Galactic challenge: A new 10-year plan for the cosmos

The investment would entail bailing out and combining the efforts of two rival projects, the Giant Magellan Telescope and the Thirty Meter Telescope. Once completed, these telescopes, with primary gathering mirrors 25 and 30 meters in diameter, would be about 100 times more sensitive than any telescope currently in operation.

They would allow astronomers to peer deep into the cores of distant galaxies, where monstrous black holes roam and sputter energy; investigate mysteries like dark matter and dark energy; and study planets around stars other than the sun. Perhaps more important, they could raise new questions about the nature of the universe. But astronomers have struggled for years to raise enough money to complete their dreams. In the new proposal, the National Science Foundation would provide $1.6 billion to finish both projects and then help run them as part of a new program called the US Extremely Large Telescope. The astronomers urged NASA to embark on a new Great Observatories Mission and Technology Maturation Program that would develop a series of astrophysics spacecraft over the next 20 to 30 years.

The first would be an optical telescope bigger than the Hubble Space Telescope and capable of finding and studying Earthlike planets — potentially habitable “exo-Earths” — in the nearby cosmos. Only NASA could accomplish this, the astronomers said, noting that it could be ready in 2040 and would cost $11 billion. Those two recommendations were the biggest in a long-awaited, 614-page report, Pathways to Discovery in Astronomy and Astrophysics for the 2020s, released by the National Academies of Sciences, Engineering and Medicine on Thursday. Every 10 years for the last 70, the academy has sponsored a survey of the astronomical community in order to set priorities for big-ticket items over the next decade. The Decadal Survey, as it is known, commands the attention of Congress, NASA, the National Science Foundation and the Department of Energy. This year’s effort — chaired by Fiona A. Harrison of the California Institute of Technology and Robert C. Kennicutt, Jr, of the University of Arizona — took three years and entailed dozens of meetings and discussions among 13 subpanels spanning every branch of astronomy. In all, 860 White Papers were submitted to the survey, describing telescopes that might be built, space missions that should be launched, experiments or observations that should be done, and issues such as diversity that the astronomical community should address. In an interview, Dr. Harrison said their committee had tried to balance ambition against the amount of time and money these projects would take.

For instance, several ideas were floated for planet-prospecting spacecraft. Some were too big, some were too small; some would take a century to execute. Rather than choose one of these, the group asked the community and NASA to come back with ideas for a space telescope six meters in diameter. (Hubble’s main mirror is 2.4 meters in diameter.) “A six-meter telescope appears to be an achievable ambition,” Dr. Harrison said. “This is an ambitious quest by nature,” she added. “Only NASA, only the U.S. can do this. We believe we can do it.”

Overbye is a journalist with NYT©2021

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