Deciphering the Universe on a Budget: New Worlds, New Horizons, Five Years Later

By Lori Ann White

Last fall, KIPAC professor Bruce Macintosh managed to make time in his busy schedule of teaching and sleuthing for extrasolar planets orbiting around distant stars to help put together a progress report for a mid-decadal review of what is arguably the most important exercise in his entire field:  The Astronomy and Astrophysics Decadal Survey.

For the past 60 years, once each decade the astronomy and astrophysics community in the US takes a good, long look in the mirror. During this comprehensive self-assessment, scientists from across the country and around the world come together to hash out issues of scientific priorities and resource allocations, enabling the field as a whole to face the future together.  "This is a good thing," Macintosh says—the democratic process results in a community that is more supportive of the resulting priorities, even if personal favorites didn't rank as highly as some scientists wanted.  Everybody knows they had a chance to be heard.

The most recent survey culminated in the fall 2010 release of "New Worlds, New Horizons in Astronomy and Astrophysics," by the National Research Council, the research arm of the National Academies of Science, Engineering, and Medicine. The committee of distinguished scientists leading the effort, chaired by KIPAC's own founding director Roger Blandford, distilled the survey results into a report informally known as Astro2010—300+ pages laying out the big questions facing researchers today, such as the natures of dark energy, dark matter, and inflation, and recommendations for new tools to help answer them.

But now, five years in, it is time for the mid-decadal assessment. The committee conducting the review has yet to issue its findings, but Macintosh agreed to give a brief preview.

The committee asked for input from representatives from each major project recommended by Astro2010, as well as NASA, the DOE, and the NSF, all major funders of astrophysics in the US, and put out the word for informal feedback as well. "For example, we had a public meeting in Irvine in December, 2015," Macintosh said, "and about a hundred astronomers showed up."

The mid-decadal assessment is "an important part of the process," Macintosh said. "The world has changed in so many ways even in just the past five years—for good and bad."  The good changes are primarily due to the fact that science is a moving target which actually regularly discovers significant things, he added—the recent announcement by the Laser Interferometer Gravitational-Wave Observatory (LIGO) of the direct detection of gravitational waves is a perfect example. One question the committee asked was whether any such changes call for a course correction in established priorities.

 

Above: Fully deployed JWST. ( Credit: Northrop Grumman.)

Funding has been and continues to be the biggest challenge, Macintosh said. Funding levels never reached even the modest levels forecast by the Astro2010 committee, while the burgeoning budget for the James Webb Space Telescope, the highest-priority space-based project from the previous survey, has caused delays in other NASA projects—most notably, Astro2010's top priority for space-based projects, the Wide-Field Infrared Survey Telescope (WFIRST). The Laser Interferometer Space Antenna, a joint project with the European Space Agency (ESA) was also a high priority in  the previous survey.  LISA is a sort of much larger version of LIGO that flies in space, and will probe gravitational waves from collisions of supermassive black holes, which occur when the nuclei of big colliding galaxies merge, vs. the gravitational waves resulting from the coalescences of stellar mass-sized black hole that LIGO sees.  And though it had been highly prioritized previously, funding constraints caused NASA to essentially drop out of being a part of the LISA collaboration. 

Above: An artist’s depiction of the WFIRST telescope, which will study dark energy, extrasolar planets, and objects in the near-infrared.  (Credit: NASA.)

Other funding agencies have their own challenges. The National Science Foundation (NSF), which is responsible for supporting much of the ground-based astronomical and astrophysical research in the US, has seen budgets remain mostly flat for the last several years. The situation has required them to make some hard choices when divvying up the pot among research grants, operating existing facilities, and building and operating new ones.

The Department of Energy (DOE), which funds fundamental physics research through its Office of Science arm, has its own funding woes to consider. High-energy physicists also went through their own exercise in soul searching which informed their own list of priorities that the DOE has to juggle.

But dedicated people create opportunities, and both NASA and the NSF have plenty of dedicated people. NASA also got a surprise gift—two telescopes from the National Reconnaissance Office—that kickstarted the current design for WFIRST.  Plugging a different telescope into the WFIRST design has required a certain amount of flexibility, but the benefits to the mission of a larger telescope, especially for studying exoplanets, outweigh the costs, and the project is now on the march. LISA is still alive as eLISA, now a fully European project, which illustrates the importance of international cooperation.  And with the recent direct detection of gravitational waves on Earth, perhaps this entire arena of research will get a boost in support in the long term.

Above: In this artist's rendition, the LSST primary mirror is seen through the slit of the dome at sunset. The LSST will carry out a deep, ten-year imaging survey in six broad optical bands over the main survey area of 18,000 square degrees, or nearly the entire sky visible from its location high in the Chilean Andes. (Credit: Todd Mason, Mason Productions Inc. / LSST Corporation.)

The NSF is looking for other partners besides the DOE, especially for funds to operate existing facilities. Astro2010's top priority for ground-based projects, the Large Synoptic Survey Telescope (LSST) is currently under construction on a mountaintop in Chile (you can even watch it go up via the LSST summit webcam). The people building LSST are aware of this prioritization and are getting a jump on finding operating funds for when the telescope goes into operation—currently scheduled for 2022–23.

In addition to checking in on the current decade's progress, Macintosh said the mid-decadal assessment committee is also concerned with laying the groundwork for the 2020 survey. "There are projects that people want to start up again," he said. "For example, one recommendation that hasn’t happened is the US government getting involved in 30-meter-class telescopes," or giant ground-based telescopes with primary mirrors which span 30 meters in diameter (in other words, nearly 10 times the collecting area of the current largest telescopes on the Earth today). Other issues under discussion, Macintosh said, included career-related topics such as the availability of jobs and the demographics of the field.

Macintosh said he got involved, despite a very busy schedule, because he's broadly interested in science policy.

I was glad to do it because I believe these issues are important,” he said. “Astronomy is a science that has lots of popular interest, because we grapple with questions that are both big and fundamental and direct enough that almost anyone can understand them, like ‘What is the universe made of?’ or, ‘Is there another planet like Earth?’ In part due to that broad interest, we get a lot of resources from people and the government, and it’s the job of the Decadal Surveys—and this mid-decadal check-in—to make sure we use those resources sensibly and keep doing really groundbreaking science.”