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Dark Matter and Its Interactions

by Paul Gilster | Aug 28, 2008 | Deep Sky Astronomy & Telescopes | 2 Comments

Keeping our eyes open over a whole range of wavelengths makes priceless science possible. Thus the new data on dark matter, culled from observations of the galactic cluster known as MACSJ0025.4-1222. The Hubble Space Telescope offered up images in the visual light range, sufficient to provide astronomers (thanks to the effects of gravitational lensing) with a map of dark matter associated with the cluster. The Chandra X-Ray Observatory provided a balancing map of ordinary matter by showing us the distribution of hot gas in the cluster, the latter readily visible in the X-ray wavelengths Chandra works at. The result is the beautiful, if color-coded, image at the left. Here the dark matter is shown in blue, the ordinary matter in pink. The assumption is this: The two galactic clusters that formed MACSJ0025.4-1222 (each a quadrillion times the mass of the Sun) merged at titanic speeds, causing the hot gas (ordinary matter) within each to collide and slow. The dark matter, however, seems...

Fermi’s Whole-Sky Portrait

by Paul Gilster | Aug 27, 2008 | Deep Sky Astronomy & Telescopes | 8 Comments

I like the logo for the Fermi Gamma-Ray Space Telescope, shown at the right. It's appropriately stylish and, with that 'beamed' F emerging out of a galactic core, reminds us that the instrument will be opening a data window on the supermassive black holes found in such places. Fermi was until yesterday known as GLAST (Gamma-Ray Large Area Space Telescope), so the change of name moves us out of acronym territory and personalizes the instrument in favor of one of the true pioneers of high-energy physics, as well as the author of the ever intriguing Fermi paradox. We've talked about the latter in the context of the search for extraterrestrial life, wondering how Fermi's famous 'where are they?' question might be answered. But the Fermi telescope, in space for just two and a half months, is giving signs of being quite a newsmaker itself, if perhaps less controversial. The image below presents a map put together from 95 hours of observation, an all-sky view showing the glow of gas and...

Advanced Propulsion: The Next Steps

by Paul Gilster | Aug 26, 2008 | Exotic Physics | 31 Comments

by Kimberly Trent Here we depart briefly from the norm by looking at the work of Kimberly Trent, a graduate student in the Applied Physics Program at the University of Michigan. Working as an intern with Marc Millis at NASA's Glenn Research Center, Trent examined the broad issues of advanced propulsion and focused on a research topic that takes off on a Robert Forward idea from the 1960s. The goal: To develop a propulsion concept involving non-Newtonian frame-dragging effects, which Trent studies in relation to the work of Martin Tajmar. The details follow, in an article designed to show one student's involvement in the kind of studies Tau Zero hopes to encourage at other institutions. This past summer, I interned at the NASA Glenn Research Center in Cleveland, OH through the NASA Academy program. My individual research project was in theoretical spacecraft propulsion. This area involves research into devices and concepts such as space drives, warp drives, gravity control, and...

Twisting the Copernican Tail

by Paul Gilster | Aug 25, 2008 | Culture and Society | 11 Comments

The latest Carnival of Space offers several posts with an interstellar bent in addition to our own discussion, linked to from the Carnival, about antimatter rocketry and the recent thinking of JPL's Robert Frisbee. I notice that Gerald Cleaver and Richard Obousy's ideas about warp drive continue to get play, with particular reference to the amount of energy that this purely theoretical construct might demand. As with Alcubierre's own warp drive speculations, the energy levels are daunting, in Cleaver and Obousy's case the equivalent of converting the planet Jupiter into energy (that actually beats many Alcubierre demands!). Thus NextBigFuture's comment, rising naturally from this conundrum: ...it makes no sense to assume being able to convert a planetary mass into energy without having increased control of technology and information and increased economy. It is like assuming a group of cavemen get the designs for a supersonic plane but only have the economy of their tribe of six to...

Rosetta and the Language of Hope

by Paul Gilster | Aug 22, 2008 | Culture and Society | 15 Comments

There are several reasons to keep an eye on Rosetta, the European Space Agency's mission to comet 67P/Churyumov-Gerasimenko. In 2014, the spacecraft will go into orbit around the comet before deploying a lander to the nucleus. Watching changes as the comet heads toward the Sun should prove interesting indeed, but these short term effects take place within a provocative longer-term context. For aboard Rosetta is a 2.8-inch diameter disc inside a small glass sphere containing some 6000 pages of information. The subject: The languages of planet Earth, many of which will disappear before century's end. The synergy here is fascinating. The Rosetta Stone, one of the most impressive objects in the British Museum when you realize what you're looking at, contains inscriptions that include Egyptian hieroglyphics, Demotic and classical Greek. The Greek, readily understood by linguists, helped researchers unravel the meaning of the hieroglyphics, a pioneering task performed 200 years ago at the...

Star Formation Near Black Holes

by Paul Gilster | Aug 21, 2008 | Deep Sky Astronomy & Telescopes | 3 Comments

Simulations showing how giant gas clouds evolve -- clouds as large as 100,000 times the mass of the Sun -- have demonstrated that stars can form in the neighborhood of supermassive black holes, the kind of black holes found at the center of galaxies. As you would expect, the clouds are disrupted when they move close to the black hole, but only part of the cloud is captured, with the rest contributing to the formation of massive stars that move about the black hole in eccentric orbits. Usefully, the results match what we see near the center of the Milky Way. These are short-lived stars, says Ian Bonnell (St Andrews University), which in itself may be telling us something: "That the stars currently present around the Galaxy's supermassive black hole have relatively short lifetimes of ~10 million years, suggests that this process is likely to be repetitive. Such a steady supply of stars into the vicinity of the black hole, and a diet of gas directly accreted by the black hole, may...

The Interstellar Conundrum Reconsidered

by Paul Gilster | Aug 20, 2008 | Antimatter | 32 Comments

Just how hard would it be to build a true interstellar craft? I'm not talking about a spacecraft that might, in tens of thousands of years, drift past a star by happenstance, but about a true, dedicated interstellar mission. Those of you who've been following my bet with Tibor Pacher on Long Bets (now active, with terms available for scrutiny on the site) know that I think such a mission will happen, but not any time soon. And the proceedings of the Joint Propulsion Conference, held last month in Hartford, go a long way toward explaining why the problem is so difficult. Wired looked at the conference results in a just published article, the most interesting part of which contained Robert Frisbee's speculations about antimatter rocketry. Two things have been clear about antimatter for a long time. The first is that producing sufficient antimatter is a problem in and of itself, one that may keep us working with tiny amounts of the stuff for some time to come. Even so, interesting...

NanoSail-D: Duplicate Exists, Needs to Fly

by Paul Gilster | Aug 19, 2008 | Sail Concepts | 0 Comments

Remember the great scene in Contact, when the fabulously rich S. R. Hadden (John Hurt), who funded the stargate device that has been destroyed by sabotage, says "Why build one when you can build two for twice the price?" He then reveals the existence of a second facility off the coast of Japan, which is what Ellie Arroway uses on her interstellar trip. So is solar sail expert Greg Matloff a ringer for S. R. Hadden? Read on. Greg's recent phone call may not have been as dramatic as that scene in Contact, but he was able to tell me that although NanoSail-D did perish in the SpaceX Falcon explosion, there is a second sail. Marshall Space Flight Center built two. So now we're in the energizing position of having a second chance at a sail deployment in space, and it could be done soon via the next Falcon launch, if SpaceX will cooperate in the enterprise. And here's why they should: Launching a payload on the Space Shuttle costs approximately $10,000 per pound. That's pricey, and the...

An Icy Wanderer from the Oort Cloud

by Paul Gilster | Aug 18, 2008 | Outer Solar System | 8 Comments

A symposium called Sloan Digital Sky Survey:Asteroids to Cosmology, held in Chicago this past weekend, is producing interesting news, not the least of which is the discovery of a 'minor planet' that is currently inside the orbit of Neptune. 2006 SQ372 is only in the neighborhood briefly, already setting out on a journey that will take it 150 billion miles from the Sun. Its orbit is an ellipse four times longer than it is wide, not dissimilar from the dwarf world called Sedna, which was discovered in 2003. But SQ372 strays even further out and takes twice as long to complete its orbit. You'll need to click to enlarge the image below to see the details. Image (click to enlarge): The orbit of the newly discovered solar system object SQ372 (blue), in comparison to the orbits of Neptune, Pluto, and Sedna (white, green, red). The location of the Sun is marked by the yellow dot at the center. The inset panel shows an expanded view, including the orbits of Uranus, Saturn, and Jupiter inside...

On Science and Public Scrutiny

by Paul Gilster | Aug 16, 2008 | Culture and Society | 5 Comments

Hanny's Voorwerp, that odd object discovered by Dutch school teacher Hanny van Arkel via the Galaxy Zoo project, has provoked press reaction all over the world. And Chris Lintott, a key player in the Galaxy Zoo's ongoing survey of galaxies, notes the uneasiness he feels in discussing theories about the object before the paper that attempts to explain it has even gone through peer review. The speed with which the Internet allows science to be discussed can be disconcerting, as Lintott makes clear in the latest edition of the Space Carnival, conducted this week by David Chandler at his Next Generation site. Now the Galaxy Zoo is doing good science in an obviously public fashion. Anyone can sign up to participate in the classification of the images of one million galaxies drawn from the Sloan Digital Sky Survey, and that makes participating computer users scientific collaborators. Seeing this, the Galaxy Zoo blogs about its work out of a sense of obligation to its contributors, but...

‘Arabian Nights’ on Enceladus

by Paul Gilster | Aug 15, 2008 | Outer Solar System | 2 Comments

As someone who has always been interested in how we name things, the choices on Enceladus have been particularly pleasing. On the remote Saturnian moon, place names are chosen from the The Arabian Nights, which is how we wind up with Damascus Sulcus, as seen in the photo below. A sulcus is a large fracture, a 'tiger stripe,' as they're called on Enceladus. The four most prominent are named Alexandria, Cairo, Baghdad and Damascus, adding yet a further tinge of exotica to a tiny world that has already shown itself to be highly unusual. Cassini's August 11 flyby is, as the photo shows, paying off big. The intent was to focus in on sources for the jets that spew water vapor, ice and trace organics into space -- the yellow circles in the image show two particular sources of jets. What we're after, of course, is a closer look at geological activity in the sulci, in hopes of determining whether liquid water exists beneath the surface. The new details show that the fractures are some 300...

A New Look at Near Earth Asteroids

by Paul Gilster | Aug 14, 2008 | Asteroid and Comet Deflection | 3 Comments

We could do with as much information as possible about near-Earth asteroids. A manned mission is a natural step, both for investigating a class of object that could one day hit our planet, and also for continuing to develop technologies in directions that will be useful for our future infrastructure in space. You would think we would know much of what we needed from examining meteorites, which generally are chunks of asteroid material, but that assumption turns out to be erroneous. A recent paper in Nature has the story. Richard Binzel (MIT) and colleagues have been considering the properties of asteroids for a long time, looking at the spectral signatures of near-Earth asteroids and comparing them to spectra obtained from meteorites. And it turns out that most of the meteorites that fall to Earth represent types of asteroid that are different from the great bulk of near-Earth asteroids. In fact, the varied types of meteorites we find here generally resemble the mix of asteroids...

Online Research: Narrowing the Possibilities?

by Paul Gilster | Aug 13, 2008 | Culture and Society, Research Tools | 5 Comments

I want to take a momentary detour from interstellar topics to talk about how we go about doing research, astronomical and otherwise. Some years back I debated the then new trend of online peer review with an opponent who argued for the virtues of traditional print journals and their methods. At the time, what would become the arXiv pre-print site was just beginning to grow, and the benefits of having a wide audience able to examine a scientific paper before it achieved print seemed manifest. Much good research, I reasoned, would become available for scrutiny, some of it unable to get past academic referees at a specific journal but now able to be included in a broadened scientific discussion. Even so, certain trends did worry me, some of them now manifest again in a presidential report recently cited by James Evans, a University of Chicago sociologist. The report makes a jaw-dropping claim: "All citizens anywhere anytime can use any Internet-connected digital device to search all of...

Enceladus Flyby Data Streaming In

by Paul Gilster | Aug 12, 2008 | Outer Solar System | 1 Comment

Although the Cassini spacecraft has just passed no more than fifty kilometers from the surface of Saturn's moon Enceladus, the investigation of the intriguing object will only intensify in October, when Cassini moves to within half that distance. With astrobiological interest high, Enceladus is a hot place to be. Data from the most recent flyby began streaming in to the Deep Space Network station in Canberra last night, with the downlink scheduled to continue into the afternoon of the 12th (EST). The prime target, using every camera resource available and covering infrared, visible light and ultraviolet, is the area of the moon's southern pole that houses the fissures now known as 'tiger stripes.' Under intense scrutiny will be the terrain of the fissures as well as the composition of the ice grains inside, and tuning up our data on temperature should provide a better idea of whether or not liquid water lies close to the surface. Cassini will be looking for other elements -- oxygen,...

VASIMR and the Nuclear Question

by Paul Gilster | Aug 11, 2008 | Advanced Rocketry | 26 Comments

It's safe to say that Franklin Chang-Diaz knows what he's talking about when he discusses the space experience. An astronaut who has logged seven flights and over 1600 hours in space (a period that includes three spacewalks), Chang-Diaz has been making even more impressive news in recent times with his Ad Astra Rocket Company, where the VASIMR (Variable Specific Impulse Magnetoplasma Rocket) is under development. It's heartening to think of VASIMR undergoing space-based tests, a future that is now in the cards with the news that NASA has plans to test the VASIMR engine aboard the International Space Station. We naturally think long-term here, but VASIMR's uses in potential missions to Mars (Chang-Diaz talks about a 39-day trip to the planet!) and beyond will first have to be shaken out in near-Earth orbit. But ponder a VASIMR gradually becoming operational, mounting missions to communications satellites that are now economically all but unreachable. Indeed, VASIMR sets up the...

Radiation Shielding and Jupiter’s Moons

by Paul Gilster | Aug 9, 2008 | Culture and Society | 11 Comments

The latest Carnival of Space is now available at the Mars Odyssey blog, where Nancy Houser has gathered space-themed materials from the past week, many of them dealing with the question of perchlorates on Mars and the implications of that possible discovery. I'll send you straight to the Carnival for the perchlorate story, where many bloggers dissect it. My usual practice is to focus on Carnival items that connect to our theme here on Centauri Dreams -- articles about deep space starting with the outer planets and moving to regions beyond. This week the entry that fits that bill is Brian Wang's article in NextBigFuture on radiation shielding. Although Brian couches this work in the context of solutions to radiation exposure following nuclear attacks, it's also true that a drug that is 5000 times more effective at reducing the effects of radiation injury than the drugs we currently use has interesting space implications. The experimental drug, intriguingly named Nanovector Trojan...

Anomalies, Chance Finds and SETI

by Paul Gilster | Aug 8, 2008 | Astrobiology and SETI | 10 Comments

'Hanny's Voorwerp' may soon enter the astronomical lexicon as a reference to anomalous objects in deep space. 'Hanny' is Hanny van Arkel, a 25-year old Dutch school teacher and participant in the Galaxy Zoo project, where she and 150,000 other volunteers worldwide help to scan galaxy images online. 'Voorwerp' is the Dutch word for 'object,' in this case a conglomeration of gas heated to about 10,000 degrees Celsius and marked by a hole in its center. The suspicion grows that van Arkel has stumbled upon an entirely new class of astronomical object. Out of such finds does the work of a computer-armed volunteer become fodder for the Hubble Space Telescope, which will soon have 'Hanny's Voorwerp' under observation. The object is apparently being illuminated by a source we cannot see, leading the Galaxy Zoo team to look at the nearby galaxy IC 2497. The quasar at the heart of this galaxy seems to have shut down some time in the past 100,000 years -- at least, that's the theory -- while...

A ‘Rare Earth’ After All?

by Paul Gilster | Aug 7, 2008 | Exoplanetary Science | 42 Comments

A supercomputing cluster operated by a team at Northwestern University is giving us fresh simulations of the birth of planetary systems, with results that may dismay terrestrial planet hunters. For if this work is correct, the 'rare Earth' hypothesis is back, this time bolstered by computer models that are the first to simulate the formation of planetary systems all the way from earliest dust disk to full-fledged solar system. More than a hundred simulations using exoplanet data collected over the last fifteen years went into the modeling of dust, gases and the effects of gravity. Planetary systems do seem to have a few things in common, among them a violent birth. The Northwestern team found that the dynamics of the early gas disk push nascent planets inexorably toward their central star. There they may be consumed in the star or subjected to collisions with other objects as each accumulates mass. Dynamical resonances can occur that produce increasing orbital eccentricity, with...

‘Slow Life’ and its Implications

by Paul Gilster | Aug 6, 2008 | Astrobiology and SETI | 12 Comments

Imagine a form of life so unusual that we cannot figure out how it dies. That's exactly what researchers are finding beneath the floor of the sea off Peru. The microbes being studied there -- single-celled organisms called Archaea -- live in time frames that can perhaps best be described as geological. Consider: A bacterium like Escherichia Coli divides and reproduces every twenty minutes or so. But the microbes in the so-called Peruvian Margin take hundreds or thousands of years to divide. "In essence, these microbes are almost, practically dead by our normal standards," says Christopher H. House (Penn State). "They metabolize a little, but not much." House goes on to discuss what a slow metabolism may imply about environments outside our own planet. Imagine hydrothermal vents on Europa, where the energy ration may be slim. For that matter, with Phoenix still working its magic at the Martian pole, imagine subsurface aquifers on that planet whose energy resources may be just enough...

Of Solar Sails, Bets and Optimism

by Paul Gilster | Aug 5, 2008 | Culture and Society, Sail Concepts | 22 Comments

I've been surprised by the sizable reaction to my bet with Tibor Pacher, not just in terms of comments here but in related e-mails. For those of you who missed the original post, I found Tibor's prediction that the first interstellar mission would be launched by 2025 to be an irresistible target. Tibor posted the prediction on the Long Bets site, and the way this works is that someone willing to make a bet on the prediction puts down the money upfront and challenges the predictor to match it. Negotiations follow, the outcome being that if the terms are worked out and the bet is accepted, it is finalized. Both parties send in their money, and the money grows over the years in a long-term investment portfolio called the Farsight Fund. Ultimately, either the Tau Zero Foundation or (Tibor's choice) the SOS-Kinderdorf International, will enjoy the result. Now that Tibor and I have finalized the terms, the details will go up on Long Bets as soon as our funds arrive (which should be in a...

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In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For many years this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image courtesy of Marco Lorenzi).

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