Day Two of Breakthrough Discuss opened with Michaël Gillon describing the discovery of TRAPPIST-1, which has seven temperate planets, including three in the habitable zone. The planets were discovered using small ground-based telescopes, and Gillon noted that on initial viewing of the data, there were “so many transits we couldn’t make sense of them.”
Gillon described how observations from several telescopes were used to study the TRAPPIST-1 system, including Kepler to confirm the existence of the planets, and Spitzer to figure out their orbits. Similarly, a suite of telescopes, including Hubble and the James Webb Space Telescope, could be used in the future to search for signs of water and atmospheres on planets that may be detected by the next generation of giant ground-based telescopes.
The morning continued with a panel on the search for extraterrestrial intelligence. The wide-ranging discussion, chaired by the SETI Institute’s Jill Tarter, discussed how studies of unexplained phenomena might lead to new discoveries in astrophysics, or possible evidence of activity by civilizations inhabiting other star systems. From the odd variations in brightness of a star studied by Tabetha Boyajian, to searches by Beatriz Villarroel for stars that might suddenly disappear, panelists described a variety of creative ways to search large, time-domain survey datasets for events of interest. Panelist Lucianne Walkowicz described how modern machine learning algorithms could allow us to look for strange behavior in data without making presuppositions about the kinds of signals extraterrestrials might generate. Jason Wright emphasized that a great deal of work is required to rule out natural astrophysical explanations before resorting to claims of intelligent aliens, and described an upcoming revision to the Rio Scale that is used to assess the credibility of ET claims.
The afternoon sessions focused on the ambitious Breakthrough Starshot plan to send spacecraft to nearby stars. Avi Loeb described how a gram-scale camera attached to a sail propelled by a powerful ground-based laser beam might reach Proxima b during our lifetime, traveling at 20 percent of the speed of light. Feasibility studies will be completed during the next five years, potentially leading to the construction of a kilometer-scale ground station, and the launch of many small, relatively inexpensive spacecraft to explore nearby star systems.
Philip Lubin described how this technology could enable craft to travel from Earth to the Moon in an hour, to Mars in under a day, and to nearby stars in a couple of decades. He talked about the materials science and engineering challenges in designing a sensor package to fit on a thin silicon wafer, and returning data to Earth, but was optimistic that ongoing technological developments would make this “watershed moment in human history” possible in the near future.
René Heller described a “photogravitational assist” technique that might enable a spacecraft traveling at 20 percent of the speed of light to use photons from the Alpha Centauri system as a brake to enter orbit rather than flying rapidly by. The session’s other speakers discussed how a suite of observations, both remote, and in-situ, could detect spectral features of vegetation, light glinting from oceans, and signs of water and oxygen in planetary atmospheres. The conference closed with a panel on science goals and instrumentation for Breakthrough Starshot.
In total, the two-day event featured three sessions of 19 presentations and 15 panelists. The first day, Thursday, April 20, featured a session that focused on recent observations of nearby planets, including Proxima b, and new techniques for observing them. A second session on Thursday examined the possibility of intelligent life in Earth’s cosmic neighborhood, and recent attempts to search for it withBreakthrough Listen.
The conference was broadcast on Facebook Live at www.Facebook.com/BreakthroughPrize. Viewers from around the world were able to join in the conversation and submit questions, which were answered by the panelists in real-time.
Breakthrough Discuss was hosted by Stanford University’s Department of Physics and the Harvard-Smithsonian Center for Astrophysics and sponsored by the Breakthrough Initiatives.
Breakthrough Discuss is an annual academic conference focused on life in the Universe and novel ideas for space exploration.
Breakthrough Initiatives are a suite of scientific and technological programs exploring the big questions around life in the Universe, such as, Are we alone? What are the nearest habitable planets? And can we become an interstellar civilization?
For more information see https://breakthroughinitiatives.org