Consciousness, intelligence, and being human

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Credit: psychologytoday.com

Susan Schneider is a philosopher of science and the 2019-20 Baruch Blumberg NASA/Library of Congress Chair in Astrobiology. (She is an associate professor of philosophy and director of the AI, Mind, and Society Group at the University of Connecticut.) She’s studyingthe nature of self and mind, especially from the vantage point of issues in philosophy of mind, artificial intelligence, astrobiology, metaphysics and cognitive science.I’ve recently read a couple of interviews with her, which were fascinating. I’ll review them here.

In an interview with Dan Turello, staffer with the Kluge Center of the Library of Congress, she provided her definition of consciousness: “the felt quality of experience.”

“Science is still uncovering the neural basis of experience,” she said. “But even when we have the full neuroscientific picture of how the brain works, many philosophers believe there will still be a puzzle, which they call the ‘hard problem of consciousness.’ It is the following: Why do we need to be conscious? That is, the brain is an information processing system, so why does it need to feel like anything, from the inside, when we process certain information? If you think about the fact that the world is comprised of fundamental particles in certain configurations, it is bizarre to think that when these particles organize in certain, highly complex ways, (as with brains), a felt quality arises. This is astonishing.”

(Indeed, it is.)

As to creating human-like intelligence, she’s skeptical. “We don’t know enough about the brain to reverse engineer it, for one thing,” she noted. That said, “Even today’s AIs can be programmed to state they are conscious and feel emotion. So we need to devise tests that can be used at the R&D stage – before the programmed responses to such questions happens…even if AI becomes ‘superintelligent,’ surpassing us intellectually in every domain, we may still be unique in a crucial dimension. It feels like something to be us.”

In a recent interview with Mac Observer, Schneider observed that the human mind is not like a computer program. “A program is akin to an equation.” But human beings are concrete beings in space and time, and our thoughts change things. “We know so little about consciousness in humans,” she said. “The nature of consciousness is…one of the fundamental mysteries of the world, the universe…. I’m not sure we’re going to have an answer” to the question, what is consciousness, “any time soon.”

As to speculations about the development of human-like artificial intelligence, “It’s possible that human consciousness may not be replicable in silica,” she said. “We just don’t know” whether entities other than biological creatures can have consciousness, or not. And also, most of human brain activity is “non-conscious computation,” she noted, so why would artificial intelligence systems require consciousness at all?

As to the idea of “post-biological intelligence” – that is, non-corporeal intelligent life – Schneider said she’s surprised by how accepted this idea is in the astrobiology community. (I’m with her. It seems far-fetched.)

Could AI be implanted in human brains, as some people suggest? First, we don’t know if it would be possible, she said. Second, if possible, “it could be super-wonderful or super-dystopian,” depending on how the technology would be regulated. At the same time, “government control of AI technology can also be scary…. That’s why it’s so important that we have a public dialogue” about this emerging technology.

Schneider has a new book out, Artificial You – AI And The Future Of Your Mind. Check it out.

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Space debris: how to clean it up?

 

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Credit: wikipedia.org

Last week I blogged about the space debris problem. Today I’m blogging about technologies being developed and demonstrated to clean up space debris.

Several methods for the removal and de-orbiting of debris have been proposed so far, classified as either contact – for example, a robotic arm, a net, an electrodynamic tether – or contactless – for example, laser or “ion beam shepherd.”

Researchers at Tohoku University and Australian National University are developing an ion beam shepherd method of debris removal, which would use a plasma beam ejected from a satellite to impart a force to the debris, thereby decelerating it, which would result in the debris falling to a lower altitude, entering Earth’s atmosphere, and burning up.

Astroscale, a company founded in 2013 by a Japanese information-technology entrepreneur, proposes “to aid in the removal of orbital debris through the provision of End of Life and Active Debris Removal services.” A few years back, the company launched a 25-kilogram microsatellite designed to measure sub-millimeter-size debris in low-Earth orbit. The mission failed. The company plans to launch another debris-removal mission next year, designed to demonstrate capabilities for target search, target inspection, target rendezvous, and non-tumbling and tumbling docking. As far as I can tell, the company’s web site does not provide any information on who is paying for these demonstrations.

A company called Tethers Unlimited has developed three different approachesto space debris removal:

  • “Terminator Tape,” a 250 meter long conductive tape, is designed to de-orbit microsatellites (less than 50 kilograms) operating at altitudes of less than 1000 kilometers. (I am not going to explain how this thing works – go to the web site.) The company has developed several Terminator Tape modules: theCubeSat Terminator Tape (CSTT),sized for cubesats; the NanoSat Terminator Tape,sized for large nanosats to small microsats (less than 100 kg); and the MicroSat Terminator Tape, sized for microsats less than 200 kg.
  • “Terminator Tether,” which is designed to use“active electron emission technologies to greatly increase the electrodynamic forces, enabling it to deorbit most LEO [low Earth orbit] spacecraft with in a period of several months.The company says it has demonstrated this technology, but it does not provide details about the demonstration on its web site.
  • “GRASP” – Grapple, Retrieve, And Secure PayloadTechnology for Capture of Non-Cooperative Space Objects – “a deployable net technology that enables small satellites to capture and manipulate space objects such as orbital debris, small asteroids, and defunct spacecraft.”

Earlier this month, Tethers Unlimited, TriSept. Corp., Millennium Space Systems, and RocketLab USA announced that they have formed a partnership to develop a mission called Dragracer, designed to demonstrate Terminator Tape. Scheduled to be launched next year, this mission will involve placing a module on a smallsat that can unwind a stretch of electrically conductive tape that can capture a dead satellite. (The company says it already has tested Terminator Tape on several space missions, but details not available on the company’s web site.)

In June 2018, a consortium of European aerospace companies launched an experimental space-debris-removal satellite from the International Space Station. The RemoveDEBRIS satellite featured two active-debris-removal technologies developed by Airbus:  a net and a harpoon. This project was funded by the European Union. In September 2018, the RemoveDEBRIS net was demonstrated. A cubesat target representing an element of space debris was launched from the RemoveDEBRIS spacecraft and targeted by the net at a distance of several meters. The cubesat was captured, and the target/net combination subsequently deorbited and burned up upon atmospheric entry.

Also in 2018, another European space-debris-removal demonstration –DeOrbitSail – was intended to deploy a 4 x 4 meter drag sail designed to change the satellite’s orbit through drag and solar radiation pressure. DeOrbitSail was successfully put into orbit, but failed to deploy.

In February 2019, the RemoveDEBRIS harpoon was fired at a panel mounted on a boom extended from the RemoveDEBRIS spacecraft, hitting and penetrating the panel.

In May 2019, Surrey Satellite Technology Ltd’s TechDemoSat-1 successfully deployed a space-debris-removal drag sail supplied by Cranfield University. According to the European Space Agency, the UK’s Technology Strategy Board and the South East England Development Agency (SEEDA funded the design of the core elements of this mission, and Surrey Satellite Technology along with partners in UK industry and funded the payload technologies.

All well and good, yes? Efforts to mitigate the space debris problem are also under way (see last week’s post). Meanwhile, I keep wondering: who will pay for debris removal?

 

 

Space debris: can we clean it up before something awful happens?

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Credit: wikipedia.org

Earlier this month, I gave a talk to the Environmental Caucus of the Sarasota Democratic Party on environmental issues in space: space debris, planetary defense, and planetary protection. I’ve blogged frequently here about planetary defense and planetary protection, so in this post I’ll focus on space debris.

Here’s my quick take on the space debris problem. The world is increasingly dependent on space-based services, for everything from communications to environmental monitoring, weather forecasting, and national security.A growing number of nations are building and launching their own rockets and spacecraft: the U.S., China, India, Japan, Russia….Actors in the space sector are increasingly concerned about the hazard of collisions between space assets and space debris.

Who’s keeping track of space debris? In the U.S., it’s a military operation, so limited information is available. In Europe, it’s a civilian operation, so more information is available.

The United States Space Surveillance Network (SSN) detects, tracks, catalogs and identifies artificial objects orbiting Earth – active and inactive satellites, spent rocket bodies, and fragmentation debris. The system is the responsibility of the Joint Functional Component Command for Space, part of the United States Strategic Command (USSTRATCOM).

The SSN says it has been tracking space objects since 1957 when Sputnik 1 was launched. Since then, the SSN has tracked more than 39,000 space objects orbiting Earth. Of that number, the SSN currentlytracks more than 8,000 orbiting objects. The rest have descended into Earth’s atmosphere and disintegrated, or (more rarely) survived entry and impacted Earth. Space objects now orbiting Earth range from satellites weighing several tons to pieces of spent rocket bodies weighing only 10 pounds. According to the SSN, about 7 percent of the space objects are operational satellites, the rest are debris. The SSN tracks space objects that are 10 centimeters in size or larger.

According to the European Space Agency’s (ESA’s) Space Debris Office:

  • 5,000 satellites are in orbit around Earth, only 1950 of them still operational.
  • 34,000 pieces of space debris that are 10 centimeters in size or larger are currently being tracked.
  • 130 million pieces of debris smaller than 1 centimeter in size can’t be tracked.
  • Debris is traveling in orbit around Earth at speeds up to 28,100 kilometers per hour.
  • 500 collisions, break-ups, and explosions have already occurred in Earth orbit.

Antisatellite weapons (ASAT) testing since the 1960s has made some contribution to the space debris problem, though I did not find any authoritative source of information on the extent of the contribution. The U.S. government admits to working on ASATs from 1958 to 1988. However, in February 2008, the U.S. Navy destroyed a malfunctioning U.S. spy satellite using a ship-fired missile (a.k.a. Operation Burnt Frost). The U.S. government said it decided to shoot down this satellite because it carried toxic hydrazine fuel. China and Russia suspected that this operation was actually an ASAT test. Reuters reported in 2009 that Air Force Gen. Kevin Chilton, chief of the Defense Department’s U.S. Strategic Command, said, “Every bit of debris created by that (U.S.) intercept has de-orbited.” Chilton also claimed that some of the debris caused when China used a ground-based ballistic missile to destroy a defunct weather satellite in 2007 would remain in orbit for another 80 or 90 years.

China’s 2007missile-defense/anti-satellite system test reportedly created about 3,000 pieces of debris. Since then, the U.S. Defense Department claims, China has continued to develop anti-satellite weapons and conduct similar tests in 2010, 2013 and 2014, tests that apparently have not created debris.

Earlier this year, India conducted a missile-defense/anti-satellite system test that destroyed an Indian microsat, reportedly creating about 400 pieces of debris.

Also this year, the Indian Space Research Organization (ISRO) established a Space Situational Awareness Control Center to protect Indian space assets from space debris, near Earth asteroids, and adverse space weather conditions. ISRO says it plans to work on methods of active debris removal, space debris modeling and mitigation. It also plans to establish its own debris tracking system.

There are a lot of guidelines in place for mitigating space debris. How enforceable are they? Not much, I’d say. They’re guidelines, not regulations.

In 1995, NASA issued orbital debris mitigation guidelines. In 1997, the U.S. government established “Orbital Debris Mitigation Standard Practices” based on NASA’s guidelines. In 2007, an Inter-Agency Space debris Coordination Committee, organized by the United Nations Office of Outer Space Affairs (UNOOSA), published space debris mitigation guidelines.

Japan, France, Russia, and ESA have adopted orbital debris mitigation guidelines.

The U.S. Federal Aviation Administration’s Office of Commercial Space Transportation, which licenses space launches, requires licensees to complete a flight safety analysis, which includes, among other things, a debris analysis and a debris risk analysis:

“A debris analysis accounts for the debris produced by both normal events, such as the planned jettison of stages in an ocean, and abnormal events, such as destruction of the launch vehicle. This analysis must identify the inert, explosive and other hazardous launch vehicle debris that results from normal and malfunctioning launch vehicle flight. A debris analysis also requires a debris list, which is commonly referred to as a ‘‘debris model,’’ and must account for each cause of launch vehicle breakup. The debris lists describe and account for all debris fragments and their physical characteristics. A debris model categorizes, or groups, debris fragments into classes where the characteristics of the mean fragment in each class represent every fragment in the class. These debris lists are used as input to other flight safety analyses, such as those performed to establish flight safety limits and hazard areas and to determine whether a launch satisfies the public risk criteria of section 417.107.A debris risk analysis determines the expected number of casualties to the collective members of the public, if the public were exposed to inert and explosive debris hazards from the proposed flight of a launch vehicle. “

Last year, the Federal Communications Commission (FCC), which licenses the operation of U.S. comsats, proposed a new rule intended to update its 2004 orbital debris mitigation requirements:

“In several recent instances, applicants have sought to deploy satellites using mechanisms that detach from or are ejected from a launch vehicle upper stage and are designed solely as means of deploying a satellite and not intended for other operations. Once these mechanisms have deployed the onboard satellite(s), they become orbital debris.”

“Certain types of liquids, such as low vapor pressure ionic liquids, will, if released from a satellite, persist in the form of droplets. At orbital velocities, such droplets can cause substantial or catastrophic damage if they collide with other objects.  In the last several years, there has been increasing interest in the use by satellites (including small satellites) of alternative propellants and coolants, some of which would become persistent liquids when released by a deployed satellite. The Commission also expects that the orbital debris mitigation plan for any system utilizing persistent liquids should address the measures taken, including design and testing, to eliminate the risk of release of liquids, and to minimize risk from any unplanned release of liquids.”

In June, Stijn Lemmens, ESA’s senior space debris mitigation analyst, had this to say:

“Several nations have launched almost 9,000 satellites over the past six decades. Of these, about 5,000 are still in orbit. So we are talking about doubling the amount of traffic in space over a couple of years, or over a decade at most, compared to the last 60 years.”

“The space debris issue is mostly caused by the fact that we leave objects behind in orbit, which are then a target for collisions either with fragments of a previous collision event or with big, intact objects. Currently, most space debris comes from explosive breakup events; in the future, we predict collisions will be the driver. It’s like a cascade event: Once you have one collision, other satellites are at risk for further collisions.”

“Over the past two decades, there has been a lot of effort to establish guidelines and codes of conduct. For low-Earth orbit (LEO), there is a well-known guideline to take out your spacecraft, satellite, or launch vehicle upper stage, within 25 years after the end of mission. To have a reasonable shot at having a stable space environment, the goal is to have at least 90% of the satellites and launch-vehicle upper stages with lifetimes longer than 25 years take themselves out of orbit, or put themselves into orbits with lifetimes less than 25 years.”

“However, we are not really good at doing this at the moment. We’re talking about success rates of 5 to 15 percent for satellites (launch vehicle orbital stages do notably better, with success rates of 40-70% in low-Earth orbit). Already with current traffic, we have reasonable concerns that we’re creating a real debris issue out there.”

In 2018, Swarm Technologies bypassed the required FCC approval process for sending communication satellites into space, launching four experimental communication smallsats. In December 2018, the FCC fined Swarm $900,000 for launching and operating these smallsats without approval.

In May of this year, SpaceX launched the first 60 of a proposed constellation of 12,000 Starlink communication smallsats. SpaceX claims its Starlink satellites “are designed to be capable of fully autonomous collision avoidance.” (I guess time will tell whether this capability is functional.)

My next blog post will be about space debris removal technology developments and demonstrations.

 

How did (does) life begin? We don’t know (yet)

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Credit: Youtube.com

I’m still plowing through my notes on the 2019 Astrobiology Science Conference (AbSciCon, June 24-28, Bellevue, Washington). Here are some tidbits from a session on “unresolved issues” in origins of life research.

Someone, whose name I regrettably did not write down, said in introducing this session that only three percent of reactions run by professional chemists since 1771 have been run for more than two days. What does this mean? It means that scientists might be missing something…. In understanding prebiotic chemistry and how it led (or leads) to the chemistry of life, we’ve learned so much but have yet to be able to explain how life began on Earth (and how life might have began elsewhere).

Open questions in origins of life research include: What is life? (There is no consensus definition.) What is the origin of life? (We don’t know yet. Theories abound.) Is the origin of life easy or hard? Is the origin of life frequent or rare? Is the origin of life a unique process, or are there many pathways to go from nonlife to life? Are there different classes of life? Where is life possible? That is, in what environments might life be possible?

And what about the possibility of life beyond Earth? What is the current search space? In looking for signs of life, we’re restricted to a small segment of our own galaxy. The Milky Way resides in the Laniakea galaxy supercluster, which includes another 100,000 galaxies. And this is just a tiny sliver of the observable universe. So, astrobiologists have plenty of work to do for the next few centuries, at least.

For now, astrobiologists are interested in exploring abiotic and prebiotic chemistry in solar system environments, including Earth environments, to compare with lab experiments in abiotic and prebiotic chemistry. The aim is to determine whether terrestrial abiotic and prebiotic chemistry is “universal” or unique to Earth. We don’t know.

NASA Goddard Space Flight Center astrobiologist Jamie Elsila noted at the AbSciCon session that in studies of prebiotic chemistry in the solar system, analyses of carbonaceous chondrites—making up less than 5 percent of meteorites collected on Earth – have dominated the literature on the topic for 30 years. The Murchison meteorite, recovered in Australia in 1969, weighing in at 220 pounds, has been a particular focus of study. However, Elsila said, “Murchison is neither unique nor representative.”

In other words, many pieces of the puzzle to be solved could be missing….

Eric Smith of the Georgia Institute of Technology and the Environmental and Life Sciences Institute (Tokyo) observed that “this is still really early days” in origins of life research. His description of the origin of life? “A cascade of non-equilibrium phase transitions in planetary geochemistry.” He said that the fact that scientists are growing further away from, rather than closer to, consensus on a theory of the origin(s) of life is a bit of a relief. Answering the question, what is the origin of life?, will require that researchers “become theorists of the complex in ways that are completely new.”

Jamie Elsila acknowledged that different astrobiologists use the term “complexity” in different ways. “It means different things in different contexts and different conversations.” (So, there’s complexity to complexity….)

Nick Hud of the NASA-National Science Foundation-funded Center for Chemical Evolution (CCE), based at Georgia Tech, said at the session that the assumptions guiding the CCE’s origins of life research over the past 10 years are that “life is based on biopolymers,” that the “emergence of biopolymers was essential to the origin of life,” and that molecules and reactions that gave rise to biopolymers “were simple and robust.” (Okay, if you find this confusing, check out the title of a recent paper by Hud’s group, published in the Proceedings of the National Academy of Sciences (PNAS): “Selective incorporation of proteinaceous over nonproteinaceous cationic amino acids in model prebiotic oligomerization reactions.”)

In another session at AbSciCon, Reggie Hudson, lead scientist for the Cosmic Ice Laboratory at NASA’s Goddard Space Flight Center, said that some organic chemical reactions appear to be “unstoppable” throughout the solar system – for example, on Saturn’s moon Titan, and on the dwarf planet Pluto. His advice to astrobiologists? “Seek and ye shall find rings” – that is, the ring structures of hydrocarbon molecules (which could be prebiotic or biotic).

To wrap up, origins of life research is complicated – and deeply interesting.

What’s coming up in exoplanet research?

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Credit: spacetelescope.org

At this year’s Astrobiology Science Conference (AbSciCon, June 24-28, Bellevue, Washington), a panel of experts reported on what’s coming up exoplanet science.

The pace of exoplanet discoveries is now doubling every two years, said Karl Stapelfeldt, chief scientist for the NASA Exoplanet Exploration Program at the Jet Propulsion Laboratory.

(As of August 1, according to NASA’s Exoplanet Archive, 4,031 exoplanet discoveries have been confirmed.)

NASA’s James Webb Space Telescope (JWST – alas, behind schedule and over budget, but now scheduled for launch in 2021) is the only mission currently planned that has the “potential to study exoplanet habitability and biosignatures,” Stapelfeldt said.

Though JWST is designed to be an all-purpose infrared astrophysical observatory, not specifically engineered for exoplanet studies, exoplanet researchers have great expectations for the telescope’s contributions to their work.

Kevin Stephenson of the Space Telescope Science Institute noted that while JWST originally was conceived, and funded, as an infrared survey telescope project, one of three primary goals for JWST is to explore whether m-dwarf systems can support life.

Exoplanet researcher Vikki Meadows, who is principal investigator of the Virtual Planetary Laboratory (VPL) at the University of Washington, expressed high hopes for JWST’s contribution to her field. Though JWST will not be able to image exoplanets, she noted, JWST will be able to probe the atmospheres of terrestrial exoplanets. “But this will be quite a challenge,” She added. That is it will be difficult to definitively identify evidence of habitability.

“JWST will favor observations of planets orbiting smaller dwarf stars, Meadows said. The TRAPPIST-1 exoplanet system – 39 light years away from our solar system – is an ideal target for JWST to explore, she said.

The ultra-cool red dwarf star* TRAPPIST-1A is only slightly larger than the planet Jupiter (though more massive), and 12 times less massive than our Sun. Seven terrestrial planets have been detected in this system, and astronomers have gauged their sizes and masses to be similar to those of Earth and Venus.

Meadows noted that in m-dwarf systems, stars emit intense radiation in their early stages, meaning that planets in the so-called habitable zone in these systems might end up like Venus did in our solar system – that is, fried.

She also noted that while prospects for detecting oxygen as a biosignature with JWST are grim, but prospects for detecting methane are good.

NASA Goddard Space Flight Center astrobiologist Giada Arney offered methane as an example of a challenging biosignature. On Earth, methane makes up 1 part per mission of the atmosphere, most (but not all) of it produced by life. On Saturn’s moon Titan, methane makes up 3 percent – that is, 3 parts per 100 – of the atmosphere, likely not produced by life.

Arney is working on a concept study for a large-scale dedicated space-based exoplanet telescope – LUVOIR, the Large UV/Optical/IR Surveyor.  Two versions of LUVOIR have been proposed – one with an eight-meter-diameter light-collecting mirror and one with a 15-meter mirror. JWST’s mirror is 6.5 meters in diameter. Why so big for LUVOIR? We don’t yet know how common habitable (or inhabited) planets are, and we want to be able to see other earths, she said.

JPL’s Stapelfeldt described a concept study for a next-generation x-ray telescope, Lynx, that could make a contribution to exoplanet studies. While x-rays are certainly not a biosignature, the high-energy environment in a planetary system is critical to habitability (or inhabitability…), he said.

Ohio State University exoplanet scientist Scott Gaudi noted that the definition of “habitable zone” in a planetary system is “controversial” – that is, there is much disagreement about how to bound habitable zones. (My observation is that there’s no such thing as a “standard” habitable zone, as exoplanet hunters have detected planets and planetary systems that don’t fit any kind of standard model. But then again, I’m not an exoplanet scientist….)

Gaudi reported that science definition teams for LUVOIR, HabEx— a concept study for a Habitable Exoplanet Observatory – Lynx, and Origins— a concept study for a far-infrared surveyor, the Origins Space Telescope – will be submitting white papers on their projects to the National Academies’ Astro2020 astronomy and astrophysics decadal survey, which will sort out input from the science community and recommend priorities for NASA spending moving forward.

To wrap up this post, I’ll offer a couple of observations.

While we are not in a “new age” of space exploration (nor are we in a new “space race”), as pundits and headlines so often proclaim, it is, indeed, an exciting time to be a space scientist. (That said, I’m not sure there’s ever been a boring time to be a space scientist….) Over many years of working with the space science community, I have yet to meet a scientist who wasn’t excited about his or her work.

The difficulties involved in defining, detecting, and confirming extraterrestrial biosignatures is likely what inspires so many astrobiologists to do the work they do. The work presents the kind of challenge that might prompt one to work into the wee hours and through the weekend – and love it.

* Apparently m-dwarf and red-dwarf are synonymous.

 

Detecting life on other planets: it’s complicated

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Credit: youtube.com

I have a pile of notes from this year’s Astrobiology Science Conference (AbSciCon), which took place June 24-28 in Bellevue, Washington. I organized a workshop for the media on developing methods for detecting evidence of life on other planets, held the Sunday afternoon before the conference began. The proceedings were fascinating. I’ll try to summarize here, very briefly. (Full disclosure: I am a part-time consultant to the NASA astrobiology program. No one asked me to write this post.)

First, I want to say that life detection is a top priority for astrobiologists. Second, I want to say that a definitive detection of life on another planetary body will be, to put it mildly, extremely difficult, and certainly not a single-point “discovery.” The challenge is not deterring astrobiologists, however.

At the workshop, NASA senior scientist for astrobiology Mary Voytek said that finding biosignatures – that is, signs of life – will require,a priori, consideration of reliability, survivability, and detectability. That is, “context matters.”

NASA Goddard Space Flight Center planetary scientist and instrument developer Stephanie Getty, who is working on NASA’s Mars Science Laboratory mission and NASA’s contribution to the European Space Agency’s Exomars 2020 mission, said at the workshop, “multiple life signatures provide high confidence; abiotic signatures provide context.” In their quest to find evidence of life beyond Earth, she said, astrobiologists need to be “healthy skeptics…. You want your life detection instrument to be sensitive, rugged, and precise.”

Georgetown University planetary scientist Sarah Johnson gave a presentation on “agnostic” biosignatures – that is, signs of life that are not based on the assumption that life elsewhere will be like Earth life. She posed this question: “What might the molecular and polymeric building blocks of life look like on a non-water world like Titan?” Titan’s lakes contain liquid methane, not liquid water. Thus, different chemistry could be taking place. Johnson is principal investigator of the Laboratory for Agnostic Biosignatures, funded by the NASA astrobiology program. The point is to keep an open mind. As Getty said, astrobiologists need to be healthy skeptics….

Woods Hole Oceanographic Institution ocean explorer Chris German said his 2017 expedition to study deep-sea vents in the mid-Cayman rise of the Caribbean Sea has led him to believe that these vents might be decent analogues to deep-sea vents on Enceladus. With colleagues, he is working on a project to demonstrate autonomous sea-floor vent detection under ice, this fall. By this September, German hinted, findings of the 2017 exploration of the mid-Cayman rise might be outdated, because there might be a better analogue to Enceladus’s ocean in the Arctic Ocean, just north of Greenland. (Stay tuned.)

NASA Goddard Space Flight Center’s Giada Arney, who focuses on ways to detect evidence of habitability on extrasolar planets, noted that scientists don’t yet know whether any exoplanets discovered thus far might be habitable (despite optimistic reports on the media, I should note…). Arney works on modeling and measuring properties of planets with an emphasis on worlds enshrouded by global cloud and haze layers, because aerosols appear to be a common planetary phenomenon.

No extrasolar planet missions in operation thus far – mainly NASA’s Kepler and TESS (Transiting Exoplanet Survey Telescope) missions – have been capable of characterizing exoplanets, Arney said. Characterization is a key element of determining whether a planet is potentially habitable.

In a presentation at AbSciCon, NASA astrobiologist Dave Des Marais explained that biosignatures could be objects (such as fossils), substances (such as certain types of molecules), patterns, or processes. He reiterated the message that context is critical: “context can help rule out false positives.”

The NASA astrobiology program has developed a tool called the “ladder of life detection” – intended “to stimulate and support discussions among scientists and engineers about how one would detect extant life beyond Earth within the practical constraints of robotic space missions” – and asked for community input to refine it. Context is key, again. Says NASA: “The Ladder of Life Detection is not intended to endorse specific biosignatures or instruments for life-detection measurements, and is by no means a definitive, final product. It is intended as a starting point to stimulate community discussion, debate, and further research on the characteristics of life, what constitutes a biosignature, and the means to measure them. For example, there is room for debate regarding the specific order of each feature in the Ladder, which is highly dependent on the environment in which the measurements would be made.”

A paper published in the journal Astrobiology this month (it’s open-access, at least for now), “Deciphering biosignatures in planetary contexts,” also addresses the issue of “context.”* As the authors of this paper (who include Des Marais) explain, “In the search for extraterrestrial life in the Universe, it is critical to determine what constitutes a biosignature across multiple scales, and how this compares with ‘abiosignatures’ formed by nonliving processes. Developing standards for abiotic and biotic characteristics would provide quantitative metrics for comparison across different data types and observational time frames.”

Here’s a quick review, taken from the Astrobiology paper, of the different types of “signatures” that astrobiologists are trying to sort out:

  • Abiosignature: “a substance, object, or pattern that has a non-biological origin. The usefulness of an abiosignature is determined not only by the probability that an abiotic process produced it, but also by the improbability that biological processes produced it.”
  • Biosignature:“an object, substance, and/or pattern whose origin specifically requires a biological agent (from Des Marais et al., 2008).
  • Ambiguous biosignature (a.k.a. potential biosignature): “a feature that occupies the ‘gray zone’ of uncertainty between biosignatures and abiosignatures…. Navigating this ‘gray zone’ is a central challenge for astrobiology life detection efforts.”
  • Agnostic biosignature: “a substance, object, and/or pattern whose origins specifically require biological agents and also includes features that might not have originated on Earth.” (LB note: put simply – though there’s nothing simple about it – an agnostic biosignature is a sign of life as we do not know it.) As noted in the 2018 Exoplanet Science Strategy, agnostic biosignatures compel astrobiologists “to envision attributes of life that are more fundamental and widespread in the cosmos” than attributes that apparent in Earth’s biosphere.

Back to the Astrobiology paper: “Five key challenges that warrant future exploration by the astrobiology community include the following: (1) examining phenomena at the ‘right’ spatial scales because biosignatures may elude us if not examined with the appropriate instrumentation or modeling approach at that specific scale; (2) identifying the precise context across multiple spatial and temporal scales to understand how tangible biosignatures may or may not be preserved; (3) increasing capability to mine big data sets to reveal relationships, for example, how Earth’s mineral diversity may have evolved in conjunction with life; (4) leveraging cyberinfrastructure for data management of biosignature types, characteristics, and classifications; and (5) using three-dimensional to n-D representations of biotic and abiotic models overlain on multiple overlapping spatial and temporal relationships to provide new insights.”

At AbSciCon, Arizona State University astrobiologist Sara Imari Walker proposed that rather than trying to define what life is, astrobiologists should try to answer these questions: What does life do? What does life produce? What does biology do that chemistry and physics cannot?

To wrap up, the search for evidence of life beyond Earth is at the heart of astrobiology. But finding and verifying evidence will be a daunting task.

*M.A. Chan, et al, Deciphering biosignatures in planetary contexts, Astrobiology 19(9), 2019. DOI: 10.1089/ast.2018.1903

Asteroid close approaches: keeping things in perspective

teepublic

Credit: teepublic.com

On July 25, the Sydney Morning Herald reported on a close approach of a newly discovered near-Earth object (NEO), asteroid 2019 OK. The asteroid was detected at what might appear, to the non-expert, the last minute (a couple of days before fly-by, I believe.) In actuality, the detection and observation of this NEO as it passed by Earth at 70,000 kilometers (43,496 miles) was routine – certainly nothing to panic about.

The Sydney paper quoted four Australian scientists – understandably, since it’s an Australian news outlet. None of those scientists actually observed the asteroid, as far as I can tell. Two of them, in my humble opinion, made much ado about nothing.

“[If it hit Earth] it makes the bang of a very large nuclear weapon – a very large one.”

It didn’t, and it posed no risk of doing so.

“It would have hit with over 30 times the energy of the atomic blast at Hiroshima.”

It didn’t hit. And it posed no risk of hitting. Not to mention that when asteroids do impact Earth, they do not release any nuclear radiation.

“It’s a city-killer asteroid.”

No it’s not. It did not pose any risk of impact with Earth.

“Definitely too close for comfort.”

This close approach did not make me uncomfortable.

Nonetheless, several other news outlets, ranging from (usually) reliable – such as the Washington Post – to flaky (U.K. tabloids), picked up this story, repeating the sensational framing.

On July 26, the Washington Post picked up on this story, surprisingly interviewing only the two seemingly panic-stricken Australian scientists who generated the comments above. The Post’s story reiterated the “city killer” and “nuclear” tropes, which most asteroid scientists I know tend to avoid. It seems odd that a Washington news outlet would not check in with Washington-based experts – such as my colleagues with the planetary defense program at NASA headquarters (for which I am a consultant, and, for the record, no one asked me to write this post). Oh well….

According to NASA’s public web site for planetary defense:

  • A near-Earth object (NEO) is an asteroid or comet whose orbit brings it into or through a zone between approximately 91 million and 121 million miles (195 million kilometers) from the Sun, meaning that it can pass within about 30 million miles (50 million kilometers) of Earth’s orbit.”
  • A potentially hazardous object (PHO) is a near-Earth object whose orbit brings it within 4.7 million miles (7.5 million km) of Earth’s orbit, and is greater than 500 feet (140 meters) in size.”
  • “A NEO close approach is of particular interest when it passes within the distance from the Earth to the Moon…. The Jet Propulsion Laboratory’s Center for NEO Studies maintains close approach tables that are updated daily.”
  • “Small asteroids a few meters in size are detected passing between Earth and the Moon’s orbit several times a month.”

According to NASA’s Center for NEO Studies (CNEOS), 2019 OK was estimated to be between 59 and 130 meters in size. Yes, an asteroid in this size range could cause damage IF it were to explode in the atmosphere or impact water or land. But, again, 2019 OK didn’t, and it posed no risk of doing so.

A global system is in place for finding, tracking, and characterizing asteroids and predicting their future orbits and any possible impact hazards. Detection and tracking of asteroid 2019 OK – though it may have seemed last-minute to some – is evidence that this global system is working just the way it’s supposed to.

Observers around the world – both professional and amateur – report detections to the Minor Planet Center (MPC), which is funded by NASA’s planetary defense program. The MPC analyzes and archives data received and relays observations to CNEOS, also funded by NASA’s planetary defense program. This is what occurred in the case of 2019 OK.

CNEOS verifies observations and predicts future orbits of the asteroid. (No known asteroid is on an impact course with Earth for the next 100 years.) In the case of asteroid 2019 OK, SONEAR, a Brazilian observation team, first detected this NEO and reported its observations to the MPC. Astronomers at McDonald Observatory in Texas also detected 2019 OK and reported its observations to the MPC. Other astronomers received notification of these observations and conducted follow-up observations, also reported to the MPC. The MPC has a public recordof these observations.

In addition to the MPC and CNEOS, the European Space Agency funds the NEODys-2 system, which performs the same functions as NASA’s CNEOS does using different methods, providing further verification of observational and orbit-prediction data.

The Sydney paper reported, “Asteroids this size tend to pass by once every decade.” According to CNEOS director Paul Chodas, a close approach by an object of the size of 2019 OK is predicted to occur perhaps a couple of times each century, and an impact of an object of this size might occur once every few thousand years. It’s important to note, as always, that considerable uncertainty underlies such predictions.

The International Asteroid Warning Network (IAWN) is a multinational organization of space agencies and observatories involved in finding, tracking, and characterizing asteroids, predicting their future orbits, and identifying any possible future impact hazards.

The multinational Space Mission Planning Advisory Group (SMPAG) is responsible for preparing for an international response to an actual asteroid impact threat (none have, as yet, been identified) through the exchange of information, development of options for collaborative research and mission opportunities, and the conduct of asteroid impact mitigation planning activities.

All of these organizations are in close communication with each other (and I have worked with representatives of all of them).

I realize that in the global, 24-7, news and information environment, where journalists’ deadlines are always NOW, we can’t expect to see as much careful and thorough reporting as we’d like to. In the case of the Sydney paper’s story, I don’t know who reached out to whom: reporter to scientists, or scientists to reporter…. I also realize that we’ll likely never wean journalists off grabby headlines and leads (city killer etc.).  After working on four workshops for the media on planetary defense over the past year, I can only hope that, over time, we might see some improvement.