You are currently browsing the tag archive for the ‘extraterrestrial’ tag.
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”)
Exciting news from the heavens! Today NASA has reported that the Kepler mission has discovered 3 new planets in the habitable zones of two distant stars. Of the thousands of worlds so far discovered, these three are most likely to be habitable. Best of all the planets are crazy!
Kepler is a NASA space telescope which was launched on March, 2009. It makes use of an incredibly sensitive photometer to simultaneously & incessantly monitor the brightness of over 150,000 nearby stars. The brightness of a star dims slightly whenever an exoplanet transits between it and Kepler. Thanks to Kepler’s inhuman vigilance and robotic ability to perceive nearly imperceptible light changes, we are now discovering thousands of new planets, although most of them are Jovian sized gas worlds.
Kepler Space Telescope
The three worlds reported today lie in the habitable zone—the region around a star where water exists in a liquid form (as it does here on beautiful Earth). Two of the newly discovered habitable zone planets are in a five planet system orbiting a dwarf star just two-thirds the size of the sun which lies 1,200 light years from Earth. Here is a diagram of the Kepler 62 system.
Kepler 62 System (Art by NASA)
Of these five worlds, two lie in the habitable zone, Kepler 62f and Kepler 62e. Kepler 62 F is most likely a rocky planet and is only 40 percent larger than Earth. It has an orbit which last 267 (Earth) days. So far it is the smallest exoplanet found in the habitable zone. The star it orbits is 7 billion years old (as opposed to the sun which is four and a half billion years old) so life would have had plenty of time to develop. The other habitable zone planet in the Kepler 62 system, Kepler 62e is probably about 60% larger than our planet. It is somewhat closer to the star and astrophysicists speculate it may be a water world of deep oceans.
No! Not that sort of Waterworld!
The other new exoplanet Kepler-69c appears to orbit a star very similar to Earth’s sun. It orbits at the inward edge of the habitable zone (nearing where Venus is in our solar system) so it may be hot. The planet is estimated to be about 70% larger than Earth, and is also thought to be a water world with oceans thousands of kilometers deep. I am finding it impossible not to imagine those vast oceans filled with asbestos shelled sea-turtles the size of dump trucks, huge shoals of thermophile micro-squid, and burning-hot chartreuse uber-penguins, but if any life is actually on Kepler-69c, it is probably extremely different from Earth life.
I understand why they are green and have gills, but why are they inside gelatin capsules? (DC Comics)
Of course Kepler can only find these planets; it is unable to observe very much about them. In order to do that, humankind will need some sort of huge amazing super telescope. Speaking of which, tune in next week when I write about humankind’s plans for building a huge amazing super telescope in the Chilean Andes!
Gibbous Europa
(Credit: Galileo Project, JPL, NASA)
Tonight is Yuri’s Night, when space enthusiasts around the world celebrate the first human trip to outer space made by Yuri Gagarin fifty two years ago. You can read about Yuri here. It is an excellent occasion to assess what is most exciting in space exploration. Unfortunately nobody has jumped forward to build a floating colony on Venus. Indeed NASA seems rather flat footed lately—building a series of colorless rockets and sending successive similar rovers to Mars. Fortunately there is one exciting mission which still has not definitively been cancelled because of budget stalemate.
Proposed Europa Clipper (NASA)
The Europa Clipper mission is a $2bn dollar project to launch a probe to Jupiter’s moon Europa, a large icy satellite covered in cracked ice. Europa is slightly smaller than Earth’s moon and has a thin oxygen atmosphere. It is one of the smoothest items in the solar system. Astronomers believe that an ocean of liquid water lies beneath Europa which is warmed by tidal flexing (a process which causes orbital and rotational energy to be converted into heat). The surface of Europa is bathed in exotic radiation which rips apart water molecules and leaves oxidants like hydrogen peroxide. All of this means that Europa is the most likely planet in the solar system to harbor unknown life. It has even been theorized that beneath the ice the ocean could have black smoker type environments–and just possibly thermal vent or “cold seep” ecosystems.
Artist’s concept of the cryobot and hydrobot probes (NASA)
Because of this, scientists have been anxious to get a closer look at the intriguing moon. Various proposals have been put forward for missions directly to the moon. The Pioneer and Voyager spacecraft took pictures of it as they flew through the solar system and subsequent missions also took readings and photos—but there has been no Europa-centric mission to really find out about the oceans below the cracked ice. One (amazing!) proposal was to send a nuclear powered melt probe to melt through the ice and sink to the bottom of the ocean, whereupon a mini-sub probe would emerge and explore the extraterrestrial ocean! That plan was shelved because it was too expensive (and nobody could figure out how to sterilize the probe). The proposed Europa Clipper mission is more modest but still quite amazing. Here’s how the Jet Propulsion Laboratory describes it:
The Europa Clipper mission would send a highly capable, radiation-tolerant spacecraft into a long, looping orbit around Jupiter to perform repeated close flybys of Europa.
The possible payload of science instruments under consideration includes radar to penetrate the frozen crust and determine the thickness of the ice shell, an infrared spectrometer to investigate the composition of Europa’s surface materials, a topographic camera for high-resolution imaging of surface features, and an ion and neutral mass spectrometer to analyze the moon’s trace atmosphere during flybys…The nominal Europa Clipper mission would perform 32 flybys of Europa at altitudes varying from 2700 km to 25 km.
That sounds amazing! Join me in lifting a glass to Yuri Gagarin and also join me in hoping that our moribund government funds this far-sighted mission to what might be life’s other home in the solar system!
Yuri Gagarin–the first human to go to space
This week’s posts [concerning translucent sea slugs, wasps named for a crazy pop star, an elusive Indochinese cousin of the cow, and whole sunless ecoystems] have all been about finding new life-forms. There is, of course, only one place such a topic can ultimately wind up—far beyond the living jungles, azure seas, and swirling clouds of our beautiful home planet, out in the immensity of space where the greatest question of all waits like a magic golden apple spinning in darkness.
Is there life elsewhere?
Unfortunately the current answer is incomplete: all known life–in all of its ineffable variety–is Earth-based…yet the universe is vast beyond comprehension. So I’m going to mark this down as “probably.”
Chang E and the Lunarians
Many ancient societies reckoned that other worlds existed. The Norse had their nine worlds joined together by the great ash tree Yggrdasil. The Chinese had myths about Chang’e and the Jade rabbit on the moon. Even the stolid Christians believe in heaven & hell, which are places filled with intelligent beings that are not on earth (ergo, alien realms somewhere out there in the multiverse). William Herschel, great astronomer of the Enlightenment, believed that life was everwhere—particularly everywhere in the solar system.
Sigh–those were simpler times…
When humankind entered space age, we used our burgeoning technology to examine the solar system for signs of Sir William’s spacefolk. Although we did not find the Venusian space hotties we were looking for (dammit), we did discover that among our neighboring planets, there are several other possible homes for earthlike living things. The cloud tops of Venus are inviting and could host bacteria-like life (although I hope not, since I want us to build a second home there). For centuries, scientists and fabulists speculated about life of Mars. We now know that the Martian magnetosphere died and the planet’s atmosphere was swept away, but perhaps there are some hardy extremophile bacteria living in the Martian rocks somewhere. It’s a sad scenario to imagine them on their dying world—like little kids left in a bathtub going cold. Certain moons of Jupiter & Saturn seem to be the real best bet for life in the solar system. The Jovian moons Europa, Ganymede, and Callisto are all believed to have extensive liquid oceans beneath their crust. Likewise the Saturn moons Titan and Enceladus are believed to have subsurface water. The discovery of life on Earth which did not directly require photosynthesis (like the cold seeps from yesterday’s post) has given scientists hope that bacterial mats—or maybe something even more advanced–exists on one of these moons.
So maybe there are some bacteria analogs or conodont-like creatures squiggling around in some cranny of the solar system. Perhaps life takes on an unknown form and we already flew over a clever, good-hearted ammonia-based life form on Enceladus (which NASA analysts then promptly dismissed as a snowbank), but I doubt it. The true answers to the questions about life lie out there among the stars. Exoplanets are being discovered at a tremendous rate and everyone hopes that some of the more earthlike examples harbor life. Unfortunately our technology is nowhere close to being able to spot the planets themselves and gauge whether life is there by means of spectrograph. We are stuck waiting for peers who are either broadcasting radio signals or screwing around with the fundamental nature of existence in such a way that would bring them to our attention. Indeed as humankind’s technological savvy grows, scientists are looking for more sophisticated signs of advanced life such as black holes of less than 3.5 solar masses or sophisticated particle radiation which could only be created (or detected) by civilizations of huge sophistication. All we can say right now is that, after a hundred years of looking, we have not found a lot of radio chatter in our neck of the galaxy—which is an answer of sorts itself.
Perhaps we are among the first sentient beings in this area of space (or anywhere, for that matter). The first generation of stars had to live and die before there were any raw materials for chemically based life. It took billions of years to get where we are, and, despite a few perilous missteps and accidents, life on Earth has been lucky. In my opinion some of those planets we are discovering are almost certainly covered with microbial life, but not many have little green scientists in many-armed lab coats firing up their radio telescopes (or forging little suits of chain mail a few hundred years behind us).
The Arecibo message as sent 1974 from the Arecibo Observatory.
In writing about the Curiosity rover, I humorously mentioned how much it looked like the aliens from golden age science fiction. It seems we are also broadcasting retro style messages to the stars. Above is the print-out version of the Arecibo message—one of the loudest broadcasts we have sent. It’s like a macramé knitted by Dr. Zoidberg’s great aunt or a valentine from Atari’s space invaders! Imagine if you pointed your radio telescope at the heavens and received a message like that! Maybe the aliens are scared of us or maybe they don’t want to talk to a species with such homespun tastes!
Some day in the future (artist’s interpretation)
So, after the whole post we are no closer to knowing if there is life in the cosmos, but what did you expect? Did you think I would tell you some secret here before you saw it blaring out of every news station on the planet? [If you did think that, then thank you so much!] I believe that extraterrestrial life is out there. I even believe that intelligent extraterrestrials are out there, but the universe really is ridiculously, ridiculously vast. It’s going to take a while to find our fellow living beings. In the mean time have faith (which is not advice I thought I would be giving) and keep looking up at the cold distant heavens.
NASA's Kepler Spacecraft
As I write this, astronomers know of about 700 planets which lie beyond the solar system. Yet in just 16 months, NASA’s Kepler mission has discovered an additional 2,326 potential new planets. This figure is hitting the mainstream news today thanks to NASA’s announcement that the Kepler space observatory has confirmed the existence of Kepler-22b, a planet which exists within the so-called habitable zone of a yellow G-class star about 600 light years from here. Kepler-22b orbits its star every 290 Earth days and is reckoned to have an average temperature of about 22 degrees Celsius (approximately 72 degrees Fahrenheit). Although closer in size to Earth than most exoplanets, the new world still has a radius which is more than twice that of our planet(which means that Kepler-22b’s mass is immensely greater). Scientists have no idea what Kepler-22b is made of, but because of its high gravity, its atmosphere is likely to be a heavier, sludgier affair than that of Earth.
A Diagram Contrasting the Solar System with Kepler 22-b's Star System (Image credit: NASA/Ames/JPL-Caltech)
The discovery of new worlds is becoming progressively more common–which means that new planets are more difficult to write about (I can testify to this because I have been trying to think of novel and exciting things to say about this new exoplanet). The top google search result for Kepler-22b is currently a smug caricature of the foibles of earthlings. Within a few days the sparse prose of Wikipedia’s equally scanty entry will probably be the top search result—and that is likely the way that things will remain for a long time (or forever). We are beginning to compile a massive database of different worlds. As the numbers add up, the true stories will be within the statistical understanding of new planets–unless of course a habitable zone planet leaps out of the news with electromagnetic signatures characteristic of life and intelligence. That result becomes progressively likely as we begin to learn where to point our telescopes. Out of the thousands of planets the Kepler mission is finding, Kepler-22b is the first habitable zone world of dozens–or of hundreds.
Someday
[Alien clipart by Elizabeth Aragon at www.sweetclipart.com]
Ceres (optimized image from the Hubble Space telescope)
Today’s post topic is located in the depths of space far far away from the bats, pumpkins, and haunted deserts I have been writing about for October. The dwarf planet Ceres is located in the midst of the asteroid belt between Jupiter and Mars. The only dwarf planet in the inner solar system, Ceres is only 950 km (590 miles) in diameter, but it is sufficiently large to have become spherical from its own gravity (and it is by far the largest asteroid). Named after Ceres (Demeter), the mythological goddess of growing things whose daughter was abducted by Hades and who gave the secrets of agriculture to humankind through the farmer Triptolemus, the dwarf planet was discovered in 1801 by Italian astronomer Giuseppe Piazzi, a Roman Catholic priest of the Theatine order. Ceres was the first asteroid to be discovered and it comprises a third of the asteroid belt’s total mass.
A comparison of the sizes of the Earth, Moon, and Ceres
The nebular hypothesis proposes that the solar system formed as a great cloud of space dust and gas coalesced into a disk which then further coagulated into small clumps, then into planetesimals, then into moon-sized planetary embryos, and finally into planets. Ceres is one of the few (or maybe the only) planetary embryos which formed four and a half billion years ago but somehow did not get smushed together with other like bodies to form a planet or hurled off into deep space. The dwarf planet probably consists of a rocky core surrounded with an icy mantle of frozen water. Ceres is believed to contains 200 million cubic kilometers of water–more fresh water than in all the lakes, rivers, clouds, swamps, ponds (and everything else) on Earth. The Hubble telescope has photographed several mysterious surface features on Ceres including a dark spot believed to be a crater (now informally named after Piazzi) and several bright spots, the nature of which is unknown.
Image of the bright spots on Ceres (taken by the Hubble Space telescope)
Astronomers are profoundly curious about Ceres and hope to better understand the history of the solar system by examining this surviving planetary embryo. Additionally, the chemical makeup of Ceres is similar to that of Earth. Scientists seeking extraterrestrial life have concentrated on Europa and Mars, but Ceres is next on their short list.
Astronomers will soon have some of their answers about Ceres. The asteroid probe Dawn is currently orbiting the asteroid Vesta–but its mission there is scheduled to end in July of 2012. At that point Dawn will power up its ion thrusters and fly to Ceres. In February of 2015 Dawn will enter permanent orbit around the little planet and we will finally have some of our answers.
Lake Lonar
Approximately 650,000 years ago, an outer space object–either a comet or a meteor– struck the Deccan plateau (an immense basaltic flow on the Indian subcontinent dating back to the twilight of the dinosaurs). The resultant crater in Maharashtra is now the sight of a very interesting saltwater lake, Lake Lonar. The geology of this region has been intensely studied because the great basaltic mass of the Deccan traps is thought to mirror the igneous geology of Mars and the moon.
Lake Lonar proper is nearly circular with a diameter of 1.2 kilometers. The greater meteor crater rim is about 1.8 kilometers and the crater measures 500 feet deep in the deepest part of the lake. In addition to the obvious features of an extraterrestrial impact (um, a large round hole), the region features many other unique geological signs of such an event. Maskelynite, a material only naturally known from meteorites and meteorite impact areas, is found around Lake Lonar, as are silicate minerals with planar deformation features (distinctive high-stress crystalline irregularities which have only been found in silicates from meteorites, craters, and nuclear test areas). The deeper geology of the lake region displays shatter cones in the bedrock, and extreme deformation of the basalt layers. Finally the surrounding region has been spattered with a non-volcanic ejecta blanket.
Lake Lonar: pink-beige indicates bare ground, blue and off-white indicate human-made structures, dark blue indicates water, green indicates vegetation, and dull purple indicates fallow fields (NASA: Terra Satellite)
By measuring the accumulated radiation in certain crystals (aka thermoluminescence) scientists had assigned an approximate age of 50,000 years to the crater. However a 2010 study of isotopic Argon in Lonar impact melt rock estimated the true time of impact to be 650,000 years ago (give or take 80,000 years). The compelling 2010 study drily notes “The discrepancy between the thermoluminescence age and the new isotopic 40/Ar/39Ar age is flagrant.”
Daitya Sudan, a temple to Vishnu
Several abandoned temples and archaeological sights are also located around the lake. For example, the beautiful Daitya Sudan Temple to Vishnu was built by the Chalukya Dynasty which ruled of Maharashtra from the 6th and 12th centuries. The local town, Lonar, still has an active temple to Vishnu, the great protector of the universe who features prominently in local legend. According to the Skanda Purana (a canon of Hindu scripture universally cited when a story is doubtful or can not be found elsewhere) a great underworld demon, Lonasur, lived where Lake Lonar is today. From time to time the demon would venture from his subterranean abode to torment the countryside and challenge the gods. Assuming the form of an extremely beautiful young man, Vishnu…somehow convinced the demon’s sisters to divulge where the monster could be found. The god then lifted up the countryside like a great lid and found the demon hiding in his huge circular lair. After Vishnu slew the demon, the demon’s dwelling place filled up with water made salty by the fiend’s blood.
Although threatened by India’s ever growing sprawl, Lonar Lake is a rich wetland with abundant wildlife—particularly birds. The jungles, fields, and lake are a birder’s paradise featuring flamingos, grebes, black-winged stilts, dabchicks, ducks, shell-ducks, shovellers, teals, herons, rollers, parakeets, hoopoes, weavers, larks, tailorbirds, magpies, robins, swallows, peacocks, coots, white-necked storks, lapwings, grey wagtails, black droungos, green bee-eaters, and tailorbirds (to name just some).
The Jungle around Lake Lonar
ferrebeekeeper 