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WASP-189b: An Impressive Debut for CHEOPS

by Paul Gilster | Sep 30, 2020 | Exoplanetary Science | 10 Comments

The European Space Agency’s CHaracterising ExOPlanet Satellite (CHEOPS) space telescope reached space in December of 2019, achieving a Sun-synchronous orbit some 700 kilometers up. The instrument has begun its observations of stars near the Sun that are already known to have planetary companions. The idea is to use the 30 cm optical telescope to constrain radius information for these worlds, previously identified in transit and radial velocity studies. Transiting planets are particularly useful here, because tightening up their radius measurements means we get a better idea of their density, factoring in mass estimates provided by subsequent radial velocity follow-ups. It’s great to see the instrument already hard at work, with measurements of the giant planet WASP-189b, some 325 light years from the Sun, showing us a world that is one of the hottest known, with a likely temperature around 3400?. By comparison, the surface temperature of the Sun is about 6000 ?, while smaller M...

New Approaches to the Age of Saturn’s Moons

by Paul Gilster | Sep 29, 2020 | Outer Solar System | 6 Comments

The presence of the always intriguing Titan brings into sharper focus recent work on the age of the moons of Saturn conducted by Samuel Bell (Planetary Science Institute). Given the active weathering visible on Titan, the assumption that it is at least four billion years old, which draws on earlier work on the age of Saturn’s moon system, is challenged by the lakes, mountains, riverbeds and dunes we see in the Cassini data. Bell argues that an older Titan would have to be one with an extremely low erosion rate and minimal resurfacing. But maybe Titan is younger than we’ve thought. Bell assembles the context of Titan in the overall system at Saturn by studying the cratering rate on the various moons. Determining the age of a planetary surface -- think Mars or the Moon -- is generally done by counting the impact craters and weighing this against the cratering rate. At Saturn, the problem is that the cratering rate is not known. It would be one value if, as previous work has assumed,...

The Technological Indispensability Hypothesis: An Addendum to ‘Bound in Shallows’

by Paul Gilster | Sep 25, 2020 | Culture and Society | 125 Comments

Is there a single technology that can take us from being capable of reaching space to actually building an infrastructure system-wide? Or at least getting to a tipping point that makes the latter possible, one that Nick Nielsen, in today's essay, refers to as a 'space breakout'? We can think of game-changing devices like the printing press with Gutenberg's movable type, or James Watt's steam engine, as altering — even creating — the shape and texture of their times. The issue for space enthusiasts is how our times might be similarly altered. Nick here follows up an earlier investigation of spacefaring mythologies with this look at indispensable technologies, forcing the question of whether there are such, or whether technologies necessarily come in clusters that enforce each other's effects. The more topical question: What is holding back a spacefaring future that after the Apollo landings had seemed all but certain? Nielsen, a frequent author in these pages, is a...

K2-315b: Tight Orbits and the Joy of Numbers

by Paul Gilster | Sep 23, 2020 | Exoplanetary Science | 31 Comments

The newly found planet K2-315b catches the eye because of its 3.14-day orbit, a catch from the K2 extension of the Kepler Space Telescope mission that reminds us of a mathematical constant. As I’m prowling through David Berlinski’s Infinite Ascent (Modern Library, 2011), a quirky and quite lively history of mathematics at the moment, the references to ‘pi in the sky’ that I’m seeing in coverage of the discovery are worth a chuckle. Maybe the Pythagoreans were right that everything is number. Pythagoras would have loved K2-315b and would have speculated on its nature. After all, as Berlinski notes about Pythagoras (ca. 570 to ca. 490 BCE) and his followers, they were devoted to what he calls ‘a higher spookiness”: The Pythagoreans never succeeded in explaining what they meant by claiming that number is the essence of all things. Early in the life of the sect, they conjectured that numbers might be the essence of all things because quite literally “the elements of numbers were the...

Radar for a Giant Planet’s Moons

by Paul Gilster | Sep 22, 2020 | Outer Solar System | 15 Comments

One of my better memories involving space exploration is getting the chance to be at the Jet Propulsion Laboratory to see the Mars rovers Spirit and Opportunity just days before they were shipped off to Florida for their eventual launch. Being near an object that, though crafted by human hands, is about to be a presence on another world is an unusual experience, one that made me reflect on artifacts from deep in the human past and their excavation by archaeologists today. Will future humans one day recover our early robotic explorers? That reflection was prompted by news from JPL that engineers have delivered the key elements of a critical ice-penetrating radar instrument for the European Space Agency's mission to three of Jupiter's icy moons. JUICE -- JUpiter ICy moons Explorer -- is scheduled for a launch in 2022, with plans to orbit Jupiter for three years, involving multiple flybys of both Europa and Callisto, with eventual orbital insertion at Ganymede. Analyses of the interiors...

On White Dwarf Planets as Biosignature Targets

by Paul Gilster | Sep 21, 2020 | Exoplanetary Science | 24 Comments

So often a discovery sets off a follow-up study that strikes me as even more significant in practical terms. This is not for a moment to downplay the accomplishment of Andrew Vanderburg (University of Wisconsin - Madison) and team that discovered a planet in close orbit around a white dwarf. This is the first time we've found a planet that has survived its star's red giant phase and remains in orbit around the remnant, and quite a tight orbit at that. Previously, we've had good evidence only of atmospheric pollution in such stars, indicating infalling material from possible asteroids or other objects during the primary's cataclysmic re-configuration. The white dwarf planet, found via data gathered from TESS (Transiting Exoplanet Survey Satellite) and the Spitzer Space Telescope, makes for quite a discovery. But coming out of this work, I also love the idea of studying such a world with tools we're likely to have soon, such as the James Webb Space Telescope, and on that score, Lisa...

SETI and Altruism: A Dialogue with Keith Cooper

by Paul Gilster | Sep 18, 2020 | Astrobiology and SETI | 72 Comments

Keith Cooper's The Contact Paradox is as thoroughgoing a look at the issues involved in SETI as I have seen in any one volume. After I finished it, I wrote to Keith, a Centauri Dreams contributor from way back, and we began a series of dialogues on SETI and other matters, the first of which ran here last February as Exploring the Contact Paradox. Below is a second installment of our exchanges, which were slowed by external factors at my end, but the correspondence continues. What can we infer from human traits about possible contact with an extraterrestrial culture? And how would we evaluate its level of intelligence? Keith is working on a new book involving both the Cosmic Microwave Background and quantum gravity, the research into which will likewise figure into our future musings that will include SETI but go even further afield. Keith, in our last dialogue I mentioned a factor you singled out in your book The Contact Paradox as hugely significant in our consideration of SETI and...

Odds and Ends on the Clouds of Venus

by Paul Gilster | Sep 17, 2020 | Astrobiology and SETI | 55 Comments

James Gunn may have been the first science fiction author to anticipate the 'new Venus,' i.e., the one we later discovered thanks to observations and Soviet landings on the planet that revealed what its surface was really like. His 1955 tale "The Naked Sky" described "unbearable pressures and burning temperatures" when it ran in Startling Stories for the fall of that year. Gunn was guessing, but we soon learned Venus really did live up to that depiction. I think Larry Niven came up with the best title among SF stories set on the Venus we found in our data. "Becalmed in Hell" is a 1965 tale in Niven's 'Known Space' sequence that deals with clouds of carbon dioxide, hydrochloric and hydrofluoric acids. No more a tropical paradise, this Venus was a serious do-over of Venus as a story environment, and the more we learned about the planet, the worse the scenario got. But when it comes to life in the Venusian clouds -- human, no less -- I always think of Geoffray Landis, not only because...

What Phosphine Means on Venus

by Paul Gilster | Sep 15, 2020 | Astrobiology and SETI | 82 Comments

A biosignature is always going to create a rolling discussion that gradually homes in on a consensus. Which is to say that the recent discovery of phosphine in the upper atmosphere of Venus has inspired a major effort to figure out how phosphine could emerge abiotically. After all, the scientists behind the just published paper on the phosphine discovery seem to be saying something to the community like "We can't come up with a solution other than life to explain this. Maybe you can." The 'maybes' are out there and they include life, but what a tough spot for life to develop, for obvious reasons, not the least of which is the hyper-acidic nature of its clouds. So let's dig into the story a bit more. The idea of life in the cloud layers of an atmosphere has a long pedigree, even on Venus, where discussions go back at least to the 1960s. Harold Morowitz and Carl Sagan examined the matter in a paper in Science in 1967, a speculation that led them to conclude "it is by no means difficult...

Exploring Tidal Heating in Large Moons

by Paul Gilster | Sep 14, 2020 | Outer Solar System | 7 Comments

Io, Jupiter’s large, inner Galilean moon, is the very definition of a tortured surface, as seen in the image below, taken by the Galileo spacecraft in 1997. Discovering volcanic activity -- and plenty of it -- on Io was one of the early Voyager surprises, even if it didn’t surprise astrophysicist Stanton Peale (UC-Santa Barbara) and colleagues, who predicted the phenomenon in a paper published shortly before Voyager 1’s encounter. We now know that Io is home to over 400 active volcanoes, making it the most geologically active body in the Solar System. We’re a long way from the Sun here, but we know to ascribe Io’s surface upheaval to tidal heating forced by the presence of Jupiter as the gravitational forces involved stretch and squeeze not just Io but, of course, Europa, Ganymede and Callisto, all of them interesting because of the possibility of liquid oceans beneath the surface. Io is close enough to the giant world that rock can be melted into magma, but it’s the ice under more...

Janus: Twin Spacecraft to Study Binary Asteroids

by Paul Gilster | Sep 11, 2020 | Outer Solar System | 8 Comments

When we looked earlier this week at the Solaris mission, a concept designed to study the Sun's polar regions, I commented on another early concept called the Auroral Reconstruction CubeSwarm (ARCS). The mission intrigued me because it consisted of CubeSats in swarm formation, working together with numerous ground observatories, to study the Earth's auroras. The paradigm of miniaturization, low cost and creative design surfaces yet again in Janus, a proposal out of the University of Colorado at Boulder and Lockheed Martin that would involve twin spacecraft studying twin targets, the binary asteroids 1996 FG3 and 1991 VH. Daniel Scheeres (CU-Boulder) is principal investigator for Janus, the plan being for the university to handle the analysis of data and images from the mission, with Lockheed Martin building and operating the two spacecraft. It should be a familiar role for both entities, as Lockheed Martin supports operations for OSIRIS-REx at asteroid Bennu, while Scheeres leads the...

OSIRIS-REx: Tracking Bennu’s Unusual Activity

by Paul Gilster | Sep 10, 2020 | Asteroid and Comet Deflection | 10 Comments

OSIRIS-REx, the little spacecraft with the big acronym (standing for Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) has been on station for a year and a half at asteroid Bennu, monitoring the unexpected activity that distinguishes the object. Particle ejection from the surface is the subject of a revised special issue of the Journal of Geophysical Research: Planets collecting 10 papers on the matter. Specifically, the spacecraft has found that particles of rock mostly of pebble-size are being ejected repeatedly -- one or two per day -- from the asteroid’s surface, some of them escaping into space, some moving into a temporary orbit, with the rest falling back onto the surface. Just days after entering orbit on December 31 of 2018, OSIRIS-REx began to spot the activity, which the introduction to the special issue refers to as “ongoing mass shedding” involving millimeter- to centimeter-scale particles. What we have on our hands here is an...

A SETI Search of 10 Million Star Systems

by Paul Gilster | Sep 9, 2020 | Astrobiology and SETI | 27 Comments

As it is considered a precursor installation, the Murchison Widefield Array (MWA) in Western Australia doesn't get the press that its proposed successor, the Square Kilometer Array (SKA) regularly receives. That's to be expected, given the scope of the SKA, which will involve telescopes in both Australia and South Africa. 14 member countries are developing a project that is to reach over a square kilometer of collecting area, containing thousands of dishes and up to a million low-frequency antennas. If it is built, SKA's angular resolution and survey speed will allow surveys thousands of times faster than those now being conducted. But the Murchison precursor is alive and well, working the 70-300 MHz range and mapping the radio sky. Established by a consortium of universities -- MIT, Swinburne, Curtin and Australian National University -- the telescope is located on a site selected by these universities and managed by Curtin University. CSIRO, Australia's national science agency,...

Solaris: To the Sun’s High Latitudes

by Paul Gilster | Sep 8, 2020 | Missions | 34 Comments

I can think of more than one way to get a good look at the Sun's polar regions. After all, we've done it before, through the Ulysses spacecraft, which passed over the Sun's north and south poles in 1994-1995. A gravity assist at Jupiter was the key to the mission, allowing Ulysses to arc out of the ecliptic and inward to the Sun. But Ulysses lacked the kind of remote-sensing instruments we'd like to use to compile an extensive dataset on the polar magnetic field and, as Don Hassler (SwRI) adds, "the surface/sub-surface flows" we might find in the polar regions. It's good to see a mission designed for that purpose. For Hassler is principal investigator on a concept that has just been approved for further study by NASA, with the haunting name Solaris. I say 'haunting' because it's hard for this Stanislaw Lem reader to forget the novel of the same name, published in 1961, that explores the implications of a vast intelligence on a planet far from Earth. I realize this has been done as a...

A Deformed Protoplanetary Disk in a Triple Star System

by Paul Gilster | Sep 4, 2020 | Exoplanetary Science | 8 Comments

This morning we have two interesting and complementary studies of GW Orionis to look at, both analyzing what is apparently a planet-forming disk with multiple, misaligned rings around this triple star system some 1300 light years from the Sun. In the more recent of the two, Stefan Kraus (University of Exeter) and colleagues used data from both the Atacama Large Millimeter/submillimeter Array (ALMA) and the European Observatory's Very Large Telescope (VLT) in detecting warm gas at the inner edge of the misaligned ring, which has broken away from the larger disc, and scattered light from the warped disk surface. So what could be going on at GW Orionis? What the images reveal is an evolving young system much different from our own. Consider: The inner stars GW Ori A and GW Ori B orbit each other at a separation of a scant 1 AU, while the third star, GW Ori C, orbits the inner stars at a distance of roughly 8 AU, the latter in an orbit that is not aligned with the plane of the inner duo....

SETI: Going Deep with the Data Search

by Paul Gilster | Sep 3, 2020 | Astrobiology and SETI | 48 Comments

What Breakthrough Listen is calling the most comprehensive SETI search to date is now in the books, or at least, the journals, with results accepted and in process at Monthly Notices of the Royal Astronomical Society. Here we are in the realm of data reanalysis, using previously acquired results to serve as a matrix for re-calculation, with the catalog produced by the European Space Agency’s Gaia spacecraft as the key that turns the lock. No signatures of extraterrestrial technology were detected in the two analyses produced by Breakthrough Listen in 2017 and 2020. The data for these efforts come largely from the Green Bank Telescope (GBT) in West Virginia and the CSIRO Parkes Radio Telescope in Australia, with a focus on 1327 individual stars. Results were published by the Breakthrough Listen science team at UC-Berkeley, and the choice of targets was telling. The search homed in on relatively nearby stars within about 160 light years of the Sun, under the assumption that less...

Andromeda’s Vast Halo Offers Clues about Galactic Evolution

by Paul Gilster | Sep 2, 2020 | Deep Sky Astronomy & Telescopes | 11 Comments

Wait long enough -- something like 4.5 billion years -- and we'll have a huge elliptical galaxy resulting from the merger of our own Milky Way with Andromeda (M31). I've always been fascinated with Andromeda because being the nearest large galaxy, and a fine spiral at that, it gives us a look at how our own galaxy must appear from the outside. Its faintness to the naked eye belies its size, an object considerably larger than the Moon from our perspective, though best seen, of course, on a Moonless night. And now we learn it is even bigger than we thought. The Absorption Map of Ionized Gas in Andromeda (Project AMIGA) is the source for this information. A new study coming out of this program uses Hubble data to map the vast gas envelope surrounding Andromeda, a diffuse halo of plasma extending 1.3 million light years from the galaxy and in some directions, as far as 2 million light years. To put this into perspective, Andromeda itself is 2.5 million light years away, meaning that our...

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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