We live our life through numerous short-term challenges and alerts. Some appear extremely important at the moment, others rise to the level of existential threats, but once we overcome them — their significance fades over time as we approach new challenges. The experience resembles swimming though high waves in the ocean, with limited time to catch our breath.
Eventually one of these waves appears stronger than us and so it takes our life. Ecclesiastes recognized this thread: “No one remembers the former generations, and even those yet to come will not be remembered by those who follow them.” The mark of success is to survive for the longest time. This longevity game is the foundation for “survival of the fittest,” the principle advocated in the fifth edition of “On the Origin of Species” by Charles Darwin, who suggested that organisms best adjusted to their environment are the most successful.
Given this perspective, the highest value must be attributed to the elements of reality that survive the longest. In our personal life, these are not related to status symbols or the “likes” we garner on social media, nor to the honors or awards that we receive, but rather to the more persistent connections we cherish with loved ones.
Eventually, even those connections disappear. After about a century, the bodies of everyone we meet disintegrates and returns to Earth. Ecclesiastes recognized this insight: “What do people gain from all their labors at which they toil under the Sun? Generations come and generations go, but the Earth remains forever.” He was wrong about the fate of the Earth.
In fact, the Earth is expected to disintegrate in 7.6 billion years, when the Sun will expand to become a red giant star and engulf it. Friction on the Sun’s gaseous envelope will drive the Earth towards the solar core — where it will completely evaporate at temperatures reaching up to 100 million degrees. Everything we value on this Earth will be consumed by a giant solar wave that will erase all records that we ever existed. Our ultimate existential threat is the source of our life, the Sun.
Ecclesiastes was also wrong in stating: “What has been will be again, what has been done will be done again; there is nothing new under the Sun.” Even the Sun will eventually die and fade into a white dwarf, a metallic dense remnant with about 60% of the mass of the Sun and the size of the Earth that will fade away by cooling over time. The graveyard of the Milky-Way galaxy contains billions of white dwarfs from stars which died over billions of years. The Sun is a newcomer, born in the last third of cosmic history. Many of the white dwarf corpses might encapsulate the ashes of civilizations that existed on a habitable rocky planet which evaporated in the envelope of a red giant.
And so, we are left with the question of who to respect the most in the physical reality that we were born into. For the moment, we can enjoy patterns that come and go, but the fittest entities will survive. Who will be the survivors?
The nearest star to the Sun is Proxima Centauri, a dwarf star which carries only 12% of the mass of the Sun. The star is faint, radiating only 0.16% of the solar luminosity. But its faintness is a virtue, as it promises longevity. The slow burning of its nuclear fuel will allow Proxima Centauri to live for 4 trillion years, nearly a thousand times longer than the age of Earth. In Greek mythology, Gaia is the personification of the Earth and a primal deity, often referred to as Mother Earth, the ancestor of all terrestrial life. But in the context of Proxima Centauri being personified to have the longevity of a human, Gaia is equivalent to an infant with a life expectancy of a month.
And so, in the cosmic longevity game, slow-burners like Proxima Centauri should receive our utmost respect. The longest-lived stars among them have a mass of 7% solar masses and are expected to shine for 12 trillion years. In a paper I wrote with my former postdoc, John Forbes, we showed that accretion of gas from a companion star could supply additional energy to power objects just below the hydrogen burning limit for somewhat longer times.
Survival of the fittest also applies to all civilizations that had already existed or will be born throughout cosmic history. Those civilizations which are intelligent enough to avoid existential risks from asteroids, stellar explosion, artificial intelligence or alien predators, could live even longer than dwarf stars by staying warm next to their artificially created nuclear reactors.
But eventually, over a period of a quadrillion years, all lights might turn off and the Universe will experience a heat death. In capturing that end time, Ecclesiastes finally got it right: “Everything is meaningless.” Without the appreciation and love cheers from an audience of living spectators, what is the point of having a universe?
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 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. The paperback edition of his new book, titled “Interstellar”, was published in August 2024.
