As we reached a summit of the Swiss Alps at an altitude of 2 kilometers above sea level, the bright Sun burned up small clouds below us over the magnificent Lake Geneva. Five months earlier, I led an expedition to the Pacific Ocean to retrieve meteor spherules from a depth of 2 kilometers below sea level. The symmetric change in elevation from the depths of the warm Pacific Ocean to the frozen Swiss Alps, spans less than one part in a thousand of Earth’s radius, but displays distinctly different forms of life.
If lifeforms are so different across this range of elevations on Earth, imagine how bizarre it might be across the variety of environments offered in the Milky-Way disk of stars which stretches over a scale that is a hundred trillion times larger than Earth. Given the limited speed of current rocket engines, there is no way for me to visit environments outside the solar system during my short lifespan. As a result, I focus on studying objects that already made the interstellar journey and arrived near Earth. They offer me the only hope of acquiring new knowledge on the physical materials out there. The first known interstellar objects from the past decade appeared anomalous compared to rocks from the Solar system. The two meteors: IM1 from January 2014 and IM2 from March 2017, showed exceptional material strength, whereas `Oumuamua which was discovered in October 2017, exhibited an extreme shape and non-gravitational acceleration with no visible evaporation.
The visibility from the Swiss Alps summit was fantastic all the way to the horizon, which featured the snow-covered Mont Blanc mountain peaks in France. I am used to snow and freezing temperatures, since just before boarding my plane from Boston, Massachusetts, I jogged at sunrise in an even colder weather. “This summit would constitute a perfect site for a new observatory of the Galileo Project in search of extraterrestrial objects near Earth”, I noted to my generous hosts, John and Lola Grace. In addition to the benefit of seeing far, I joked that the oxygen level at this elevation is too low for my critics to survive.
On the following day, I was scheduled to deliver the Distinguished John Grace lecture at CERN in Geneva. The lecture, titled: “The New Frontier of Interstellar Objects”, reviews our latest research team’s findings on the differentiated spherules near IM1’s path with a unique fingerprint of an abundance pattern of 60 elements from the periodic table, unlike the composition patterns of solar system spherules or terrestrial particles including coal ash. The lecture also features my latest thoughts on `Oumuamua, which could have been a piece of a Dyson sphere whose tiles were blown apart by increased radiation pressure from the host star or asteroid impacts.
In the morning preceding my public lecture, I gave a brief presentation followed by a Fireside Chat with an audience that gathered at CERN’s library to discuss my new book, Interstellar. This inspiring conversation extended well beyond its time limit and was followed by a book signing event, during which I was honored to autograph my book for local librarians, the caretakers of the numerous science books that surrounded us which appeared like gardeners caring for a field of blossoming flowers.
At lunch time in CERN’s cafeteria, I met by chance the current President of the CERN Council, Eliezer Rabinovici, and greeted him warmly as we know each other for nearly forty years since the time I received my PhD at age 24 from the Hebrew University in Jerusalem.
Subsequently, we benefitted from a guided tour through the history of CERN. As a theoretical physicist who is currently embarked on experimental work, I was delighted to learn that the idea for this cathedral of experimental physics was conceived in 1949 by a theoretical physicist, Luis de Broglie. As I get older, I favor experimental data over the opinions of theorists. Even though the collection of evidence takes more time, it offers a far more efficient path for uncovering new knowledge about our cosmic neighborhood. CERN’s flagship principles of advancing scientific knowledge through international collaborations resonate deeply with me.
After that, we visited the antimatter laboratories at CERN. So far, anti-hydrogen, the stable atoms containing a positively-charged positron (anti-electron) bound to a negatively-charged anti-proton, were found to behave in these laboratories just as hydrogen atoms do under the influence of gravity, showing no hint of a new force that distinguishes matter from antimatter. We owe our existence to a slight overabundance of matter relative to antimatter in the infant universe. Without this asymmetry of one part in two billion — whose origin is still unknown, the cosmos would have been filled with the annihilation product of pure radiation within a few seconds after the Big Bing.
Artificially produced antimatter could potentially be trapped and delivered to space. If produced at industrial quantities, it could serve as the ideal rocket fuel, converting mass to pure energy and potentially propelling rockets to the speed of light. An antimatter engine could offer us a chance to reach the stars during our lifetime, since accelerating at a comfortable 1 gee for two decades would deliver the needed time dilation to traverse the Milky Way galaxy on the relativistic spacecraft. The engineering challenges involve producing antimatter at scale, avoiding damage from collisions with interstellar matter along the path, and handling the risk of fuel leakage and accidental annihilation of passengers. Funerals in remembrance of those who died by antimatter annihilation would need to replace the commonly-used phrase “ashes to ashes” by “ashes to gamma-rays”, where the term `ashes’ commonly refers to the basic elements that make the Earth.
A few hours later, I delivered the public lecture in the amazing CERN Globe of Science and Innovation. This wooden structure appeared to me like a giant Noah’s ark that could be turned into a flagship vehicle sent to promote peaceful scientific collaboration in space. All we need to do is attach the Globe to the Raptor rocket engine of Starship. It would constitute a better ambassador of our civilization than Elon Musk’s Tesla Roadster car, which was launched into space on SpaceX’s first test launch of its Falcon Heavy rocket in February 2018. The Tesla car launch was just a few months after `Oumuamua was discovered. If telescopes were to notice the reflection of sunlight from SpaceX’s metallic space trash without the observers knowing that it was launched, would mainstream astronomers argue forcefully that it is a dark comet made of pure hydrogen or nitrogen or perhaps a fluffy dust bunny as suggested for `Oumuamua?
After another hour-long Fireside Chat and Q&A session, another book signing line formed spontaneously in front of the stage. I was humbled to learn that some members of the audience travelled all the way from Germany, France, and remote regions of Switzerland in order to meet me in person. At the end of the line was a brilliant instrumentalist who demonstrated a spectrograph that he built with the hope of a potential collaboration with the Galileo Project. Many people told me that they had been following my writings for years. Speaking with them encourages me to follow CERN’s guiding principles of acquiring new knowledge though the hard work of experimental science. This provides the best antidote to superficial toxicity against innovation and the anti-science sentiments promoted by social media mobs and academic jealousy.
At the end of my public deliberations, I emphasized the importance of fostering an open-minded academic culture that encourages young scholars to think differently and find low-hanging fruits along research paths that were not taken so far. Staying a member of that community is the greatest professional honor that I can aspire to have on the stage of CERN’s Globe of Science and Innovation.
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”, was published in August 2023.
