A New Way to Find Signals of Habitable Exoplanets?

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Scientists propose a new and more indirect way of determining whether an exoplanet has a good, bad or unknowable chance of being habitable.  (NASA’s Goddard Space Flight Center/Mary Pat Hrybyk)

The search for biosignatures in the atmospheres of distant exoplanets is extremely difficult and time-consuming work.  The telescopes that can potentially take the measurements required are few and more will come only slowly.  And for the current and next generation of observatories, staring at a single exoplanet long enough to get a measurement of the compounds in its atmosphere will be a time-consuming and expensive process — and thus a relatively infrequent one.

As a way to potentially improve the chances of finding habitable conditions on those exoplanets that are observed, a new approach has been proposed by a group of NASA scientists.

The novel technique takes advantage of the frequent stellar storms emanating from cool, young dwarf stars. These storms throw huge clouds of stellar material and radiation into space – traveling near the speed of light — and the high energy particles then interact with exoplanet atmospheres and produce chemical biosignatures that can be detected.

The study, titled “Atmospheric Beacons of Life from Exoplanets Around G and K Stars“, recently appeared in Nature Scientific Reports. 

“We’re in search of molecules formed from fundamental prerequisites to life — specifically molecular nitrogen, which is 78 percent of our atmosphere,” said Airapetian, who is a solar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and at American University in Washington, D.C. “These are basic molecules that are biologically friendly and have strong infrared emitting power, increasing our chance of detecting them.”

The thin gauzy rim of the planet in foreground is an illustration of its atmosphere. (NASA’s Goddard Space Flight Center)

So this technique, called a search for  “Beacons of Life,” would not detect signs of life per se, but would detect secondary or tertiary signals that would, in effect, tell observers to “look here.”

The scientific logic is as follows:

When high-energy particles from a stellar storm reach an exoplanet, they break the nitrogen, oxygen and water molecules that may be in the atmosphere into their individual components.

Water molecules become hydroxyl — one atom each of oxygen and hydrogen, bound together. This sparks a cascade of chemical reactions that ultimately produce what the scientists call the atmospheric beacons of hydroxyl, more molecular oxygen, and nitric oxide.

For researchers, these chemical reactions are very useful guides. When starlight strikes the atmosphere, spring-like bonds within the beacon molecules absorb the energy and vibrate, sending that energy back into space as heat, or infrared radiation. Scientists know which gases emit radiation at particular wavelengths of light.  So by looking at all the radiation coming from the that planet’s atmosphere, it’s possible to get a sense of what chemicals are present and roughly in what amounts..

Forming a detectable amount of these beacons requires a large quantity of molecular oxygen and nitrogen.  As a result, if detected these compounds would suggest the planet has an atmosphere filled with biologically friendly chemistry as well as Earth-like atmospheric pressure.  The odds of the planet being a habitable world remain small, but those odds do grow.

“These conditions are not life, but are fundamental prerequisites for life and are comparable to our Earth’s atmosphere,” Airapetian wrote in an email.

Stellar storms and related coronal mass ejections are thought to burst into space when magnetic reconnections in various regions of the star.  For stars like our sun,  the storms become less frequent within a relatively short period, astronomically speaking.  Smaller and less luminous red dwarf stars, which are the most common in the universe, continue to send out intense stellar flares for a much longer time.

Vladimir Airapetian is a senior researcher
at NASA Goddard and a member of NASA’s  Nexus for Exoplanet System Science (NExSS) initiative.

The effect of stellar weather on planets orbiting young stars, including our own four billion years ago, has been a focus of Airapetian’s work for some time.

For instance, Airapetian and Goddard colleague William Danchi published a paper in the journal Nature last year proposing that solar flares warmed the early Earth to make it habitable.  They concluded that the high-energy particles also provided the vast amounts of energy needed to combine evenly scattered simple molecules into the kind of complex molecules that could keep the planet warm and form some of the chemical building blocks of life.

In other words, they argue, the solar flares were an essential part of the process that led to us.

What Airapetian is proposing now is to look at the chemical results of stellar flares hitting exoplanet atmospheres to see if they might be an essential part of a life-producing process as well, or of a process that creates a potentially habitable planet.

Airapetian said that he is again working with Danchi, a Goddard astrophysicist, and the team from heliophysics to propose a NASA mission that would use some of their solar and stellar flare findings.  The mission being conceived, the Exo Life Beacon Space Telescope (ELBST),  would measure infrared emissions of an exoplanet atmosphere using direct imaging observations, along with technology to block the infrared emissions of the host star.

For this latest paper, Airapetian and colleagues used a computer simulation to study the interaction between the atmosphere and high-energy space weather around a cool, active star. They found that ozone drops to a minimum and that the decline reflects the production of atmospheric beacons.

They then used a model to calculate just how much nitric oxide and hydroxyl would form and how much ozone would be destroyed in an Earth-like atmosphere around an active star. Earth scientists have used this model for decades to study how ozone — which forms naturally when sunlight strikes oxygenin t he upper atmosphere — responds to solar storms.  But the ozone reactions found a new application in this study; Earth is, after all, the best case study in the search for habitable planets and life.

Will this new approach to searching for habitable planets out?

“This is an exciting new proposed way to look for life,” said Shawn Domagal-Goldman, a Goddard astrobiologist not connected with the study. “But as with all signs of life, the exoplanet community needs to think hard about context. What are the ways non-biological processes could mimic this signature?”

 

A 2012 coronal mass ejection from the sun. Earth is placed into the image to give a sense of the size of the solar flare, but our planet is of course nowhere near the sun. (NASA, Goddard Media Studios)

Today, Earth enjoys a layer of protection from the high-energy particles of solar storms due to its strong magnetic field.  However, some particularly strong solar events can still interact with the magnetosphere and potentially wreak havoc on certain technology on Earth.

The National Oceanic and Atmospheric Administration classifies solar storms on a scale of one to five (one being the weakest; five being the most severe). For instance, a storm forecast to be a G3 event means it could have the strength to cause fluctuations in some power grids, intermittent radio blackouts in higher latitudes and possible GPS issues.

This is what can happen to a planet with a strong magnetic field and a sun that is no longer prone to sending out frequent solar flares.  Imagine what stellar storms can do when the star is younger and more prone to powerful flaring, and the planet less protected.

Exoplanet scientists often talk of the possibility that a particular planet was “sterilized” by the high-energy storms, and so could never be habitable.  But this new research suggests that some stellar storms could have just the opposite effect — making the planet more habitable.

 

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One Planet, But Many Different Earths

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Artist conception of early Earth. (NASA/JPL-Caltech)
Artist conception of early Earth. (NASA/JPL-Caltech)

We all know that life has not been found so far on any planet beyond Earth — at least not yet.  This lack of discovery of extraterrestrial life has long been used as a knock on the field of astrobiology and has sometimes been put forward as a measure of Earth’s uniqueness.

But the more recent explosion in exoplanet discoveries and the next-stage efforts to characterize their atmospheres and determine their habitability has led to rethinking about how to understand the lessons of life of Earth.

Because when seen from the perspective of scientists working to understand what might constitute an exoplanet that can sustain life,  Earth is a frequent model but hardly a stationary or singular one.  Rather, our 4.5 billion year history — and especially the almost four billion years when life is believed to have been present  — tells many different stories.

For example, our atmosphere is now oxygen-rich, but for billions of years had very little of that compound most associated with complex life.  And yet life existed.

The same with temperature.  Earth went through snowball or slushball periods when most of the planet’s surface was frozen over.  Hardly a good candidate for life, and yet the planet remained habitable and inhabited.

And in its early days, Earth had a very weak magnetic field and was receiving only 70 to 80 percent as much energy from the sun as it does today.  Yet it supported life.

“It’s often said that there’s an N of one in terms of life detected in the universe,” that there is but one example, said Timothy Lyons, a biogeochemist and distinguished professor at University of California, Riverside.

“But when you look at the conditions on Earth over billion of years, it’s pretty clear that the planet had very different kinds of atmospheres and oceans, very different climate regimes, very different luminosity coming from the sun.  Yet we know there was life under all those very different conditions.

“It’s one planet, but it’s silly to think of it as one planetary regime. Each of our past chapters is a potential exoplanet.”

 

A rendering of the theorized "Snowball Earth" period when, for millions of years, the Earth was entirely or largely covered by ice, stretching from the poles to the tropics. This freezing happened over 650 million years ago in the Pre-Cambrian, though it's now thought that there may have been more than one of these global glaciations. They varied in duration and extent but during a full-on snowball event, life could only cling on in ice-free refuges, or where sunlight managed to penetrate through the ice to allow photosynthesis.
A particularly extreme phase of our planet’s history is called  the “Snowball Earth” period.  During these episodes, the Earth’s surface was entirely or largely covered by ice for millions of years, stretching from the poles to the tropics. One such freezing happened over 700 to 800 million years ago in the Pre-Cambrian, around the time that animals appeared. Others are now thought to have occurred much further back in time. They varied in duration and extent but during a full-on snowball event, life could only survive in ice-free refuges, or where sunlight managed to penetrate through the ice to allow photosynthesis.

Lyons is the principal investigator for one of the newer science teams selected to join the NASA Astrobiology Institute (NAI), an interdisciplinary group hat calls itself “Alternative Earths.”

Consisting of 23 scientists from 14 institutions, its self-described mission is to address and answer these questions: How has Earth remained persistently inhabited through most of its highly changeable history?  How has the presence of very different kinds of lifeforms been manifested in the atmosphere, and simultaneously been captured in what would become the rock record? And how might this approach to early Earth help in the search for life beyond Earth?

“The idea that early Earth can help us understand other planets and moons, especially in our solar system, is certainly not new,” Lyons said.  “Scientists have studied possible Mars analogues and extreme life for years.  But we’re taking it to the next level with exoplanets, and pushing hard on the many ways that conditions on early Earth can help us study exoplanet atmospheres and habitability.”

The importance of this work was apparent at a recent workshop on biosignatures held by NASA’s initiative, the Nexus for Exoplanet System Science (NExSS.)  As Earth scientists, Lyons and his group are expert at finding proxy records in ancient rocks that hold information important to exoplanet scientists (among others) want to know.

Those proxy fingerprints occur as elemental, molecular, and isotopic properties preserved in rocks that correspond to ancient characteristics in the ocean or atmosphere that can no longer be observed directly.

“We can’t measure the pH in ancient oceans, and we can’t measure the composition of ancient atmospheres,” Lyons said.  “So what we have to do is go to the chemistry of ocean and land deposits formed at the same time and look for the chemical fingerprints locked away and preserved.”

At the exoplanet biosignatures workshop, Lyons was struck by how eager exoplanet modelers were to learn about the proxy chemicals they could profitably put in their models for clues about how distant planet atmospheres might form and behave.  It’s clear that no single element or compound will be a silver bullet for understanding whether there’s life on an exoplanet, but a variety of proxy results together can begin to tell an important story.

chromium
The element chromium and its isotopes have become important proxies for the measurement of oxygen levels in the atmosphere of early Earth and have led to some revised theories about when those concentrations jumped.  Understanding the potential makeup of early Earth’s atmosphere and oceans is a pathway to understanding exoplanets.

“We told them about the range of things they should be modeling and, wow, they were interested.  I was thinking at the time that ‘you guys really need us — and vice versa.'”

Some of the researchers most intrigued by potentially new geochemical proxies from the University of Washington’s Virtual Planetary Laboratory,  They’ve been a pioneer in modeling how different atmospheric, geological, stellar and other factors characterize particular kinds of planets and solar systems and their possibilities for life.

In keeping with the growing connection between exoplanet and Earth science, Lyons just brought one of the VPL top modellers, Edward Schwieterman, to UC Riverside for a postdoc as part of the Alternative Earths project.

Among his initial projects will take the new data being generated by the Alternative Earths team about the atmosphere and oceans of early Earth, and model what would happen on a planet with that kind of atmosphere if it was orbiting a very different type of star from our own.

“It’s a direct use of early Earth research on exoplanet studies, and is exactly the kind of work we plan to do be doing,” Lyons said. “Eddie is the perfect bridge between the lessons learned from early Earth and their implications for exoplanets.”

Banded iron formations Karijini National Park, Western Australia. The layers of reddish iron show the presence of oxygen, which bonded with the iron to form a rust-like iron oxide. These formations date most commonly from the period of 2.4 to 1.9 billion years ago, after the Great Oxidation Event.
Banded iron formations at Karijini National Park, Western Australia. The layers of reddish iron point to an early ocean poor in oxygen and rich in dissolved iron. These formations date most commonly from the periods just before and right after the Great Oxidation Event, which spanned from about 2.4 to 2.0 billion years ago. Their distributions over times and their chemical properties are key proxies for the tempo and fabric of the earliest permanent oxygenation of Earth’s atmosphere.

Lyons, along with colleagues Christopher Reinhard of Georgia Tech and Noah Planavsky of Yale and other members of their Alternative Earths team, are especially focused on an effort to understand Earth’s atmosphere—as tracked in the rock record—over the eons and especially the levels of oxygen present.

The concentration of oxygen in the atmosphere is now about about 21 percent and, by some estimates, reached as high as 35 percent within the past 500 million years.

In comparison, early Earth had but trace amounts of oxygen for two billion years before what is called the Great Oxidation Event—when marine O2-producing photosynthesis outpaced reactions that consumed O2 and allowed for the beginnings of its permanent accumulation in the atmosphere.  Estimated to have occurred 2.4 billion years ago, it began (or was part of) an oxidizing process that led to ever more complex life forms over the following one to two billion years.

Timothy Lyons, distinguished professor of geobiochemistry at the University of California, Riverside. He is also the principal investigator of a National Astrobiology Institute project xxx.
Timothy Lyons, distinguished professor of biogeochemistry at the University of California, Riverside. He is also the principal investigator of a National Astrobiology Institute project “Alternative Earths:  Explaining Persistent Inhabitation on a Dynamic Early Earth.

There is a spirited scientific debate underway now about whether that “Great Oxidation Event” triggered permanently high levels of oxygen in the atmosphere and the oceans, or whether it began an up and down process through which the presence of oxygen was quite unstable and still well below current levels until relatively recent times.

Lyons and Reinhard are of the “boring billion” school, arguing that oxygen levels did not head continuously upwards after the Oxidation Event, but rather stayed relatively stable and still very low for most of a billion and half years after the Great Oxidation Event and continued to challenge O2-requiring life—for almost a third of Earth history.

This would be primarily an Earth science issue if not for the fact that oxygen — on its own and in conjunction with other compounds — is among the most prominent and promising biosignatures that exoplanet scientists are looking for.

Christopher Reinhard, Georgia Institute of technology. (Brad...
Christopher Reinhard of Georgia Institute of Technology and Alternative Earths project. (Ben Brumfield/Georgia Tech.)

In fact, not that long ago, it was widely accepted that a discovery of oxygen and/or ozone in the atmosphere of a planet pretty much proved, or at least strongly suggested, the presence of some sort of biology on the planet below.  That view has been modified of late by the identification of ways that free oxygen can be formed abiotically (without the presence of photosynthesis and life), potentially producing false positives for potential life.

While the field is a long way from an active search for direct, in situ fingerprints of life on exoplanets light years away, oxygen and its relationship with other atmospheric gases remains a lodestar in thinking about what biosignatures to search for. The technology is already in place for characterizing the compositions of very distant atmospheres.

And this is where, for Lyons, Reinhard and others, things get both interesting and complicated.

For more than a billion years before the Great Oxidation Event Earth demonstrably supported life.  It consisted mostly of anaerobic microbes that did just fine without oxygen, but in many cases needed and produced methane, an organic compound with one carbon atom and four hydrogens.

So if an exoplanet scientist from a distant world were to search for life on Earth during that period via the detection of oxygen only, they would entirely miss the presence of an already long history of life.  Searching for a potentially large-scale presence of methane might have been more productive, though that is a source of rigorous debate as well.

 

An image of a rock with fossilized stromatolites, tiny layered structures from 3.7 billion years ago that are remnants from a community of microbes. Found in a newly melted part of Greenland, Australian scientists reported in the journal Nature that the stromatolites lived on an ancient seafloor at a time when Earth's skies were orange and its oceans green. They describe the stromatolites as perhaps the oldest fossil found so far on Earth. (Allen Nutman/University of Wollongong)
An image of a rock with fossilized stromatolites, tiny layered structures from 3.7 billion years ago that are remnants from a community of microbes. Found in a part of Greenland new exposed by melting glaciers, Australian scientists reported in the journal Nature that the stromatolites lived on an ancient seafloor at a time when Earth’s skies may well have been orange and its oceans green. They describe the stromatolites as perhaps the oldest fossil found so far on Earth, although chemical suggestions of life may extend further back in time . (Allen Nutman/University of Wollongong)

Because both oxygen and methane can be formed without life, a current gold standard for detecting future biosignatures on exoplanets is the presence of the two together.  As a result of the way the two interact, they would remain in an atmosphere together only if both were being replenished on a substantial, on-going scale.  And as far as is now understood, the only way to do that is through biology.

Yet as described by Reinhard, the most current research suggest that oxygen and methane were probably never in the Earth’s atmosphere together at levels that would be detectable from afar.  There is some evidence that Earth’s atmosphere held a lot of methane in its early times, and there has been a lot of oxygen for the past 600 million years or so, but as one grew in concentration the other declined — and during the “boring billion” both were likely low.

“So we have a complicated situation here where using the best exoplanet biosignatures we have now, intelligent beings looking at Earth over the past 4.5 billion years would not find a convincing signature of life for most, or maybe all, of that time if they relied only on co-occurrence of oxygen and methane,” Reinhard said.  Yet there has been life for at least 3.7 billion years, and those beings studying Earth would have come up with a very false negative.

Lyons insists this is should not be a source of pessimism in the search for life on exoplanets, instead it is a “call to arms for new and more creative possibilities rather than the lowest hanging fruit.” It’s a challenge “to help us sharpen our thinking in a search that was never going to be easy.”

And the best test bed available for coming up with different answers, he said, may very well be the many different Earths that have come and gone on our planet.

 

 

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Breaking Down Exoplanet Stovepipes

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he search for life beyond our solar system requires unprecedented cooperation across scientific disciplines. NASA's NExSS collaboration includes those who study Earth as a life-bearing planet (lower right), those researching the diversity of solar system planets (left), and those on the new frontier, discovering worlds orbiting other stars in the galaxy (upper right). Credits: NASA
The search for life beyond our solar system requires unprecedented cooperation across scientific disciplines. NASA’s NExSS collaboration includes those who study Earth as a life-bearing planet (lower right), those researching the diversity of solar system planets (left), and those on the new frontier, discovering worlds orbiting other stars in the galaxy (upper right). (NASA)

That fields of science can benefit greatly from cross-fertilization with other disciplines is hardly a new idea.  We have, after all, long-standing formal disciplines such as biogeochemistry — a mash-up of many fields that has the potential to tell us more about the natural environment than any single approach.  Astrobiology in another field that inherently needs expertise and inputs from a myriad of disciplines, and the NASA Astrobiology Institute was founded (in 1998) to make sure that happened.

Until fairly recently, the world of exoplanet study was not especially interdisciplinary.  Astronomers and astrophysicists searched for distant planets and when they succeeded came away with some measures of planetary masses, their orbits, and sometimes their densities.  It was only in recent years, with the advent of a serious search for exoplanets with the potential to support life,  that it became apparent that chemists (astrochemists, that is), planetary and stellar scientists,  cloud specialists, geoscientists and more were needed at the table.

Universities were the first to create more wide-ranging exoplanet centers and studies, and by now there are a number of active sites here and abroad.  NASA formally weighed in one year ago with the creation of the Nexus for Exoplanet System Science (NExSS) — an initiative which brought together 17 university and research center teams with the goal of supercharging exoplanet studies, or at least to see if a formal, national network could produce otherwise unlikely collaborations and science.

That network is virtual, unpaid, and comes with no promises to the scientists.  Still, NASA leaders point to it as an important experiment, and some interesting collabortions, proposals and workshops have come out of it.

“A year is a very short time to judge an effort like this,” said Douglas Hudgins, program scientist for NASA’s Exoplanet Exploration Program, and one of the NASA people who helped NExSS come into being.

“Our attitude was to pull together a group of people, do our best to give them tool to work well together, let them have some time to get to know each other, and see what happens.  One year down the road, though, I think NExSS is developing and good ideas are coming out of it.”

Illustration of what a sunset might look like on a moon orbiting Kepler 47c and its two suns. (Softpedia)
Illustration of what a sunset might look like on a moon orbiting Kepler 47c and its two suns. (Softpedia)

 

One collaboration resulted in a “White Paper” on how laboratory work today can prepare researchers to better understand future exoplanet measurements coming from new generation missions. Led by NExSS member Jonathan Fortney of the University of Clalfornia, Santa Cruz, it was the result of discussions at the first NExSS meeting in Washington, and was expanded by others from the broader community.

Another NExSS collaboration between Steven Desch of Arizona State University and Jason Wright of Penn State led to a proposal to NASA to study a planet being pulled apart by the gravitational force a white dwarf star.  The interior of the disintegrating planet could potentially be analyzed as its parts scatter.

Leaders of NExSS say that other collaborations and proposals are in the works but are not ready for public discussion yet.

In addition, NExSS — along with the NASA Astrobiology Institute (NAI) and the National Science Foundation (NSF) — sponsored an unusual workshop this winter at Arizona State University focused on a novel way to looking at whether an exoplanet might support life.  Astrophysicists and geoscientists (some paertr of NExSS teams; some not) spent three days discussing and debating how the field might gather and use information about the formation, evolution and insides of exoplanets to determine whether they might be habitable.

One participant was Shawn Domogal-Goldman, a research space scientist at the Goddard Space Flight Center and a leader of the NExSS group.  He’s an expert in ancient earth as well the astrophysics of exoplanets, and his view is that the Earth provides 4.5 billion years of physical, chemical, climatic and biological dynamics  that need to be mined for useful insights about exoplanets.

When the workshop was over he said: “For me, and I think for others, we’ll look back at this meeting years from now and say to ourselves, ‘We were there at the beginning of something big.”

NExSS has two more workshops coming up, one on “Biosignatures” July 27 t0 29 in Seattle and another on stellar-exoplanet interactions in November.  Reflecting the broad reach of NExSS, the biosignatures program has additional sponsors include the NASA Astrobiology Institute (NAI), NASA’s Exoplanet Exploration Program (ExEP), and international partners, including the European Astrobiology Network Association (EANA) and Japan’s Earth-Life Science Institute (ELSI).

SA (2001) By looking for signs of life like we have on earth, we focus on trying to find the presence of oxygen, ozone, water, carbon dioxide, methane and nitrous oxide; indicating plant or bacterial life. Looking at the figure above, we can see how complex Earth’s spectra is compared to Mars or Venus. This is because of various factors that balance and control the elements needed for life as a whole. In the same way, we’re hoping to find life that strongly interacts with its atmosphere on a global scale.
By looking for signs of life, scientists focus on the potential presence of oxygen, ozone, water, carbon dioxide, methane and nitrous oxide, which could indicate plant or bacterial life. The figure above shows how complex Earth’s spectra is compared to Mars or Venus. This is a reflection of the intricate balance and control of elements needed to support life. The upcoming NExSS workshop will focus on what we know, and need to know, about what future missions and observations should be looking for in terms of exoplanet biosignatures. (ESA)

The initial idea for NExSS came from Mary Voytek, senior scientist for astrobiology in NASA’s Planetary Sciences Division.  Interdisciplinary collaboration and solutions are baked into the DNA of astrobiology, so it is not surprising that an interdisciplinary approach to exoplanets would come from that direction.  In addition, as the study of exoplanets increasingly becomes a search for possible life or biosignatures on those planets, it falls very much into the realm of astrobiology.

Mary Voytek, NASA senior scientist for astrobiology, xxxx.
Mary Voytek, NASA senior scientist for astrobiology, who initially proposed the idea that became the NExSS initiative.

Hudgins said that while this dynamic is well understood at NASA headquarters, the structure of the agency does not necessarily reflect the convergence.  Exoplanet studies are funded through the Division of Astrophysics while astrobiology is in the Planetary Sciences Division.

NExSS is a beginning effort to bring the overlapping fields closer together within the agency,  and more may be on the way.  Said Hudgins:  “We could very well see some evolution in how NASA approaches the problem, with more bridges between astrobiology and exoplanets.”

NExSS is led by Natalie Batalha of NASA’s Ames Research Center in Moffett Field, California; Dawn Gelino with NExScI, the NASA Exoplanet Science Institute at the California Institute of Technology in Pasadena; and Anthony Del Genio of NASA’s Goddard Institute for Space Studies in New York City.

All three see NExSS as an experiment and work in progress, with some promising accomplishments already.  And some clear challenges.

NASA's NExSS initiative seeks to bring together scientists from varied backgrounds to address questions of exoplanet research. The initiative consists of 17 teams that had applied for NASA grants under a variety of different programs, but organizers are looking to bring other scientists into the process as well. (NASA)
NASA’s NExSS initiative seeks to bring together scientists from varied backgrounds to address questions of exoplanet research. The initiative consists of 17 teams that had applied for NASA grants under a variety of different programs, but organizers are looking to bring other scientists into the process as well. (NASA)

 

Del Genio, for instance, described the complex dynamics involved in having a team like his own — climate modelers who have spent years understanding the workings of our planet — determine how their expertise can be useful in better understanding exoplanets.

These are some of his thoughts:

“This sounds great, but in practice it is very difficult to do for a number of reasons.  First, all the disciplines speak different languages. Jargon from one field has to be learned by people in another field, and unlike when I travel to Europe with a Berlitz phrase book, there is no Earth-to-Astrophysics translation guide to consult.

Tony del Genio, a veteran research scientists at NASA's Goddard Institute for Space Studies in Manhattan.
Tony Del Genio, a veteran research scientists at NASA’s Goddard Institute for Space Studies in Manhattan.

“Second, we don’t appreciate what the important questions are in each others’ fields, what the limitations of each field are, etc.  We have been trying to address these roadblocks in the first year by having roughly monthly webinars where different people present research that their team is doing.  But there are 17 teams, so this takes a while to do, and we are only part way through having all the teams present.

“Third, NExSS is a combination of teams that proposed to different NASA programs for funding, and we are a combination of big and small teams.  We are also a combination of teams in areas whose science is more mature, and teams in areas whose science is not yet very mature (and maybe if you asked all of us you’d get 10 different opinions on whose science is mature and whose isn’t).

What’s more, he wrote, he sees an inevitable imbalance between the astrophysics teams — which have been thinking about exoplanets for a long time — and teams from other disciplines that have mature models and theories for their own work but are now applying those tools to think about exoplanets for the first time.

But he sees these issues as challenges rather than show-stoppers, and expects to see important — and unpredictable — progress during the three-year life of the initiative.

Natalie Batalie said that she became involved with NExSS because “I wanted to help expedite the search for life on exoplanets.”

Natalie Batalha, project scientist for the Kepler mission and a leader of the NExSS initiative.
Natalie Batalha, project scientist for the Kepler mission and a leader of the NExSS initiative.

“Reaching this goal requires interdisciplinary thinking that’s been difficult to achieve given the divisional boundaries within NASA’s science mission directorate.  NExSS is an experiment to see if cooperation between the divisions can lead to cross-fertilization of ideas and a deeper understanding of planetary habitability.”

She said that in the last year, scientists working on planetary habitability both inside and outside of NExSS — and funded by different science divisions within NASA — have had numerous NExSS-sponsored opportunities to interact, learn from each other and begin collaborations.

The Fortney et al “White Paper” on experimental data gaps, for example, was conceived during one of these gatherings, as was the need for a biosignatures analysis group to support NASA’s Science & Technology Definition Teams studying the possible flagship missions of the future.

Dawn Gelino sees NExSS as an opportunity to speed the pace of addressing and answering open questions in the exoplanet field.  “As a community, we’re making progress towards answering some of them faster than others,” she wrote to me.

 Dawn Gelino, NExScI Science Affairs senior scientist and a leader of the NExSS initiative.
Dawn Gelino, NExScI Science Affairs senior scientist and a leader of the NExSS initiative.

“NExSS gives us an opportunity to look at all of these questions from many points of view.  Suddenly, a problem that a team of researchers has been stuck on has the potential to be solved quickly by learning from those in other disciplines who have dealt with similar problems. ”

Gelino said that NExSS is also working with various NASA study and analysis groups, the teams that come together to take on complicated questions and can later guide and sometimes define some of the science of a NASA mission. The discussion and conclusions from the upcoming Seattle biosignatures workshop, for instance, will be taken up by NASA’s Exoplanet Program Analysis Group (ExoPAG).

As a result, Gelino said, “NExSS scientists can share the knowledge gained from their interactions with earth scientists, heliophysicists, and planetary scientists, which broadens the knowledge of the community as a whole.”

In full disclosure, Many Worlds is funded by NExSS but represents only the views of the writer.

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