Diary of an Interstellar Voyage: Part 5 (June 15, 2023)
The grinding sound of the Silver Star bow thruster sounds like the moan of a giant whale. I jogged this morning on the ship’s wide deck before sunrise with ocean water splashing around and felt like a cowboy riding the back of a whale into the sunrise.
A few hours later, I surveyed the diagnostic instruments that Ryan Weed will be using as soon as we retrieve materials from the ocean floor. The X-ray fluorescence analyzer will provide information about the surface composition of any fragment we retrieve. The gamma-ray spectrometer could detect the abundances of radioactive isotopes.
While speaking with Ryan I realized that if we detect isotopes with a half-lifelonger than a million years, we could potentially infer the star from where the material came. We know the full velocity vector of the first recognized interstellar meteor, IM1, before it entered the solar system based on its arrival trajectory at Earth. Multiplying this vector by the decay time would give us the maximum distance and direction from where it came, and the absence of some isotopes could give us a minimum distance. If the composition reflects a natural source with known initial abundances of isotopes characterized by different lifetimes, we could potentially identify candidate source stars based on the distance and direction constraints. This is a new method that is feasible as a result of the discovery of interstellar meteors, like IM1. My realization could end in an exciting paper if we find sufficiently heavy elements with long lifetime like Uranium. My wildest dream is that we find an object the size of a ping-pong ball with long-lived isotopes that allow us to identify its parent star.
At lunchtime, we pulled the magnetic sled from our second control region. Amazingly, there was debris attached to some of the sled magnets. I have found that the most effective method of removing the debris from the magnets is with a brush. As I held a painter’s brush in my hand, Jeff Wynn snapped a photo of me and noted that I look like the artist of science.
Most of the recovered material was on the heavy side of the sled on the far side from the winch cable. Clearly, this side spent more time in contact with the ocean floor. The good news is that the sled design was successful in collecting magnetic particles. Most importantly, the abundance of these particles was not overwhelming and their size was mostly a tenth of a millimeter, so we can easily separate fragments of IM1 that could be bigger than a millimeter.
Silver Star is now heading towards the impact site of the first interstellar meteor, IM1 based on the Manus Island seismometer signal from the fireball’s blast wave. It will take us a couple of hours to get there and several additional hours before we pull our interstellar hook and see if any interstellar materials are stuck on its magnets.
IM1 arrived at this site on January 8, 2014, almost a decade ago. This rendezvous is long overdue. We are now ready to retrieve anything left from the decade-old encounter. Once we find IM1 materials, we might be able to figure out which star it came from based on the abundance versus lifetime of its radioactive isotopes. The Galileo Project video on display at Times Square will be updated instantly based on what we find.
ABOUT THE AUTHOR
Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He chairs the advisory board for the Breakthrough Starshot project, and is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. His new book, titled “Interstellar”, is scheduled for publication in August 2023.