OSIRIS-REx and the Hayabusa spacecraft have sample asteroids to understand what they're made of. NASA sent the DART mission to change the orbit of a tiny asteroid orbiting another asteroid. ESA sent Hera as a follow-up mission to see what the impactor did. All of these missions have been done in the name of planetary defense -- protecting Earth from the worst of the rocks in space. While none of the asteroids so far discovered are a threat to our planet in the next century, there are still more out there that are small enough to do major damage to a city or even country. So what do we do if we find a near-Earth asteroid that's a real threat? Launch a team a la "Armageddon"? Ignore the problem? Try to flee off-planet or below ground? As DART showed, the best answer seems to be "move it out of the way". In his new book "How to Kill an Asteroid", Dr. Robin George Andrews tells the story of planetary defense and how we got to this point in saving ourselves. Join communications specialist Beth Johnson in a fun (and slightly scary) conversation with Dr. Andrews about killer asteroids this Halloween on SETI Live. (Recorded 31 October 2024.)

In September 2022, a small spacecraft called DART hit the surface of a tiny asteroid moonlet called Dimorphos. That spacecraft was the first test of a planetary defense system, attempting to change an asteroid's orbit in the hope of being able to do so under a real near-Earth threat. The test succeeded, shortening the moonlet's orbit by 32 minutes. Now, a follow-up mission called Hera is on its way to the system, complete with an orbiter and a lander. The European Space Agency plans to observe the impact site and measure any changes to the shape and any craters left behind. Join communications specialist Beth Johnson as she chats with Hera's principal investigator, Patrick Michel, from the Université Côte d'Azur about the mission, the science, and the technology being tested. (Recorded live 24 October 2024.)

The cosmos is full of huge questions: "What caused the Big Bang? What happens inside black holes? Are there other dimensions?" Scientists have been working to answer these questions, but sometimes, we feel like the answers are unknowable. Astrophysicist Kelsey Johnson contemplates what this paradox means for science, particularly where philosophy and even religion come into play. In her latest book, "Into the Unknown", Johnson takes us to the edge of our understanding. Join communications specialist Beth Johnson as she chats with author Kelsey Johnson about science, philosophy, and our quest for answers that may not be available. (Recorded live 21 October 2024.)