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SETI: Let the Search Continue

by Paul Gilster | Sep 2, 2011 | Astrobiology and SETI | 125 Comments

Most people think that SETI is worth doing, whether or not they actually believe there are other technological civilizations in the galaxy. Ben Zuckerman, a professor of astronomy at UCLA, is certainly in the skeptics' camp, thinking there are no technological ETs in the Milky Way, but he's quoted in this story from QUEST (KQED San Francisco) as calling for more SETI. "Given that the costs are not very high," says Zuckerman, "why not continue the search?" Zuckerman, who once worked with Carl Sagan in graduate school, no longer thinks we live in a crowded galaxy, but a potential discovery of this magnitude justifies the relatively modest expenditure. It's not surprising to find Jill Tarter echoing Zuckerman. The recent funding problems of the Allen Telescope Array have not daunted the woman who more than anyone else has come to represent the search for other intelligent life. And although she believes we may one day come to the 'extraordinary conclusion' that we really are alone, the...

Three Views from Outside

by Paul Gilster | Sep 1, 2011 | Culture and Society | 5 Comments

The key to a sane life is perspective. Or at least that's how I feel when I see an image like the famous Apollo 8 shot of a gorgeous blue Earth rising over the barren, cratered Moon. Great images of the kind the space program deals up can change how we see everything -- the Apollo 8 image is widely thought to have energized environmental and ecological thinking in its day. We also have a few striking images showing both the Earth and the Moon together. The one I always fall back on is the one below, a barren Moon with a living Earth swimming in black space. It was a departing gift from the Galileo spacecraft as it left on its long journey to Jupiter in 1989. Image: On its way to Jupiter, the Galileo spacecraft looked back and captured this remarkable view of Earth and the moon. The image was taken from a distance of about 3.9 million miles. The brightly colored Earth contrasts strongly with the moon, which reflects only about a third as much sunlight as Earth. Contrast and color have...

Colonizing the Galaxy Using World Ships

by Paul Gilster | Aug 31, 2011 | Missions | 38 Comments

The British Interplanetary Society's Kelvin Long is no stranger to these pages, perhaps best known as the founder and first leader of Project Icarus, but an indefatigable writer on interstellar topics as well. Kelvin's first book, Deep Space Propulsion: A Roadmap to Interstellar Flight, is scheduled for publication by Springer later this year. Fellow writer Pat Galea has a background in electronic engineering and physics, and has been a professional software engineer since 1993. As well as contributing to the Project Icarus starship design, he is a supporter of Monkey World in the UK, and a staunch advocate for preserving Bletchley Park, home of World War 2 code breaking. Both Long and Galea are Tau Zero practitioners as well. The duo here offer us an overview of a symposium Kelvin recently organized in London that as far as I know was a first: A conference entirely devoted to the breathtaking concept of interstellar colony craft potentially hundreds of kilometers long. by Kelvin F....

Entering the Age of Sail

by Paul Gilster | Aug 30, 2011 | Sail Concepts | 4 Comments

I see that the new agenda for the 100 Year Starship Study symposium has now been posted. The meeting will be held in Orlando in about a month, set up along a number of parallel tracks from interstellar destinations to propulsion options and habitats, a wide-ranging set of sessions that will allow many in the far-flung interstellar community to exchange ideas in person for the first time. DARPA's intention is to spur research and select an organization that will sustain and develop interstellar ideas over the next century, an exciting long-term prospect indeed. That interstellar flight demands long-term thinking should be obvious given the state of propulsion research today. Over the last sixty years, numerous ideas on how to drive a vehicle to a substantial percentage of the speed of light have been advanced, but almost all of these remain no more than concepts in journals. We're not remotely at the stage where we can choose a single option as the likely propulsion choice for...

Cassini’s Latest from Hyperion

by Paul Gilster | Aug 29, 2011 | Outer Solar System | 9 Comments

We can thank the British astronomer John Herschel (1792-1871) for giving the moons of Saturn their classical theme, resulting in the familiar names Mimas, Dione, Enceladus, Tethys, Titan, Rhea, and Iapetus for the seven moons known to him when he wrote his Results of Astronomical Observations Made at the Royal Observatory, Cape of Good Hope (1847). It was a natural, then, that the moon discovered shortly thereafter would get a name like Hyperion (although it wasn't Herschel but merchant and astronomer Willam Lassell who suggested the name). Hyperion was an elder brother of Cronos (Saturn), and was associated with watchfulness and observation. Only recently have we discovered just how unusual Hyperion turns out to be, as the unprocessed image from the Cassini mission below clearly demonstrates. Its shape is irregular, indicating it may be the remnant of a larger body broken by some ancient impact. Its low density indicates large amounts of water ice mixing with small amounts of rock....

In the Sky with Diamonds

by Paul Gilster | Aug 26, 2011 | Deep Sky Astronomy & Telescopes | 43 Comments

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...

WISE: Coolest Brown Dwarfs Yet

by Paul Gilster | Aug 25, 2011 | Deep Sky Astronomy & Telescopes | 37 Comments

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...

Changing Face of an Icy Dwarf

by Paul Gilster | Aug 24, 2011 | Outer Solar System | 4 Comments

2007 OR10 is an innocuous enough designation (discoverer Mike Brown calls it 'an official license plate number' based on date of discovery), but 'Snow White' isn't. The dwarf planet that acquired the latter monniker from Caltech astronomer and KBO-hunter Brown seemed to deserve its name because at the time, Brown thought it was an icy chunk that had broken off from the dwarf planet Haumea. Ice in the outer system is almost always white, and that's what you would expect on a world called 'Snow White.' But recent spectral analysis has revealed that while 'Snow White' is indeed covered in water ice, it's not white at all. In fact, it is one of the reddest objects in the Solar System, about half the size of Pluto in its orbit at system's edge. What to make of this? It turns out that another dwarf planet fits the same characteristics, in being both red and covered with water ice. Although a bit smaller than Snow White, Quaoar is thought to have had an atmosphere and to have once been...

HARPS: Hunting for Nearby Earth-like Planets

by Paul Gilster | Aug 23, 2011 | Exoplanetary Science, Uncategorized | 19 Comments

Ever more refined radial velocity searches for exoplanets are reaching into the domain of lower and lower mass targets. It's natural enough that we're most interested in planets of Earth mass and even smaller, but as a new paper on the work of the European Southern Observatory's HARPS instrument reminds us, one of the great values of this work is that we're getting a broad view of how exoplanets form and evolve in their systems, no matter what their size. Characterizing not just planets but entire systems is becoming a profitable investigation. But small worlds continue to fascinate us, particularly in the hopes of finding possible abodes for life. HARPS' involvement in the hunt now includes an intense campaign to monitor ten stars that are relatively near our Sun, all of them slowly rotating and quiet solar-type stars. Mounted on ESO's 3.6-meter instrument at La Silla Observatory in Chile, HARPS (High Accuracy Radial Velocity Planet Searcher) has produced more than 100 exoplanet...

Catching Up with New Horizons

by Paul Gilster | Aug 22, 2011 | Outer Solar System | 11 Comments

New Horizons continues on its inexorable way to Pluto/Charon, now some 21 AU out, which places it between the orbits of Uranus and Neptune. The latest report from principal investigator Alan Stern tells us that the 2011 checkout of the spacecraft was completed on July 1, a two-month process that included a test of the REX radio occultation experiment, coordinating with the Deep Space Network as the Moon interrupted a radio signal from Earth. According to Stern, spacecraft tracking over May and June shows New Horizons on a 'perfect course' toward the distant world, one that will demand no course correction until, at the earliest, 2013. I wanted to bring Stern's report into play here because of the image below, which shows Pluto's newly discovered moon P4 along with the other moons now known in the system. The fact that I hadn't yet run it told me that it was time to do some catching up with this impressive mission. Image: These two images, taken about a week apart by NASA's Hubble...

The Times and the Starship

by Paul Gilster | Aug 19, 2011 | Culture and Society | 14 Comments

Why think seriously about mounting an effort to reach the stars? In yesterday's New York Times, Dennis Overbye runs through some of the basic drivers: The discovery of a habitable planet around a nearby star would create intense interest in sending a probe or, depending on how technology develops, mounting an expedition The demands of human nature include a basic restlessness that has always impelled us to explore The danger of a future impact from an asteroid or other space debris will force us to think not only about how to mitigate the threat, but also about a 'backup' plan for humanity The article is worth looking at for the gorgeous Adrian Mann illustration alone -- it shows a future starship on a 'shakeout' cruise near Jupiter. Overbye then goes on to discuss the 100 Year Starship Study and its upcoming symposium, with plentiful references to Project Icarus and the Tau Zero Foundation. It's good to see the press continuing to focus on the real goals of the 100 Year Starship...

On Habitable Worlds and Their Moons

by Paul Gilster | Aug 18, 2011 | Exoplanetary Science | 37 Comments

One of the problems with building a backlog of stories is that items occasionally get pushed farther back in the rotation than I had intended. Such is the case with an article in Astrobiology Magazine that talks about how much of a factor a large moon may be in making a planet habitable (thanks to Mark Wakely for passing the link along). It's an interesting question because some have argued that without our own Moon, the tilt of the Earth's axis, its 'obliquity,' would move over time from zero degrees to 85 degrees, a massive swing that would take the Sun from a position over the equator to one where it would shine almost directly over one of the poles. The resulting climate changes would be severe, potentially affecting the development of life. The thinking is that just as the direction of the tilt of a planet varies with time -- astronomers say that it 'precesses' -- so does the orbital plane of the planet. The gravity of a large moon like ours affords a stabilizing effect by...

Worldships: A Interview with Greg Matloff

by Paul Gilster | Aug 17, 2011 | Missions | 39 Comments

The first conference devoted solely to worldships takes place today in London at the headquarters of the British Interplanetary Society. It seemed a good time to check in with Gregory Matloff, a man I described when writing Centauri Dreams (the book) as the 'renaissance man of interstellar studies.' Perhaps best known for his continuing work on solar sails, Matloff's interests have nonetheless ranged widely. He brought deep space propulsion to a wide audience in his book The Starflight Handbook (1989), which covers the full spectrum of interstellar options, but for over three decades has continued to produce scientific papers investigating issues ranging from laser ramjets to beamed microwave missions. A recent interest has been the expansion of the human biosphere into space, as discussed in books like Paradise Regained: The Regreening of Earth (Springer, 2009) and the soon to be published Biosphere Extension: Solar System Resources for the Earth, written with C Bangs. These last...

Report on the 2011 Mars Society Annual Convention

by Paul Gilster | Aug 16, 2011 | Missions | 10 Comments

by Richard Obousy After a stint as project leader for the Project Icarus starship design study, Richard Obousy now serves as Module Lead Primary Propulsion for the effort. Dr. Obousy's doctoral work at Baylor University focused on the possibility that dark energy could be an artifact of Casimir energy in extra dimensions. For Icarus, he has pivoted to the study of fusion propulsion systems for this ongoing reworking of the original Project Daedalus concept. He's also fascinated with the possibilities of getting off our planet more easily and establishing a human presence on Mars, all ideas he was able to explore at the Mars Society's latest meeting, from which this report. As a native of Texas, living only a couple of hours drive from Dallas, I was thrilled to discover that that was where the Mars Society planned to hold its 14th International Mars Society Convention. This was a perfect opportunity for me to meet space enthusiasts, to present to this community some of the ideas...

Heinlein and the 100 Year Starship Study

by Paul Gilster | Aug 15, 2011 | Missions | 20 Comments

Anyone who looks back on Robert Heinlein's 'juvenile' novels, twelve books written for young adults between 1947 and 1958, as inspiration for his current work gets my attention. I loved every one of those novels, particularly Citizen of the Galaxy (1957) and Starman Jones (1953), but David Neyland says it was Time for the Stars (1956) that got him thinking about the 100 Year Starship Study. If you've been keeping up with Centauri Dreams, you know that the Defense Advanced Research Projects Agency (DARPA), which handles cutting-edge research and development for the US military, is putting on a starship symposium this fall in Orlando, FL. This follows up on the earlier DARPA Request for Information and will lead to the award of $500,000 or so in seed money to an organization that can best pursue the study's goals. Neyland, who is director of DARPA's Tactical Technology Office, has been explaining what the study is all about to newspapers like the Los Angeles Times, which ran a story on...

Studying the Darkest World

by Paul Gilster | Aug 12, 2011 | Exoplanetary Science | 7 Comments

A planet orbiting the star GSC 03549-02811, about 750 light years away in direction of the constellation Draco, is showing us a new way of extracting information about a distant system. The planet is a gas giant called TrES-2b, discovered by the Trans-Atlantic Exoplanet Survey in 2006. Studying the star using data from Kepler observations over a span of 50 orbits, David Kipping (Harvard-Smithsonian Center for Astrophysics) and David Spiegel (Princeton University) have detected the faint brightness variations caused by planetary phase changes during its orbits. The light from the planet dims and brightens as it moves through its phases around the star. "In other words, Kepler was able to directly detect visible light coming from the planet itself," says Kipping, and what we've learned is that TrES-2b is remarkably dark, reflecting less than one percent of the sunlight falling on it. The planet is blacker than any moon or planet in our solar system, as black as coal, or in Kipping's...

New Evidence for Life’s Precursors in Space

by Paul Gilster | Aug 11, 2011 | Astrobiology and SETI | 14 Comments

Is there a 'goldilocks' class of meteorite, one in which we can say that conditions were just right for producing the stuff of life? That's one of the conclusions scientists at NASA's Goddard Space Flight Center are reaching by studying samples taken from twelve carbon-rich meteorites, nine of them recovered from Antarctica. Their evidence shows that some of the building blocks of DNA, which carries the genetic blueprint for life, were most likely created in space before falling to Earth through meteorite and comet impacts. Thus we move closer to answering a key question: "People have been discovering components of DNA in meteorites since the 1960's, but researchers were unsure whether they were really created in space or if instead they came from contamination by terrestrial life," said Dr. Michael Callahan of NASA's Goddard Space Flight Center, Greenbelt, Md. "For the first time, we have three lines of evidence that together give us confidence these DNA building blocks actually...

Antimatter Source Near the Earth

by Paul Gilster | Aug 10, 2011 | Antimatter | 7 Comments

Now that NASA's Institute for Advanced Concepts (NIAC) is back in business, I'm reminded that it was through NIAC studies that both Gerald Jackson and James Bickford introduced the possibility of harvesting antimatter rather than producing it in huge particle accelerators. The idea resonates at a time when the worldwide output of antimatter is measured in nanograms per year, and the overall cost pegged at something like $100 trillion per gram. Find natural antimatter sources in space and you can think about collecting the ten micrograms that might power a 100-ton payload for a one-year round trip mission to Jupiter. Contrast that with Juno's pace! That assumes, of course, that we can gather enough antimatter to test the concept and develop propulsion systems -- doubtless hybrids at first -- that begin to draw on antimatter's power. Bickford (Draper Laboratory, Cambridge MA) became interested in near-Earth antimatter when he realized that the bombardment of the upper atmosphere of the...

Icarus Eyes Interstellar Symposium

by Paul Gilster | Aug 9, 2011 | Missions | 15 Comments

The Project Icarus team has founded a non-profit research organization called Icarus Interstellar, its goal being to 'foster research into those necessary technologies which can make interstellar research a reality' through the study of such topics as fusion, nanotechnology, advanced power sources and other critical drivers for interstellar flight. We've tracked Icarus here from the beginning, when it emerged as an ambitious attempt to update and re-think the original Project Daedalus starship design of the 1970s. Taking fusion as its propulsion mechanism, the Icarus team now seeks to analyze and design a probe in terms of recent advances in numerous fields. How do you go about designing a starship? Something this speculative, which must of necessity rely on extrapolations of where technology is going, happens outside the normal 9-5 workday. Centauri Dreams readers know that the Icarus team is composed of volunteers, most of whom work and exchange ideas over the Internet -- only a...

Juno: Into the Jovian Magnetosphere

by Paul Gilster | Aug 8, 2011 | Outer Solar System | 24 Comments

The launch of the Juno spacecraft last Friday gets us back in business around the Solar System's largest planet, but also has useful exoplanet implications. To understand why, consider just one of the instruments carried aboard the spacecraft. The Jupiter Energetic-particle Detector Instrument (JEDI) is designed to measure how energetic particles flow through Jupiter's magnetosphere and interact with its atmosphere. Developed at Johns Hopkins Applied Physics Laboratory, JEDI will be looking at the interactions that produce the most powerful auroral phenomena in our system, and what we will learn has broad applications. After all, new tools like the Low Frequency Array (LOFAR) are coming online, bringing hitherto unavailable sensitivity to radio frequencies below 250 MHz. Not so long ago, Jonathan Nichols (University of Leicester) proposed using LOFAR to look for aurorae similar to those on Jupiter in exoplanetary systems. In fact, his research shows that gas giants in orbits up to 50...

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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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