NASA has just increased the likelihood that the asteroid 2024 YR4 will hit the Earth on December 22, 2032 to 3.1%!
This asteroid is estimated to have a diameter of 55 meters and a mass of 220,000 tons. At its expected impact speed of 17.3 kilometers per second, it would release an energy of 7.8 megaton of TNT, about 500 times the energy released by the atomic bomb over Hiroshima on August 6, 1945.
If the likelihood for impact will keep increasing up to 100% in the seven years leading to 2032, astronomers might gain the highest status in modern society. This is not unprecedented, as astronomer-priests had the highest status in the Mayan culture whose leadership embraced astrology when choosing the timing of wars. A variety of practical considerations will contribute to this new promotion.
First, as James Carville noted in 1992: “It’s the economy, stupid”. Real estate prices and insurance costs in the impact region will depend on the accurate forecast of astronomers. Estimates of the shape, structure and material strength of the asteroid will dictate at which altitude 2024 YR4 might disintegrate as a result of its friction with air and how wide the affected region will be.
Second, space agencies worldwide will get a funding boost in an effort to design missions that will deflect the asteroid’s trajectory in advance of its imminent impact. NASA’s Double Asteroid Redirection Test (DART) demonstrated recently the simplest technique for planetary defense. DART collided with Dimorphos on September 26, 2022 and deflected it through the recoil associated with ejected debris. But this method should be employed with caution. Similarly to the risk from the Patriot missiles during the Gulf war, the asteroid deflection mission should be careful not to increase the damage on Earth by breaking a single object into multiple projectiles.
Third, young adults will be inspired to become scientists and avoid the fate of non-avian dinosaurs, whose extinction 66 million years ago was triggered by a 10-kilometer rock. Asteroids of this scale are much rarer, impacting the Earth once per 100 million years, but asteroids with a diameter of a few meters impact the Earth every year. Given that, a meteor fireball with the energy output of the Hiroshima atomic bomb strikes the Earth once a year. The damage is minimal because the explosion often occurs at a high altitude of tens of kilometers and the blast wave weakens considerably by the time it hits the ground. Moreover, 71% of the Earth is covered by oceans.
This century is special. For the first time in the 4.6 billion years history of Earth, humans had constructed over the past century expensive technological infrastructures that could be severely damaged by rocks falling from the sky. There are at least 230,000 objects larger than 50 meters in size that will come near Earth and could destroy a city, but less than 8% of them are documented. Future generations of scientists will be obligated to find them and mitigate the risk for humanity’s wellbeing.
It is often argued that we should solve our problems on Earth before investing funds in space exploration. The rationale is equivalent to arguing that we should help our family members at home before engaging with our neighbors on the street. But what if a neighbor comes at our front door and poses an existential risk to our family? Shouldn’t we engage with the outside world for that reason? We cannot afford the luxury of ignoring the cosmos for too long. Eventually the Universe will come to bite us. Ultimately, within 7.6 billion years, the hot envelope of a boiling red giant will arrive at our doorstep as the future manifestation of the Sun.
Ironically, the existential threat from an asteroid impact could be good news for science, especially in the recent backdrop of funding cuts and firing of personnel at NIH, NSF and NASA. If the impact likelihood of 2024 YR4 will increase to 100%, the current concerns about the future of science will be replaced by rejuvenated funding and renewed respect for the ability of scientists to help society and promote a better future.
2024 YR4 will also have a good impact on the intellectual future of physics. Theorists who imagined for five decades new physics in extra dimensions and developed highly sophisticated mathematical structures that have no contact with experimental data, will be brought down to Earth. Let this be a teaching moment for all of us about the invaluable service of science to the benefit of humanity in the physical reality that we all share. The message of science is much better than that of polarized politics: we are all in the same boat and we better cooperate to survive.
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.
