Einstein's Special Theory of Relativity remains much in the news after a weekend of speculation about the curious neutrino results at CERN. Exactly what is going on with the CERN measurements remains to be seen, but the buzz in the press has been intense as the specifics of the experiment are dissected. It will be a while before we have follow-up experiments that could conceivably replicate these results, but it's interesting to see that another aspect of Einstein's work, the General Theory of Relativity, has received a new kind of confirmation, this time on a cosmological scale. Here we're talking not about the speed of light but the way light is affected by gravitational fields. The work is out of the Niels Bohr Institute at the University of Copenhagen, where researchers say they have tested the General Theory at a scale 1022 times larger than any laboratory experiment. Radek Wojtak, an astrophysicist at the Institute, has worked with a team of colleagues to analyze measurements...

Are dozens of Type Ia supernovae waiting to happen within a few thousand light years of the Earth? New research from the Harvard-Smithsonian Center for Astrophysics suggests the answer is yes. Type Ia events are thought to occur when a white dwarf accretes material from a companion star. The idea is that the white dwarf -- a stellar remnant that is no longer capable of fusion -- eventually exceeds the so-called Chandrasekhar mass, roughly 1.4 times the mass of the Sun. When a star pushes past the limit, gravity compacts the dwarf to the point of runaway nuclear fusion, and a spectacular stellar event appears in the heavens. Type Ia supernovae are a well studied phenomenon, but a continuing problem with these events is that the scenario doesn't quite explain everything we see, or don't see. Most Type Ia supernovae show none of the hydrogen and helium near the explosion that we would expect. As this news release from the CfA notes, the gas should be there, in the form of remnant...

The idea of a planet around a pulsar is so bizarre that we often forget that three planets around the pulsar PSR B1257+12 were the first exoplanets ever detected. This pulsar is the remnant of a once massive star in the constellation Virgo that became a supernova, and the planets there -- detected by Alex Wolszczan (Penn State) -- were the first new planets discovered since the era when Clyde Tombaugh was putting the blink comparator through its paces at Lowell Observatory, an effort that led to the discovery of Pluto in 1930. And these are tiny worlds at that. A newly found fourth planet in the B1257+12 system is thought to be no more than one-fifth the mass of Pluto itself. We can find worlds like this because the beam of electromagnetic radiation pulsars emit is extraordinarily regular, making planetary signatures apparent. Now another pulsar -- PSR J1719-1438, some 4,000 light years away in the constellation Serpens (the Snake) -- is in the news because of the discovery that its...

The WISE mission has again come through, this time in the form of a discovery we've been more or less anticipating but now see confirmed. The Wide-field Infrared Survey Explorer works at infrared wavelengths ideal for spotting things we just can't find with ground-based telescopes. WISE has now turned up six Y dwarfs, stars so cool that you could set your office thermostat to match them without real discomfort. The Y dwarfs range from nine to 40 light years away. Consider them the coldest class of brown dwarfs, completely incapable of reaching the temperatures needed to induce stable fusion at the core, their light gradually fading with time. And if the line between gas giant planets and brown dwarfs was ever malleable, it's here. The atmosphere of these stars is similar to that of Jupiter, and one of them, WISE 1828+2650, now becomes the coldest brown dwarf known, its estimated atmospheric temperature something less than 25 degrees Celsius. Says WISE science team member Davy...

Although I wasn't able to do any traveling during my recent week off, I did manage to get in some backed up reading, including Iain Banks' Use of Weapons (2008), the third in his series of novels about the interstellar civilization known as 'The Culture.' I've developed quite an interest in Banks, whose novels paint a future so finely textured that the memory of it lingers like a flashback to an actual experience, an intuitive, almost mystical sense that I remember having encountered when I first read Cordwainer Smith (Paul Linebarger) many years ago (some of Jay Lake's short stories also have this effect on me). Thanks to the many Centauri Dreams readers who put me on to Banks' novels. Among the events in astrophysics that occurred during my absence, I was most struck by the discovery of vast amounts of water surrounding a black hole more than 12 billion light years away, an indication, in the words of JPL's Matt Bradford, that "water is pervasive throughout the universe, even at...

Two brown dwarfs relatively near to the Sun may be just the first such objects we'll soon identify with data from the WISE (Wide-field Infrared Survey Explorer) satellite. Ralf-Dieter Scholz (Leibniz-Institut für Astrophysik, Potsdam) and colleagues have gone to work on a search for brown dwarfs with high proper motion, looking for brown dwarfs in the immediate solar neighborhood using not just the preliminary WISE data release but the previous near-infrared (2MASS) and deep optical (SDSS) surveys. The search has already begun to pay off. The two brown dwarf discoveries -- WISE J0254+0223 and WISE J1741+2553 -- are at estimated distances of 15 and 18 light years respectively. Their strong infrared signature and their extremely faint appearance at visible wavelengths attracted the team's attention, and both show the high proper motion across the sky that flags nearby stellar objects. The team was able to use the Large Binocular Telescope (LBT) in Arizona to determine spectral type and...

A pair of white dwarf stars too close together to distinguish visually may help us in the hunt for gravitational waves, while potentially explaining a whole class of rare, relatively faint supernovae. The system in question -- called SDSS J065133.33+284423.3, or J0651 for short -- was found during a spectroscopic survey looking for extremely low mass white dwarfs. J0651 includes one white dwarf with about a quarter of the Sun's mass compacted down to Neptune-size, along with a companion white dwarf that is half the Sun's mass and about the size of the Earth. Usefully, this is a system oriented so that we can observe eclipses of each star by the other, which is how we can measure orbital parameters, masses and white dwarf radii. The General Theory of Relativity predicts that close pairs of stars produce gravitational waves that are ripples in the curvature of spacetime, and as the paper on the new work points out, the binary pulsar PSR B1913+16 has already given us indirect evidence...

The supernova called SN 1987A is a prime object for scrutiny because it gives us the chance to see the various phases of stellar death over time. And as you might guess from the fact that it was visible to the naked eye when first detected back in 1987, it's located relatively nearby, in the Large Magellanic Cloud. Working in the far-infrared, the European Space Agency's Herschel space observatory has made new discoveries about SN 1987A while studying this small galaxy's cold dust emissions. The surprise result: SN 1987A is shrouded with enormous amounts of dust, 10,000 times more than previous estimates. The dust was at a temperature of roughly minus 256 to minus 249 degrees Celsius, making it a bit colder than Pluto (minus 240 degrees Celsius). These are the first far-infrared observations of this object, showing that the dust is emitting more than 200 times the energy of the Sun. Moreover, there is enough dust here to account for 200,000 planets the size of the Earth. Thus we...

Big explosions make news, as proven by ubiquitous reports in the popular media about a distant star that wandered too close to the black hole at the center of its galaxy. The beam of energy that resulted from its destruction was composed of high-energy X-rays and gamma rays, and was unusual not only for its brightness but its duration. The event has persisted for more than ten weeks as pieces of the star fell into the black hole, with a brightness at optical and infrared wavelengths that at its peak equalled that of a hundred billion suns. How do you get a beam that bright? Evidently this one was pointed directly at our galaxy, concentrating the signature of the event into a small fraction of the sky. Andrew Levan (University of Warwick), says we saw the cataclysm only because "...our solar system happened to be looking right down the barrel of this jet of energy." The source of the event, which is now called Swift 1644+57, is at the heart of a galaxy some 3.8 billion light years...

I'm fascinated by how much the exoplanet hunt is telling us about celestial objects other than planets. The other day we looked at some of the stellar spinoffs from the Kepler mission, including the unusual pulsations of the star HD 187091, now known to be not one star but two. But the examples run well beyond Kepler. Back in 2006, a survey called the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS) used Hubble data to study 180,000 stars in the galaxy's central bulge, the object being to find 'hot Jupiters' orbiting close to their stars. But the seven-day survey also turned up 42 so-called 'blue straggler' stars in the galactic bulge, their brightness and temperature far more typical of stars younger than those around them. It's generally accepted that star formation in the central bulge has all but stopped, the giant blue stars of the region having exploded into supernovae billions of years ago. Blue stragglers are unusual because they are more luminous and bluer that...

Data from the first 57 percent of the sky surveyed by the WISE mission (Wide-Field Infrared Survey Explorer) are now available and accessible through the online archive. You can dig into the archive hunting for WISE imagery right now, as I did this morning to retrieve this Alpha Centauri image. The WISE team has put up a help page on the image data service with useful information about how to find and work with color images. The method is straightforward: You enter a name or set of coordinates for stars, nebulae or galaxies, choose the size of the image to retrieve (the defaults bring you images from each of the four WISE detectors), and select three of the four WISE bands to pull up a color image that combines their results. Play around with the help page a bit and you'll quickly become familiar with the setup, and there is further help available within the archive itself. We have much more to come from WISE, with the complete survey, including improved data processing, scheduled...

We’ve got to come up with a better name that ‘Milkomeda’ to describe what’s going to eventually happen when the Milky Way and Andromeda merge. Remember that Andromeda is one of the galaxies with a blueshift, showing that it is moving toward us. That the merger will probably happen -- in about five billion years -- appears inevitable, and it’s fascinating to speculate on the evolution of the elliptical galaxy that should result from all this. In fact, Avi Loeb (Harvard-Smithsonian Center for Astrophysics) and colleague T.J. Cox have run computer simulations showing a faint possibility that our Solar System will be pulled into a ‘tidal tail’ of orphan stars and eventually, before the final merger, wind up in the Andromeda galaxy. But after a series of close passes, the galaxies will most likely begin to intermingle. Loeb is the one behind the Milkomeda coinage, but I’ve also heard the even worse ‘Milkymeda’ and the at least acceptable ‘Andromeda Way.’ There’s plenty of time to work...

With April approaching, my thoughts turn more and more to the release of the WISE data, which should tell us a great deal about brown dwarfs and other relatively cool objects in our stellar neighborhood. The Wide-Field Infrared Explorer mission hasn't gained the media attention of a Kepler or a CoRoT because it's not specifically a planet-hunter and isn't in the business of turning up small, rocky worlds. But if you've been following our discussions here, you know how important a mission this is. We'll get a bit more than half the data WISE has generated in April, and the rest of the dataset in 2012, by which time we may be able to identify, or else lay to rest the idea of, a gas giant ('Tyche') at 15000 AU, or a brown dwarf closer than Alpha Centauri. It's at the low end of the temperature range that so much interest is focusing these days, and the fact is that until we can get a read on how common brown dwarfs are, we won't have a good idea about what kind of stars are most common...

Having a constant named after you ensures a hallowed place in astronomical history, and we can assume that Edwin Hubble would have been delighted with our continuing studies of the constant that bears his name. It was Hubble who showed that the velocity of distant galaxies as measured by their Doppler shift is proportional to their distance from the Earth. But what would the man behind the Hubble Constant have made of the 'Hubble Bubble'? It's based on the idea that our region of the cosmos is surrounded by a bubble of relatively empty space, a bubble some eight-billion light years across that helps account for our observations of the universe's expansion. The theory goes something like this: We assume that the Hubble Constant should be the same no matter where it is measured, because we make the larger assumption that our planet does not occupy a special position in the universe. But suppose that's wrong, and that the Earth is near the center of a region of extremely low density. If...

We recently looked at protoplanetary disks around the stars AB Aur and LkCa 15, new studies using adaptive optics at the Subaru telescope on Mauna Kea. Today we learn about another interesting disk, this one around the young star T Chamaeleontis (T Cha), about 350 light years from Earth in the southern constellation called the Chamaeleon. The star is a scant seven million years old and, as was the case with the Subaru studies, we've gained evidence for planet formation within the disk. The latest work, performed with the European Southern Observatory's Very Large Telescope, has delivered powerful evidence for a small companion. Brown dwarf or planet? At this point, we don't know. T Cha is a T Tauri star, meaning it is young, luminous and too cool for hydrogen fusion to operate. Instead, the star is powered by energy released as it contracts for the tens of millions of years it will take to reach the main sequence. The Very Large Telescope used adaptive optics technology and a...

As we improve our ability to look back to the early universe, the changes we see in galaxies at this period compared to later eras are striking. A new study, using data from the Hubble Space Telescope's Wide Field Planetary Camera 3 has been gathering infrared imagery back to a period as early as 480 million years after the Big Bang. What stands out in this work is the rate of star formation. In the period between 480 million to 650 million years after the Big Bang, the rate of star birth increased ten times. Garth Illingworth (UC-Santa Cruz) calls the result "...an astonishing increase in such a short period, just 1 percent of the current age of the universe." Moreover, the number of galaxies themselves showed a marked change. Says Illingworth: "We're getting back very close to the first galaxies, which we think formed around 200 to 300 million years after the Big Bang... Our previous searches had found 47 galaxies at somewhat later times when the universe was about 650 million...

Be aware of a NASA teleconference coming up at 1 PM EST (1800 UTC) today to discuss interesting Hubble data re the early universe. I'll be publishing today's entry on these findings not long after the teleconference starts. You can follow audio of the event here.

Next week I'll be reviewing Richard Panek's The 4 Percent Universe (Houghton Mifflin Harcourt, 2011), a penetrating look at our investigations of dark matter and dark energy. But plenty of information has also come out of the American Astronomical Society's 217th meeting, which ended yesterday. We looked at interesting gravitational lensing results in the previous post, pondering how they affected our census of high-redshift galaxies, but equally intriguing is a study of 14 massive galaxies that helps us map out the distribution of dark matter within them. The work was led by David Pooley (Eureka Scientific), focusing on galaxies with strong gravitational lensing characteristics. The 14 galaxies average about 6 billion light years away, and they appear almost directly in front of even more distant galaxies that each include a supermassive black hole at galactic center with associated quasar. You know from our ongoing discussions of the FOCAL mission what to expect -- light from the...

As we continue to investigate the parameters of the proposed FOCAL mission to the Sun's gravitational lens, it's worth recalling how the idea of lensing has taken hold in recent decades. Einstein noted the possibilities of such lensing as far back as 1936, but it wasn't until 1964 that Sydney Liebes (Stanford University) worked out the mathematical theory, explaining how a galaxy between the Earth and an extremely distant object like a quasar could focus the latter's light in ways that should be detectable by astronomers. And it wasn't until 1979 that Von Eshleman (also at Stanford) applied the notion to using the Sun as a focusing object. It was Eshleman who suggested sending a spacecraft to the Sun's gravitational focus at 550 AU for the first time, where magnifications, especially at microwave frequencies like the hydrogen line at 1420 MHz, are potentially enormous. This was a year after the first 'twin quasar' image caused by the gravitational field of a galaxy was identified by...

Yesterday's news conference on the Planck mission, held at the Millimeter and Submillimeter Sky in the Planck Mission Era conference in Paris, was so absorbing that I abandoned previous plans and stayed glued to the monitor most of the afternoon, replaying particular points from the various presenters (although keeping an eye on AAS happenings via Twitter as well). The video is available here, and it's well worth a look given Planck's interesting results so far, and the rich study of the Cosmic Microwave Background that will eventually flow from its data. The European Space Agency has been offering broad coverage of the Planck findings, but before you check these out, bear in mind that the primary mission of the spacecraft is to measure the fluctuations in the CMB that both COBE and, to a higher level of detail, WMAP observed. It was fun to watch the sparring between the assembled Planck team and journalists at the conference when the question of data release came up. We won't have...