Ever since the presence of exoplanets was announced in the TRAPPIST-1 system, SETI has been monitoring the system for signs of alien life.
The post SETI Has Already Tried Listening to TRAPPIST-1 for Aliens appeared first on Universe Today.
Ever since the presence of exoplanets was announced in the TRAPPIST-1 system, SETI has been monitoring the system for signs of alien life.
The post SETI Has Already Tried Listening to TRAPPIST-1 for Aliens appeared first on Universe Today.
Saturn’s largest moon Titan is a truly fascinating place. Aside from Earth, it is the only place in the Solar System where rainfall occurs and there are active exchanges between liquids on the surface and fog in the atmosphere – albeit with methane instead of water. It’s atmospheric pressure is also comparable to Earth’s, and it is the only other body in the Solar System that has a dense atmosphere that is nitrogen-rich.
For some time, astronomers and planetary scientists have speculated that Titan might also have the prebiotic conditions necessary for life. Others, meanwhile, have argued that the absence of water on the surface rules out the possibility of life existing there. But according to a recent study produced by a research team from Cornell University, the conditions on Titan’s surface might support the formation of life without the need for water.
When it comes to searching for life beyond Earth, scientists focus on targets that possess the necessary ingredients for life as we know it – i.e. heat, a viable atmosphere, and water. This is essentially the “low-hanging fruit” approach, where we search for conditions resembling those here on Earth. Titan – which is very cold, quite distant from our Sun, and has a thick, hazy atmosphere – does not seem like a viable candidate, given these criteria.
However, according to the Cornell research team – which is led by Dr. Martin Rahm – Titan presents an opportunity to see how life could emerge under different conditions, one which are much colder than Earth and don’t involve water.
Their study – titled “Polymorphism and electronic structure of polyimine and its potential significance for prebiotic chemistry on Titan” – appeared recently in the Proceedings of the National Academy of Sciences (PNAS). In it, Rahm and his colleagues examined the role that hydrogen cyanide, which is believed to be central to the origin of life question, may play in Titan’s atmosphere.
Previous experiments have shown that hydrogen cyanide (HCN) molecules can link together to form polyimine, a polymer that can serve as a precursor to amino acids and nucleic acids (the basis for protein cells and DNA). Previous surveys have also shown that hydrogen cyanide is the most abundant hydrogen-containing molecule in Titan’s atmosphere.
As Professor Lunine – the David C. Duncan Professor in the Physical Sciences and Director of the Cornell Center for Astrophysics and Planetary Science and co-author of the study – told Universe Today via email: “Organic molecules, liquid lakes and seas (but of methane, not water) and some amount of solar energy reaches the surface. So this suggests the possibility of an environment that might host an exotic form of life.”
Using quantum mechanical calculations, the Cornell team showed that polyimine has electronic and structural properties that could facilitate prebiotic chemistry under very cold conditions. These involve the ability to absorb a wide spectrum of light, which is predicted to occur in a window of relative transparency in Titan’s atmosphere.
Another is the fact that polyimine has a flexible backbone, and can therefore take on many different structures (aka. polymorphs). These range from flat sheets to complex coiled structures, which are relatively close in energy. Some of these structures, according to the team, could work to accelerate prebiotic chemical reactions, or even form structures that could act as hosts for them.
“Polyimine can form sheets,” said Lunine, “which like clays might serve as a catalytic surface for prebiotic reactions. We also find the polyimine absorbs sunlight where Titan’s atmosphere is quite transparent, which might help to energize reactions.”
In short, the presence of polyimine could mean that Titan’s surface gets the energy its needs to drive photochemical reactions necessary for the creation of organic life, and that it could even assist in the development of that life. But of course, no evidence has been found that polyimine has been produced on the surface of Titan, which means that these research findings are still academic at this point.
However, Lunine and his team indicate that hydrogen cyanide may very well have lead to the creation of polyimine on Titan, and that it might have simply escaped detection because of Titan’s murky atmosphere. They also added that future missions to Titan might be able to look for signs of the polymer, as part of ongoing research into the possibility of exotic life emerging in other parts of the Solar System.
“We would need an advanced payload on the surface to sample and search for polyimines,” answered Lunine, “or possibly by a next generation spectrometer from orbit. Both of these are “beyond Cassini”, that is, the next generation of missions.”
Perhaps when Juno is finished surveying Jupiter’s atmosphere in two years time, NASA might consider retasking it for a flyby of Titan? After all, Juno was specifically designed to peer beneath a veil of thick clouds. They don’t come much thicker than on Titan!
Further Reading: PNAS
Finding examples of intelligent life other than our own in the Universe is hard work. Between spending decades listening to space for signs of radio traffic – which is what the good people at the SETI Institute have been doing – and waiting for the day when it is possible to send spacecraft to neighboring star systems, there simply haven’t been a lot of options for finding extra-terrestrials.
But in recent years, efforts have begun to simplify the search for intelligent life. Thanks to the efforts of groups like the Breakthrough Foundation, it may be possible in the coming years to send “nanoscraft” on interstellar voyages using laser-driven propulsion. But just as significant is the fact that developments like these may also make it easier for us to detect extra-terrestrials that are trying to find us.
Not long ago, Breakthrough Initiatives made headlines when they announced that luminaries like Stephen Hawking and Mark Zuckerberg were backing their plan to send a tiny spacecraft to Alpha Centauri. Known as Breakthrough Starshot, this plan involved a refrigerator-sized magnet being towed by a laser sail, which would be pushed by a ground-based laser array to speeds fast enough to reach Alpha Centauri in about 20 years.
In addition to offering a possible interstellar space mission that could reach another star in our lifetime, projects like this have the added benefit of letting us broadcast our presence to the rest of the Universe. Such is the argument put forward by Philip Lubin, a professor at the University of California, Santa Barbara, and the brains behind Starshot.
In a paper titled “The Search for Directed Intelligence” – which appeared recently in arXiv and will be published soon in REACH – Reviews in Human Space Exploration – Lubin explains how systems that are becoming technologically feasible on Earth could allow us to search for similar technology being used elsewhere. In this case, by alien civilizations. As Lubin shared with Universe Today via email:
“In our SETI paper we examine the implications of a civilization having directed energy systems like we are proposing for both our NASA and Starshot programs. In this sense the NASA (DE-STAR) and Starshot arrays represent what other civilizations may possess. In another way, the receive mode (Phased Array Telescope) may be useful to search and study nearby exoplanets.”
DE-STAR, or the Directed Energy System for Targeting of Asteroids and exploRation, is another project being developed by scientists at UCSB. This proposed system will use lasers to target and deflect asteroids, comets, and other Near-Earth Objects (NEOs). Along with the Directed Energy Propulsion for Interstellar Exploration (DEEP-IN), a NASA-backed UCSB project that is based on Lubin’s directed-energy concept, they represent some of the most ambitious directed-energy concepts currently being pursued.
Using these as a teplate, Lubin believes that other species in the Universe could be using this same kind of directed energy systems for the same purposes – i.e. propulsion, planetary defense, scanning, power beaming, and communications. And by using a rather modest search strategy, he and colleagues propose observing nearby star and planetary systems to see if there are any signs of civilizations that possess this technology.
This could take the form of “spill-over”, where surveys are able to detect errant flashes of energy. Or they could be from an actual beacon, assuming the extra-terrestrials us DE to communicate. As is stated in the paper authored by Lubin and his colleagues:
“There are a number of reasons a civilization would use directed energy systems of the type discussed here. If other civilizations have an environment like we do they might use DE system for applications such as propulsion, planetary defense against “debris” such as asteroids and comets, illumination or scanning systems to survey their local environment, power beaming across large distances among many others. Surveys that are sensitive to these “utilitarian” applications are a natural byproduct of the “spill over” of these uses, though a systematic beacon would be much easier to detect.”
Even using directed-energy, which moves at the speed of light, it would still take a message over 4 years to the nearest star, 1000 years to reach the Kepler planets, and 2 million years to the nearest galaxy (Andromeda). So aside from the nearest stars, these time scales are far beyond a human lifetime; and by the time the message arrived, far better means would have evolved to communicate.
Second, there is also the issue of the targets being in motion over the vast timescales involved. All stars have a transverse velocity relative to our line of sight, which means that any star system or planet targeted with a burst of laser communication would have moved by the time the beam arrived. So by adopting a pro-active approach, which involves looking for specific kinds of behavior, we could bolster our efforts to find intelligent life on distant exoplanets.
But of course, there are still many challenges that need to be overcome, not the least of which are technical. But more than that, there is also the fact that what we are looking for may not exist. As Lubin and his colleagues state in one section of the paper: “What is an assumption, of course, is that electromagnetic communications has any relevance on times scales that are millions of years and in particular that electromagnetic communications (which includes beacons) should have anything to do with wavelengths near human vision.”
In other words, assuming that aliens are using technology similar to our own is potentially anthropocentric. However, when it comes to space exploration and finding other intelligent species, we have to work with what we have, and with what we know. And as it stands, humanity is the only example of a space-faring civilization known to us. As such, we can hardly be faulted for projecting ourselves out there.
Here’s hoping ET is out there, and relies on energy beaming to get things done. And, fingers crossed, here’s hoping they aren’t too shy about being noticed!
Further Reading: arXiv
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Every year, the NASA Innovative Advanced Concepts (NIAC) program puts out the call to the general public, hoping to find better or entirely new aerospace architectures, systems, or mission ideas. As part of the Space Technology Mission Directorate, this program has been in operation since 1998, serving as a high-level entry point to entrepreneurs, innovators and researchers who want to contribute to human space exploration.
This year, thirteen concepts were chosen for Phase I of the NIAC program, ranging from reprogrammed microorganisms for Mars, a two-dimensional spacecraft that could de-orbit space debris, an analog rover for extreme environments, a robot that turn asteroids into spacecraft, and a next-generation exoplanet hunter. These proposals were awarded $100,000 each for a nine month period to assess the feasibility of their concept.
Of the thirteen proposals, four came from NASA’s own Jet Propulsion Laboratory, with the remainder coming either from other NASA bodies, private research institutions, universities and aerospace companies from around the country. Taken as a whole, these ideas serve to illustrate of the kinds of missions NASA intends to purse in the coming years, as well as the cutting-edge technology they hope to leverage to make them happen.
“The NASA Innovative Advanced Concepts (NIAC) program is one of NASA’s early stage technology development programs. At NIAC, we concentrate on mission studies that demonstrate the benefit of new technologies that are on the very edge of science fiction, but while still remaining firmly rooted in science fact.”
Those proposals that are deemed feasible will be eligible to apply for a Phase II award, which consists of up to $500,000 of additional funding and two more years of concept development. And as with previous years, those concepts that were selected for Phase I were highly representative of NASA’s research and exploration goals, which include missions beyond Low-Earth Orbit (LEO) to near-Earth asteroids, Mars, Venus, and the outer Solar System.
For example, the Jet Propulsion Laboratory’s submissions included a mission that would send a probe back to Venus to explore its atmosphere in greater depth. Known as the Venus Interior Probe Using In-situ Power and Propulsion (VIP-INSPR), this small solar-powered craft would use hydrogen harvested from Venus’ atmosphere – which would be isolated through electrolysis – for altitude control at high altitudes (in a balloon), and as a back-up power source at lower altitudes.
Within Venus’ atmosphere, solar power is no longer a viable option (due to low solar intensity) and primary batteries tend to survive for only an hour or two. What’s more, radioisotope thermoelectric generators (RTGs) – like those that powered the Voyager missions – were dismissed as inefficient for the purposes of a Venus probe.
VIP-INSPR will address these problems by refilling hydrogen on one end of its structure and providing power on the other, thus enabling sustained exploration of the Venusian atmosphere. This is a creative solution to addressing the challenge of keeping a probe powered as it enters Venus’ thick atmosphere, and is sure to have applications beyond the exploration of just Venus.
Similarly, another concept from the JPL involves sending a next-generation rover to Venus, known as the Automaton Rover for Extreme Environments (AREE). This rover seeks to build on the accomplishments of the Soviet Venera and Vega programs, which were the only missions to ever successfully land rovers on Venus’ hostile surface.
Unfortunately, those probes that successfully landed only survived for 23 to 127 minutes before their electronics failed and they could no longer send back information. But by using an entirely mechanical design and a hardened metal structure, the AREE could survive for weeks or months, long enough to collect and return valuable long-term scientific data.
In essence, they proposed reverting back to an ancient concept, using analog gears instead of electronics to enable exploration of the most extreme environment within the Solar System. Beyond Venus, such a probe would also be useful in such hostile environments as Mercury, Jupiter’s radiation belt, and the interior of gas giants, within volcanoes, and perhaps even the mantle of Earth.
Then there is the Icy-moon Cryovolcano Explorer (ICE), another JPL submission which, it is hoped, will one-day explore icy, volcanically-active environments like Europa and Enceladus. The concept of an autonomous underwater vehicle (AUV) is something that has been explored a lot in recent years, but the task of getting such a vehicle to Jupiter or Saturn and beneath the surface of one of their moons presents many challenges.
The ICE team addresses these by designing a surface-to-subsurface robotic system that consists of three modules. The first is the Surface Module (SM), which will remain on the surface after the craft has landed, providing power and communications with Earth. Meanwhile, the Descent Module (DM) will use a combination of roving, climbing, rappelling and hopping to descend into a volcanic vent. Once it reaches the subsurface ocean, it will launch the AUV module, which will explore the subsurface ocean environment and seek out any signs of life.
Last, but not least, the JPL also proposed the Electostatic-Glider (E-Glider) for this year’s NIAC program. This proposal calls for the creation of an active, electrostatically-powered spacecraft to explore airless bodies. Basically, near the surface of comets, asteroids and the Moon, the environment is both airless and full of electrically-charged dust, due to the Sun’s photoelectric bombardment.
A glider equipped with a pair of thin, charged appendages could therefore use the interactions with these particles to create electrostatic lift and propel itself around the body. These appendages are also articulated to direct the levitation force in the whatever direction is most convenient for propulsion and maneuvering. It would also be able to land by simply retracing these appendages (or possibly using thrusters or an anchor).
Beyond NASA, other concepts that made the cut include the Tension Adjustable Novel Deployable Entry Mechanism (TANDEM). In a novel approach, the TANDEM consists of a tensegrity frame with a semi-rigid deployable heat shield composed of 3-D woven carbon-cloth. The same infrastructure is used for every part of the mission, with the shield providing protection during entry, and the frame providing locomotion on the surface.
By reusing the same infrastructure, TANDEM seeks to be the most efficient system ever proposed. The use of tensegrity robotics, which is a largely unexplored concept at present, also provides numerous potential benefits during entry and descent. These include the ability to adjust its shape to achieve an optimal landing, and the ability to reorient itself and charge its aerodynamic center if it gets overturned.
What’s more, conventional tensegrity locomotion depends largely on the actuation of outer cables, which requires mechanical devices in each strut to reel in the cables. However, such a system can prove impractical when used in extreme environments, since it requires that each strut be protected from the environment. This can make the vehicle overly-heavy and contribute to higher launch costs.
The TANDEM, in contrast, relies on only inner cable actuation, which allows the locomotion mechanisms to be housed in the central payload module. Taken together, this means that the TANDEM concept can allow for landings in new locations (opening up the possibility for new missions), can traverse significantly rougher terrain than existing rovers, and provide a higher level of reliability, safety and cost-effectiveness to surface missions.
From the private sector, Made In Space was awarded a Phase I grant for their concept of Reconstituting Asteroids into Mechanical Automata (RAMA). In brief, this concept boils down to using analog computers and mechanisms to convert asteroids into enormous, autonomous mechanical spacecraft, which is likely to have applications when it comes to diverting Potentially-Hazardous Asteroids (PHAs) from Earth, or bringing NEOs closer to Earth to be studied.
The concept was designed with recent developments in additive manufacturing (3-D printing) and in-situ resource utilization (ISRU) in mind. The mission would consist of a series of technically simple robotic components being sent to an asteroid, which would then convert elements of it into very basic parts of spacecraft subsystems – such as guidance, navigation and control (GNC) systems, propulsion, and avionics.
Such a proposal offers cost-saving measures since it eliminates the need to launch all spacecraft subsystems into space. It also offers an affordable and scalable way for NASA to realize future mission concepts, such as the Asteroid Redirect Mission (ARM), the New Frontiers Comet Surface Sample Return, and other Near Earth Object (NEO) applications. If all goes according to plan, Made In Space believes that it will be able to create a space mission that utilizes 3-D printing and ISRU within 20 to 30 years.
Another interesting concept is the Direct Fusion Drive (DFD), which was proposed by Princeton Satellite Systems Inc. Based on the Princeton Field-Reversed Configuration (PFRC) fusion reactor, which is under development at the Princeton Plasma Physics Laboratory, this mission would involve sending a 1000 kg lander to Pluto within 4 to 6 years. By comparison, the New Horizons space probe took roughly 9 years to reach Pluto and didn’t have the necessary fuel to slow down or make a landing.
NASA’s Ames Research Center also proposed a mission that would rely on bioprinting and an end-to-end recycling system to turn Mars’ own atmosphere into replacement electronics. Under the guidance of Dr. Lynn Rothschild, this revolutionary idea calls for small living cells to be printed out in a gel which will then consume resources (like the local atmosphere) and excrete metals, or plastics, or other useful materials.
With this kind of technology, the mass of missions could be significantly reduced, and replacement electronics could be created on-site to address failures or breakdowns. This proposal will not only enhance the likelihood of mission success, but could also have immediate applications to environmental issues here on Earth (not the least of which is the problem of e-waste).
The other winning proposals can be read about here, and include a probe that will analyze the molecular composition of “cold targets” in the Solar System (such as asteroids, comets, planets and moons), a 2-dimensional brane craft that could merge with orbital debris to deorbit it, and the Nano Icy Moons Propellant Harvester (NIMPH) – a proposed Europa mission that would involve Cubesat-sized microlanders harvesting water from the moon’s interior ocean.
There is also the NASA Kennedy Space Center’s Mars Molniya Orbit Atmospheric Resource Mining craft, which would use resources in Mars orbit to make travel to the Red Planet more affordable for future missions. And last, but not least, there was the exoplanet-hunter proposed by Nanohmics Inc., which would use a technique known as stellar echo imaging to provide more detailed imaging of exoplanets than existing techniques.
All in all, this year’s Phase I awards represent a good smattering of the research goals NASA intends to pursue in the coming years. These include, bu are not limited to, studying NEOs, returning to Venus, more missions to Mars and Pluto, and exploring the exotic environments of the outer Solar System. Only time will tell which missions will move from science fiction into the realm of science fact, and which ones will have to be put aside for later consideration.
The post NASA Invests In Radical Game-Changing Concepts For Exploration appeared first on Universe Today.
In 1950, physicist Enrico Fermi raised a very important question about the Universe and the existence of extra-terrestrial life. Given the size and age of the Universe, he stated, and the statistical probability of life emerging in other solar systems, why is it that humanity has not seen any indications of intelligence life in the cosmos? This query, known as the Fermi Paradox, continues to haunt us to this day.
If, indeed, there are billions of star systems in our galaxy, and the conditions needed for life are not so rare, then where are all the aliens? According to a recent paper by researchers at Australian National University’s Research School of Earth Sciences., the answer may be simple: they’re all dead. In what the research teams calls the “Gaian Bottleneck”, the solution to this paradox may be that life is so fragile that most of it simply doesn’t make it.
To put this in perspective, let’s first consider some of the numbers. As of the penning of this article, scientists have discovered a total of 2049 planets in 1297 planetary systems, including 507 multiple planetary systems. In addition, a report issued in 2013 by the Proceedings of the National Academy of Sciences of the USA indicated that, based on Kepler mission data, there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way, and that 11 billion of these may be orbiting Sun-like stars.
So really, there should be no shortage of alien civilizations out there. And given that some scientists estimate that our galaxy is 16 billion years old, there’s been no shortage of time for some of that life to evolve and crate all the necessary technology to reach out and find us. But according to Dr Aditya Chopra, the lead author on the ANU paper, one needs take into account that the evolutionary process is filled with its share of hurdles.
“Early life is fragile, so we believe it rarely evolves quickly enough to survive,” he says. “Most early planetary environments are unstable. To produce a habitable planet, life forms need to regulate greenhouse gases such as water and carbon dioxide to keep surface temperatures stable.”
Consider our Solar System. We all know that planet Earth has all the right elements to give rise to life as we know it. It sits within the Sun’s so-called “Goldilocks Zone” (aka. habitable zone), it has liquid water on its surface, an atmosphere, and a magnetosphere to protect this atmosphere and ensure that life on the surface isn’t exposed to too much radiation. As such, Earth is the only place in our Solar System where life is known to thrive.
But what about Venus and Mars? Both of these planets sit within the Sun’s Goldilocks Zone and are believed to have had microbial life on them at one time. But roughly 3 billion years ago, when life on Earth was beginning to convert the Earth’s primordial atmosphere by producing oxygen, Venus and Mars both underwent cataclysmic change.
Whereas Venus experienced a runaway Greenhouse Effect and became the hot, hostile world it is today, Mars lost its atmosphere and surface water and became the cold, desiccated place it is today. So whereas Earth’s microbial life played a key role in stabilizing our environment, any lifeforms on Venus and Mars would have been wiped out by the sudden temperature extremes.
In other words, when considering the likelihood of life in the cosmos, we need to look beyond the mere statistics and consider whether or not it may come down to an “emergence bottleneck”. Essentially, those planets where lifeforms fail to emerge quickly enough, thus stabilizing the planet and paving the way for more life, will be doomed to remain uninhabited.
In their report, “The Case for a Gaian Bottleneck: The Biology of Habitability” – which appears in the first issue of Astrobiology for 2016 – Dr. Chopra and his associates summarize their argument as follows:
If life emerges on a planet, it only rarely evolves quickly enough to regulate greenhouse gases and albedo, thereby maintaining surface temperatures compatible with liquid water and habitability. Such a Gaian bottleneck suggests that (i) extinction is the cosmic default for most life that has ever emerged on the surfaces of wet rocky planets in the Universe and (ii) rocky planets need to be inhabited to remain habitable.
While potentially depressing, this theory does offer a resolution to the Fermi Paradox. Given the sheer number of warm, wet terrestrial planets in the Milky Way Galaxy, there ought to be at least a few thousand civilizations kicking around. And of those, surely there are a few who have climbed their way up the Kardashev Scale and built something like a Dyson Sphere, or at least some flying saucers!
And yet, not only have we not detected any signs of life in other solar systems, but the Search for Extra Terrestrial Intelligence (SETI) hasn’t detecting any radio waves from other star systems since its inception. The only possible explanations for this are that either life is far more rare than we think, or that we aren’t looking in the right places. In the former case, an emergence bottleneck may be the reason why life has been so hard to find.
But if the latter possibility should be the case, it means our methodology needs to change. So far, all of our searches have been for the “low-hanging fruit” of alien life – looking for signs of it on warm, watery planets like our own. Perhaps life does exist out there, but in more complex and exotic forms that we have yet to consider. Or, as is often suggested, it is possible that extra-terrestrial life is taking great pains to avoid us.
Regardless, Fermi’s Paradox has endured for over 50 years, and will continue to endure until such time that we make contact with an extra-terrestrial civilization. In the meantime, all we can do is speculate. To quote Arthur C. Clarke, “Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.”
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Beam us up, Scotty. There’s no signs of intelligent life out there. At least, no obvious signs, according to a recent survey performed by researchers at Penn State University. After reviewing data taken by the NASA Wide-field Infrared Survey Explorer (WISE) space telescope of over 100,000 galaxies, there appears to be little evidence that advanced, […]