A 'defect' in spacetime may be one of the most curious findings of the data collected from the Wilkinson Anisotropy Probe. What WMAP gave us is the earliest image of the cosmos we have in our repertoire, showing temperature changes across the microwave background thought to be the aftereffect of the Big Bang. When Marcos Cruz (Instituto de Fisica de Cantabria) and colleagues found a cold spot in the data, they launched an investigation to determine what in heaven could be causing it. A random fluctuation in the data? Possibly, but the Spanish and British team studying the cold spot think the odds on that are only about one percent. A cosmic defect would be quite a find, evidence of exotic phase transitions in the infant universe involving the breaking of symmetry between particles. A cooling universe would see a phase transition when quarks, for example, became distinct from electrons and neutrinos. A homely analogy is to a kitchen freezer, where the defects in ice cubes show how...

The massive galaxy M87, the central object of the Virgo cluster, has drawn our attention for a long time. It was in 1918 that Heber Curtis discovered a jet pushing at least 5000 light years away from the center of the galaxy. In 1949, the radio source Virgo A was identified with M87, and by the 1960s it was believed that the jet was actually two sided, its one-sided appearance due to relativistic Doppler beaming, which increased the luminosity of the jet in the direction of the observer. That latter point was confirmed by recent observations using the Very Long Baseline Array (VLBA), with a resulting image showing detail down to a resolution of one milli-arcsecond. Some fifty times better than what Hubble can manage at optical wavelengths, the radio image (seen below in false color) shows the faint counter-jet structure that had been posited by the Russian astrophysicist Iosif Shklovsky. The latter noted that the jet liberated as much energy as the explosion of ten million...

What we know about gamma-ray bursts is dwarfed by what we don't, but chipping away at the problem is getting us places, particularly with the help of amateur astronomers. Thus the news that Finnish amateur Arto Oksanen had found the optical afterglow of GRB 071010B, a gamma-ray burst detected by NASA's Swift satellite. Oksanen did his work with a 40-centimeter telescope at the Hankasalmi Observatory in Finland. This is the kind of discovery that would have been all but impossible until recently, relying as it does not only on the Swift satellite's detection capabilities but also on immediate notification of Earth-based observers over the Internet. Remember: Gamma-ray bursts last anywhere from a few milliseconds to a few hundred seconds, and even though they seem to occur once a day, aligning the Swift data with an optical afterglow means looking just as soon as the notification comes in. Is luck involved? You would think so, and Oksanen agrees: ...you have to be very lucky (and...

Following up on our recent discussion of interstellar distances and how they are determined comes word of a reassessment of the distance to the Orion Nebula. The star forming region is famous not only for its beauty but for the opportunity it gives us to assess young stars as they emerge from the interstellar gases around them. Their distance tells us something about their intrinsic brightness and thus their ages. The change in distance revealed in the new studies is considerable. Whereas the previous best estimate to the Nebula was 1565 light years, the new one, drawn with an uncertainty of six percent, is 1270 light years, a twenty percent adjustment. The Very Long Baseline Array was behind this work, using familiar parallax methods to observe a star called GMR A from opposite sides of Earth's orbit. "This measurement is four times more precise than previous distance estimates," says Geoff Bower (UC-Berkeley). "Because our measurement reduces the distance to this region, it tells...

From the Cape of Good Hope, Alpha Centauri is a beacon in the sky, the third brightest star after Sirius and Canopus. The combined light of Centauri A and B (and Proxima as well, though at 11th magnitude, its contribution is minimal) caught the eye of Scottish lawyer Thomas Henderson, who in the course of a varied career found himself director of the Royal Observatory in South Africa. Cursed with poor eyesight, Henderson fixed on a mathematical approach to astronomy and chose to subject the Centauri stars to distance measurements, observing the system from both sides of Earth's orbit to look for apparent motion. And find it he did, a movement of three quarters of a second of arc that, using some basic math, gave him a distance of 41 trillion kilometers. This stellar parallax method has since been used on countless stars, but it's really suitable only within 200 light years or so. Which is why older astronomy texts show such variation in stellar distances. One estimate of the distance...

An odd radio burst that seems to signal a previously undiscovered astrophysical phenomenon is now on the scene. Culled out of archival data gathered from the Parkes radio telescope in Australia, the burst may signal something exotic indeed, the last stages of the evaporation of a black hole. Another candidate: A collision between two neutron stars. And while the data in question come from a survey that included 480 hours of observation of the Magellanic Clouds, some 200,000 light years from Earth, the phenomenon they've uncovered is far more distant. Drawing the attention of astronomers was the fact that no radio burst yet found shows the same characteristics. Despite its strength, the signal lasted less than five milliseconds. Dispersion effects caused by its passage through ionized gas in deep space caused higher frequencies to arrive at the telescope before lower frequencies. Image: Visible-light (negative greyscale) and radio (contours) image of Small Magellanic Cloud and area...

By Larry Klaes Tau Zero journalist Larry Klaes here offers a look at a revolutionary telescope that will soon take our vision of the universe into new domains. In the early half of the next decade, an instrument called the Cornell Caltech Atacama Telescope (CCAT) is planned to examine the Universe through a less-studied region of the electromagnetic spectrum from an observatory in the remote deserts of Chile higher than any current major ground-based facility. CCAT is the culmination of plans by Cornell University and the California Institute of Technology (Caltech) initiated in 2004 to jointly conduct submillimeter astronomy with the largest telescope ever conceived for such an endeavor. The 25-meter (82-foot) wide mirror of the CCAT will allow astronomers to see the Cosmos in the area between the infrared and radio realms of the electromagnetic spectrum, an area well beyond the region that is visible to human eyes. The moisture in Earth's atmosphere normally blocks light waves...

Speaking of absorbing views from a planetary surface, as we've been doing recently when discussing the Magellanic Clouds and what an observer there might see of the Milky Way, consider a much darker scenario. A galaxy called ESO 137-001 is in headlong flight toward the center of the galactic cluster Abell 3627. It is leaving in its wake a trail of gas that extends for more than 200,000 light years and is forming stars. Bear in mind that the Milky Way itself is 100,000 light years across and you'll get an idea of the magnitude of this tail, which Michigan State's Ming Sun calls one of the longest of its kind his team has ever seen. Millions of stars have now come to life in the tail, apparently forming within the last ten million years. Adding to optical studies are Chandra X-ray data that show additional regions thought to be star-bearing. Give these stars a few billion years to produce planets bearing intelligent life and you have a civilization coming into its own with skies that...

Centauri Dreams has always been captivated with the Magellanic Clouds, two galaxies that are the Milky Way's nearest neighbors in space. The fascination is in many respects visual. Knowing that they're a beautiful sight to those below the equator, the counter-thought came quickly to mind -- what would the Milky Way look like from one of these small satellite galaxies? How bright would it be, how much of the sky would it fill? While pondering such questions, have a look at the Large Magellanic Cloud below, and be sure to click to enlarge this gorgeous image. Pondering such things, I wrote a story called "Magellanic," a sort of Weird Tales-era fantasy (I realize that Weird Tales still exists, but I refer to the fabled issues of the 20's and 30's). Mixing in a first contact scenario in 1920's Tibet, a mountain-climbing adventurer at the end of his career, a bit of intelligence agency intrigue and throwing in Edwin Hubble for good measure, I thought I had a winner, but the story remained...

Considering that we can't see dark matter and have little idea what it is, the notion that we could take its temperature seems preposterous. But new work out of Durham University (UK) points to a way of using visible astronomical sources to draw conclusions about dark matter's effects in the early universe. Using computer simulations to examine the formation of the first stars, the researchers have applied 'cold' and 'warm' dark matter models, noting the effects we might expect to see today. These, in turn, should tell us something about how dark matter operates. Cold, or slow-moving dark matter particles have a particular signature. After the first 100 million years of expansion, dark and more or less uniform, the universe would have begun to witness the birth of structure as dark matter's gravity drew hydrogen, helium and lithium into the condensations that produced the first stars. In this model, the cold dark matter, clumping into spherical structures, would have produced stars...

Following up on yesterday's news about spectrometer advances at the Automated Planet Finder installation at Lick Observatory comes news of a different kind of telescope breakthrough. A radio telescope in Shanghai was linked via computer network to a five telescopes in Europe and another in Australia to study the active galaxy 3C273. A galaxy with a major black hole at its core is obviously interesting, but what stands out in the recent experiment is the working procedure. Never has very long baseline interferometry been pushed to such extremes. Image: Widely spaced telescopes combine their data to boost resolution, creating a kind of 'world telescope.' Credit: Paul Boven/JIVE. Satellite image: Blue Marble Next Generation, courtesy of NASA Visible Earth (visibleearth.nasa.gov). The idea of interferometry is straightforward: Combine signals from multiple telescopes to produce higher resolution data than could be obtained by any of the telescopes individually. Spread your telescopes out...

A Class 0 protostar is a star so young that the bulk of its light is emitted at long infrared wavelengths, blocked from Earth-based observatories by our atmosphere. It takes space-borne platforms like the Spitzer Space Telescope to make sense out of these objects, hundreds of which have now been identified, though few studied with the precision of the one designated IRAS 4B. There, signs abound of a region within the protostellar envelope that is warmer and denser than the material around it. Located about a thousand light years from Earth in the nebula NGC 1333, the infant star presents an interesting signature to Spitzer's infrared spectrograph. Out of thirty protostars examined by University of Rochester astronomers, IRAS 4B is the only one to show the infrared spectrum of water vapor, a fact understood to mean that material is falling from the protostar's envelope onto the surrounding, denser disk. As the ice hits the protoplanetary disk, it heats rapidly and emits its...

A vast, empty region in Eridanus may be giving us hints about the operation of dark energy in the distant universe. The region shows up on the Wilkinson Microwave Anisotropy Probe's map of the cosmic microwave background (CMB) radiation. The remnant of the Big Bang, the faint radio waves of the CMB provide the earliest picture we have of the cosmos. What the WMAP displayed to us was a view of its structure at a time just a few hundred thousand years after the Big Bang. The Eridanus region stands out on the WMAP data because it's slightly colder, and I do mean 'slightly' -- we're talking about temperature differences in the area of millionths of a degree. Two possibilities thus arise: The cold spot could be intrinsic to the CMB itself, a structural anomaly in the early universe. Or it could indicate something through which the CMB radiation had to pass on its way to our detectors. Now a study using data from the National Radio Astronomy Observatory VLA Sky Survey offers a possible...

A long-time old movie buff, I am delighted with the choice of name for a recently discovered neutron star that may be the closest such object to Earth. It's being called Calvera, after the bandit played so brilliantly by Eli Wallach in the 1960 western The Magnificent Seven. In astronomical terms, the 'Magnificent Seven' are the seven isolated neutron stars -- neutron stars with no associated binary companion, supernova remnant or radio pulsations -- known until the discovery of Calvera, which brings the number to eight. Co-discoverer Derek Fox (Penn State) calls the choice of names "...a bit of an inside joke on our part." And indeed, Calvera started life with a far less interesting name. The German-American ROSAT satellite (named after x-ray discoverer Wilhelm Röntgen) had compiled 18,000 x-ray sources. Comparing these with catalogs of visible, infrared and radio objects, Robert Rutledge (McGill University) discovered that the source known as 1RXS J141256.0+792204 had no known...

GALEX -- the Galaxy Evolution Explorer -- was an interesting mission to begin with, a space-based observatory conducting an all-sky survey of distant galaxies at ultraviolet wavelengths. Now it's come up with a real newsmaker, a star moving at an unusually fast 130 kilometers a second and sporting a comet-like tail. The material blowing off the red giant Mira is, in fact, forming a wake some thirteen light years long. No such phenomenon has ever been seen around a star before. Image: Mira appears as a small white dot in the bulb-shaped structure at right, and is moving from left to right in this view. The shed material can be seen in light blue. The dots in the picture are stars and distant galaxies. The large blue dot at left is a star that is closer to us than Mira. Credit: NASA/JPL-Caltech. From what GALEX is telling us, the elements Mira is leaving behind, including carbon, oxygen and other building blocks for future star and planet formation, have been shed over a period of...

Could it be that vast magnetic structures filling as much as ten percent of the universe have remained all but invisible to us until now? That's the startling possibility raised by Gregory Benford (UC-Irvine) and Raymond Protheroe (University of Adelaide) in a new paper describing a possible source for ultra-high energy cosmic rays. They're looking at the remnants of jets that can be found in active galactic nuclei (AGN), and suggesting that even after these jets have turned off, a fossil structure may remain that is stable for billions of years. What exactly is the remnant of a jet? Here's the notion as explained in the authors' upcoming paper: Remnants of jets and their surrounding cocoons may persist long after their parent AGN fade from view. These colossal MHD structures decay slowly and yet may retain their relatively stable self-organized con?gurations. Decay depends on the structure circuit resistance, and lifetimes could be quite long, given the large inductance of the...

A research team using data from the Chandra x-ray observatory has examined supermassive black hole activity in galaxy clusters of different ages. Also known as active galactic nuclei (AGN), the black holes are the result of rapid growth in gas-rich environments in the early universe, explaining why they are more common in young clusters than in older ones. Comparing the fraction of AGN in clusters at large distance (when the universe was 58 percent of its current age) to relatively nearby clusters, the team found 20 times more AGN in the more distant sample. Paul Martini (Ohio State University) sees this as confirmation of earlier theory: "It's been predicted that there would be fast-track black holes in clusters, but we never had good evidence until now. This can help solve a couple of mysteries about galaxy clusters." Mysteries such as why the number of blue, star-forming galaxies seems to diminish as we move to nearer, older galactic clusters. The process would seem to involve...

We're so used to thinking of our Sun as a solitary object that having two Suns in the sky inspires the imagination of artist and writer alike. But what about whole clusters of stars? Evidence is mounting that the Sun was actually born in such a cluster. That's quite a jump from the era, not so long ago, when astronomers assumed stars like ours formed without companions, but cosmochemists like the wonderfully named Martin Bizzarro (University of Copenhagen) think they have the data to prove it. So here's the new notion: Most single stars like the Sun evolve in multiple systems, clusters of stars that also contain massive stars that burn their hydrogen and explode while the cluster is still producing young stars. If this is the case, then we should expect the early history of the surviving younger stars to be affected by the nearby fireworks. Bizzarro's team studied short-lived isotopes like aluminum-26 (26Al) and iron-60 (60Fe) as found in meteorites to see whether stellar debris from...

Among the numerous problems in actually imaging an exoplanet is the fact that telescopes produce artifacts that can mask the faint planetary signature. Light diffracts as it passes through the aperture of an optical telescope, causing a series of concentric rings to surround the observed star. This effect, known as an Airy pattern, has a bright disk at center whose size determines how small an object the telescope can see. But there are always ways of making a virtue of necessity. A team led by Niranjan Thatte (Oxford University) and Laird Close (University of Arizona) have developed a technique that effectively uses the artifacts produced by diffraction to determine the position of a dim stellar companion and retrieve its spectrum. The idea is that when the wavelength of light being studied is changed, the telescope artifacts can be seen to shift position, while the actual object around the star will not move. Here's how an ESO news release puts the matter: So if the image has an...

Putting an enormous radio telescope on the far side of the Moon has so many advantages that it's hard to imagine not doing it, once our technology makes such ventures possible. Whatever the time frame, imagine an attentuation of radio noise from Earth many orders of magnitude over what is possible anywhere on the near side, much less on Earth itself. In a recent telephone conversation, I discussed these matters with Italian space scientist Claudio Maccone, whose work on a mission to the Sun's gravity focus we've examined in these pages before. Having just completed a week at Rutgers attending its Symposium on Lunar Settlements, Maccone anticipates the publication of his new paper on the lunar far side and its scientific potential -- I'll have to put off the specifics of those interesting ideas until the paper actually appears. But do ponder the implications of a radio observatory conceivably able to probe extrasolar planets. As a news item in New Scientist explains: The interaction...