For reminding us what technology can do. And what people can become. Image: Members of the Cassini mission team. Cassini has benefited from the work of some 260 scientists at NASA, ESA and Agenzia Spaziale Italiana (ASI), as well as several European academic and industrial contributors. Credit: JPL/Caltech.
Cassini mission engineers are referring to its final pass by Titan as 'the goodbye kiss,' a phrase that sounds like something from a Raymond Chandler novel. Maybe it's the juxtaposition of intimacy and death that Chandler exploited so well. In any case, what counts in the last of Cassini's hundreds of passes over Titan in its 13-year exploration of the system is the gravitational nudge that is sending the spacecraft into Saturn's atmosphere tomorrow. "Cassini has been in a long-term relationship with Titan, with a new rendezvous nearly every month for more than a decade," said Cassini Project Manager Earl Maize at NASA's Jet Propulsion Laboratory in Pasadena, California. "This final encounter is something of a bittersweet goodbye, but as it has done throughout the mission, Titan's gravity is once again sending Cassini where we need it to go." Closest approach for the final pass at Titan occurred at 1504 EDT (1904 UTC) on September 12, at an altitude of 119,049 kilometers, with data...
The recent reminder of spacecraft longevity that the Voyagers have given us on their 40th anniversary keeps the memory of their famous Golden Records fresh. After all, only the passage of time -- and a lot of it -- can degrade these human artifacts, and they carry sights and sounds of our planet specifically chosen to represent us. Now Jon Lomberg, who was design director for the Golden Record, has thoughts of doing something similar with another long-haul spacecraft, the outer system explorer New Horizons, and has launched a Kickstarter campaign to make it happen. Clearly the method has to change, given that New Horizons launched without artifacts designed to carry information about our species, other than the obvious message implicit in its own technology. The plan is to take advantage of the spacecraft's computer memory, or in this case, a few hundred megabytes out of a 4 GB memory chip, which was state of the art in the days when the New Horizons design was finalized. What...
In which Larry Klaes concludes his analysis of Forbidden Planet, the still revered science fiction classic from the 1950s. If you ever had any questions about this film, Larry is your man, and note the full complement of online resources at the end of the essay. by Larry Klaes Space Madness Adams: "How have the men stood the voyage?" Doc: "About average. A few cases of space-blues - a little epidemic of claustro during the seventh month. But nobody's had to have shock therapy except the Cook." Adams: "Yes, I could taste it in the chow." The above was yet another bit of dialogue from the indispensable 1954 version of the Forbidden Planet film script which did not survive to the 1956 release. The Captain and the ship's doctor were discussing the psychological state of the C-57D crew after their year-long journey from Earth Base just before landing on Altair 4. I presume this was largely done for the knowledge benefit of the viewing audience - either that or Adams is surprisingly...
Larry Klaes takes the helm today and tomorrow while I finish up some necessary (not space related) business. Most Centauri Dreams readers, I'm assuming, have seen Forbidden Planet, the 1956 science fiction tale that proved so influential on later depictions of interstellar travel and encounters with alien intelligence, not just in film but on radio and television. Looking at everything from the film's original script to its effect on Star Trek and beyond, Larry connects the world of Forbidden Planet to its historical context as well as its echoes, which still resonate as we continue the exploration of our own Solar System. What can a 1950's movie tell us about flight to the stars? Quite a lot, as Larry explains. By Larry Klaes The cinema has had a huge influence on modern society since the day it was introduced to the world in the late Nineteenth Century. I am referring not just to the masses being regularly entertained by "the movies" for generations on a global scale or Hollywood...
We've learned a great deal about comet 67P Churyumov-Gerasimenko thanks to the European Space Agency's Rosetta mission. What stands out to me is the fact that 40 percent of the comet, in terms of mass, is made up of organic compounds -- combinations of hydrogen, carbon, oxygen and nitrogen. These 'building blocks' of life on Earth are readily available and could have been delivered over and over again through our planet's long impact history. But where did the organic compounds themselves come from? Jean-Loup Bertaux (CNRS / UPMC / Université de Versailles Saint-Quentin-en-Yvelines), working with Rosine Lallement (Observatoire de Paris / CNRS / Université Paris Diderot), has put forth the idea that the organics formed in interstellar space long before the formation of the Solar System. The idea no longer seems as startling as it once might have, thanks to our continuing study of what are called diffuse interstellar bands, or DIBs. Revealed by spectroscopic studies,...
While we track hurricane Irma and its path of devastation in the Caribbean, another kind of storm is affecting the skies over more northerly areas. A strong geomagnetic storm watch continues in effect, making it possible that the aurora borealis -- northern lights -- will be visible further south than usual, in Scotland and southern Scandinavia but perhaps into the continental United States as well, while the aurora australis could be active for those in the more southerly latitudes below the equator. All of this is due to sunspot AR2673, which is the source of a flare and coronal mass ejection hurled out of the Sun on Monday. I've seen the northern lights in Iceland on one spectacular October night, but only once -- in Iowa, in 1970 -- have I seen them in the US. The phenomenon results from electrons accelerated as they encounter the Earth's magnetosphere, following the magnetic field lines to the polar regions, where from 500 kilometers down to 80 kilometers up, they collide with...
You would think that seven planets around TRAPPIST-1 would be more than enough, but Alan Boss and colleagues at the Carnegie Institution for Science are asking whether this system might not also contain one or more gas giants. It's a theoretical question given weight by the desire to learn more about planet formation, for if we can find gas giants here, it would give credence to a model of gas giant formation championed by Boss. The team has now put constraints on the mass of any gas giants that might lurk here, a prelude to further study. The core accretion model is widely accepted as a way to create planets like our Earth. Here, the gas and dust disk surrounding a young star shows slow accretion as small particles begin to clump together, gradually forming into planetesimals and, via collisions and other interactions, eventually assembling planets, along with a great deal of leftover debris. Core accretion can be modeled and seems to fit what we see in other infant planetary...
We're going to need a lot more information about the effects of ultraviolet light as we begin assessing the possibility of life on the planets of red dwarf stars. We already know that young red dwarfs in particular can throw flares at UV wavelengths that can damage planetary atmospheres. They can also complicate our search for biosignatures through processes like the photodissociation of water vapor into hydrogen and oxygen, a non-biological source of oxygen of the kind we have to rule out before we can draw even tentative conclusions about life. Could flares have astrobiological benefits as well? That's a question that emerges from a new paper from Sukrit Ranjan (Harvard-Smithsonian Center for Astrophysics) and colleagues. What concerns Ranjan's team is that red dwarf stars may not emit enough ultraviolet to benefit early forms of life. On the primitive Earth, UV may have played a key role in the formation of ribonucleic acid. If this is the case, then UV flare activity could...
We're going to eventually get to know the seven planets of the TRAPPIST-1 system well. That's because they present the ideal targets for upcoming attempts to probe the atmospheres of Earth-sized rocky planets. Orbiting an M-dwarf some 39 light years out, all seven of the planets here transit. Because of the faintness of their star and the size of the planets themselves, they present excellent candidates for transit spectroscopy, in which we look at the light from the star through planetary atmospheres to deduce their constituents. Using the Space Telescope Imaging Spectrograph on the Hubble instrument, an international team led by Vincent Bourrier (Observatoire de l'Université de Genève) has been studying the ultraviolet radiation received by each of the planets in the system. The more we know about the star's output, the more we can plug values into the atmospheric escape processes that can occur in its planets, with huge consequences for surface conditions. The team in...
Andrew Siemion, who heads up the Breakthrough Listen initiative and is director of the Berkeley SETI Research Center, sent out a message to astronomers on August 29 noting recent activity from the radio source FRB 121102. The heightened activity had been noted by Breakthrough Listen postdoctoral researcher Vishal Gajjar. You'll recall that Fast Radio Bursts (FRBs) are powerful but extremely short-duration radio pulses whose sources generally remain unknown. What tags FRB 121102 as especially interesting is that it is the only FRB known to repeat. In fact, more than 150 bursts have been observed coming from the dwarf galaxy 3 billion light years from Earth that is thought to be its place of origin. And now we have heightened activity in the form of 15 new bursts, as the Astronomer's Telegram notes: These are the highest frequency and widest bandwidth detections of bursts from FRB 121102 obtained to-date. Additional fully calibrated full-Stokes analysis employing coherent dedispersion...
The Jet Propulsion Laboratory has just published details about Cassini's last days and its final plunge into Saturn on September 15. That last act turns the craft into our first planetary probe of Saturn, to use Linda Spilker's memorable phrase. A Cassini project scientist at JPL, Spilker goes on to note that the probe will be "sampling Saturn's atmosphere up until the last second. We'll be sending data in near real time as we rush headlong into the atmosphere -- it's truly a first-of-its-kind event at Saturn." Image: Cassini streaks across Saturn's sky in its final moments. Credit: NASA/JPL-Caltech. I want to lift the Cassini final calendar out of this JPL news release, as many Centauri Dreams readers have expressed an interest particularly in the mission-ending atmospheric entry. We will likely lose radio contact within, JPL estimates, one to two minutes after the descent into the atmosphere begins. Eight of the twelve science instruments will be operating throughout the plunge,...
NASA's OSIRIS-REx spacecraft, now on a two year outbound journey to the near-Earth asteroid Bennu, is a good deal closer to home than you might think. At play is a gravity assist maneuver that will take the craft past the Earth on September 22nd, propelling OSIRIS-REx into the orbital plane of its target. As of August 25th, the spacecraft was 16.6 million kilometers from the Earth. Twenty-four days and a wake-up! You know I'm getting close when the one-way light time is under a minute.https://t.co/rACre4nDe4 pic.twitter.com/uvKBaNoqYM— NASA's OSIRIS-REx (@OSIRISREx) August 28, 2017 The OSIRIS-REx team is reporting that a course adjustment burn was performed on August 23rd, a successful correction that marked the first time the spacecraft's attitude control system (ACS) had been used in what is being called a 'turn-burn-turn' sequence. It's a precision maneuver requiring the momentum wheels on OSIRIS-REx to turn the spacecraft so its thrusters are lined up for the burn....
I don't usually talk about spacecraft close to our own Sun, but exceptions invariably arise. Centauri Dreams took a close look at the Parker Solar Probe back in June, because its operations close to the Sun (within about 10 solar radii) have implications for how we might build the kind of spacecraft that can perform 'sundiver' maneuvers, approaching the Sun before deploying a solar sail for maximum effect (see Parker Solar Probe: Implications for Sundiver). Sundivers are one way to maximize acceleration for future interstellar missions. And then there's Venus, a planet I've written little about in these pages. The Automaton Rover for Extreme Environments (AREE) concept study now being funded by the NASA Innovative Advanced Concepts program is intriguing because it looks at spacecraft design from a fresh angle, actually one that harkens back to generations of mechanical devices that have had little part in space exploration. At least, until now. For while the environment on Venus...
Red supergiants are stars more massive than 9 times the mass of the Sun, a late stage of stellar evolution in which the stars' atmospheres become expansive, while lowering in density. Antares, the brightest star in the constellation Scorpius, is about 12 times as massive as the Sun, but its diameter is 700 times larger. Its mass was once thought to be 15 times that of the Sun, with three solar masses of material being shed during its lifetime. If located in our Solar System, its outer edges would reach somewhere between the orbits of Mars and Jupiter. Now we have word that scientists using the European Southern Observatory's Very Large Telescope Interferometer (VLTI) at Paranal Observatory in Chile have been able to map the surface of this star, and to measure the motion of its surface material. What we get out of all this is the best image of the surface and atmosphere of any star other than our own. Image: VLTI reconstructed view of the surface of Antares. Credit: ESO. Lead author...
Looking at recent headlines about 'diamond rain' on Neptune provoked a few thoughts about headline writers, though the image is certainly striking, but then I recalled that Carl Sagan used to enjoy pulling out the stops with language as much as anyone. Listen, for example, to the beginning of his 1973 title The Cosmic Connection: There is a place with four suns in the sky -- red, white, blue and yellow; two of them are so close together that they touch, and star-stuff flows between them. I know of a world with a million moons. I know of a sun the size of the Earth - and made of diamond. There are atomic nuclei a mile across that rotate thirty times a second. There are tiny grains between the stars, with the size and atomic composition of bacteria. There are stars leaving the Milky Way. There are immense gas clouds falling into the Milky Way. There are turbulent plasmas writhing with X- and gamma rays and mighty stellar explosions. There are, perhaps, places outside our universe. And...
I've spent part of each day recently working on a short presentation I'll be giving at the Tennessee Valley Interstellar Workshop, coming up in early October. I like this year's motto -- "Step by Step: Building a Ladder to the Stars" -- because it picks up on a theme I've cited here before, the maxim by Lao Tzu that "You accomplish the great task by a series of small acts." Despite its regional name, TVIW now draws speakers from all over the world. Co-founder Les Johnson encapsulates the idea behind the sessions, emphasizing the workshop concept: "The Tennessee Valley Interstellar Workshop is an opportunity for relaxed sharing of ideas in directions that will stimulate and encourage Interstellar exploration including propulsion, communications, and research. The 'Workshop' theme suggests that the direction should go beyond that of a 'conference'. Attendees are encouraged to not only present intellectual concepts but to develop these concepts to suggest projects, collaboration, active...
I often think of brown dwarfs in terms of the planets that might form around them, and the question of whether even these small 'failed stars' may be capable of sustaining life. Have a look, for example, at Luhman 16AB, two brown dwarfs in the Sun's immediate neighborhood. There are some indications of a planet here which, if it were ever confirmed, would make it the second closest known exoplanet to the Earth, at least for now. We can rule out planets of Neptune mass or greater with a period of between one and two years, but future Hubble observations, already approved for August of next year, may tell us more. Image: Luhman 16AB, two brown dwarfs in the Sun's neighborhood. Credit: NASA / JPL / Gemini Observatory / AURA / NSF. But brown dwarfs, incapable of fusing chemical elements, have their own planetary characteristics. It's this intriguing aspect of this population that gives us a kind of bridge to exoplanet systems, because brown dwarfs are often found alone, without a bright...
Talk about transit depth! Those of you in the path of totality are fortunate indeed as we see just how deep a light curve can get. I've never experienced totality and won't this time, but we'll get plenty of good science out of this event and a spectacular 160 seconds for those in the path. As the Sun's corona is revealed, think about the solar wind -- the stream of charged particles flowing from the corona out to the heliosphere -- and how we might one day use similar stellar winds to brake the onrush of an interstellar probe with a magsail as it nears destination. Image: The Moon's shadow will dramatically affect insolation — the amount of sunlight reaching the ground — during the total solar eclipse. Credit: NASA's Scientific Visualization Studio 160 seconds of totality is a fleeting but, so I'm told, haunting experience. For scientists, though, we'd like a good bit more. Thus it's welcome news that the European Space Agency is working on Proba-3, a duo of small...
The SETI Institute's Laser SETI campaign made it past the finish line. Many thanks to the many Centauri Dreams readers who helped to make this happen. All sky, all the time SETI should produce astrophysical discoveries we haven't imagined, and of course we'll keep hoping for that intriguing transient that turns out to point to extraterrestrial intelligence. Exciting times ahead!
