The image below is striking enough that I would have run it even without the interesting story it tells about the presence of organic materials in Messier 101. Viewed at infrared wavelengths and color-coded, the Pinwheel galaxy's spiral arms are visible, as is an outer zone, marked by a coral color, in which the organic molecules called polycyclic aromatic hydrocarbons disappear. These hydrocarbons are typically found in areas of star formation, with interesting implications for the appearance of life. So what does an organic-free zone tell us about the Pinwheel galaxy? "If you were going look for life in Messier 101, you would not want to look at its edges," said Karl Gordon of the Space Telescope Science Institute in Baltimore, Md. "The organics can't survive in these regions, most likely because of high amounts of harsh radiation." Image: The Pinwheel galaxy, otherwise known as Messier 101, sports bright reddish edges in this new infrared image from NASA's Spitzer Space Telescope....

By Larry Klaes Just how dangerous a place is our universe? As Larry Klaes notes, the apparent calm of a quiet summer sky masks events that can dwarf the imagination. New instruments, particularly those in space, are now giving us an unprecedented look at stellar flares and exploding stars, allowing us to observe the earliest phases of their activity. The implications for life are also striking, as flaring red dwarfs and titanic supernova can attest. When we look up at the night sky with our eyes alone, everything about it seems calm and even peaceful. Aside from a passing airplane or satellite, only the occasional meteor or twinkling star indicate any natural activities up there. Otherwise, the Universe seems almost immobile and permanent, even when we watch the stars for a long while. Recent news by the astronomy community shows just how much of an illusion this perception actually is. On May 14, NASA announced the discovery of the youngest local supernova remnant yet known, an...

Figuring out what makes up 74 percent of the universe is no small matter. But the late 20th Century discovery that the rate of expansion of the universe is not slowing but accelerating makes the research all but imperative. The Dark Energy Survey is behind the construction of an extraordinarily sensitive camera that will be installed on the Cerro Tololo Inter-American Observatory (CTIA) 4-meter telescope in Chile, with the aim of creating an unprecedented sky survey to probe these questions. I'm looking at the original proposal for the DES survey as submitted to the National Optical Astronomy Observatory office (NOAO controls the Cerro Tololo site). The document calls the discovery of accelerated expansion 'arguably the most important discovery in cosmology since the serendipitous detection of the cosmic microwave background radiation by Penzias and Wilson in 1965' (it's hard to argue with that!). And it goes on to state the challenge posed by dark energy in stark terms: According to...

Have the laws of physics stayed the same throughout the history of the cosmos? It's an interesting question because even minute changes to physical constants could imply the existence of extra dimensions, of the sort posited by string theorists. But that's a big 'could', because despite earlier controversial findings, at least one cornerstone constant -- the ratio of a proton's mass to that of an electron -- looks to be exactly the same in a galaxy some 6 billion light years away as it is when we measure it on Earth. A study led by Michael Murphy (Swinburne University) presents the result in a recent issue of Science. The constant, known as mu, determines the value of the strong nuclear force, so it has everything to do with how atomic nuclei hold themselves together. No one can say why the mass of a proton should be 1836 times that of an electron. All we know is that it is. To be more precise, the value is 1836.15. The recently published research studied light from the quasar...

Start thinking about large telescopes on the Moon and the imagination quickly runs riot. With no atmosphere to contend with, a 50-meter instrument of the sort now under discussion would be able to dwarf what telescopes can do on Earth. Exoplanet detections would be commonplace, but that's only a beginning, for this kind of telescope could take the spectra of the planets it finds and search for biomarkers. Ponder this: Even a twenty-meter telescope would be seventy times more sensitive than Hubble, and able to detect objects 100 times fainter than what the James Webb Space Telescope will be able to see. Now think about putting two telescopes on the Moon. Space them widely to take advantage of interferometry, creating an instrument that can, in essence, act as a single collecting surface. Mixing such possibilities with current work on detecting exoplanetary oceans and continents, we would be able to move quickly from the indirect signature of planets found by radial velocity,...

The feeling I have when deciding what to discuss next about this year's American Astronomical Society meeting is like what I get in a good used bookstore. Where to turn next? We've already looked at several stories with exoplanetary significance, but the arrival of a new type of star entirely seems to vault past even these in significance. If, of course, the so-called 'quark star' is real, a question sure to remain controversial as the study of extremely bright supernovae continues. When I say bright, I'm talking about three events in particular, each of which produced one hundred times more light energy than normal supernovae. The events, designated SN2006gy, SN2005gj and SN2005ap, have been under intense scrutiny, among the researchers a team from the University of Calgary, who point to the lack of a satisfactory explanation of these events. The hypothesis they defended at AAS is that neutron stars are not the most compact solid objects known to exist. That honor belongs to still...

Following up on yesterday's post on EPOCh, the extended exoplanet mission of the Deep Impact spacecraft, I want to mention that principal investigator Drake Deming (NASA GSFC) will be in my old home town of St. Louis on June 2 as part of the 212th meeting of the American Astronomical Society. Deming will be giving an update on the search for 'super Earths' of the sort that EPOCh may be able to spot during its investigations, while David Bennett (Notre Dame) as well as Michael Liu and Trent Dupuy (University of Hawaii) will be discussing other developments related to the exoplanet hunt and the study of brown dwarfs. We'll keep an eye out for EPOCh results, particularly re GJ 436. Also of relevance to future exoplanet as well as other astronomical studies is an upcoming report by Paul Chen (Catholic University) on work at NASA Goddard on inexpensive ways to make giant telescope mirrors on the Moon. That session will take place at the AAS on June 4 under the heading 'Speculative...

If you want to understand the size of the Milky Way, you have to know something about how fast stars move. Measuring the velocities of stars in the galaxy's stellar halo -- a spherical halo of old stars and globular clusters surrounding the disk -- you can figure out the mass of the whole by examining the gravity needed to keep these stars in their orbits. The Milky Way's stars are a part of that mass, of course, but so is the extended distribution of dark matter, about which we know all too little. This is where the so-called 'blue horizontal branch' stars (BHB) come into play. These ancient objects have evolved past their red giant phase and now burn helium. Because they tend to be both distant and bright (BHB stars are generally of spectral class B or A), they make useful markers for measuring stellar velocities out to a distance of 180,000 light years from the Sun, far beyond the confines of the primary galaxy. The huge star survey called SEGUE (a part of the Sloan Digital Sky...

If the pace of discovery seems to be accelerating, that's surely because of the network of tools we're putting into place, able to work with each other both in space and on the ground to ferret out new information. Thus the collaborative effort that followed the remarkable observation of a new supernova, one caught so early in the process that it was found before visible light from the blast had begun to become apparent. We have such tools as the Swift satellite to thank for this. Its ongoing observations of a supernova in the spiral galaxy NGC 2770, ninety million light years from Earth in the constellation called the Lynx, caught a three-minute, 40 second x-ray burst from the same galaxy, another supernova in the process of happening. What Swift seems to have uncovered was the shock wave of kinetic energy heating gas in the star's outer layers to the temperatures that produce X-ray emissions. Such an event would be undetectable at optical wavelengths, which is where most supernovae...

By Larry Klaes An alternative title for Larry's new story might be "Toward a Science of Galactic Archaeology." For the vast cities of stars we see in the night sky are in a constant, if extremely long-term, process of re-shaping themselves through encounters with other galaxies, an activity whose traces in the distant past may still be detectable. In fact, astronomers hoping to learn more about such collisions may have a interesting remnant close at hand. As Larry writes, Omega Centauri offers some characteristics that set it apart from the average globular cluster, and point to a much different origin. Just days ago, the team that operates the Hubble Space Telescope (HST) released a large collection of images on the eighteenth anniversary of the astronomical instrument's deployment into Earth orbit that show dozens of galaxies doing what the team called "interactions" with each other, but which can just as easily be described as collisions. The new Hubble images show massive islands...

A tricky aspect of modern astronomy is keeping all the wavelengths straight. Take the case of G1.9+0.3, a supernova remnant (SNR) near the center of the Milky Way. If you look at an X-ray image of this object made with the Chandra satellite in 2007, you'll see clear signs of growth compared to what the Very Large Array saw in 1985. But the VLA was working at radio wavelengths, making the image comparison problematic. Scientists studying G1.9+0.3 therefore went back to the VLA to observe the object for a second time in order to verify their initial impression. The later study confirmed that this supernova remnant -- consisting of the materials ejected by the vast explosion -- really is growing at what seems to be an unprecedented pace. Fifteen percent growth in 23 years is no small matter in astronomical terms, and the growth also makes it possible to work backwards in time to arrive at the time the supernova went off, now pegged at 150 years ago. That makes G1.9+0.3 the youngest of...

With the GLAST mission near launch, keep in mind the possibilities of this unique observatory in terms of findings that could revolutionize our view of distant events. GLAST (Gamma-Ray Large Area Space Telescope) will be looking at things we've only recently learned about, such as the enigmatic gamma-ray bursts (GRBs) now flagged by the Swift satellite and quickly pinpointed for the use of Earth-based observatories. We know we're pushing into uncharted waters given that GLAST represents a major step forward over all previous satellites designed to study gamma ray events. And major new instruments usually deliver new classes of objects. Because of the increase in GLAST's sensitivity over earlier tools like the EGRET instrument on NASA's Compton Gamma-ray Observatory (CGRO), the satellite may find thousands of new point sources. And we have plenty of questions already on the table. Gamma-ray bursts, for example, may be the result of black hole mergers, or the merger of a black hole and...

It's hard enough to figure out what dark energy and dark matter are, a task that will occupy physicists for a long time to come. But even if we confine ourselves to 'normal' or 'baryonic' matter (accounting only for some four or five percent of the universe), we're still left with a problem. Baryons are heavy subatomic particles like protons and neutrons that experience the strong nuclear force, and the problem is that even these relatively familiar particles are only partially accounted for. So where is the missing baryonic matter? The answer may lie in a thin haze of hot, low-density gas that connects galactic clusters. Call it WHIM, for warm-hot intergalactic medium. Dutch and German scientists now think they have uncovered a filament of such gas that connects the clusters Abell 222 and Abell 223. The properties of the gas, visible primarily in the far ultraviolet and X-ray bands, fit with simulations in terms of density and temperature. The scientists used the XMM-Newton X-ray...

Just how different were things in the early universe? One answer comes from a study of galaxies whose light has taken eleven billion years to reach us. In this early era -- the universe would have been less than three billion years old -- researchers have found galaxies so unusually compact that they compress a galaxy's worth of stars into a space only five thousand light years across. Such objects would be able to fit into the central hub of the Milky Way. What's more, these ultra-dense galaxies may account for as much as half the number of all galaxies of their mass that existed at this time. "In the Hubble Deep Field, astronomers found that star-forming galaxies are small," said Marijn Franx of Leiden University, The Netherlands. "However, these galaxies were also very low in mass. They weigh much less than our Milky Way. Our study, which surveyed a much larger area than in the Hubble Deep Field, surprisingly shows that galaxies with the same weight as our Milky Way were also very...

Looking at the central black holes in galaxies other than our own has forced a question: What's going at Milky Way galactic central? We know there is a black hole there, and a big one, weighing in at about four million solar masses. But the Milky Way's black hole, called Sagittarius A* (pronounced 'A-star') seems quiet compared to what we see in other galaxies, emitting but a trace of the radiation they are pushing into the cosmos. A new study from a Japanese team proposes an answer. Three hundred years ago, Sgr A* put out a huge flare, making it a million times brighter than today. Today's quiet black hole may simply be the slumbering aftermath of what must have been a frenetic round of activity. "We have wondered why the Milky Way's black hole appears to be a slumbering giant," says team leader Tatsuya Inui of Kyoto University in Japan. "But now we realize that the black hole was far more active in the past. Perhaps it's just resting after a major outburst." Figuring out this...

The death of a star fifty times more massive than our Sun may well result in a hypernova, far more powerful than a supernova and, if you're in line with the concentrated beam of its energies, far more luminous. Such events are hypothesized to be associated with long-duration gamma ray bursts (GRBs). We've just had a spectacular example of an apparent hypernova/GRB combination in the form of GRB 080319B, the record-holder for brightest naked eye object ever seen from Earth. The image shows the fading light of this event as seen by the Hubble spacecraft on April 7. Bear in mind that the flash of gamma rays and other radiation was detected on March 19, at which point the GRB could be viewed at 5th magnitude in the constellation Boötes. The kicker is that a full three weeks after the explosion, the light of the galaxy in which this event originated is still drowned out by the light of the GRB. Image: The gamma ray burst GRB 080319B leaves us with an optical remnant and a puzzle. What...

By Larry Klaes One response to Fermi's famous 'Where are they?' question is to speculate on factors that might destroy incipient life forms. The recent gamma ray burst seen halfway across the universe reminds us of the powers that can be unleashed within a galaxy. Now Tau Zero journalist Larry Klaes goes to work on two galaxies 1.4 billion light years from Earth whose destinies are in some ways intertwined. Are we witnessing the possible annihilation of civilizations? Being tiny creatures who have spent our existence on and around a rather insignificant ball of rock, it is often quite difficult for humans to imagine the infinitely vaster Universe we live in. As the late author Douglas Adams once said in his famous series, The Hitchhiker's Guide to the Galaxy: "Space…is big. Really big. You just won't believe how vastly hugely mindboggingly big it is. I mean you may think it's a long way down the road to the chemist [pharmacy], but that's just peanuts to space." Not only are...

The recent news of a record-setting gamma ray burst (GRB) in a distant galaxy doesn't just raise eyebrows. It practically singes them. Occurring in the midst of a 24-hour period that saw five gamma ray bursts (a story in itself), the burst called GRB 080319B was picked up by the Swift satellite on March 19 and traced to the constellation Boötes. The afterglow brightened to magnitudes between 5 and 6, meaning that in dark locations, people with normal vision could have seen the burst remnant with the naked eye. How extreme was this burst? Ponder the implications of what Derek Fox (Pennsylvania State University) has to say: "These optical flashes from gamma-ray bursts are the most extreme such phenomena that we know of. If this burst had happened in our galaxy it would have been shining brighter than the Sun for almost a minute -- sunglasses would definitely be advised." Brighter than the Sun. All of this makes the optical afterglow of GRB 080319B 2.5 million times more luminous than...

How light travels through various media can tell us volumes. Take the phenomenon called 'extinction,' which describes what happens to light as it encounters dust and gas between the original object and our position on Earth. Studying this effect led to our earliest understanding of interstellar dust as a factor to be taken into account of when discussing the space between the stars. And because we have much to learn about what is in that space, a new observation proves useful indeed, adding to our options for the study of 'dark energy,' the mysterious repulsive force that seems to account for the accelerating expansion of the universe. Examining what they describe as a new form of carbon found within minerals in meteorites, Andrew Steele and Marc Fries (Carnegie Institution) examine the question of how these so-called 'graphite whiskers' might affect astronomical observations. The going theory is that the whiskers may have formed near the Sun early in our Solar System's life, being...