Intelligence without ambition is a bird without wings. This quote by Salvador Dali resonates deeply with the concept of intelligent civilizations in the Milky Way galaxy. Many of these civilizations might have engaged in geopolitical conflicts on their rocky planets and perished by now. The fate of humanity is no different. We must be ambitious enough to venture into interstellar space to ensure our survival and to document the night sky on exoplanets. But how did the Sun complete its journey around the Milky-Way center? With an orbital speed of about 240 kilometers per second and an orbital radius of about 26,000 light years, the Sun has completed about 23 circles around the Milky-Way since it was born. During these 23 circles, the solar system crossed the path of many dense clouds of interstellar gas, where massive stars exploded as supernovae or hypernovae. A camera on the young Earth could have captured the most spectacular movie of all times. But what about interstellar visitors? Meter-scale rocks from interstellar space may impact the Earth roughly once per decade, adding up to half a billion such collisions over the Earth’s history. If any of these interstellar rocks carried resilient forms of life that survived the interstellar journey, Earth could have been exposed to extraterrestrial forms of life. However, if an interstellar gardener chose to seed the Earth with life, then our Galactic history could have been very different. We often consider the history of Earth as isolated from its Galactic environment, but this may not be the case. We do not know how much traffic of technological objects there was or is through the inner solar system. Our telescopes cannot detect the reflection of sunlight from objects smaller than our biggest rocket, Starship, at distances of order the Earth-Sun separation. In addition, objects that are faster by orders of magnitude than our spacecraft would appear as a faint streak across our images of the sky and be missed by astronomers. To truly understand our cosmic neighborhood, we would have to invest a significant fraction of our military budget worldwide in space exploration. An investment of a trillion dollars per year would have led to a detection of all interstellar objects larger than a CubeSat which are passing through the orbit of the Earth around the Sun. Another part of this ambitious plan would have included a space platform that could carry humans on long journeys into interstellar space. The most accomplished siblings of our family of intelligent civilizations may have followed this ambitious plan already. Finding their products in our neighborhood would inspire us to do the same. If we had access to the documentary of the night sky over the past 4.6 billion years, we have been more ambitious. But how can we find other Galactic civilizations? The first step would be to recognize that other Galactic civilizations did it already. Finding them requires the humility to learn that not all space objects are comets or asteroids. It also requires the investment in large survey telescopes, like the NSF-DOE Rubin Observatory in Chile. Before we fly out of the solar system, we can find out what comes into it from interstellar space. Both I/Oumuamua and 3I/ATLAS had anomalies, listed here and here respectively. There must be many smaller or faster objects that we are not aware of. The “unknown unknowns”, namely things that we do not even know that we do not know, offer the most exciting prospects in learning about our cosmic neighborhood. The CEOs were excited last night. Will their excitement translate into related investments? I have no doubt that it will, as soon as we have undisputable evidence for alien technology. But what about the personal connection to this topic? One such connection is shared by Victoria Freeman, who wrote to Professor Loeb, expressing her lifelong fascination with the stars and her desire to contribute to the research surrounding interstellar objects. Her passion and enthusiasm are a reminder that curiosity and wonder are essential in the pursuit of knowledge and exploration.
