Tiny Asteroids, Big Threats: JWST Reveals a Hidden World of Mini Asteroids
One significant threat to life here on Earth is the possibility that a massive asteroid will collide with our planet and destroy life as we know it. To understand the possibilities, large surveys of the sky have found around 95% of potentially hazardous asteroids larger than a kilometer. Smaller asteroids, however, can also cause massive amounts of damage. Estimates range from 40 to 60 percent when it comes to asteroids over 100 meters in diameter, which would be considered city-killers. Even smaller asteroids, such as the 20-meter one that exploded over Chelyabinsk in 2013, can cause destruction and injury. The more asteroids we can find, the better our predictions and future protections will be. In light of this threat, scientists have used the JWST to detect 138 of the smallest asteroids (as small as 10 meters) ever observed in the asteroid belt. These tiny asteroids are important because they can become near-Earth objects (NEOs), posing a risk to Earth through possible impacts, including powerful explosions. By analyzing the size and frequency of asteroids, researchers found a significant change in the population of asteroids around 100 meters in size, likely due to collisions breaking larger asteroids into smaller ones. The observed asteroids originated from known asteroid families and were detected using advanced tracking and infrared imaging techniques. This research enhances our understanding of asteroid behavior and may aid in predicting and mitigating future asteroid threats. Join planetary astronomer Franck Marchis in a conversation with lead authors Artem Y. Burdanov and Julien de Wit as they discuss these smaller asteroids and what they can reveal about potential threats to our planet. (Recorded live 1 May 2025.)
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Is Intelligent Life Easy? Human-Like Life Probably Evolves "Right on Time"
A recent study proposes a new model for the evolution of intelligent life, which challenges the long-standing "hard steps" theory that the emergence of intelligent life is an exceedingly rare event due to a series of improbable evolutionary milestones. A team led by postdoctoral researcher Dan Mills from the University of Munich suggests that the development of intelligent life is a natural outcome of planetary evolution. They argue that Earth's environment underwent sequential "windows of habitability," periods when conditions became favorable for complex life to emerge. (Past Drake Award winner Jason Wright is a co-author on the study.) The study emphasizes the importance of interdisciplinary collaboration between astrophysics and geobiology to understand the evolution of life. Join planetary astronomer Franck Marchis in an in-depth discussion with Dr. Mills about why intelligent life may be common and how this could affect our search for life beyond Earth. (Recorded live 24 April 2025.)
Join Dr. Franck Marchis, Chief Science Officer and co-founder at Unistellar and director of Citizen Science at SETI Institute, and Dr. Lauren Sgro, Outreach Manager at the SETI Institute, for a conversation on citizen science with the Unistellar network in partnership with the SETI Institute. We will give an update on T CrB, share our new Satellites mode, discuss an exoplanet candidate campaign to confirm a planet, and look ahead to an occultation of asteroid 319 Leona. We will also answer your questions about our program from the Unistellar community page and discuss recent highlights. (Recorded live 17 April 2025.)
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Chasing Martian Microbes: A New Technique for Finding Microbial Fossils in Minerals
A road trip to a gypsum quarry in Algeria led Youcef Sellam on a journey of scientific discovery. From the road trip to an internship in Italy, he and his colleagues later discovered microbial fossils—marking a first for Algerian gypsum. As a Ph.D. student at the University of Bern, Sellam and his team took this research further. They used a special instrument to detect the chemical signatures of these ancient microbes, demonstrating a method that could one day help search for traces of life on Mars. Their findings, published in Frontiers in Astronomy and Space Sciences, highlight how chemical analysis can reveal biological traces in minerals. Join planetary scientist Beth Johnson and Youcef for a discussion of how this research brings us one step closer to understanding how we might detect past life on the Red Planet. (Recorded live 10 April 2025.)
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Why is Mars Red? New Research Suggests Ferrihydrite is the Key
In a recent study, Dr. Janice Bishop of the SETI Institute, along with postdoctoral researcher Adomas Valantinas from Brown University, propose that Mars' characteristic red hue is primarily due to ferrihydrite—a water-rich iron oxide mineral—rather than the previously assumed hematite. Analyses of data collected by Martian orbiters, rovers, and laboratory experiments showed that ferrihydrite closely matches the composition of the dust covering Mars' surface. Ferrihydrite typically forms in environments abundant in cool water, suggesting Mars once had significant liquid water on its surface. The research implies that Mars transitioned from a wet to a dry environment billions of years ago. Confirming these findings would require returning samples from Mars to Earth for comprehensive analysis. Join planetary scientist Beth Johnson for a chat with Dr. Bishop about the evidence for ferrihydrite and what it could have meant for life on Mars. (Recorded live 3 April 2025.)
SETI Live is a weekly production of the SETI Institute and is recorded live on stream with viewers on YouTube, Facebook, LinkedIn, X (formerly known as Twitter), and Twitch. Guests include astronomers, planetary scientists, cosmologists, and more, working on current scientific research. Founded in 1984, the SETI Institute is a non-profit, multi-disciplinary research and education organization whose mission is to lead humanity’s quest to understand the origins and prevalence of life and intelligence in the Universe and to share that knowledge with the world.
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