From Many Worlds: “Breaking Down Exoplanet Stovepipes”



Many Worlds

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Marc Kaufman

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)

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 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).

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.

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.

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.

“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.”

“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.

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

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About Many Worlds

There are many worlds out there waiting to fire your imagination.

Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

About NExSS

The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.