A Bit More Detail

We live in an age of miracles and wonders, when our species’ astronomers really can detect relatively fine details of extrasolar planets from the comfort of its home planetary system. Two Universe Today stories today highlighted the scope of our accomplishements, the first being Nancy Atkinson’s post reporting the detection of light by the Spitzer telescope from the superterrestrial planet 55 Cancri e.

The first planet around 55 Cancri was reported in 1997 and 55 Cancri e – the innermost planet in the system — was discovered via radial velocity measurements in 2004. This planet has been studied as much as possible, and astronomers were able to determine its mass and radius.

But now, Spitzer has measured how much infrared light comes from the planet itself. The results reveal the planet is likely dark, and its sun-facing side is more than 2,000 Kelvin (1,726 degrees Celsius, 3,140 degrees Fahrenheit), hot enough to melt metal.

In 2005, Spitzer became the first telescope to detect light from a planet beyond our solar system, when it saw the infrared light of a “hot Jupiter,” a gaseous planet much larger than 55 Cancri e. Since then, other telescopes, including NASA’s Hubble and Kepler space telescopes, have performed similar feats with gas giants using the same method.

In this method, a telescope gazes at a star as a planet circles behind it. When the planet disappears from view, the light from the star system dips ever so slightly, but enough that astronomers can determine how much light came from the planet itself. This information reveals the temperature of a planet, and, in some cases, its atmospheric components. Most other current planet-hunting methods obtain indirect measurements of a planet by observing its effects on the star.

The new information about 55 Cancri e, along with knowing it is about 8.57 Earth masses, the radius is 1.63 times that of Earth, and the density is 10.9 ± 3.1 g cm-3 (the average density of Earth is 5.515 g cm-3), places the planet firmly into the categories of a rocky super-Earth. But it could be surrounded by a layer of water in a “supercritical” state where it is both liquid and gas, and topped by a blanket of steam.

“It could be very similar to Neptune, if you pulled Neptune in toward our sun and watched its atmosphere boil away,” said Michaël Gillon of Université de Liège in Belgium, principal investigator of the research, which appears in the Astrophysical Journal. The lead author is Brice-Olivier Demory of the Massachusetts Institute of Technology in Cambridge.

[. . .]

“When we conceived of Spitzer more than 40 years ago, exoplanets hadn’t even been discovered,” said Michael Werner, Spitzer project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Because Spitzer was built very well, it’s been able to adapt to this new field and make historic advances such as this.”

During Spitzer’s ongoing extended mission, steps were taken to enhance its unique ability to see exoplanets, including 55 Cancri e. Those steps, which included changing the cycling of a heater and using an instrument in a new way, led to improvements in how precisely the telescope points at targets.

Next, Jon Voisey described how one proposed method for detecting the existence of water oceans on distant worlds really isn’t all that. (One method, mind, for now.)

One of the most promising methods was proposed in 2008 and considered the reflective properties of water oceans. In particular when the angle between a light source (a parent star) and an observer is small, the light is not reflected well and ends up being scattered into the ocean. However, if the angle is large, the light is reflected. This effect can be easily seen during sunset over the ocean when the angle is nearly 180° and the ocean waves are tipped with bright reflections and is known as specular reflection.

Translating this to exoplanets, this would imply that planets with oceans should reflect more light during their crescent phases than their gibbous phase. Thus, they proposed, we might detect oceans on extrasolar planets by the “glint” on their oceans. Even better, light reflecting off a smoother surface like water tends to be more polarized than it might be otherwise.

The first criticisms of this hypothesis came in 2010 when other astronomers pointed out that similar effects may be produced on planets with a thick cloud layer could mimic this glinting effect. Thus, the method would likely be invalid unless astronomers were able to accurately model the atmosphere to take its contribution into consideration.

The new paper brings additional challenges by further considering the way material would likely be distributed. Specifically, it is quite likely that planets in the habitable zones without oceans may have polar ice caps (like Mars) which are more reflective all around. Since the polar regions make up a larger percentage of the illuminated body in the crescent phase than during the gibbous, this would naturally lead to a relative diminishing in overall reflectivity and could give false positives for a glint.

This would be especially true for planets that are more oblique (are “tilted”). In this case, the poles receive more sunlight which makes the reflections from any ice caps even more pronounced and mask the effect further. The authors of the new study conclude that this as well as the other difficulties “severely limits the utility of specular reflection for detecting oceans on exoplanets.”

• Centauri Dreams’ Paul Gilster raises the possibility of bringing an asteroid into lunar orbit, for scientific and space-settlement purposes both.
• Daniel Drezner is pleasantly surprised that the situation of Chinese dissident Chen Guangcheng hasn’t led to anything like a breakdown of Sino-American relations.
• Eastern Approaches notes the Polish holiday of “Flag Day” on the 2nd of May, commemorating the substantial Polish participation in the conquest of Berlin in 1945.
• Far Outliers’ Joel discusses the Canary Islands and the role they played in the emerging imperium, both vis-a-vis Portugal and the later imperial strategies of unified Spain.
• Geocurrents describes the Sino-Soviet border disputes in eastern Siberia in 1969 that killed hundreds of people, nearly led to a Sino-Soviet war, and played a critical role in deciding the future of the world.
• Language Hat starts a discussion about the depressing plight of non-Russian languages inside Russia that quickly expands to include discussions of Turkish immigrants in Russia, the situation of Gaelic in Ireland, and Canada’s own language situation.
• Laywers, Guns and Money reviews a book describing how environmentalism in the Colorado ski resort of Aspen helps to legitimate anti-immigrant sentiment.
• At NewAPPSBlog, Mohan Matthen makes the contrarian argument–compelling, but I think ultimately incorrect–that a “Oui” outcome in the 1995 Québec referendum would have been good for Québec and rump Canada both.
• Yorkshire Ranter Alexander Harrowell discusses the consequences of Bo Xilai’s wiretapping of other officials in China, in the context of ubiquitous state surveillance generally.

Universe Today’s Jason Major wrote about a new theory for the formation of brown dwarfs, presented in the Astrophysical Journal paper “A Hybrid Scenario for the Formation of Brown Dwarfs and Very Low Mass Stars” by Basu and Vorobyov.

According to research by Shantanu Basu of the University of Western Ontario and Eduard I. Vorobyov from the University of Vienna in Austria and Russia’s Southern Federal University, brown dwarfs may have been flung out of other protostellar disks as they were forming, taking clumps of material with them to complete their development.

Basu and Vorobyov modeled the dynamics of protostellar disks, the clouds of gas and dust that form “real” stars. (Our own solar system formed from one such disk nearly five billion years ago.) What they found was that given enough angular momentum — that is, spin — the disk could easily eject larger clumps of material while still having enough left over to eventually form a star.

Model of how a clump of low-mass material gets ejected from a disk (S. Basu/E. Vorobyev)

The ejected clumps would then continue condensing into a massive object, but never quite enough to begin hydrogen fusion. Rather than stars, they become brown dwarfs — still radiating heat but nothing like a true star. (And they’re not really brown, by the way… they’re probably more of a dull red.)

In fact a single protostellar disk could eject more than one clump during its development, Basu and Vorobyov found, leading to the creation of multiple brown dwarfs.

If this scenario is indeed the way brown dwarfs form, it stands to reason that the Universe may be full of them. Since they are not very luminous and difficult to detect at long distances, the researchers suggest that brown dwarfs may be part of the answer to the dark matter mystery.

“There could be significant mass in the universe that is locked up in brown dwarfs and contribute at least part of the budget for the universe’s missing dark matter,” Basu said. “And the common idea that the first stars in the early universe were only of very high mass may also need revision.”

Based on this hypothesis, with the potential number of brown dwarfs that could be in our galaxy alone we may find that these “failed stars” are actually quite successful after all.

Over at his blog Infinite Recursion, my old friend Stephen DeGrace wrote a blog post with the above title.

Stephen’s point still stands in the context of Planetary Resources’ announcement, would still stand if it succeeded in its goal of mining asteroids for platinum-group metals. Planetary Resources’ plan wouldn’t involve shipping humans into Earth orbit by the thousands to mine asteroids, but would instead depend on robots. If the robotic asteroid mines were successful, perhaps helping humanity meet its necessary task of producing enough energy to run a high-tech civilization cleanly enough to avoid deterraforming the only world capable of supporting non-trivial numbers of human beings, then manned space travel and even colonization might be viable in the long term. Might. For the time being, getting started on viable robotic asteroid mines is challenge enough.

(Incidentally, after I linked to Stephen’s post on Facebook an extensive discussion got started. The comments are worth reading.)

I feel like manned space travel, especially travel to other planets, is a kind of revenge-of-the-nerds wish fulfillment for many of its proponents. Don’t worry if those ignorant yobs destroy the Earth. They deserve what they get. We will build a new society elsewhere that will be better without their ignorance.

The less negative type of argument is that life on Earth is finite. Since life on Earth will come to an end, humanity will come to an end unless we colonize other worlds. I’m slightly sympathetic to that argument over the very long term, say on a scale of millennia, but over a timescale that matters to any of us, this argument is meaningless.

Note that I am at pains to say manned space flight. I think scientific curiosity is a good enough reason to continue to send unmanned probes into space.

[. . .]

First of all, it is incredibly expensive. Trillions of dollars expensive for major colonization projects. This will represent a significant diversion of resources away from other priorities – it’s not trivial.

Secondly, everywhere in space is very hostile. To put it in perspective, the Antarctic ice cap is a friendly environment compared to anywhere off-Earth in the solar system. Antarctica has water and oxygen, considered major problems to be solved in other settlement schemes, so it already has a leg up. Build thriving cities in Antarctica before you talk to me about the moon.

Thirdly, I am happy to go out on a limb and say that I predict the central speed limit problem of space travel will never go away, i.e., nothing can travel faster than light and we will never find a way around that. So in terms of other solar systems, we would have to put together a mission on a wing and a prayer based on data from automated probes sent to random-ish star systems, with a cycle time of years.

Finally, due to the expense and technical challenges, space travel will never be a mass activity, and any escape hatch into space will be so for only a tiny and privileged few.

No corporation is ever likely to have the resources to do all this, SpaceX notwithstanding, without significant public help. So what, the take-home message is that taxpayers should fund this giant technological whack-off fantasy to the tune of trillions of dollars that will never help most of them in any way out of a nebulous sense of ideological accomplishment in getting some human genes into space? Personally, this is not something I can support.

[. . .]

Space travel was a product of the era of cheap and plentiful energy, which is drawing to a close. Luxuries like space depend on cheap energy, and so to does the ability to feed seven billion people. I think that that latter problem is just slightly more urgent.

Cheap, clean and renewable energy is an absolute prerequisite for humans to have a future more than a generation or two into the future with anything remotely like the lifestyle we want to enjoy and with anything like our present population (i.e., without a massive die-off). Being a humanitarian rather than an environmentalist, this is a vision that I have to endorse. If this problem is solved, then stupid fripperies like space are on the table, but otherwise, space is a waste of valuable time and energy.

Planetary Resources’ announced plan to start evaluating near-Earth asteroids for possible mining is awesome.

Andrew Barton is right: this sort of thing does feel very futuristic.

Can asteroid mining be done safely, in an economic manner? We’ll find out soon enough, I hope. If you could make robotic mining of near-Earth asteroids a viable enterprise in my lifetime, I’d be happy.

A group of wealthy, adventurous entrepreneurs will announce on Apr. 24 a new venture called Planetary Resources, Inc., which plans to send swarms of robots to space to scout asteroids for precious metals and set up mines to bring resources back to Earth, in the process adding trillions of dollars to the global GDP, helping ensure humanity’s prosperity and paving the way for the human settlement of space.

“The resources of Earth pale in comparison to the wealth of the solar system,” said Eric Anderson, who founded the commercial space tourism company Space Adventures, and is co-founder of a new company along with Peter Diamandis, who started the X Prize foundation, which offers prize-based incentives for advanced technology development.

Nearly 9,000 asteroids larger than 150 feet in diameter orbit near the Earth. Some could contain as much platinum as is mined in an entire year on Earth, making them potentially worth several billion dollars each. The right kinds of investment could reap huge rewards for those willing to take the risk.

[. . .]

Despite the promise of astronomical profits, the long time-scales and uncertain return on asteroid mining has historically driven most investors away from such undertakings. But the new company is also backed by a number of other billionaire luminaries, including Google’s CEO Larry Page and executive chairman Eric Schmidt, former Microsoft chief architect Charles Simonyi, and Ross Perot Jr. The venture also counts on filmmaker James Cameron, former astronaut Tom Jones, former JPL engineer Chris Lewicki, and planetary scientist Sara Seager as advisers.

Still, this new undertaking will be much larger and more ambitious than anything Anderson and Diamandis have attempted before. The hurdles are many and high. While the endeavor is technically feasible, the technology has not yet been developed. And beyond their initial steps, the details of Planetary Resources’ plans remain scarce.

[. . .]

In terms of extraction, Planetary Resources hopes to go after the platinum-group metals — which include platinum, palladium, osmium, and iridium — highly valuable commodities used in medical devices, renewable energy products, catalytic converters, and potentially in automotive fuel cells.

Platinum alone is worth around $23,000 a pound — nearly the same as gold. Mining the top few feet of a single modestly sized, half-mile-diameter asteroid could yield around 130 tons of platinum, worth roughly $6 billion.

Within the next 18 to 24 months, Planetary Resources hopes to launch between two and five space-based telescopes at an estimated cost of a few million dollars each that will identify potentially valuable asteroids. Other than their size and orbit, little detailed information is available about the current catalog of near-Earth asteroids. Planetary Resources’ Arkyd-101 Space Telescopes will figure out whether any are worth the trouble of resource extraction.

Proxima Centauri is the star other than the Sun nearest to us, a mere 4.2 light years away. The star is also commonly known as Alpha Centauri C, for the majority of recent studies suggest that Proxima is bound in a distant orbit a half-million years long around the A-B pair. A and B are Sun-like stars; Proxima, in contrast, is a dim red dwarf, with a total luminosity fractions of a percentage of Sol’s even when it flares.

Centauri Dreams has made a couple of posts about Proxima. In the post yesterday, Paul Gilster discusses the nature of Proxima’s orbit around A-B, and the apparently emerging consensus that Proxima does orbit the A-B pair in a distant orbit. If Proxima is gravitationally bound, this has implications for potential life on planets orbiting either star.

Given our age estimates of these stars, that would mean Proxima has orbited Centauri A and B roughly 6500 times. Its presence, note Laughlin and Wertheimer, introduces a mechanism for dislodging comets from outer orbits and pushing them into the inner system(s), allowing for the water they might otherwise lack. Even in terms of astrobiology, then, Proxima Centauri may play a role in making planets around Centauri A and B interesting, not to mention what it offers up in its own right.

What of planets orbiting Proxima Centauri itself? No planets have been definitively sighted in orbit of Proxima, but the state of the astronomical art does set upper limits on the worlds that could orbit it.

p[A] planet larger than Neptune could conceivably still be there around Proxima Centauri, but the odds do not favor it. We also learn from Endl and Kürster that no super-Earths have been detected larger than about 8.5 Earth masses in orbits with a period of less than 100 days. As for the habitable zone of this star — thought to be 0.022 to 0.054 AU, which corresponds to an orbital period ranging from 3.6 to 13.8 days — we can rule out super-Earths of 2-3 Earth masses in circular orbits. Here we pause again: The authors stress that their mass limits apply only to planets in circular orbits. Planets above these mass thresholds could still exist on eccentric orbits around this star.

So no planets yet around Proxima Centauri, and we’re beginning to rule out entire categories of planet here. We also have the possibility of smaller worlds in interesting orbits. The encouraging thing is that the radial velocity work on Proxima is getting better and better, and the authors see us closing in on planets of Earth size[.]

Might an Earth-mass planet orbit Proxima in the habitable zone? Sure, but it would be exposed to flares, great upsurges of radiation that would complicate life.

More, doubtless, to come.

Centauri Dreams’ Paul Gilster reports on the search for Earth-size–and potentially Earth-like–planets orbiting one of the stars of Alpha Centauri, nearest star system to our own. Alpha Centauri A and B are both broadly Sun-like stars, A brighter than B, are roughly as old as our sun, and computer models suggest that rocky planets could form around the two stars and enjoy stable orbits. According to Gilster, the discovery is just a matter of time and money.

A warm and cozy planet around the K-class Centauri B would be just the ticket, and the planet hunt continues. One thing we’ve learned in the past decade is that neither Centauri A or B is orbited by a gas giant — planets of this size should have shown up in the data by now. We’ve also learned that stable orbits reach out maybe 2 AU from either star. Remember that while Centauri A and B are separated by almost 40 AU at their widest point, they close to within 11 AU, thus disrupting outer orbits, as demonstrated by computer simulations. We should expect planets, if they exist, to be no further out than the main asteroid belt in our own system.

Debra Fischer (Yale University) has been working on the Alpha Centauri problem at Cerro Tololo (Chile) in addition to her efforts at improving instrument sensitivity for planet hunting at the Keck and Lick observatories. The goal is to reach the precision needed to turn up planets the size of the Earth with radial velocity methods. If we’re going to get a Centauri detection, odds are it favors Centauri B because A does not seem to be as stable as B, and the latter is more likely to be the first to yield what Fischer calls the ‘tiny whisper’ that would flag an Earth-like world. Usefully, the 79 degree orbital plane of these stars means that planets in this system, assuming they share this tilt, should be generating a reflex velocity close to the line of sight from the Earth.

Radial velocity methods, in other words, should work here if we can attain sufficient sensitivity. The detection effort calls for telescope time at the Cerro Tololo Inter-American Observatory this spring and summer, and The Planetary Society is campaigning to raise money to support the effort. What Fischer needs is 20 nights of observing time, but the team’s NASA and NSF grants cannot be used to pay for telescope time, which at Cerro Tololo runs to $1650 per night. A total of $33,000 will do it, then, money the community should be able to raise. Have a look at the Planetary Society’s donation page and let’s see if we can’t make this happen.

Anyone involved with The Planetary Society is probably already aware of Fischer’s work with astronomer and Tau Zero practitioner Geoff Marcy (UC-Berkeley) on FINDS Exo-Earths (Fiber-optic Improved Next generation Doppler Search for Exo-Earths). The collaboration has resulted in a high-end optical system installed on the 3-meter Lick Observatory telescope and is now feeding the FINDS 2 effort to provide advanced optics for the Keck Observatory in Hawaii. Marcy and Fischer are working with a fiber optics array that adjusts light entering the telescope’s spectrometer and an adaptive optics system that offers the best signal to noise ratio.

FINDS worked out well at the Lick Observatory, improving the ability to detect Doppler velocities from the pre-existing 5 meters per second down to the 1 meter per second range, allowing us to detect smaller planets. Fischer and Marcy are hopeful of attaining precisions down to 0.5 meters per second with their work at Keck, which should get us into the range of Earth-sized planets. FINDS 2 will then be used with Keck to provide follow-up data about planets found by the Kepler mission, ruling out false positives in the ongoing hunt for planets like our own. The work on FINDS has led directly into the commissioning of a new spectrometer at Cerro-Tololo.

Jason Major’s Universe Today post highlights the latest discovery about Ontario Lacus, a lake in Titan’s south polar region that may well be not a permanent body of liquid but rather an intermittent one, a basin that’s empty most of the time but fills up when new liquid is introduced, probably precipitation in the case of Ontario Lacus.

I find it amusing that Titan, with its cryogenic environment, is a world that may be too hot for year-round lakes, even in its polar region. Calling Titan an icy desert makes sense.

Ontario Lacus, so named because of its similarity both in shape and size to Lake Ontario here on Earth, was first discovered near the south pole of Titan by the Cassini spacecraft in 2009. Its smooth, dark appearance in radar images indicated a uniform and reflective surface, implying a large — although likely shallow — body of liquid.

Of course, on Titan the liquid isn’t water — it’s methane, which is the main ingredient of the hydrologic cycle found on the giant moon. That far from the Sun the temperatures at Titan’s poles fall to a frigid -300ºF (-185ºC), much too cold for water to exist as a liquid and so, on this world, methane has taken its place.

A research team led by Thomas Cornet of the Université de Nantes, France has taken a closer look at Cassini’s radar data of Ontario Lacus and found evidence of channels carved into the southern portion. According to the team, this likely indicates that the lakebed surface is exposed.

“We conclude that the solid floor of Ontario Lacus is most probably exposed in those areas,” said Cornet.

In addition, sediment layers surrounding the lake suggest that the liquid level has varied.

All in all, this reveals a striking resemblance between Ontario Lacus and Namibia’s Etosha Pan — an “ephemeral lake” that is dry for much of the year, occasionally filling with a shallow layer of water which evaporates, leaving salty rings of sediment.

[. . .]

Although Ontario Lacus was initially thought to be permanently filled with liquid hydrocarbons, the team’s findings draw a strong correlation with this well-known Earthly environment, suggesting a much more temporary nature and showing the value of comparative research.

Images of Lake Ontario and Ontario Lacus are below.

• A BCer in Toronto’s Jeff Jedras argues that the Liberal Party should try to become the party of federalists, inside Québec particularly.
• Centauri Dreams links to astudy suggesting that elliptical galaxies, older galaxies with less dust than our Milky Way, could still support planets and potential life.
• Geocurrents reports on the various problems–economic, environmental, political–facing the timber industtry in the Russian Far East.
• Marginal Revolution’s Tyler Cowen questions Ross Douthat’s arguments about the decline of religious practice and its imports in the United States by wondering how, given the social and economic changes of the post-war period, this could have been prevented.
• Naked Anthropologist Laura Agustín takes issue with a recent New York Times article on the sex trade in Spain. Unquestioned narratives are not good analysis.
• At Personal Reflections, Paul Belshaw considers definitions of the Enlightenment and civilization as seen from different places–West versus non-West, England versus Scotland–with links.
• Registan’s Nathan Hamm comments on the unseemly ties between Susan G. Komen Uzbekistan Race for the Cure, a breast cancer charity that recently featured in the American culture war, and various charities run by Gulnora Karimova, daughter of Uzbekistan’s dictator.
• Torontoist’s Jamie Woo makes the point that Rob Ford’s disinterest in doing anything with Pride doesn’t speak to his being very up-to-date.
• Kenneth Anderson at the Volokh Conspiracy notes that the background of the emergent war between the Sudans over oil pipelines proves that clear property rights can diminish conflict.

The latest news item announcing that the experiments used by the Vikings Mars landers of the 1970s to determine if there might be Mars actually did detect life, just life that we did know how to identify back in the 1970s before we learned of the extremophiles of Earth, something that Livejournaler absinthe-dot-ca linked to, just as james-nicoll did. The former linked to the paper, “Complexity Analysis of the Viking Labeled Release Experiments”.

The only extraterrestrial life detection experiments ever conducted were the three which were components of the 1976 Viking Mission to Mars. Of these, only the Labeled Release experiment obtained a clearly positive response. In this experiment 14C radiolabeled nutrient was added to the Mars soil samples. Active soils exhibited rapid, substantial gas release. The gas was probably CO2 and, possibly, other radiocarbon-containing gases. We have applied complexity analysis to the Viking LR data. Measures of mathematical complexity permit deep analysis of data structure along continua including signal vs. noise, entropy vs.negentropy, periodicity vs. aperiodicity, order vs. disorder etc. We have employed seven complexity variables, all derived from LR data, to show that Viking LR active responses can be distinguished from controls via cluster analysis and other multivariate techniques. Furthermore, Martian LR active response data cluster with known biological time series while the control data cluster with purely physical measures. We conclude that the complexity pattern seen in active experiments strongly suggests biology while the different pattern in the control responses is more likely to be non-biological. Control responses that exhibit relatively low initial order rapidly devolve into near-random noise, while the active experiments exhibit higher initial order which decays only slowly. This suggests a robust biological response. These analyses support the interpretation that the Viking LR experiment did detect extant microbial life on Mars.

At best, this is provocative stuff, and makes the case for a followup mission to Mars. Comments in Jason Major’s Universe Today item make the point that retroactive analyses of the data are great at picking up patterns, just patterns that are imposed by the researchers combing through the data again as much as patterns that actually exist. One of the authors of the paper, Gilbert Levin, designed some of the Viking probes’ life-detection experimental kit and has since argued at length that NASA scientists almost went of their way to interpret the evidence as proof of an absence of life.