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Uncertain Propulsion Breakthroughs?

by Paul Gilster | Dec 30, 2016 | Exotic Physics | 110 Comments

Now that the EmDrive has made its way into the peer-reviewed literature, it falls in range of Tau Zero's network of scientist reviewers. Marc Millis, former head of NASA's Breakthrough Propulsion Physics project and founding architect of the Tau Zero Foundation, has spent the last two months reviewing the relevant papers. Although he is the primary author of what follows, he has enlisted the help of scientists with expertise in experimental issues, all of whom also contributed to BPP, and all of whom remain active in experimental work. The revisions and insertions of George Hathaway (Hathaway Consulting), Martin Tajmar (Dresden University), Eric Davis (EarthTech) and Jordan Maclay (Quantum Fields, LLC) have been discussed through frequent email exchanges as the final text began to emerge. Next week I'll also be presenting a supplemental report from George Hathaway. So is EmDrive new physics or the result of experimental error? The answer turns out to be surprisingly complex. by Marc...

New Horizons: Going Deep in the Kuiper Belt

by Paul Gilster | Dec 29, 2016 | Outer Solar System | 11 Comments

We've retrieved all the data from New Horizons' flyby of Pluto/Charon in 2015, the last of it being acquired on October 25 of this year. But data analysis is a long and fascinating process, with papers emerging in the journals and new discoveries peppering their pages. The New Horizons science team submitted almost 50 scientific papers in 2016, and we can expect that stream of publication to continue in high gear as we move deeper into the Kuiper Belt. For New Horizons is very much an ongoing enterprise, as Alan Stern's latest PI's Perspective makes clear. We have an encounter with a small Kuiper Belt object (KBO) called 2014 MU69 to think about, and the symmetry that Stern points to in his essay is striking. Two years ago New Horizons had just emerged from cruise hibernation as preparations for the Pluto/Charon encounter began. And exactly two years from now, we'll be again following the incoming datastream as the last of the New Horizons targets comes into breathtaking proximity....

Vera Rubin (1928-2016)

by Paul Gilster | Dec 28, 2016 | Deep Sky Astronomy & Telescopes | 11 Comments

When Vera Rubin went to Cornell University to earn a master's degree, she quickly found herself immersed in galaxy dynamics, lured to the topic by Martha Stahr Carpenter. The interest, though, was a natural one; it drew on Rubin's childhood fascination with the motion of stars across the sky. You could say that motion captivated her from her earliest days. At Cornell, she studied physics from such luminaries as Richard Feynman, Philip Morrison and Hans Bethe. She would complete the degree in 1951 and head on to Georgetown. Rubin, who died on Christmas day, was possessed of a curiosity that made her ask questions others hadn't thought of. In Bright Galaxies, Dark Matters (1997), a collection of her papers, the astronomer recalls writing to Milton Humason in 1949, asking him about the redshifts he and his colleagues were compiling. Rubin had heard that many had yet to be published, and she would use those she had to look for systematic motion among the galaxies, motion that would show...

Orbital Determination for Proxima Centauri

by Paul Gilster | Dec 27, 2016 | Exoplanetary Science | 20 Comments

Let’s talk this morning about the relationship of Proxima Centauri to nearby Centauri A and B, because it’s an important issue in our investigations of Proxima b, not to mention the evolution of the entire system. Have a look at the image below, which shows Proxima Centauri’s orbit as determined by Pierre Kervella (CNRS/Universidad de Chile), Frédéric Thévenin (Observatoire de la Côte d'Azur) and Christophe Lovis (Observatoire astronomique de l’Universite? de Gene?ve). The three astronomers have demonstrated that all three stars -- Proxima Centauri as well as Centauri A and B -- form a single, gravitationally bound system. Image: Proxima Centauri’s orbit (shown in yellow) around the Centauri A and B binary. Credit: Kervella, Thévenin and Lovis. A couple of things to point out here, the first being the overall image. You’ll see Alpha Centauri clearly labeled within the yellow ellipse of Proxima’s orbit. Off to the right of the ellipse, you’ll see Beta Centauri. I often see the image...

Seasonal Break

by Paul Gilster | Dec 22, 2016 | Administrative | 30 Comments

The other day on the hugely enjoyable Galactic Journey site, I ran into an interesting historical tidbit. Here, from the 1753 Cyclopædia: or, An Universal Dictionary of Arts and Sciences by Ephraim Chambers is a definition of the word 'interstellar.' And with a modernized presentation: "Interstellar, is a word used by some authors to express those parts of the universe that are without and beyond our Solar system; in which are supposed to several other systems of planets moving around the fixed stars as the centers of their respective motions: and if it be true, as it is not improbable, that each fixed star is thus a sun to some habitable orbs, that move round it, the interstellar world will be infinitely the greater part of the universe." Another early instance of planetary systems around other stars in wide circulation at an early date. Chambers was working for John Senex, a London-based globe-maker, when he conceived the plan for his Cyclopædia, a project to which he soon devoted...

Citizen SETI

by Paul Gilster | Dec 21, 2016 | Astrobiology and SETI | 63 Comments

I love watching people who have a passion for science constructing projects in ways that benefit the community. I once dabbled in radio astronomy through the Society of Amateur Radio Astronomers, and I could also point to the SETI League, with 1500 members on all seven continents engaged in one way or another with local SETI projects. And these days most everyone has heard the story of Planet Hunters, the citizen science project that identified the unusual Boyajian's Star (KIC 8462852). When I heard from Roger Guay and Scott Guerin, who have been making their own theoretical contributions to SETI, I knew I wanted to tell their story here. The post that follows lays out an alien civilization detection simulation and a tool for visualizing how technological cultures might interact, with an entertaining coda about an unusual construct called a 'Dyson shutter.' I'm going to let Roger and Scott introduce themselves as they explain how their ideas developed. by Roger Guay and Scott Guerin...

PanSTARRS: Digital Sky Survey Data Release

by Paul Gilster | Dec 20, 2016 | Deep Sky Astronomy & Telescopes | 18 Comments

A 1.8 meter telescope at the summit of Haleakal? on Maui is the first instrument in use at the Pan-STARRS (Panoramic Survey Telescope & Rapid Response System) observatory. Pan-STARRS recently completed a digital survey of the sky in visible and infrared wavelengths that began in May of 2010, a project that surveyed the entire sky visible from Hawaii over a period of four years, scanning it 12 times in each of five filters. The result is a collection of 3 billion separate sources, including not just stars and galaxies but numerous transient, moving and variable objects. All told, we’re dealing with about 2 petabytes of data. Now we learn that data from the survey is being made available worldwide. Ken Chambers, director of the Pan-STARRS observatories, comments: "The Pan-STARRS1 Surveys allow anyone to access millions of images and use the database and catalogs containing precision measurements of billions of stars and galaxies. Pan-STARRS has made discoveries from Near Earth Objects...

Learning More about Outer System Planets

by Paul Gilster | Dec 19, 2016 | Exoplanetary Science | 20 Comments

What kind of planets are most common in the outer reaches of a planetary system? It's a tricky question because most of the data we've gathered on exoplanets has to do with the inner regions. Both transit and radial velocity studies work best with large planets near their stars. But a new gravitational microlensing study looks hard at outer system planets, finding that planets of Neptune's mass are those most likely to be found in these icy regions. It should be no surprise that gravitational microlensing has produced few planets, about 50 so far, compared to the thousands detected through transit studies and radial velocity methods. After all, microlensing relies upon alignments that are far more unusual than even the transit method, in which a planet crosses the face of its star as seen from Earth. In microlensing, astronomers look for rare alignments between a distant star and one much nearer. Given the right alignment, the 'bending' of spacetime caused by the nearer star's mass...

A New Look at Ice on Ceres

by Paul Gilster | Dec 16, 2016 | Outer Solar System | 19 Comments

Ceres, that interesting dwarf planet in the asteroid belt, is confirmed to be just as icy as we had assumed. In fact, a new study of the world, led by Thomas Prettyman (Planetary Science Institute), was the subject of a press conference yesterday at the American Geophysical Union fall meeting in San Francisco. Prettyman and team used data from the Dawn spacecraft's Gamma Ray and Neutron Detector (GRaND) instrument to measure the concentrations of iron, hydrogen and potassium in the uppermost meter of Ceres' surface. Prettyman, who is principal investigator on GRaND, oversees an instrument that works by measuring the number and energy of gamma rays and neutrons coming from Ceres. The neutrons are the result of galactic cosmic rays interacting with the surface, some of them being absorbed while others escape. The number and kind of these interactions allows researchers to investigate surface composition. Hydrogen on Ceres is thought to be in the form of frozen water, allowing the...

Surviving the Journey: Spacecraft on a Chip

by Paul Gilster | Dec 15, 2016 | Missions | 75 Comments

If Breakthrough Starshot can achieve its goal of delivering small silicon chip payloads to Proxima Centauri or other nearby stars, it will be because we've solved any number of daunting problems in the next 30 years. That's the length of time the project's leaders currently sketch out to get the mission designed, built and launched, assuming it survives its current phase of intense scrutiny. The $100 million that currently funds the project will go into several years of feasibility analysis and design to see what is possible. That means scientists will work a wide range of issues, from the huge ground-based array that will propel the payload-bearing sails to the methods of communications each will use to return data to the Earth. Also looming is the matter of how to develop a chip that can act as all-purpose controller for the numerous observations we would like to make in the target system. If the idea of a spacecraft on a chip is familiar, it's doubtless because you've come across...

OSIRIS-REx to Hunt for Earth ‘Trojans’

by Paul Gilster | Dec 14, 2016 | Asteroid and Comet Deflection | 18 Comments

The so-called 'trojan' asteroids that cluster at 60° ahead and behind the planet Jupiter make up a surprisingly populous category. Consider that thus far we have found only one trojan at Earth's Lagrangian points, while over 6000 have been discovered in Jupiter's orbit. The total number of trojans larger than 1 km in diameter associated with Jupiter has been estimated to be about 1 million, which matches up well with objects of equivalent size in the main asteroid belt. These days 'trojans' can also refer to similar bodies associated with other planets. We know, for example, of about 20 trojans involved with Neptune. That solitary Earth trojan, 2010 TK7, was discovered oscillating around Earth's L4 Lagrangian point in 2010 by the NEOWISE team using NASA's Wide-field Infrared Survey Explorer spacecraft. The object has a diameter of about 300 meters; its oscillations take it back and forth on a nearly 400 year cycle that at times puts it close to opposite the Sun with respect to...

Tidal Disruption by Black Hole?

by Paul Gilster | Dec 13, 2016 | Deep Sky Astronomy & Telescopes | 14 Comments

The supernova considered to be the brightest ever recorded may have been evidence of something even more exotic. The explosion was caught by the All Sky Automated Survey for SuperNovae (ASAS-SN), the event itself dubbed ASASSN-15h. Yesterday we looked at what happens to a star roughly as massive as the Sun as it goes through a red giant phase and becomes a white dwarf, but stars significantly more massive than the Sun take no such route. A star a minimum of 8 times the mass of the Sun can explode as a Type II supernova. But is that what ASASSN-15h really was? Detected in 2015 in a galaxy about 4 billion light years from Earth, the event has now been the subject of new work by an international team led by Giorgos Leloudas (Weizmann Institute of Science, Israel) and the Dark Cosmology Centre (Denmark). From this we get a new explanation: ASASSN-15h may have been the result of a rapidly spinning supermassive black hole tearing a relatively low mass star apart. The passing star, in other...

Glimpsing Our Solar System’s Future

by Paul Gilster | Dec 12, 2016 | Deep Sky Astronomy & Telescopes | 18 Comments

The star L2 Puppis (HD 56096), a red giant in the direction of the southern constellation Puppis (the Poop Deck), is the subject of interesting new investigations using data from the ALMA array in Chile. The star appears to belong on the asymptotic giant branch of the Hertzsprung-Russell diagram, a category dominated by highly evolved cool stars. The new study sees L2 Puppis as an analog for what our own Sun will become in billions of years. Thus Ward Homan (KU Leuven Institute of Astronomy, Belgium): "We discovered that L2 Puppis is about 10 billion years old. Five billion years ago, the star was an almost perfect twin of our Sun as it is today, with the same mass. One third of this mass was lost during the evolution of the star. The same will happen with our Sun in the very distant future." Image: Composite view of L2 Puppis in visible light | © P. Kervella et al. (CNRS/U. de Chile/Observatoire de Paris/LESIA/ESO/ALMA). But L2 Puppis is more than just an interesting glimpse at what...

John Glenn: An Arc of Fire

by Paul Gilster | Dec 9, 2016 | Uncategorized | 23 Comments

John Glenn was 95 when he died, but I have to admit I didn't think he'd make it to 41. The first American to orbit the Earth was 40 years old when he rode an Atlas rocket into the sky on February 20, 1962. I was a gawky kid, space-crazed, who had read absolutely everything I could find about the space program, and I knew just enough to understand that the Atlas, for all its muscular beauty, wasn't necessarily the safest thing you'd want to fly. Our school had set up a black and white television on the stage in the auditorium so we could all see the liftoff, which took place at 8:47 A.M. in St. Louis. In this era of enormous home viewing screens it's hard to imagine what a single small television could show to an auditorium filled with students, but at the time it was a window into history and we watched avidly as the rocket cut into the sky, and got later updates from teachers as Glenn orbited. We all assumed the hard part was over after the launch, and I know I was certainly...

Photonic Chip Boosts Exoplanet Detection

by Paul Gilster | Dec 8, 2016 | Exoplanetary Science | 17 Comments

The Australian Institute of Physics Congress ends today in Brisbane, concluding a schedule of talks that can be viewed here. Among the numerous research presentations was the description of a new optical chip for telescopes that should help astronomers tease out the image of a planet through thermal imaging, nulling out the light of the host star. The new photonic chip could be a replacement for bulk optics at the needed mid-infrared wavelengths. Harry-Dean Kenchington Goldsmith, a PhD candidate who built the chip at the Australian National University Physics Center, says that the same technology that allows astronomers to penetrate dust clouds to see planets in formation will also be used to study the atmospheres of potentially life-bearing planets. ANU's Steve Madden describes the chip as an interferometer that "adds equal but opposite light waves from a host sun which cancels out the light from the sun," making it possible to detect the much fainter light of a planet. He likened...

Loretta Jackson Delong (1948-2016)

by Paul Gilster | Dec 7, 2016 | Culture and Society | 2 Comments

I was saddened to learn through Tau Zero Foundation CEO Rhonda Stevenson of the recent death of Loretta Jackson Delong. Stevenson issued this statement The Tau Zero Foundation extends its sincerest condolences to Dan DeLong, the XCOR and Agile families for the great loss of Loretta Jackson Delong. She was a pioneer from the start, as she knew from the time she was twelve that she would build and fly spaceships. Through her life's journey, she repeatedly demonstrated rigor and grit, and she will be missed. The loss hits home particularly at Tau Zero because Aleta, as she was known to her friends, was a co-founder of XCOR, where she worked closely with co-founder and former CEO Jeff Greason, who is now chairman of the Tau Zero Foundation board. She would go on to collaborate with Greason again in the creation of Agile Aero, a Midland, TX-based startup targeting rapid design and prototyping techniques for space launch, hypersonic vehicles, and innovative aircraft. Greason is CEO of...

Up Close at Alpha Centauri

by Paul Gilster | Dec 6, 2016 | Missions | 20 Comments

In early December the Harvard-Smithsonian Center for Astrophysics offered as part of its fall colloquium series a talk by Harvard's Avi Loeb, fortunately captured on YouTube as Project Starshot: Visiting the Nearest Star Within Our Lifetime. We've looked at Breakthrough Starshot in many posts on Centauri Dreams, including my reports from the last set of meetings in Palo Alto, but for those new to the concept of using a laser array to send small, instrumented sails to the Alpha Centauri stars, this video is a fine introduction. You'll recall that yesterday I talked about Robert Austin's futuristic Asteroid Belt Astronomical Telescope, with an illustration of what such an instrument might see of the exoplanet Gliese 832c. If Starshot can achieve its goals, it will be able to make out continent sized features on the surface of Proxima b, or perhaps a planet around Centauri A or B. It would achieve, in other words, what it would take a near-Earth space-based telescope 300 kilometers wide...

Thought Experiment: The Asteroid Belt Astronomical Telescope

by Paul Gilster | Dec 5, 2016 | Deep Sky Astronomy & Telescopes | 33 Comments

Could laser light be used to shape and polish an asteroid to high optical standards? That's the question raised in an imaginative essay in Physics Today that posits the creation, a century from now, of the Asteroid Belt Astronomical Telescope (ABAT). It's science fiction today, part of the series of speculations that the magazine has been running to explore possible futures, but what a concept for an SF novel, and perhaps someday real astronomy (thanks to Centauri Dreams reader Klaus Seidensticker for sending me the link). Author Robert Austin (Florida Polytechnic University) creates a backstory involving a "self-described over-the-hill assistant professor at Purdue University" who uses a research grant to polish a 1-centimeter sphere of pyrolytic carbon magnetically levitated in a vacuum. He achieves the needed flat optical surface along with a reflective hemispherical 'bump' on the object's backside that can be used to reorient the mirror by photon pressure. Soon the idea of using...

Shifting Perspectives on Pluto’s ‘Heart’

by Paul Gilster | Dec 2, 2016 | Outer Solar System | 9 Comments

One of the great pleasures of doing this site is watching researchers matching ideas in peer-reviewed papers. A paper can meet the highest standards for publication but still present an argument that subsequent researchers question, igniting a new round of debate. Trying to get at the heart of a scientific question requires patience, but it's also as absorbing as a chess game, as witness the continuing debate over the history and significance of Pluto's Sputnik Planitia. And in this case, we have a researcher working both sides of the controversy. Resembling a polar ice cap, Sputnik Planitia is about 1000 kilometers across, and is centered on a latitude of 25 degrees north and a longitude of 175 degrees. Moreover, it is directly opposite the side of Pluto that always faces Charon, the result of tidal lock. Two weeks ago we looked at the possibility that this western lobe of Pluto's 'heart,' a deep basin filled with frozen gases like nitrogen, carbon dioxide and methane, was the...

Visualizing the Alien: A Hollywood Conundrum

by Paul Gilster | Dec 1, 2016 | Culture and Society | 90 Comments

Aliens used to look more or less like humans in the films of the 1950s. Think Michael Rennie in The Day the Earth Stood Still (1951), a polished alien presence if there ever was one. We got humanoid aliens with strange powers or technologies, like Jeff Morrow playing Exeter in This Island Earth (1955) -- a prominent forehead and strange hair is all it takes. Even James Arness' vegetable man (The Thing from Another World, 1951), although seen but briefly and on a rampage, is recognizably humanoid. Image: James Arness makes his appearance in Howard Hawks' The Thing from Another World. I watched all those films and many other SF movies besides when I was growing up, almost all on TV re-runs. Later, special effects would vastly improve, and non-humanoid aliens thrived, my favorite being the repulsive title character in Ridley Scott's Alien (1979), so dramatically visualized by Swiss surrealist Hans Rudolf Giger. Now we see aliens in all shapes and sizes, from the many-toothed predator...

Charter

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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