by Paul Gilster | Oct 12, 2005 | Administrative
When I began the Centauri Dreams site in August of 2004, the motivation was utilitarian. I was looking for a way to keep up with ongoing research into deep space exploration, figuring it would be helpful to establish a site that followed news day by day and maintained it in a searchable archive. Centauri Dreams the Web site actually preceded my book of the same name by several months, and it was in the back of my mind to use research collected at the site in future writing projects. That motivation still exists.
But something else happened in the intervening months. As readership grew, I found I was making new contacts in the research community, not just in the government agencies like NASA and ESA, but also in academic environments and commercial companies. Those contacts have been priceless, and have led to some fine friendships. And they’ve kept my eye on the main prize, which in my judgment is to put deep space research into the broader context of society’s awareness of time. To test and build for the long-haul, which is what interstellar work will demand, is almost unthinkable given the fast-paced nature of the modern world and its demand for quick, easy solutions.
But building for the long-haul is building for the human future, our children and our grandchildren and all those generations beyond them. Within that context, energized by a broader sense of purpose than just maintaining ready access to research materials, I began thinking of extending the site, and the limitations of my software became more and more of an issue. I also wanted to firm up features like commenting on individual entries at the same time that I extended Centauri Dreams to cover more and more research papers. All this led, after much testing, to a decision to switch to WordPress, not only because of my admiration for open-source software but also because I like the range and flexibility I was beginning to see in this lively programming project.
A Redesigned Site
What you see now is a basic WordPress setup, but one that I intend to fine-tune in terms of externals as the next few months go by. I like the easy ability to comment built into WordPress (be sure to register — it’s free — if you want to leave comments of your own). I also appreciate the more finely focused search methods, the use of categories, the easy setup with RSS for those wanting to track the site through syndication, and the fact that WordPress themes are becoming available by the hundreds. Not to mention a host of plug-ins that have brought unprecedented flexibility to basic page design.
Where are the archives? Don’t worry, they’re intact and will soon be available in their entirety here. But for various reasons, too complicated to go into now, I’ve moved only some of them over so far. The rest should be available within the next few weeks, making the search capability more and more effective at finding news events of the last fourteen months. Other features, like the list of ‘clippings’ from various news sources, will grow with time. WordPress is wonderful for extended tinkering, which is just what I intend.
Not to get too far into technicalities, but I have also been experimenting with the new WordPress theme called K2 and like it quite a bit, but its unwillingness to display properly with Internet Explorer has kept me from using it just yet (as a Firefox user, I hadn’t even noticed this problem until a friend pointed it out). But K2 is beta software, is loaded with promise, and you’ll be seeing it on this site before too long. The look will change a bit, but not overly much, though even more functionality should then be built in.
Thanks to My Readers
Let me thank the many regular readers who have contributed ideas, insights and links to good material in the months since Centauri Dreams first appeared. News on the interstellar front is happening fast, and I intend to continue covering it, from new exoplanetary discoveries to fresh ideas on antimatter containment and ongoing work on solar and beamed sail technologies. The Interstellar Flight Foundation, engaged in a slow but necessary process of ground-breaking, should start to become more visible outside the research community as we head deeper into the fall, and any events related to IFF will of course receive quick coverage here.
Centauri Dreams has, to sum it up, more or less hijacked me to become the leading focus of my work activities each day. A more satisfying focus I cannot imagine. I hope you will continue to read the site as news for comment and discussion continues to emerge. Ten years ago we learned about the first extrasolar planets ever detected. Today we have over 160, with new announcements arriving all the time as researchers tune their techniques. What a time to be alive and advocating a human future in the stars!
by Paul Gilster | Oct 12, 2005 | Astrobiology and SETI |
To make life happen you need organic molecules that contain nitrogen. Now new work at NASA’s Ames Research Center, to be reported in the October 10 issue of the Astrophysical Journal, reveals that organic molecules found throughout the galaxy do, in fact, contain nitrogen. “Our work shows a class of compounds that is critical to biochemistry is prevalent throughout the universe,” said Douglas Hudgins, an astronomer at NASA Ames and principal author of the study. The studies combined laboratory experiments and computer simulations.
We already knew, thanks to the Spitzer Space Telescope, that complex organic molecules called polycyclic aromatic hydrocarbons (PAHs) are all but ubiquitous. Learning that PAHs contain nitrogen implies that the building blocks of life are seeded everywhere in the universe. From a NASA Ames news release, quoting astrochemist and team member Louis Allamandola:
“Chlorophyll, the substance that enables photosynthesis in plants, is a good example of this class of compounds, called polycyclic aromatic nitrogen heterocycles, or PANHs. Ironically, PANHs are formed in abundance around dying stars. So even in death, the seeds of life are sewn,” Allamandola said.
You can learn much more about this research and how it proceeded from the NASA Ames site. From the analysis found there:
This is the first direct evidence for the presence of complex, prebiotically important, biogenic compounds in space and brings us a step closer to assessing if life’s origin on Earth may have had a helping hand from infalling stardust. The bulk of the astronomical evidence points to the formation of these nitrogen containing PAHs in the winds of dying stars which inject them into interstellar space. Eventually they become incorporated into the clouds of material that give birth to stars and planets. Freshly formed planets continue to collect infalling material (dust, asteroids, meteorites, and comets) from the star formation process and life on Earth is thought to have emerged from this primordial chemical soup.
A preprint of the paper is also available (PDF warning).
Image (click to enlarge): NASA Spitzer Space Telescope image of the spiral galaxy M81, located some 12 million light years from Earth. The infrared radiation emitted by polycyclic nitrogen-containing aromatic hydrocarbon (PANH) molecules is shown in red. This emission is excited by star (and planet) formation along the edges of the spiral arms. Credit: NASA Ames.
Centauri Dreams‘ take: according to the Ames researchers, more than a hundred tons of extraterrestrial materials fall to Earth every year, much of it in the form of organic compounds. Imagine how much greater the amount of such infall must have been in the era when the planets were still young and the Sun’s debris disk more congested. The primordial Earth must have been inundated with compounds now understood to be complex and significant in the formation of life. Clearly, the study of life on Earth and presumably elsewhere in the cosmos now links directly to the study of interstellar chemistry.
Does this conclusion have implications for the Fermi paradox? A recent paper in the Journal of the British Interplanetary Society discusses the ‘where are they’ question in the context of discoveries like the above. We’ll look at Deardorff, Haisch et al., “Inflation-Theory Implications for Extraterrestrial Visitation” in an upcoming entry.
by Paul Gilster | Oct 11, 2005 | Exoplanetary Science
Of the 161 planets so far detected around other stars, eight have been discovered by the transit method as they moved between that star and the line of sight to Earth. Such transits, effective as planet finders in themselves, are also useful because they allow scientists to study the properties of the atmospheres around these worlds. The first planet found by transit methods orbits the star HD 209458 and is the object of intense atmospheric study.
Can such methods be applied to transiting Earth-size planets? A new paper studies the question in terms of the kind of signatures that might be expected, and the near-term technologies that could make such detections possible. The paper focuses on terrestrial worlds orbiting K, G or F-type stars, and notes that the best targets will be K-type stars, which are in any case more abundant than the other types as well as smaller. According to the analysis, the strongest signatures in the atmosphere of such worlds could be water, ozone and carbon dioxide.
And note this conclusion, based on a model of the spectra of Earth-like worlds developed in the paper:
The presence of an atmosphere around hundreds of hypothetical ‘ocean-planets’ … could be detected with a 10-20 m telescope. The atmospheres of tens of giant exoplanet satellites … could be in the range of a 20-30 m instrument. A 30-40 m telescope would be required to probe Earth-like atmospheres around Earth-like planets …. These numbers suppose that Earth-size planets are frequent and are efficiently detected by surveys.
The paper, the first to my knowledge to examine transits of Earth-like worlds in terms of atmospheric study, is Ehrenreich, Tinetti at al., “The transmission spectrum of Earth-size transiting planets,” now available at the arXiv site, and awaiting publication in Astronomy & Astrophysics. It goes without saying that Centauri Dreams remains all but awestruck at the fact that within ten short years, we have moved from finding the first exoplanets to actually studying the atmospheres of distant worlds.
by Paul Gilster | Oct 10, 2005 | Astrobiology and SETI |
If you’re looking for a terrestrial analogue to one part of the Martian environment, you could do worse than the ice vents inside a frozen volcano on the Norwegian island of Svalbard. There, in a one million year old volcano called Sverrefjell, a team of researchers has found a community of microbes both living and fossilized. Ice-filled volcanic vents are believed to occur on Mars and may well be a potential habitat for life on the planet.
Behind the Svalbard investigations is AMASE, the Arctic Mars Analog Svalbard Expedition, which is designing devices and techniques that may one day be used by automated landers to search for life on Mars. And thus far the findings are promising. The team has been able to perform its tests while maintaining scrupulous sterility, a key factor in ensuring that ‘life’ detections on another planet aren’t simply the result of Earthly microorganisms being introduced into the local ecology.
Examining 780-million year old sedinmentary rocks, the team also found the remains of microbial structures inside, what biogeochemist and astrobiologist Marilyn Fogel (Carnegie Institution), calls “chemical markers of fossilized life.” Further good news is that AMASE’s work should be emminently adaptable to the Martian surface. “If there is similar evidence in ancient rocks on Mars,” says Fogel, “our equipment will be able to find it.”
by Paul Gilster | Oct 7, 2005 | Outer Solar System
What is that bright 300-mile wide patch on Xanadu, the continent-sized region on Titan, that Cassini noted last March? The area outshines everything else on the moon in long infrared wavelengths (it’s described as “…spectacularly bright at 5-micron wavelengths…”), and after considerable investigation does not appear to be a cloud, a mountain or a geologically active hot spot. In visible light, Cassini saw a bright arc-shaped feature of approximately the same size in late 2004 and again in 2005.
Image: Combined VIMS and ISS images of Titan’s mysterious bright red spot gives researchers more information about the feature than either single view. (Credit: NASA/JPL/University of Arizona/Space Science Institute).
That quotation above comes from a University of Arizona news release, one that goes on to note that subsequent radar imaging found no real temperature variation between the spot and the terrain around it. That rules out the possibility of an active ice volcano, and quickly eliminates the idea of a huge mountain as well (the lack of temperature drop gives this one away). And if the spot is a cloud, it’s one that hasn’t budged in three years, according to observers at the Keck Telescope and the evidence of five Cassini flybys.
“The bright spot must be a patch of surface with a composition different from anything we’ve seen yet. Titan’s surface is primarily composed of ice. It could be that something is contaminating the ice here, but what this might be is not clear,” said Jason W. Barnes, a postdoctoral researcher at UA’s Lunar and Planetary Lab.
So Titan’s surface is even more varied than previously thought. If this is indeed some kind of ice contamination, we still don’t know why it occurs here and not elsewhere. For more, see the October 7 issue of Science. The paper is Barnes, Brown, Turtle et al., “A 5-Micron-Bright Spot on Titan: Evidence for Surface Diversity,” Science 310, pp. 92-95 (2005).
