by Rex Parker, PhD director@princetonastronomers.org

Monthly Meetings on Campus Begin Sept 12.  We’re excited that the Dept of Astrophysical Sciences at Princeton University is welcoming us back again to Peyton Hall auditorium for our meetings on the second Tuesday each month at 7:30pm.  The major construction underway across from Peyton Hall means that members must park cars in the garage at 148 Fitzrandolph Rd, at the corner of Faculty and Fitzrandolph on the campus, the former site of Fitzrandolph Observatory for many decades in the 1900’s. It’s important to arrive about 15 minutes early for the walk to Peyton Hall; see the map in Victor’s article below.  We hope that you will join us in person this season, while remotely participating via Zoom will remain an option.  Of course, participating in person is a good way to get to know other members and help spark the energy that makes being in an astronomy club fun.  

Searching for Extrasolar Meteors and Alien Artifacts.  A couple years ago at a AAAP meeting we engaged in a book review of “Extraterrestrial”, by Harvard astrophysics professor Avi Loeb.  The book has become a huge best-seller while irritating some in the astrophysics community.  We invited Dr Loeb as AAAP guest speaker at the November 2022 meeting, where he told the story of his team’s research into the possibility of extrasolar archeologic artifacts.  Since then the tale has become even more interesting. Professor Loeb hypothesized that the apparent extrasolar near-Earth object known as Oumuamua, observed in 2017 by telescopes in Hawaii, might have had an extrasolar technological origin.  Based on several unusual properties Oumuamua was suggested to possibly be a light sail, long considered as a potential method of space travel.  Dr Loeb subsequently founded the Galileo Project based at Harvard (link: The Galileo Project (harvard.edu)) for the “Systematic Scientific Search for Evidence of Extraterrestrial Technological Artifacts”.  Even though Dr Loeb has taken a lot of heat from scientific peers about seeking signs of extraterrestrials, he has remained rigorous in research approaches and in mathematical analysis of the probabilities and distribution of extrasolar objects crossing interstellar space. And he has boldly pushed to loosen up the astronomy community’s taboo against the topic.

Fast forwarding to 2023, the Galileo Project team embarked on a sea mission to attempt the recovery of the remnants of a likely interstellar meteor, which in Jan 2014 was detected by US government satellite sensors as atmospheric detonations near Papua New Guinea. Previous studies by other scientists had developed an understanding of how meteors entering earth’s atmosphere at very high velocities will vaporize and explode at elevations depending on initial speed and mass. The Galileo team developed a magnetic undersea sled towed by a ship to attempt the recovery in the Pacific Ocean target zone, with outlying areas serving as control.

They retrieved from the seafloor along the meteor’s path about 700 metallic spherules of 0.05 to 1.3 mm diameter with distribution concentrated along the bolide path (see picture below). Initial chemical and isotope analysis indicated a composition unmatched by existing alloys in our solar system.  They found abundances of certain key elements, and isotope ratios for iron, which were unlike those found on Earth, the Moon, or Mars, suggesting an interstellar origin.  The initial analysis results were consistent with a fiery bolide entry into the lower atmosphere, which certainly presents a complex physics and chemistry problem. These signatures were not found in samples from the control areas outside the path.  The expedition team’s paper on the initial findings has been submitted for peer review in a scientific journal and is available as preprint here: Discovery of Spherules of Likely Extrasolar Composition in the Pacific Ocean Site of the CNEOS 2014-01-08 (IM1) Bolide (harvard.edu). The spherules will be further analyzed by four laboratories around the world (Harvard University, UC Berkeley, and the Bruker Corporation, and the Univ of Technology in Papua New Guinea) using state-of-the art instrumentation.  Depending on the results of more thorough analyses, humanity may hold the first-ever sample of material which originated in another star system and travelled an interstellar journey to reach our planet. Whether even more remarkable conclusions may emerge, including the possibility of an extraterrestrial technological origin, remains to be seen, and as the authors say “will be considered critically along with additional results from spherule analysis in future publications”.  

An early photograph of one of the spherules collected from the sea floor along the bolide path. (photo from https://avi-loeb.medium.com/what-a-wonderful-world-8769dd88ab5c)