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Hi everyone! Sorry that the posts were thin on the ground last week. The head druid told me that I needed to honor the solstice by taking some time to reflect on the meaning of things [citation needed]. Anyway…since I didn’t blog last week, I failed to post these astonishing pictures of Jupiter’s giant moon Ganymede, which were photographed by NASA’s Juno spacecraft as it slaloms though the Jovian system.
Although its lack of atmosphere and pockmarked plains of dust make it superficially resemble Earth’s moon, Gannymede is a very strange and unique heavenly object Of the 200 known moons in the solar system, it is the largest. Indeed it is 26% larger than the planet Mercury by volume (although it is only 45% as massive as the metalliferous first planet). Ganymede has a diameter of 5,268 km (3,273 mi), so each pixel in the full size image of the Jovian moon is equal to a kilometer (although you may want to check out the NASA image to really savor that scale–since WordPress has a noteworthy penchant for scrunching up my images in incomprehensible ways).
Alone among moons in the solar system, Ganymede has a magnetic field, albeit a rather meager one compared to Earth or Jupiter. Scientists surmise that the magnetic field is created by convection within the liquid iron core of the moon–although answers are not forthcoming as to why it has a liquid iron core to begin with (these planetary cores seem to be the real determinant of what planets are like, but I feel like we know precious little about them). Thanks to its size (and maybe thanks also to its magnetosphere), Ganymede has a very thin oxygen atmosphere…but that just creates more question, since elemental Oxygen has a tendency to instantly bond to all sorts of other elements. The 20 percent or so of oxygen in Earth’s atmosphere did not become a mainstay until about 1.5 billion years ago when photosynthesizing bacteria finally became so prevalent that they overcame the constant loss of atmospheric oxygen thanks to oxidation. Hopefully Juno’s survey will help us solve atmospheric mysteries on Ganymede. Ganymede is also believed to have a vast subsurface ocean of icy water tucked away somewehere beneath its surface. Astronomers have reasonably speculated that this Ganymede underworld ocean may contain more water than all of Earth’s oceans combined!
Ganymede is a Galilean moon–which means it was discovered by the great scientist, and is one of the first objects ever discovered to orbiting another planet (I still sometimes imagine the thrill Galileo must have felt when he realized what he was seeing). I wonder what surprises Juno will send back for us!
There is thrilling news for fans of our nearest planetary neighbor, the mysterious and beautiful hell-world, Venus. NASA has just announced two exploratory missions to Earth’s hot-mess of a twin. Long-time readers know that, in addition to dreaming of floating cities and artificial ecosystems on Venus in the future, Ferrebeekeeper is fascinated by the planet’s past.
In the early twentieth century, astronomers thought that beneath the clouds of Venus, there might be a lush jungle or tropical swamp teeming with strange sensuous lifeforms. Alas, the first probe to descend below the clouds melted on a surface hot enough to, uh, melt solidly constructed Soviet space probes. Enthusiasts of space colonization (and enthusiasts of exploring planets that a human visitor might possibly survive) quickly turned their attention elsewhere. But those sweaty palmed early twentieth century space buffs were not necessarily wrong. A billion years ago, Venus may well have had liquid oceans and temperate skies (if not necessarily lizard men and sultry Amazons), but then something went appallingly wrong and the world melted. The seas boiled away (assuming they ever existed). The sky turned into a mad scientist’s pressure cooker, and the surface turned inside out through a strange planet-wide volcanic process.
If this happened to your next-door neighbors’ place, you would probably be curious about what happened! Even if you didn’t care much about your neighbors, there would be prudent reasons of self-interest to figure out why their once comfy home was now 470 degrees Celsius with an atmospheric pressure akin to what is found a kilometer below the waves of Earth’s oceans! However what happens in a speck of light in the night sky is an abstract concern to a lot of people and Venus exploration has languished for decades…until now!
NASA has finally decided to see if Venus ever had liquid oceans or a surface akin to that of Earth. In coming years, the space agency will launch the DAVINCI and the VERITAS missions. Davinci will feature a spherical falling probe which will comprehensively assay Venus’ atmosphere as it drops through the clouds. Not only will Davinci sniff for traces of a lost ocean, it will seek other gases and volatile compounds which can tell us about the past of the planet (and whether we could build a flying cloud city there in the present). It will also photograph the perplexing “tesserae” features of Venus’ surface in high definition.
Veritas is even more concerned with the surface of Venus and will scan and observe the planet by means of next generation imaging technology. This should tell us about the surface (and deeper features) of the planet and finally answer whether the planet is still geologically active and document what it is actually made of. Answers to profound questions about our sister world are finally forthcoming! If you would like to know technical specifications about these missions, you should head over to NASA’s webpage.
We will be talking more about Venus as the missions get closer, but isn’t it thrilling to finally have some good news!
There is an enormous hexagonal storm on the north pole of Saturn which is large enough to drop the Earth into. Ferrebeekeeper has long been fascinated by this giant yet geometrically-regular storm, and that was before we learned that the hexastorm…changes color!
Like Earth, Saturn is tilted, and, as with Earth, the tilt affects how much sunlight reaches different hemispheres of the planet as it proceeds around the sun. Since Saturn is rather farther from the sun than the Earth is, a Saturn “year” lasts for 29 Earth years. Due to this somewhat lengthened calendar (and because we have only recently acquired some of the necessary tools to study other planets) the seasonal variances on Saturn are only now being recognized.
Using the Hubble Space telescope, scientists have been keeping an eye on Saturn’s seasons (each of which last for 7.25 years). As summer in the northern hemisphere changes to fall, the color of the atmosphere is changing and so are the appearances of the bands within the atmosphere. NASA scientists speculate that increased sunlight may lead to increased photochemical hazes in the atmosphere which causes the shift from winter blue to summer gold. As we continue to study Saturn in years to come, it will be interesting to see how much of this color shift is seasonal and how much it changes based on larger cycles.
Have you seen photos of Venus? When the planet is observed in visible light it looks like a big bland ecru ball (see above). Put a whiteboard and some plastic rolling chairs on that puppy and you would have a corporate conference room in some awful suburban office-park. Yet ultraviolet imaging of Venus paints a somewhat more interesting picture of swirling bands or darkness in the heady acid atmosphere of our sister planet. But what does that mean?
The dark bands turn out to be the result of sulfur compounds (carbonyl sulfide, hydrogen sulfide and sulfur dioxide) and other yet unknown chemical compounds in the upper atmosphere of Venus. On Earth these sulfur compounds are hallmarks of life…or of volcanic activity. Some scientists are provocatively asking whether extremophile bacteria could have a place in the temperate upper atmosphere of Earth’ closest planetary neighbor. The bacteria could use the rich sulfur and carbon clouds as building blocks and the UV (and other EM radiation!) bombardment of the sun for energy. Perhaps, they muse, these dark bands are something akin to algal blooms in Earth’s oceans.
More than a billion years ago, Venus enjoyed a period of prolonged earthlike climate with surface water and an atmosphere which was not so hellishly heavy and hot. But something went hideously awry and runaway greenhouse effect created a terrible feedback loop which changed the planet’s surface into the monstrous place it is today. Apparently the igneous/volcanic processes of Venus are rather different than those of Earth, so it was probably not all treeferns, friendly dinosaurs, and bikini-clad aliens even before the runaway greenhouse phase melted away the old surface of Venus, but perhaps bacteria (or analogous lifeforms) could have evolved and escaped the catastrophe by moving into the upper clouds (which, as previously noted here, have temperatures not unlike those of Earth’s surface).
My guess is that Venus is lifeless as a jackhammer (though, like a jackhammer it can give the alarming appearance of life), yet even if this is the case, we should know more about all of this! What happened to Venus’ original surface? Was there ever life there? What is going on with its volcanoes and internal geology? What is the composition of the clouds of Venus? Is there anything there other than strange sufur compounds and esoteric hydrocarbons formed from the mixture of sulfur, carbon dioxide, and UV radiation? Once again, our nearest neighbor is beckoning. We need to move forward with sophisticated atmospheric probes (like VAMP) and NASA should collaborate with Russia on their next Venus mission (it looks like our governments are closer than ever anyway). For some reason, popular imagination disdains Venus, yet the questions there seem salient, and the possibilities for a nearby Earth-sized world of unlimited energy and resources seem, well, unlimited.
This Friday September 15th is the final day of the astounding Cassini mission. The robotic space probe just took a final picture of Titan (which was arguably the site of the mission’s most breathtaking discoveries) and now the little spacecraft turns towards Saturn’s north pole and the grand finale…a plunge into the crushing atmosphere of the gas giant planet. A joint effort between NASA and the Italian space agency, Cassini launched in 1997 (the year I came to New York) and for 20 years it has sailed the solar system. In 2004, the craft reached Saturn and it has been discovering moons, taking pictures, and otherwise exploring the system ever since. Cassini even launched a lander to the surface of Titan, a super moon with a thick atmosphere and methane oceans.
All good things must end though, and Cassini is out of fuel. Mission scientists did not wish to leave the craft orbiting for thousands of years and they also hoped to get a last trove of data (and jolt of publicity) from the mission…so the controllers opted to fly Cassini straight into the planet to learn whatever they can before the minivan sized probe blows apart and/or is crushed. Sadly there is no camera to record this melodramatic demise (which the denizens of Earth will want to see) so I have created my own rendition of the craft’s final descent using the magic of art (image at top). Since Saturn does not have an oxidizing atmosphere (probably?) and Cassini does not talk (probably?) I took a few artistic liberties, however I think I got the great hexagonal storm on the gas giant pretty well and I also captured some of the endearing personality of an astonishing robot explorer which will be dearly missed.
Seven hundred million miles away the Cassini spacecraft is preparing for death this coming September (2017). Launched in 1997 (when I moved to Brooklyn) the joint Italian/American space exploration mission to Saturn has seen and done things beyond comprehension. Lifted out of Earth’s gravity well by means of a Titan IVB/Centaur It flew through the nothingness and slingshotted around Venus (twice), the Earth, and Jupiter. It discovered new oceans on Enceladus and launched a lander onto the supermoon Titan (the first ever landing in the outer solar system). Cassini was used to tested general relativity: the craft broadcast radio past the sun to the Earth so that scientists could measure how the star’s gravity distorted the electromagnetic waves. Powered only by pluck (and, uh, 33 kilograms of plutonium-238) the little probe visited 20 moons.
But all good things come to an end, and this final phase may be the most dramatic. On April 26th the craft began weaving between Saturn’s rings and the top of the planet’s atmosphere. The image at the top is an artist’s conception of how this might look for Cassini. The second image is a picture of the enormous hexagonal storm at the north pole taken April 30th. The image below is an infrared picture of Saturn. Cassini is scheduled to make 20 more of these passes before its final fiery plunge into Saturn itself, so prepare for more mind-boggling images of the gas giant.
Artist’s conception of Venus Express above Venus (ESA)
Tomorrow I will write the obligatory annual post about whom we lost in 2014. It’s always a solemn occasion which highlights the passing of many eminent figures (as well as the passing of yet another year) and raises troubling questions about what is truly important. But before we get to the human obituaries, I wanted to write a quick eulogy for an underappreciated figure lost to little fanfare at the end of 2014. Last month the robot explorer craft “Venus Express” was destroyed by falling into the volatile high-pressure atmosphere of our sister planet Venus (an operatic end which overshadows all but the greatest human deeds). The Venus Express was a satellite launched by the European Space Agency in November 2005. It reached polar orbit around Venus in April of 2006 and has been continuously sending back data since then until November 28th of 2014 when the last remaining fuel in the satellite was used to lift it into a high orbit. Scientists planned on monitoring the space probe during its long drift down to the top of the atmosphere, but something went wrong and the satellite was thrown into a spin (which made it unable to contact Earth). It is now presumed destroyed.
Venus Express was the first Venus mission undertaken by the ESA. Now that the craft is gone, the human race has no functional probes or spacecraft on or around Venus until the Japanese climate orbiter “AKATSUKI” is scheduled to reach there sometime in 2015 (although there have been some problems with that mission and the planned rendezvous may be postponed…or never happen).
This still from a NASA animation of a concept Venus mission shows a probe, one of many, beginning its descent into the Venus atmosphere.
Venus’ atmosphere is believed to have once been much like that of Earth. This is certainly not the case now! The data from Venus Express is now being analyzed in order to ascertain what happened to transform Venus into a hellish greenhouse (and strip it of its magnetosphere). Maybe we can also analyze this data with an eye on future sky colonies as well. Venus Express discovered hydroxyls in the atmosphere of Venus. It also discovered an ozone layer and a high cold atmospheric layer which is possibly dry ice. It undertook a series of aerobraking experiments which could prove very relevant to future craft inserted into Venus’ atmosphere. We need someone to analyze this data and plan those future missions! Speaking of which, why doesn’t NASA have more exploratory missions planned to this nearest planet? We should try to put a long-term floating probe into the upper atmosphere of Venus itself! That would be an amazing accomplishment and it would tell us more about whether floating sky colonies above Venus would even be possible. Nothing is more alluring than Venus! Let’s honor the Venus Express by learning from it and sending some more missions there pronto!
The Birth of Venus (Henry Courtney Selous, 1852, oil on canvas)
The Three Trees (Rembrandt Harmenszoon van Rijn, 1643, intaglio print)
It is Rembrandt’s birthday again—happy birthday to the great artist! Last year we looked at an enigmatic painting by the great Dutch master which could have represented several different mythological/historical scenes. This year instead of celebrating with one of his astonishing paintings of people, we turn instead to an intaglio print which Rembrandt made by combining etching, drypoint, and direct hand manipulation of the printer’s ink. Uncharacteristically, humankind is not the direct subject of the print (although if you enlarge the image, you will discover both a fisherman plying his luck at the river and a yokel loitering in the fields). Three monumental trees loom over the flat Dutch landscape—but their symbolism, if any, is not overt. A bustling city sprawls in the background, but it too is not the focal point on the composition. The real subject is the darkling sky which roils with strange clouds, abstruse turbulence, and glorious patches of sunlight. The world changes with astonishing speed: the mutable clouds are the most direct manifestation of the ever shifting nature of reality, yet the country dwellers, cows, city, and even the long-lived trees all seem to partake of the same impermanence.
When I was a child, my favorite tv show was Carl Sagan’s Cosmos. Although the good doctor’s naïveté about cold war politics sometimes dismayed my realpolitik-minded parents, the amazing breadth of his show’s exploration of the natural world–and the wider universe beyond–was a wonder to me. For the first time I was introduced to quasars, pulsars, and stellar aging. From Sagan’s delightfully filmed documentary, I learned about Kepler, the Kreb’s cycle, DNA pair sequencing, and the great library of Alexandria. The eclectic scope of Cosmos was a direct inspiration for this blog (although I can hardly claim to be such a polymath). Hopefully the new Cosmos–with a new science hero, Neil deGrasse Tyson–will inspire today’s generation of children to look beyond sports and the internet up to the soaring science of the firmament!
Jovian Life Envisioned by Adolf Schaller for COSMOS, Carl Sagan (1980)
My very favorite segment of Cosmos however, did not involve real science at all, but rather airy speculation about extraterrestrial life on a gas giant planet. Carl Sagan, his physicist colleague, E. E. Saltpeter, and the space artist, Adolf Schaller, worked together to imagine a floating ecosystem which might exist on a planet such as Jupiter. In the tempestuous atmosphere of such a world, ammonia, hydrogen, methane, and water are violently stirred together to form organic molecules. Small drifting organisms might feed on these compounds and reproduce as lighter spores before air currents bear them down to their doom (in a cycle reminiscent of phytoplankton). Giant floating life-forms like living hot-air balloons would stay in the habitable zone of the atmosphere by photosynthesis or by grazing on the microscopic “plankton”. These beings could be kilometers in diameter and would congregate in vast aerial schools. Sagan and Saltpeter even envisioned jet-propulsion super predators which would blast through the alien skies feeding on the huge clouds of “floaters”.
It is a tremendously compelling vision! Now, whenever NASA or ESA releases a new list of exoplanets, I pause to wonder whether such alien creatures are actually found floating on the super-Jupiters and strange giant worlds which orbit far-off stars. However today I would like to present an even more fantastic vision—and one which humankind could actually create! By combining Sagan’s imaginary vision with contemporary aerospace and biotech research, it is possible to visualize my own fantasy of human colonization of Venus…or even upon other worlds with complex atmospheres.
Ornithopter based on Jellyfish (Dr. Ristroph and Dr. Childress)
Just this year, two aeronautical engineers, Dr. Ristroph and Dr. Childress, crafted an ornithopter based on the swimming motion of a jellyfish. The tiny mechanism relies on four teardrop-shaped wings oriented around a dome-like apex to achieve stable, directed flight. At the same time a new array of futuristic blimps, zeppelins and dirigibles are being brought to market to transform the skies of earth. Most importantly Craig Ventner, the bioengineer-entrepreneur, is out there sampling the esoteric genetics of the deep ocean and forging ahead with synthetic genomics (which is to say he is building new living things from scratch). In our lifetime someone will figure out how to meld Ventner’s synthetic organisms with the advanced engineering and technology which are the hallmark of our age. The possibilities then grow exponentially out of this world.
“Space Zeppelin” by Rugose.
Imagine if the floating ecosphere invented by Sagan and Saltpeter were instead a floating society-economy based on advanced engineering and bioengineering. There would be levitating cities which are also bioengineered life-forms (like the vast balloon beings of Sagan’s invention). Between these cloud cities would fly flocks of tiny ornithopters that would gather resources for further farming/engineering.
Jet propelled aircrafts and super habitats would zip between the living arcologies. Armored crawlers would inch through the deeper layers of atmosphere or creep along the molten pressurized ground. Eventually there might be flying bio-colonies which self arrange out of many highly specialized flying zooids—like the siphonophores which are so prevalent in our oceans! These collective entities would act as sky factories to build an ever more symbiotic and efficient synthetic ecosystem. Humankind, living things, and technology would no longer be at odds but would grow together to form the ideal world of tomorrow. Life, beautiful and united would expand to new planets and develop into a stronger, brighter presence in the cosmos.
Siphonophorae (Ernst Haeckel, 1904, plate 7 of “Kunstformen der Natur”)
Humankind is always fixating on the Moon and Mars as the most likely spots for the first space colonies, but there is another crazy possibility. Aside from the Sun and the Moon, Venus is the brightest object in the night sky. Earth’s closest planetary neighbor, Venus is a veritable sister planet with extremely similar mass and volume. Because of its size and position in the solar system, a great deal of early science fiction concentrated around Venus. Dreamers and fabulists posited that beneath its ominously uniform cloud cover was a lush tropical rainforest filled with lizard people and pulchritudinous scantily clad women (the fact that the planet’s Greco-Roman name is synonymous with the goddess of love and beauty seems to have influenced many generations of male space enthusiasts).
Maybe we should head over there and check it out…
Alas, the space age quickly dispensed with mankind’s sweaty-palmed fantasies about life on Venus. In 1970 the Soviet space probe, Venera 7, was the first spacecraft to successfully land on another planet (after a long series of earlier space probes were melted or crushed by atmospheric pressure). In the 23 minute window before the probe’s instruments failed, the craft recorded hellish extremes of temperature and pressure. The temperature on Venus’ surface averages around 500 °C (932 °F), (higher than the melting point of lead) and the pressure on the ground is equal to the pressure beneath a kilometer of earth’s ocean. The planet’s surface is a gloomy desertlike shell of slabs interspersed with weird volcanic features not found elsewhere in the solar system (which have strange names like “farra”,” novae”, and “arachnoids”). Additionally the broiling surface is scarred by huge impact craters, and intersected by immense volcanic mountains (the tallest of which looms 2 kilometers above Everest). The tops of these mountains are covered with a metallic snow made of elemental tellurium or lead sulfide (probably).
A photo of the surface of Venus from Venera 13
The atmosphere of Venus is a hellish fug of carbon dioxide which traps the sun’s energy in a self replicating greenhouse gone wrong. Above the dense clouds of CO2, the upper atmosphere is dominated by sulfur dioxide and corrosive sulfuric acid. Once Venus may have had water oceans and more earth-like conditions, but rampant greenhouse heating caused a feedback loop which caused the planet to become superheated billions of years ago. Without an magnetosphere, solar winds stripped Venus of its molecular hydrogen (yikes!).
Artist’s Impression of the Surface of Venus
Thus Venus does not initially present a very appealing picture for colonization! Yet the planet’s mass is similar to Earth (and humans’ long term viability in low gravity is far from certain). The planet is closer than Mars and windows of opportunity for travel are more frequent. Fifty kilometers (30 miles) above the surface of Venus, the temperature is stable between 0 and 50 degrees Celsius (32 to 122 degrees Fahrenheit). Light crafts filled with oxygen and nitrogen would float above the dense carbon dioxide. Today’s visionaries and dreamers therefore have stopped thinking of tropical jungles and envision instead a world of Aerostats and floating cities. Although the rotation of Venus is too slow to craft a space elevator, the flying colonists of Venus probably could build some sort of skyhook with existing or near future technology. Such a hook could be used to lift raw materials from the surface to manufacturing facilities in the skies. As more aerostat habitats were built, the colony would gain manufacturing strength, safety, and a greater ability to alter the barren world below (increasingly overshadowed by flying cities and hovering countries).
Imagine then a world like that of the Jetsons where the surface was unseen and not thought about (except by scientists and industrialists). Floating forests and croplands could be assembled to mimic earth habitats and provide resources for a bourgeoning population of Venusian humans. Skyships would cruise between the flying city states dotted jewel-like in the glowing heavens. Over time these flying habitats could be used to alter the planetary temperature and shield the desolate lands below. Humankind and whatever friends and stowaways came with us would finally have a second home in easy shouting distance of Earth. How long would it be then before we took steps to take Earth life even farther into the universe?
ferrebeekeeper 