magnetic fields remain attached to the surface. As a result, the magnetic fields are stretched and forced together until they break under the stress, like a rubber band pulled too far, and then they reconnect to a new shape with less energy. This is depicted in the illustration above. The thin region where they reconnect is called the "reconnection layer," and it is where oppositely directed magnetic fields come close enough to merge. This magnetic reconnection could power a solar flare by heating the sun's atmosphere to tens of millions of degrees and accelerating electrically charged particles that make up the plasma to almost the speed of light.
These structures have been seen before and hinted at reconnection, but the observations were not conclusive. However, over the course of about four minutes during the most intense part of the flare, the x-ray emitting blob exhibited two characteristics consistent with large-scale magnetic reconnection. First, the blob split in two, with the top part ultimately rising away from the solar surface at a speed of about 1.1 million km/hr (700,000 mph). This is expected if extensive reconnection is occurring because as the magnetic fields stretch, the reconnection layer also stretches, like taffy being pulled. Plasma heated by reconnection squirts out of the top and bottom of the reconnection layer, forming the two x-ray blobs in the RHESSI pictures when the top and bottom are sufficiently far apart to be resolved as distinct areas. Second, in both blobs, the area closest to the apparent reconnection layer was hottest, and the area farthest away was coolest, according to temperature measurements by RHESSI. This is also expected if reconnection is occurring because, as the magnetic fields break and reconnect, other magnetic fields nearby move into the reconnection region and reconnect as well, since the overall, large-scale field continues to stretch. Thus, plasma is continuously heated and blasted from the reconnection layer. The plasma closest to the reconnection area is the most recently expelled and therefore the hottest. Plasma farther away was ejected earlier and had time to cool. Adapted from the press release on http://www.nasa.gov/home/hqnews/2003/dec/HQ_03397_solar_explosions.html. (Added 12/10/03) Amidst the flurry of probes that are currently at and en route to Mars, one lone straggler that began its journey over half a decade ago has finally been declared a lost cause. Japanese probe Nozomi - meaning "hope" in Japanese - has passed the deadline for a remedy for the problems it faces with no solution. The 540 kg (1190 lb) probe was launched in July of 1998 with the destination of Mars. It was supposed to arrive in Martian orbit in October 1999, but initial problems put its trajectory on a much longer path. The initial course was a close approach of Earth in December 1998, but a stuck valve caused an unexpected loss of propellant that left the probe unable to reach Mars under the planned mission. A new course was charted that involved more passes of Earth to slingshot the probe to Mars that were carried out in December 2002 and June 2003. However, a violent solar flare in April 2002 crippled the craft's power system and communications equipment, among other things. Remote fixes to bring the craft back to full power and perform necessary maneuvers for orbital insertion have not succeeded. Nozomi's mission was to enter Martian orbit, and from its perch to study such Martian features as the planet's magnetic field and upper atmospheric properties as they interacted with the solar wind, as well as to study Deimos and Phobos - the two small moons of Mars. The craft will fly past Mars at approximately 1000 km (660 miles) above its surface and will continue in a solar orbit. Despite the failure, officials claim they have learned several important lessons that they will carry into future projects. Adapted from an article on Spaceflight Now's website at http://spaceflightnow.com/mars/nozomi/031209abandon.html. Chandra Finds Evidence of Galaxy Collisions
The optical image of the galaxy - the right frame of the image - shows a relatively benign and unexciting elliptical galaxy. Yet the issue is thought to be in the manner in which many ellipticals form: A current popular model for elliptical galaxy formation is that two (or more) spiral galaxies merge, and the resulting cauldron of stellar cities is a lenticular elliptical. However, this only happens after many millions - or billions - of years, and in the mean time there are many streams and trails of stars and gas / dust clouds that stretch throughout the vicinity. The optical evidence for such mergers is thought to fade rather quickly against the luminous background of the galaxy, but the x-ray observations presented here could indicate that the x-ray signs of the mergers could linger for hundreds of millions of years. "This discovery shows that x-ray observations may be the best way to identify the ancient remains of mergers between galaxies," said Lars Hernquist of the Harvard-Smithsonian Center for Astrophysics in Cambridge (CfA), MA, and a coauthor on an article on the galaxy NGC 4261 in an upcoming issue of the Astrophysical Journal Letters (ApJ Lett.). "It could be a significant tool for probing he origin of elliptical galaxies." Adapted from the press release on http://chandra.harvard.edu/press/03_releases/press_120803.html. Biggest
Star Lies Within Cocoon (Added 12/06/03) The mushroom-shaped clouds that form the Homunculus Nebula surround the massive star Eta Carinae in the left image in the composite to the right. New VLT data (right in the composite) reveals the inner structure of the nebula that form the immediate surroundings. Eta Carinae is the most luminous star known in the galaxy. It is 100 times as massive as the sun and over 5 million times as luminous. It has entered the final stages of its life and is highly unstable, undergoing giant outbursts - one of the most recent occurring in 1841 that created the nebula that surrounds it now, and making it the second brightest star in the sky at the time. A team of astronomers used the NAOS-CONICA adaptive optics camera that is attached to the 8.2 m VLT YEPUN telescope to image the surroundings of Eta Carinae with a resolution of about the size of the solar system. This shows the central region of the nebula, revealing it to be dotted by the star with many luminous "blobs" in the immediate vicinity. For a sharper image of the nebula, the astronomers then used interferometry - combining the light from two or more telescopes to achieve an image as if it were taken by a telescope as large as the separation between the originals. The astronomers used the VLT INterferometer Commissioning Instrument (VINCI) along with the two 32 cm siderostat test telescopes, achieving a baseline of 62 meters. With these, the astronomers were able to resolve the shape of the outer layer of Eta Carinae, resolving 0.005 arcsec - 11 A.U. at the distance of the star. The results indicate that the stellar wind about the star is greatly elongated in a ratio of 2:3. The long axis is pointing almost directly along the axis of the two mushroom clouds of the surrounding nebula. This goes against mainstream theories, which state that stars should loose mass mostly around their equator and not the poles due to centrifugal forces from the star's rotation. But if this were so in Eta Carinae's case, then the mushroom clouds should form a torus - a ring. Adapted from the press release on http://www.eso.org/outreach/press-rel/pr-2003/pr-31-03.html. Hubble Heritage Picture - December 2003
NGC 604 is one of the largest known regions of star birth in a nearby galaxy. It is similar to those in the Milky Way, such as the Orion Nebula, but it is much larger and contains many more recently formed stars. Over 200 bright blue stars reside in this 1300 light-year across cloud - 100 times the size of the Orion Nebula which contains 4 bright blue stars. The stars in NGC 604 formed approximately 3 million years ago. Most of the hottest and brightest of the stars are in a loose cluster within a cavity near the center of the nebula. Stellar winds and supernova explosions helped to form the cavity. The most massive stars in the region are over 120 times the sun's mass and posseses surface temperatures as high as 40,000 K (72,000 °F). Ultraviolet radiation from the stars makes the surrounding gas fluoresce. NGC 604 resides in a spiral arm of M33, which is a member of the Local Group that includes the Milky Way and Andromeda Galaxies. Adapted from the information on http://heritage.stsci.edu/2003/30/fast_facts.html. Common Origin for Cosmic Explosions (Added 12/06/03) A television can produce millions of different colors, yet they all have a common origin. In a similar way, astronomers have discovered that a variety of bright cosmic explosions all have the same origin and the same total amount of energy, they just look different. This is the conclusion of an international team of astronomers that used the National Science Foundation's Very Large Array (VLA) radio telescope to study the closest known gamma-ray burst that was found earlier this year. "For some reason we don't yet understand, these explosions put greatly varying percentages of their explosive energy into the gamma-ray portion of their output," said Dale Frail of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. That means, he said, that both strong and weak gamma-ray bursts, along with X-ray flashes which emit almost no gamma rays, are just different forms of the same cosmic beast. The research team reported their results in the November 13 issue of the scientific journal Nature. The scientists trained the VLA on a gamma-ray burst discovered using NASA's HETE-2 satellite last March 29. This burst, dubbed GRB 030329, was the closest such burst yet seen, about 2.6 billion light-years from Earth. Because of this relative proximity, the burst was bright, with visible light from its explosion reaching a level that could be seen in amateur telescopes. As the burst faded, astronomers noted an underlying distinctive signature of a supernova explosion, confirming that the event was associated with the death of a massive star. Since 1999, astronomers have known that the strong outbursts of gamma rays, X-rays, visible light, and radio waves from these bursts form beams, like those from a flashlight, rather than spreading in all directions, like light from a bare bulb. The surprising result from the VLA studies of GRB 030329 is that there are two beams, not one. The scientists found that the gamma rays and the early visible light and X-ray emission were coming from a narrow beam, while the radio waves and later visible-light emission came from another, wider beam. "The strange thing is that some explosions seem to put most of their energy into the narrow beam, while others put most or nearly all their energy into the wider beam," Frail said. "This is telling us something very fundamental about the inner workings that drive these explosions." The mechanism producing these explosions is what scientists call a collapsar, which occurs when a giant star collapses of its own weight at the end of its normal, nuclear fusion-powered lifetime. In an ordinary supernova, such a collapse produces a neutron star. A collapsar, however, marks the death of a more-massive star and results in a black hole, a concentration of mass so dense that not even light can escape it. After the black hole forms, its powerful gravitational pull pulls the star's remaining material toward it. This material forms a spinning disk around the black hole that lasts only a few seconds. During that time, the disk ejects material outward from its poles. A jet of material moving at nearly the speed of light emits gamma rays, but slower material emits radio waves and visible light. "Despite the differences in how much energy comes out in gamma rays, all these things seem to be caused by the same basic mechanism," said Edo Berger, a graduate student at Cal tech and lead author of the Nature paper. "Our observations now give the data that will help us understand what causes the differences. It was astounding to suddenly realize that these apparently very different cosmic beasts all are really the same thing." The next job, Frail said, is to learn if there are, in fact, two jets, or a single jet in which the central part encounters less resistance and thus can move outward at greater speeds. Frail pointed out that the radio observations alone had the ability to show the total energy output of the burst, thus providing the breakthrough in understanding the common thread among the different types of explosions. "The key fact is that the optical, x-ray and gamma-ray telescopes missed 90% of the energy put out by this burst," Frail added. "As the VLA Expansion Project progresses and the sensitivity of the VLA improves in the coming years, it will become an even more important tool in unraveling this mystery. The exciting part of this new discovery is that explosions that we once thought were quite different now appear to all have a common origin," Frail concluded. "That insight, of course, gives us the new challenge of explaining how a single mechanism can make itself look so different." Adapted from the press release on http://www.nrao.edu/pr/2003/grbtwinjet/. Nearby Star Has Forming Jupiter-Like Planet (Added 12/06/03) Astronomers at the University of Arizona have used a new technique called "nulling interferometry" to examine a dust disk around a young, nearby star - HD 100546. Using this method, they not only confirmed that the star has a protoplanetary disk, but also discovered a gap in the disk - strong evidence for a forming planet. "It's very exciting to find a star that we think should be forming planets, and actually see evidence of that happening," said UA astronomer Philip Hinz. "The bottom line is, we not only confirmed the hypothesis that this young star has a protoplanetary disk, we found evidence that a giant, Jupiter-like protoplanet is forming in this disk," said Wilson Liu, a doctoral student and research assistant on the project. "There's evidence that this star is right on the cusp of becoming a main-sequence star. So basically, we're catching a star that is right at the point of becoming a main-sequence star, and it looks like it's caught in the act of forming planets." Earlier this year, Hinz and Liu realized that observations of HD 100546 at thermal, or mid-infrared, wavelengths showed that the star had a dust disk. Finding faint dust disks is "analogous to finding a lighted flashlight next to Arizona Stadium when the lights are on," Liu said. The nulling technique combines starlight in such a way that it is canceled out, creating a dark background where the star's image normally would be. Because HD 100546 is such a young star, its dust disk is still relatively bright, about as bright as the star itself. The nulling technique is needed to distinguish what light comes from the star, which can be suppressed, and what comes from the extended dust disk, which nulling does not suppress. Hinz and UA astronomers Michael Meyer, Eric Mamajek, and William Hoffmann took the observations in May 2002. They used BLINC, the only working nulling interferometer in the world, along with MIRAC, a state-of-the-art mid-infrared camera, on the 6.5 m (21 ft) diameter Magellan telescope in Chile to study the roughly 10 million year-old star in the Southern Hemisphere sky. Typically, dust in disks around stars is uniformly distributed, forming a continuous, flattened, orbiting cloud of material that is hot on the inner edge but cold most of the distance to the frigid outer edge. "The data reduction was complicated enough that we didn't realize until later that there was an inner gap in the disk," Hinz noted. "We realized the disk appeared about the same size at warmer (10 µm) wavelengths and at colder (20 µm) wavelengths. The only way that could be is if there's an inner gap." The most likely explanation for this gap is that it is created by the gravitational field of a giant protoplanet - an object that could be several times more massive than Jupiter. The researchers believe the protoplanet may be orbiting the star at perhaps 10 A.U. The UA team is reporting the research in Astrophysical Journal Letters (ApJ Lett) and also will present a paper on the research at the American Astronomical Society meeting in Atlanta, GA, in January 2004. Adapted from the press release on http://uanews.org/cgi-bin/WebObjects/UANews.woa/5/wa/SRStoryDetails?ArticleID=8087&wosid=Pab9mJahyGFCfQKlRpouWg. Most Distant X-ray Jet Provides Big Clues to the Big Bang (Added 12/06/03) NASA's Chandra X-ray Observatory has found the most distant jet ever observed in the image of a quasar over 12 billion light-years distant. The jet extends more than 100,000 light-years from the supermassive black hole that powers the quasar. Prior to this discovery, the most distant confirmed X-ray jet corresponded to a time about 3 billion years after the Big Bang. The discovery of this jet was a surprise to the astronomers; they had previously known the distant quasar - GB1508+5714 - to be a powerful X-ray source, but there had been no indication of any complex structure or a jet. "This jet is especially significant because it allows us to probe the cosmic background radiation 1.4 billion years after the Big Bang," said Aneta Siemiginowska of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, lead author of a report on this research in the November 20th Astrophysical Journal Letters. A quasar is thought to be a galaxy that contains an active central supermassive black hole that his fueled by infalling gas and stars. This accretion process is often observed to be accompanied by the generation of powerful high-energy jets. As the electrons in the jet are pushed away from the quasar at near light-speed, they move through the photons from the cosmic microwave background radiation left over from an early stage of the universe's formation. When the electrons collide with the photons, the photons receive an energy boos and are moved into the x-ray band. The x-ray brightness of the jet depends on the power of the electron beam and the intensity of the background radiation. "Everyone assumes that the background radiation will change in a predictable way with time, but it is important to have this check on the predictions," said Siemiginowska. "This jet is hopefully just the first in a large sample of these distant objects that can be used to tell us how the intensity of the cosmic microwave background changed over time." "In fact, if this interpretation is correct, then discovery of this jet is consistent with our previous prediction that X-ray jets can be detected at arbitrarily large distances!" said team member Dan Schwartz, also of the Harvard-Smithsonian Center for Astrophysics. Adapted from the press release on http://chandra.harvard.edu/press/03_releases/press_111703.html. NASA's Successful Ion Engine Test (Added 12/06/03) Conventional propulsion systems use large amounts of inefficient chemical fuel to create thrust to push a spacecraft along. An experimental form of propulsion has made a leap in the development process with NASA's successful test of its new Ion Engine. The Project Prometheus test involved a High Power Electric Propulsion (HiPEP) ion engine using commercial utility electrical power. The event marks the first in a series of performance tests to demonstrate new high-velocity and high-power thrust needed for use in nuclear electric propulsion (NEP) applications. "The initial test went extremely well," said Dr. John Foster, the primary investigator of the HiPEP ion engine at NASA's Glenn Research Center in Cleveland, OH. "The test involved the largest microwave ion thruster ever built. The use of microwaves for ionization would enable very long-life thrusters for probing the universe." The test was conducted in a vacuum chamber at NSAS Glen. The HiPEP ion engine was operated at power levels up to 12 KW and over an equivalent range of exhaust velocities from 60,000-80,000 meters per sec. The thruster is being designed to provide 7-10 years at high fuel efficiencies of more than 6,000-seconds specific impulse - a measure of how much thrust is generated per kg of fuel; this is a contrast to a standard chemical rocket, which has a specific impulse of about 300-400-seconds. The HiPEP thruster operates by ionizing xenon gas with microwaves. At the rear of the engine is a pair of rectangular metal grids that are charged with 6,000 volts of electric potential. The force of this electric field exerts a strong electrostatic pull on the xenon ions, accelerating them and producing the thrust that propels the spacecraft. The rectangular shape, a departure from the cylindrical ion thrusters used before, was designed to allow for an increase in engine power and performance by means of stretching the engine. The use of microwaves should provide much longer life and ion-production capability compared to current state-of-the-art technologies. Adapted from the press release on http://www.nasa.gov/home/hqnews/2003/nov/HQ_03377_ion_engine.html. Martian
Fans Suggest Ancient Rivers (Added 12/06/03) Several scenarios of Martian water have emerged over the past few decades. Perhaps the most opposites are of a recent warm and wet Mars vs. an ancient wet Mars that dried up over 3 billion years ago. Still another view is that Mars has periodically experienced intense flooding in short, brief bursts. New evidence from NASA's Mars Global Surveyor orbiter weighs in with new images of what look like deltas on Earth (see image at right). The images show what could be interpreted as eroded ancient deposits of transported sediment that hardened into interwoven, curved ridges of layered rock long ago. These have been interpreted as the paths traced by ancient rivers made in a sediment as the rivers' courses changed through time. "Meanders are key, unequivocal evidence that some valleys on early Mars held persistent flows of water over considerable periods of time," said Dr. Michale Malin of Malin Space Science Systems, San Diego, which supplied and operates the spacecrafts' Mars Orbiter Camera. "The shape of the fan and the pattern of inverted channels in it suggest it may have been a real delta, a deposit made where a river enters a body of water. If so, it would be the strongest indicator yet Mars once had lakes." The fan covers an area 13x11 km (8x7 miles) in the southern hemisphere. Dr. Jim Garvin, NASA's lead scientist for Mars Exploration, NASA Headquarters, Washington, states "it reaffirms we are on the right pathway for searching the record of Martian landscapes and eventually rocks for the record of habitats. Such localities may serve as key landing sites for future missions, such as the Mars Science Laboratory in 2009. These astounding findings suggest that 'following the water' with Mars Global Surveyor, Mars Odyssey, and soon with the Mars Exploration Rovers, is a powerful approach that will ultimately allow us to understand the history of habitats on the red planet" Adapted from the press release on http://www.nasa.gov/home/hqnews/2003/nov/HQ_03364_MGS_delta.html. Hubble Heritage Picture - November 2003 (Added 11/06/03) The Hubble Heritage Team has released November's image of the Carina Nebula, AKA NGC 3372. 8,000 light-years from us, the Carina Nebula lies in the constellation Carina; this image covers approximately 1.2 arcminutes across (2.9 light-years). The image was originally taken On July 4/5, 2003, for a total exposure time of 1.6 hours. The full expanse of the Carina Nebula is over 200 light-years - nearly 67 times the small portion shown in this month's release. The nebula - in the Southern hemisphere - is so large that it is visible with the naked eye. The nebula is full of stars that emit high-speed winds. These energetic winds act to sculpt the the nebula into the billows, curls, and dark lanes that are seen in this image. This particular vista shows a region in the nebula between two large clusters of some of the most massive and hottest known stars, including the variable star known as Eta Carinae. The filaments shown throughout the image are caused by turbulence in the gas, which in turn was caused by several stars shedding their outer layers. The cold interstellar gas mixed with the hot gas, leaving a veil of denser, opaque material in the foreground. The chemical elements in the surroundings create a potential reservoir for star formation. Areas in the brightest parts of the image at the top show elephant-trunk shaped dust clouds that may form into young solar systems in the future. This image was taken as part of a parallel observing program. The HST has many instruments that can be used to look at slightly different portions of the sky at once. For this image, the Space Telescope Imaging Spectrograph was used to study Eta Carinae itself, while the Wide Field Planetary Camera 2 was used to image the nebula. The parallel observing program increases efficiency and allows astronomer to view objects that otherwise would not have been accepted by a selection committee. Adapted from the information on http://heritage.stsci.edu/2003/31/index.html. Voyager Reaches the Edge (Added 11/06/03) NASA's Voyager 1 spacecraft is fast becoming the first craft to enter the edge of the solar system - the heliopause - the edge of the sun's influence. The sun emits a "solar wind" - a stream of charged particles - that rushes away and carves out a space which the solar system occupies. Where the solar wind meets the winds from other stars begins interstellar space, and it is into this region that the Voyager 1 probe will soon reach. However, before it reaches the heliopause, Voyager 1 must pass through the termination shock; this is a violent zone that is the source of high-energy particles. Here, the solar wind rapidly slows from an average speed of 700,000-1,500,000 mph. The exact location of this volume of space is unknown because we do not know the precise conditions of interstellar space; we do, however, know the speed and pressure of solar wind changes, which causes the termination shock to expand, contract, and ripple. Its passage through the zone will give scientists the first direct measurements of the solar system's "final frontier." "Voyager 1 has seen striking signs of the region deep in space where a giant shock wave forms, as the wind from the sun abruptly slows and presses outward against the interstellar wind. The observations surprised and puzzled us, so there is much to be discovered as it begins exploring this new region at the outer edge of the solar system," said Dr. Edward Stone, Voyager Project Scientist, California Institute of Technology, Pasadena, CA. From about August 1, 2002, to February 5, 2003, scientists noticed unusual readings from the two energetic-particle instruments on Voyager 1, indicating it had entered a region of the solar system unlike any previously encountered. This led some to claim Voyager 1 may have entered a transitory feature of the termination shock. The controversy would be resolved if Voyager could measure the speed of the solar wind because the solar wind slows abruptly at the termination shock. However, the instrument that measured solar wind speed no longer functions on the probe. Scientists must use data from instruments still working to infer if Voyager pierced the termination shock. "We have used an indirect technique to show the solar wind slowed down from about 700,000 mph to much less than 100,000 mph. We used this same technique when the instrument measuring the solar wind speed was still working. The agreement between the two measurements was better than 20% in most cases," Krimigis said. "The analysis of the Voyager 1 magnetic field observations in late 2002 indicate that it did not enter a new region of the distant heliosphere by having crossed the termination shock. Rather, the magnetic field data had the characteristics to be expected based upon many years of previous observations, although the intensity of energetic particles observed is unusually high," Burlaga said. Adapted from the press release on http://www.nasa.gov/home/hqnews/2003/nov/HQ_03354_voyager_ssu.html. Sloan Digital Sky Survey Universal Map (Added 10/30/03) The Sloan Digital Sky Survey, a multi-year and -national project to map 1/4 of the sky and produce a catalogue of over 100 million objects, has produced the most precise map to date of the large-scale clustering of galaxies and dark matter, refining our understanding of the structure and evolution of the universe. The three-dimensional map contains over 200,000 galaxies up to 2 billion light-years away in over 6% of the sky. The gravitational clustering reveal the makeup of the universe from its gravitational effects. One of the most important results from this mapping, combined with the recent measurements from the WMAP satellite, shows that the universe is made of about 70% dark energy, 25% dark matter, and 5% ordinary matter, confirming previous results. A second result from this survey is that neutrinos cannot be a major constituent of the dark matter content of the universe. This finding ranks among the strongest constraints to date on their mass, which has yet to be measured as non-zero. Thirdly, their results are consistent with the detailed predictions of the inflation model of the universe. Adapted from the press release on http://www.sdss.org/news/releases/20031028.powerspectrum.html. Week of Flares
That flare was the third strongest flare seen in the last 30 years. It was classified as an X17-category, which means that it could trigger planet-wide radio blackouts and long-lasting radiation storms. And just when we thought we were out of the line of fire, yet another massive flare was spotted on Wednesday afternoon. It is a class X10 flare. The image at left is of this latter flare; the horizontal lines are caused from over-saturation of the detector on the craft used to take the image. "It's like the Earth is looking right down the barrel of a giant gun pointed at us by the sun ... and it's taken two big shots at us," says John Kohl, a solar astrophysicist at the Harvard-Smithsonian Center for Astrophysics (CfA) and principle investigator for the Ultraviolet Chronograph Spectrometer on NASA's SOHO spacecraft (from which the image at the left was taken). "The sun is really churned up. The timing of two very large X-class flares aimed directly at the Earth, occurring one right after another, is unprecedented." The two eruptions could create combined geomagnetic storms that could influence us in many ways. The most prominent disruptions would be in satellite communications and power grids. Steps to prevent too much damage are to put satellites in a safe mode and to lower line voltages on power grids to allow leeway for surges. Adapted from the press release on http://cfa-www.harvard.edu/press/pr0323.html. Mars Might Not Have Had Liquid Water For Over 3 Billion Years (Added 10/25/03) The Mars Global Surveyor has been in orbit of Mars since September 1997. One of the experiments onboard is called TES and is used to take spectra - images that show the relative intensity of different wavelengths of light - of the planet's surface. A team headed by the U.S. Geological Survey has used TES spectra of the planet to show that Mars has likely not had liquid water on its surface for over 3 billion years. The team used the spectra to search for the signatures of various minerals on the surface, but they were specifically interested in olivine - a green mineral that is common in many rocks. When olivine is exposed to a warm and wet environment, it becomes altered and produces secondary minerals. An area found that was particularly rich in olivine is the Nili Fossae region, which contains an impact site - the Isidis basin - that has been dated to having formed approximately 3.6 billion years ago. The Isidis basin contains a relatively large amount (~30%) of surface olivine that the team believes was exposed very soon after the impact that created the basin. None of the secondary minerals that would have formed in a warm and wet environment were found. There are two main explanations for this. First, if Mars had a warm and wet environment, it would have ended over 3 billion years ago. The second possible explanation is that the olivine deposits were not exposed to the surface soon after the impact, but were revealed more recently. In this case, Mars could have been cold and dry for as little as a few thousand years. Other olivine deposits in date-able areas will help constrain this. - Stuart J. Robbins; source is: Hoefen, Todd M. et. al. "Discovery of Olivine in the Nili Fossae Region of Mars." Science 302 627 (2003). CONTOUR Investigation Board Results (Added 10/16/03) On August 15, 2002, the NASA craft CONTOUR - COmet Nucleus TOUR - was destroyed. The CONTOUR Mishap Investigation Board has released their report detailing the most likely causes of the accident. There were problems in the investigation due to lack of direct data during the accident. The craft was to remain in Earth orbit until August 15, when a solid rocket motor was fired to leave orbit and begin the craft's transit to its first cometary encounter with Encke. The design of the mission did not provide any telemetry coverage during the firing, but the craft was to establish contact with ground control after the board. No signal was received, and subsequent optical scans of the area showed three fragments where the craft should have been. The board was able to narrow down the potential causes of the accident to a few most likely ones. The Board identified a number of possible root causes as well as observations that could result in future mission failures. Probable Cause: "Overheating of the CONTOUR spacecraft by the solid rocket motor exhaust plume." Alternate Causes: "Catastrophic failure of the solid rocket motor; collision with space debris or meteoroids; loss of dynamic control of the spacecraft." Root Causes: "CONTOUR Project reliance on analysis by similarity; inadequate systems engineering process; inadequate review function." - Stuart J. Robbins; quotes from the CONTOUR Mishap Investigation Board's final manuscript, all from page 8 China Joins the Ranks of Manned Spaceflight (Added 10/16/03) In 1961, the former Soviet Union successfully launched Yuri Gargarin into space aboard Sputnik 11. In 1962, John Glenn was launched from the U.S. into space aboard Mercury Atlas 6. For over 40 years, these had been the only two nations to independently launch a manned probe into space. China has now become the third. Aboard the Shenzhou (meaning "Divine Vessel") 5 spacecraft, launched atop a Long March 2F rocket at 01:00 GMT on Wednesday, October 15, 2003, from the Jiuquan launch center in China, 38-year-old Yang Liwei became the first Chinese yuhangyuan - astronaut. It was then successfully recovered after just under one day, or 14 orbits, in space. Touchdown was at 22:23 GMT on Wednesday, October 15. The Chinese media report that the landing point was only 4.8 km (3 miles) from the target site. Yang was carried away in a seat as shown on the state television coverage of the event. Official reports from Xinhua say Yang "was confirmed to remain in good health" after his historic stay in space. The craft apparently performed flawlessly, for no technical problems were reported nor ill effects to the occupant. Conversations with the ground control in Beijing were relayed through tracking stations and sea vessels throughout the world. The mission lasted 21 hours, 23 minutes (liftoff to touchdown), completed 14 Earth orbits, and traveled about 600,000 km (370,000 miles). The next space launch could come as soon as a few months from now. It is unclear what it will entail, but a repeat of the Shenzhou 5 or possibly a larger crew are the most likely events. Adapted from the information at http://spaceflightnow.com/shenzhou/031015landing.html and http://www.spacetoday.net/Summary/1963. Hubble Heritage Picture - October 2003 (Added 10/04/03) The Hubble Heritage Team has released October's image of M104, AKA the Sombrero Galaxy, AKA NGC 4594, a spiral galaxy. 28 million light-years from us, M104 lies in the constellation Virgo; this image covers approximately 10 arcminutes across (82,000 light-years). The image was originally taken in May and June of 2003, for a total exposure time of 10.2 hours. One of the most famous and photogenic galaxies in the universe, the Sombrero is characterized by a giant blue-white core encircled by a large swath of gas. The galaxy is actually a spiral, like our own Milky Way, but it is tilted approximately 6° south of its equatorial plane. Within the bright core is a smaller disk, tilted relative to the larger disk. X-ray emissions suggest that there is material there feeding a black hole weighing approximately 1 billion times our sun. The galaxy is just beyond naked-eye visibility, and it is easily seen through small telescopes. It is at the southern edge of the Virgo cluster and is one of the most massive objects in the group, weighing in at about 800 billion suns. The galaxy is only half as large as ours at about 50,000 light-years across. Plainly visible even in this shrunk view of the galaxy are many of the globular clusters that belong to the Sombrero. Its globular cluster family is estimated at nearly 2000, compared with the approximate 150 known to belong to the Milky Way. In the 19th century, some astronomers speculated that M104 was simply an edge-on disk of luminous gas surrounding a young star, which is prototypical of the genesis of our solar system. But in 1912, astronomer V. M. Slipher discovered that the hat-like object appeared to be rushing away from us at 700 miles per second. This enormous velocity offered some of the earliest clues that the Sombrero was really another galaxy, and that the universe was expanding in all directions. The Hubble Heritage Team took these observations with the HST's Advanced Camera for Surveys. Images were taken in three filters (red, green, and blue) to yield a natural color image. The team took six pictures of the galaxy and then stitched them together to create the final composite image. One of the largest Hubble mosaics ever assembled, this magnificent galaxy is nearly one-fifth the diameter of the full moon. Adapted from the information on http://heritage.stsci.edu/2003/28/index.html. Uranian Moons - HST Finds Some Old, Some New (Added 10/01/03) The Hubble Space Telescope (HST) has again been used to find some of the smallest solar system bodies known, and this time they are circling about Uranus. Three objects were found -- two of them new, and one of them a rediscovery of the "lost" moon that was originally found by Voyager 2 in 1986.
The other discovery, or re-discovery, was of a moon named S/1986 U10, discovered in 1999 from old Voyager 2 pictures. However, follow-up observations found nothing, so it was unconfirmed for four years. "It's a testament to how much our Earth-based instruments have improved in 20 plus years that we can now see such faint objects 1.7 billion miles [2.8 billion km] away," says Mark Showalter, a senior research associate at Stanford University in Stanford, CA, who works at the NASA Ames Research Center, in Moffett Field, CA. Showalter and Jack Lissauer, a research scientist at the NASA Ames Research Center, used HST's Advanced Camera for Surveys (ACS) to make the discovery. The images were taken August 25, 2003. The newly discovered moons are temporarily designated as S/2003 U1 and S/2003 U2 until the IAU formally approves their discovery. S/2003 U1 is the larger of the two moons, measuring 10 miles (16 km) across. The Hubble telescope spotted this moon orbiting between the moons Puck, the largest satellite found by Voyager, and Miranda, the innermost of the five largest Uranian satellites. Astronomers previously thought this region was empty space. S/2003 U1 is 60,600 miles (97,700 km) away from Uranus, whirling around the giant planet in 22 hours and 9 minutes. The smallest Uranian moon yet found, S/2003 U2, is 8 miles (12 km) wide. Its orbital path is just 200-450 miles (300-700 km) from the moon Belinda. S/2003 U2 is 46,400 miles (74,800 km) away from Uranus and circles the planet in 14 hours and 50 minutes. The tiny moon is part of a densely crowded field of 11 other moons, all discovered from pictures taken by the Voyager spacecraft. "The inner swarm of 13 satellites is unlike any other system of planetary moons," says co-investigator Jack Lissauer. "The larger moons must be gravitationally perturbing the smaller moons. The region is so crowded that these moons could be gravitationally unstable. So, we are trying to understand how the moons can coexist with each other." One idea is that some of the moons are young and formed through collisions with wayward comets. For example, the Hubble telescope spotted two small moons orbiting very close to the moon Belinda. One of them is the newly detected moon, S/2003 U2, which is traveling inside Belinda's orbit. The other, designated S/1986 U10, was found in 1999 by astronomer Erich Karkoschka of the University of Arizona, who uncovered the satellite in Voyager pictures. But the finding required confirmation by an Earth-based telescope. This is the first time this moon has been seen since Voyager snapped a picture of it. S/1986 U 10 is 750 miles (1,200 km) away from Belinda. The astronomers hope to refine the orbits of the newly discovered moons with further observations. "The orbits will show how the moons interact with one another, perhaps showing how such a crowded system of satellites can be stabilized," Showalter explains. "This could provide further insight into how the moon system formed. Refining their orbits also could reveal whether these moons have any special role in confining or 'shepherding' Uranus's 10 narrow rings." Astronomers stretched the limit of Hubble's ACS to find the tiny satellites. "These moons are 40 million times fainter than Uranus," Showalter says. "The moons are at 25th magnitude and Uranus is at 6th magnitude. They are blacker than asphalt, if their composition is like the other small, inner moons. So they don't reflect much light. Even with the sensitivity and high resolution of Hubble's ACS, we had to overexpose the images of Uranus to pinpoint the moons." The newly detected moons, when approved by the IAU, will bring the Uranian satellite total to 24. Uranus ranks third in the number of IAU-certified moons behind Jupiter (38) and Saturn (30). Excluding the outer moons that travel in elongated orbits and are probably captured asteroids, Uranus holds the record for the most satellites with 18 in its inner system. All of them have nearly circular orbits. Saturn is second with 17. Adapted from the press release on http://hubblesite.org/newscenter/archive/2003/29/. ESA Launches SMART-1 (Added 10/01/03) SMART-1, Europe's first science spacecraft sent to orbit Earth's moon, was launched at 23:14 GMT on September 27, 2003, aboard Ariane Flight 162, launched from the Guiana Space Centre in Kourou, French Guiana. It achieved its initial Earth orbit within the next hour. The 368 kg (811 lb) craft is now beginning its long, 18-month journey to Earth's closest celestial neighbor, to enter into a lunar orbit in March 2005. "Science and technology go hand in hand in this exciting mission to the moon. The Earth and Moon have over 4 thousand million years of shared history, so knowing the moon better will help scientists in Europe and all over the world to better understand our planet and will give them valuable new hints on how to better safeguard it," said ESA Director of Science David Southwood, following the launch from Kourou. As the first mission in the new series of Small Missions for Advanced Research in Technology, SMART-1 is mainly designed to demonstrate innovative and key technologies for future deep space science missions. The first technology to be demonstrated on SMART-1 will be Solar Electric Primary Propulsion (SEPP), a highly efficient and lightweight propulsion system that is ideal for long-duration deep space missions in and beyond our solar system. SMART-1's propulsion system consists in a single ion engine fueled by 82 kg (181 lb) of xenon gas and pure solar energy. This plasma thruster relies on the "Hall Effect" to accelerate xenon ions to speed up to 16,000 km/hour (10,000 mph). It is able to deliver 70 mN of thrust with a specific impulse (the ratio between thrust and propellant consumption) 5 to 10 times better than traditional chemical thrusters and for much longer durations (months or even years, compared to the few minutes' operating times typical of traditional chemical engines). The ion engine was scheduled to go into action on September 30. At first, it will fire almost continuously - stopping only when the spacecraft is in the Earth's shadow - to raise the altitude of its perigee (the lowest point of its orbit) from 750 to 20,000 km (450 to 12,500 miles). This maneuver will take about 80 days to complete and will place the spacecraft safely above the radiation belts that surround the Earth. Once at a safe distance from Earth, SMART-1 will fire its thruster for periods of several days to progressively raise its apogee (the maximum altitude of its orbit) to the orbit of the moon. At 200,000 km (125,000 miles) from Earth, it will begin receiving significant tugs from the moon as it passes by. It will then perform three gravity-assist maneuvers while flying by the moon in late December 2004, late January and February 2005. Eventually, SMART-1 will be "captured" and enter a near-polar elliptical lunar orbit in March 2005. SMART-1 will then use its thruster to reduce the altitude and eccentricity of this orbit. During this 18-month transfer phase, the solar-electric primary propulsion's performance, and its interactions with the spacecraft and its environment, will be closely monitored by the Spacecraft Potential, Electron & Dust Experiment (SPEDE) and the Electric Propulsion Diagnostic Package (EPDP) to detect possible side-effects or interactions with natural electric and magnetic phenomena in nearby space. A promising technology, Solar Electric Primary Propulsion could be applied to numerous interplanetary missions in the solar system, reducing the size and cost of propulsion systems while increasing maneuvering flexibility and the mass available for scientific instrumentation. In addition to Solar Electric Primary Propulsion, SMART-1 will demonstrate a wide range of new technologies like a Li-Ion modular battery package; new-generation high-data-rate deep space communications in X and Ka bands with the X/Ka-band Telemetry and Telecommand Experiment (KaTE); and a computer technique enabling spacecraft to determine their position autonomously in space, which is the first step towards fully autonomous spacecraft navigation. Despite its relatively small budget and short development schedule, SMART-1 holds tremendous potential for future missions and is a clear illustration of Europe's ambitions in the exploration of the solar system, also highlighted by June's launch of Mars Express, which has now completed over the half on its journey to Mars, and the launch of Rosetta, due in February 2004, to visit comet Churyumov-Gerasimenko. Adapted from the press release on http://www.esa.int/export/esaCP/Pr_60_2003_p_EN.html. Iron Evidence for Spinning Black Hole
During a press conference at the "Four Years of Chandra" symposium in Huntsville, AL, Jon Miller of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, discussed recent results on the x-ray spectra of iron atoms in the gas around three stellar-sized black holes in the Milky Way. "The latest work provides the most precise measurements yet of the x-ray spectra for stellar black holes. These data help rule out competing explanations that do not require extreme gravitational effects, and provide the best look yet at the geometry of the space-time around a stellar black hole created by the death of a massive star." The orbit of a particle near a black hole depends on the curvature of space around the black hole, which also depends on how fast the black hole is spinning. A spinning black hole drags space around with it and allows atoms to orbit closer to the black hole than is possible for a non-spinning black hole. The latest Chandra data from Cygnus X-1, the first stellar-size black hole discovered, show that the gravitational effects on the signal from the iron atoms can only be due to relativistic effects, and that some of the atoms are no closer than 100 miles to the black hole. There was no evidence that the Cygnus X-1 black hole is spinning. The XMM-Newton data from the black hole XTE J1650-500 show a very similar distribution of iron atom x-rays with one important exception. More low energy x-rays from iron atoms are observed, an indication that some x-rays are coming from deep in the gravitational well around the black hole, as close as 20 miles to the black hole event horizon. This black hole must be spinning rapidly. Chandra observations of a third stellar black hole, GX 339-4, have revealed that it is also spinning rapidly, and clouds of warm absorbing gas appear to be flowing away from the black hole at speeds of about three hundred thousand miles per hour. Such warm gas flows have been observed in the vicinity of supermassive black holes. One possibility as to why some black holes spin and others don't is that differences in spin are imparted at birth when a massive star collapses. Another possibility is that the spin rate depends on how long the black hole has been devouring matter from its companion star, a process that makes the black hole spin faster. Black holes with more rapid spin, XTE J1650-500 and GX 339-4, have low-mass companion stars. These relatively long-lived stars may have been feeding the black hole for longer, allowing it to spin up to faster rates. Cygnus X-1 with its short-lived companion star may not have not time to spin up. Adapted from the press release on http://chandra.harvard.edu/press/03_releases/press_091703.html. Chandra Used to Study Lunar Composition
"We see x-rays from these elements directly, independent of assumptions about the mineralogy and other complications," said Jeremy Drake of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, at a press conference at the "Four Years with Chandra" symposium in Huntsville, AL. "Remote sensing with Chandra can cover a much wider area" than the samples from the six widely-spaced Apollo landing sites. The x-rays that Chandra detects from the moon are caused by fluorescence - a process whereby solar x-rays hit the lunar surface, knock electrons into high energy states, and cause other electrons to fill the vacant gaps, converting their energy in to the energy detected by the Observatory. The data have also served to solve a mystery about the x-rays from Luna's dark side. Data from the German ROSAT satellite in 1990 showed x-rays from the dark side. They were attributed to energetic electrons streaming from the sun and hitting the lunar surface. Chandra's observations of the x-ray's energies have shown that the x-rays actually only appear to come from the moon; they are emitted by Earth's extended outer atmosphere, through which both ROSAT and Chandra would move. Adapted from the press release on http://chandra.harvard.edu/press/03_releases/press_091603.html. Hubble Images Saturn
The images are, top to bottom, ultraviolet, visual, and infrared. The HST's Wide Field Planetary Camera 2 used 30 different filters to take the images on March 7. "The set of 30 selected filters may be the best spectral coverage of Saturn observations ever obtained," says planetary researcher Erich Karkoschka of the University of Arizona. The different wavelengths allow different features of Saturn to come into view. Only by studying the different wavelengths in a manner such as this can researchers interpret the data and better understand the planet. Through studying the hazes and clouds in these images, researchers can learn about the dynamics of Saturn's atmosphere. These images reveal the properties and sizes of aerosols in Saturn's gaseous atmosphere. For example, smaller aerosols are visible only in the ultraviolet image because they do not scatter or absorb visible or infrared light, which have longer wavelengths. By determining the characteristics of the atmosphere's constituents, researchers can describe the dynamics of cloud formation. At certain visible and infrared wavelengths, light absorption by methane gas blocks all but the uppermost layers of Saturn's atmosphere, which helps researchers discern clouds at different altitudes. In addition, when compared with images of Saturn from seasons past (1991 and 1995), this view of the planet also offers scientists a better comprehension of Saturn's seasonal changes. Adapted from the press release on http://hubblesite.org/newscenter/archive/2003/23/. Hubble Helps Rosetta
Hubble was used to precisely measure the size, shape, and rotational period of the comet. It is approximately 3x2 miles - football-shaped - different than the 6 km (3.6 miles) nucleus that mission scientists had thought. "Although 67P/C-G is roughly three times larger than the original Rosetta target, its elongated shape should make landing on its nucleus feasible, now that measures are in place to adapt the lander package to the new configuration before next year's launch," says Dr. Philippe Lamy of the Laboratoire d'Astronomie Spatiale in France. Other data determined about the comet include its rotation period of approximately 12 hours. Once it was realized that the delays in the Rosetta mission would make a rendezvous with comet 46P/Wirtanen impossible, new targets were sought. Once a list was created, mission scientists sought data from the world's largest and best telescopes to find more information about the target comets. 61 images of 67P/C-G were taken over 21 hours between March 11-12, 2003. Rosetta is set to launch in February 2004 with a rendezvous with the comet about 10 years later. Adapted from the press release on http://hubblesite.org/newscenter/archive/2003/26/. Hubble Finds Faintest Solar System Object
Now, astronomers have used the Hubble Space Telescope (HST) to discover the three faintest and smallest - roughly the size of Philadelphia - KBO's found to date. The only big surprise was how few KBO's were found. With the resolution afforded by HST, the team expected to find at least 60 KBO's, some as small as 15 km (10 miles) in diameter. "Discovering many fewer Kuiper Belt Objects than was predicted makes it difficult to understand how so many comets appear near Earth, since many comets are thought to originate in the Kuiper Belt," says Gary Bernstein of the University of Pennsylvania at a meeting of the Division of Planetary Sciences in Monterey, CA. "This is a sign that perhaps the smaller planetesimals have been shattered into dust by colliding with each other over the past few billion years." The HST Advanced Camera for Surveys was pointed at a region in the constellation Virgo over a 15-day period in January and February 2003. 10 computers worked for six months searching for fast-moving spots in the Hubble images - the tell-tale sign of a solar system object. 2003 BF91, 2003 BG91, and 2003 BH91 were the three object found, and they range in size from 25-45 km (15-28 miles) in diameter. They are a billion time fainter (29th magnitude) than the dimmest objects visible to the naked eye at their current distance. The interest in finding KBO's lies in their primordial makeup; they are thought to be the undisturbed remains of the material that formed the solar system - 4-5 billion-year-old fossils of the original building blocks of the solar system. Current theories hold that the planets and moons formed from the blocks - called planetesimals - and their gravity later ejected the left over material from the solar system or to its outer reaches. If The HST could search the entire sky, it would find about 500,000 planetesimals. that would collectively form a body a few times larger than Pluto. Adapted from the press release on http://hubblesite.org/newscenter/archive/2003/25/; preliminary results are available at http://arxiv.org/abs/astro-ph/0308467. NASA's Last "Great Observatory" Starts Imaging
The images were taken as part of a test of the infrared array camera. A full month is still needed to fully focus and fine-tune the telescope, as well as to cool it to optimal operating temperature. Therefore, these images are tantalizing treats of what's in store once the optics can be used to their full potential. "We're extremely pleased, because these first images have exceeded out expectations," said Dr. Michael Warner, the SIRTIF project scientist at NASA's Jet Propulsion Laboratory in Pasadena, CA. The dust cover was ejected on August 29 and the aperture door opened on August 30. All systems are operating normally. In addition to the infrared array camera, the multi=band imaging photometer instrument has also been successfully tested. The pointing calibration and reference sensor detected light from a star cluster. The third instrument - an infrared spectrograph - will be turned on later this month. The current in-orbit checkout is scheduled to last two months, and it will be followed by a one-month science verification phase. After that, the telescope will begin its formal operation for scientific discoveries. Adapted from the press release on http://www.nasa.gov/home/hqnews/2003/sep/HQ_03282_infrared_telescop.html. Chandra Hears a Black Hole (Added 09/10/03) For the first time, sound waves have been detected from a supermassive black hole. NASA's Chandra X-ray Observatory was able to spot this "note" - a B flat - and it is the deepest pitch ever detected by an object in the universe. The energy carried by these sound waves may now help to solve a longstanding problem in astrophysics. The black hole lies in the Perseus cluster, 250 million light-years away. Chandra was used in 2002 to view ripples in the gas filling the cluster - evidence for sound waves that have traveled hundreds of thousands of light-years from the cluster's central black hole. The B flat note is 57 octaves below middle C. It's frequency is over a million billion times deeper than the limits of human hearing; however, "these sound waves may be the key in figuring out how galaxy clusters, the largest structures in the universe, grow," said Steve Allen of the Institute of Astronomy in Cambridge, England, a co-investigator in the study. For years, astronomers have tried to understand why there is so much hot gas in galaxy clusters and so little cool gas. Hot gas should be cool and the dense, central gas should cool the fastest. The pressure in the cool central gas should fall, causing gas further out to sing towards the galaxy, forming trillions of stars along the way. Very little evidence has been found of such events, forcing astronomers to invent different ways to explain why the gas remained hot. A popular mechanism was heating by a central black hole. Jets had been observed at radio wavelengths, but their effect was unclear since the gas is visible only in x-rays. Cavities had previously been found around the central Perseus cluster black hole, but the mechanism for forming them and then heating the surrounding gas was unknown. The sound waves found by Chandra could provide the mechanism. The combined energy from 100 million supernovae is required to generate the cavities. Energy carried by the sound waves should dissipate in the cluster gas, keeping it warm and preventing cool flow. If so, the B flat would have remained roughly constant for about 2.5 billion years - a cosmic tuner. Adapted from the press release on http://www.nasa.gov/home/hqnews/2003/sep/HQ_03284_Chandra_Hears.html. Hubble Heritage Picture - September 2003 (Added 09/09/03) The Hubble Heritage Team has released September's image of NGC 3370, a spiral galaxy. 8200 light-years from us, NGC 3370 lies in the constellation Leo; this image covers approximately 3.4 arcminutes across (98,000,000 light-years). The image was originally taken in April and May of 2003, for a total exposure time of 25 hours. Nearly ten years ago, this galaxy hosted a bright exploding star. In November of 1994, the supernova's light reached Earth, briefly outshining the billions of other stars in this galaxy. Supernovae are common, occurring once every few seconds somewhere in the universe, but this one was special. Named SN 1994ae, it was one of the nearest and best observed since the advent of modern, digital detectors. It also is a type Ia supernova, meaning that astronomers have a standard model for how they occur, and thus how bright they really are, so the distances to them can be accurately determined. The more type Ia supernovae that are observed, the more the extragalactic distance scale can be refined. The importance of nearby supernovae is to correctly calibrate the scale with a closer measurement stick - cepheid variable stars. Cepheid variables are used to determine distances to more nearby objects than supernovae because cepheids are far dimmer than the stellar explosions. However, if one can observe both cepheids and a type Ia supernova in the same galaxy, then the two scales can be tested and calibrated. That is where the Hubble Space Telescope comes into play. Its new Advanced Camera for Surveys has the ability to resolve individual cepheids within NGC 3370. Observed twelve times over a month, many of these stars have been found in the galaxy - the most distant cepheids yet observed. Adapted from the information on http://heritage.stsci.edu/2003/24/index.html. Colombia Accident Investigation Board's Findings (Added 08/31/03) On August 26, the independent Columbia Accident Investigation Board released a 248-page report detailing the Board's findings as to the nature and cause of the accident that occurred on February 1, 2003, resulting in the destruction of the Space Shuttle Columbia and the seven astronauts who were aboard.
The Board determined the physical cause of the tragedy as well as organizational causes; it also posed recommendations for NASA that will help prevent future accidents from occurring.
- Stuart J. Robbins; quotes from the Columbia Accident Investigation Board's final manuscript Hubble Heritage Picture - August 2003 (Added 08/07/03) The Hubble Heritage Team has released August's image of NGC 6397, a globular cluster. 8200 light-years from us, NGC 6397 lies in the constellation Ara; this image covers approximately 2 arcminutes across (3.8 light-years). The image was originally taken March 6-7, 1996, April 3-4, 1999, and November 4, 2001, for a total exposure time of 7 hours. In this, one of the nearest globular clusters, the stellar density is about a million times larger than our local volume of space; the stars are a few light-weeks apart, whereas the closest star to the sun is over four light-years away. Estimated to be over 12 billion years, old, thousands of stellar collisions have occurred in the cluster's lifetime. The purpose of the images that were composited to make this vista was to study what is left behind from the star collisions - the "blue stragglers." Blue stragglers are so-called because of their bright blue color, which is normally characteristic of very young stars. However, due to the enormous age of the cluster, the cluster should have stopped making stars long ago, so there should not be any blue stars. Hence the term "straggler." These can be theoretically formed in one of two ways. First, two stars collide. Their combined mass and the convection caused by the collision results in a larger star that glows hot enough to be blue. The second way is that if there is a near-miss, some material may be transferred from one of the stars to the other, and the result will be the same as in the previous model. If the two stars do not collide but end up forming a binary system, a cataclysmic variable star could result. The program was specifically looking for the cataclysmic variable stars. To search for these, 55 images were taken over a period of about 20 hours. Most were taken in ultraviolet (UV) and blue filters, but some were in green and infrared (IR). Comparing the brightness of all the stars in the images, the astronomers were able to identify several cataclysmic variable stars in the cluster. A few of them are visible in the Hubble Heritage image as faint blue or violet stars. An unexpected result is from three faint blue stars near the center of the cluster (turquoise in the image). These don't vary in brightness, and they are not cataclysmic variables. They may be very low-mass white dwarfs, formed in the cores of giant stars whose evolution was interrupted before a full-fledged white dwarf was formed. Such an interruption could occur as the result of a collision or interaction. When the giant star interacts with another star, it can lose its outer layers, exposing its hot, blue core. The end result will be a white dwarf of a smaller mass than would have otherwise evolved. A large number of normal white dwarfs were also identified and studied. These stars appear throughout the cluster since they form through normal stellar evolution processes and don't involve any stellar interactions, which occur predominantly near the cluster center. Nearly 100 such burned-out stars were identified in these images, the brightest of which can be seen here as faint blue stars. Adapted from the information on http://heritage.stsci.edu/2003/21/index.html. Goodbye to Earth and Moon by Mars Express (Added 07/20/03) As the ESA's Mars Express continues on its voyage to Mars, one of the first data sets to come back is a unique picture of Earth and Moon. "It is very good news for the mission," says ESA's Mars Express Project Scientist, Agustin Chicarro. These and other data, such as spectra of Earth, are proof that the instruments on Mars Express are working perfectly.
The images of Earth and Moon were taken on July 3, 2003, by Mars Express High Resolution Stereo Camera (HRSC), when the craft was 8 million km (5 million miles) from Earth. The image is in true color, showing the Pacific Ocean and clouds. Testing will continue on the instruments up until the arrival to Mars, this December. The instruments will enormously increase our understanding of the morphology and topography of the Martian surface, past and present geological structures and processes, and eventually of Mars' geological evolution. Adapted from the press release on http://www.esa.int/export/esaCP/SEMTNOXO4HD_index_0.html. Link Between Black Holes and Galaxies (Added 07/20/03) A group of German and U.S. astronomers has been able to show the growth of supermassive black holes is closely linked with the birth of new stars in their host galaxies. The group made this discovery - the first direct evidence of a connection - by studying over 120,000 nearby galaxies observed as part of the Sloan Digital Sky Survey. The journal paper accompanying this is entitled The Host Galaxies of the Active Galactic Nuclei and was submitted to the Monthly Notices of the Royal Astronomical Society. The main question in recent years since the discovery that every large galaxy contains a central supermassive black hole has been whether the black hole controls the growth of the host, or if the host controls the growth of the black hole. By studying the spectra of more than 120,000 galaxies, the team was able to show that more than 20,000 of them contain black holes that are currently growing. These are located almost exclusively in galaxies more massive than the Milky Way. The rate of growth is inferred from the strength of characteristic emission lines known to be correlated with how much material is falling into the black hole. The team was able to conclude that as the rate of black hole growth increases, so does the amount of star formation within the past 100 million years. In the most extreme cases, the black hole is growing as fast as in bright quasars and the galaxy is dominated by young stars. This probably means that the black hole is growing by swallowing some of the supply of gas from which the stars are forming elsewhere in the galaxy. The stellar mass of the galaxies and the masses of their black holes are growing together, each necessary for the other. Adapted from the press release on http://www.sdss.org/news/releases/20030715.blackhole.html. Hubble Weighs Ancient Planet (Added 07/10/03) In one of the Milky Way's ancient globular clusters, there lies a star system consisting of a pulsar and a white dwarf trapped as a binary system. And orbiting this pair, the Hubble Space Telescope has confirmed the existence of the oldest known planet - extrasolar or otherwise - in existence. The planet is approximately 2.5 times Jupiter's mass, and it takes about 100 years to make one complete orbit about its stars. The most amazing property of it, however, is that its age is 13 billion years. This planet had formed when the universe was less than 7% its current age. The globular cluster in which the system resides, M4, is approximately 5,600 light-years away in the constellation Scorpius. Previous thinking had been that globular clusters, old and so devoid of heavy metals which had seemed necessary for planet-making, would not contain planets. This reasoning had been reinforced by the finding in 1999 of no "hot Jupiters" in the cluster 47 Tucanae. This newest finding contradicts previous reasoning, leaving the door wide open for planets to be found in great abundance in globular clusters. The pulsar, PSR B1620-26, was discovered in 1988, and spins at just under 100 times per second. The white dwarf was found quickly through its effects on the pulsar, and they orbit each other twice per year. Further irregularities in the pulsar implied a third object orbiting the stars, and the suspect was a planet, brown dwarf, or low-mass star. The debate has finally been settled by measuring the planet's actual mass. Hubble data from the mid-1990's that was taken to study white dwarfs in M4 was examined, and the team was able to measure the color and temperature of the dwarf in the system. Evolutionary models were then used to compute the dwarf's mass. The true mass lead to the system's inclination relative to Earth, and combined with radio studies of the pulsar, the planet's tilt could be determined, leading to the exact mass. At 2.5 Jupiters, it is a planet. Adapted from the press release on http://www.nasa.gov/home/hqnews/2003/jul/HQ_03234_Oldest_Planet.html. Second of NASA's Twin Mars Exploration Rovers Launches (Added 07/08/03) After two days of rain delay, the first of two rovers in NASA's Mars Exploration Rover (MER) mission launched from Cape Canaveral Air Force Station, FL, on July 7, 2003. The rover is on a seven-month mission to the red planet where it will land on January 25, 2004 (UT). Lift-off occurred aboard a Delta II launch vehicle at 23:18:15 EDT. The probe separated from the Delta II's third stage about 83 minutes after the launch, and was heard from at 00:23 EDT by the Goldstone, CA , ground-based tracking station. The rover had originally been scheduled to be launched on June 28, but poor weather conditions held back the initial launch, and the discovery of insulation de-bonding further delayed it. The second of the twin rovers in the MER project, this one is named "Opportunity." - Stuart J. Robbins Hubble Heritage Picture - July 2003 (Added 07/04/03) The Hubble Heritage Team has released July's image of LMC N 49, AKA DEM L 190, a supernova remnant. 160,000 light-years from us, the LMC N 49 lies in the constellation Dorado; this image covers approximately 1.9 arcminutes across (0.91 light-years). The image was origina |
(Added
12/19/03) 
(Added
12/10/03) A long time ago, in a galaxy far, far away, a signpost
of rapid star formation began its journey through space. Using the
National Science Foundation's Very Large Array (VLA) radio telescope,
scientists have honed in on this.
At
such high temperatures, solar plasma will shine in x-rays, and RHESSI
observed these high-energy x-rays, emitted by plasma, heated to tens
of millions of degrees in a 20-minute flare on April 15, 2002. The hot
plasma initially appeared in the RHESSI images as a blob atop an arch
of relatively cooler plasma protruding from the sun's surface. The blob-and-arch
structure is consistent with reconnection, because the x-ray blob could
be heated by reconnection, and the part of the magnetic field that breaks
and snaps back to the solar surface will assume an arch shape.
(Added
12/09/03) The elliptical galaxy NGC 4261 has some new components,
according to recent Chandra X-ray Observatory data. The data, in the
left frame of the image to the left, show dozens of bright points indicating
never-before seen 
(Added
12/06/03) The 
(Added
10/30/03) Last Thursday and Friday, the news was crawling with
stories about a 
The
two new moons are between 12-16 km (8-10 miles) - about the size of San
Francisco. They are so faint that even Voyager 2, which discovered 10
new moons of Uranus, was unable to detect them. The moons orbit closer
to Uranus than its five largest satellites, and represent the first inner
Uranian moons discovered from an Earth-based telescope in over 50 years.
(Added
09/17/03) X-rays may have a new calling - to reveal whether or
not a 
(Added
09/17/03) Our closest celestial neighbor, the 
(Added
09/10/03) In March of 2003, 
(Added
09/10/03) The ESA's 
(Added
09/10/03) Beyond the orbit of 
(Added
09/10/03) The Space Infrared Telescope Facility (SIRTIF), launched
from Cape Canaveral, FL, on August 25, has switched on two of its onboard
instruments to take preliminary images of stars.
The
astronauts aboard were Rick D. Husband - Commander, William C. McCool
- Pilot, Michael P. Anderson - Payload Commander, David M. Brown - Mission
Specialist, Kapana Chawla - Mission Specialist, Laurel Blair Salton Clark
- Mission Specialist, and Ilan Ramon - Payload Specialist and the first
Israeli in space. The original mission patch appears to the left.
The
routine check-outs of Mars Express' instruments and the Beagle-2 lander
over the last few weeks have been very successful.