Earth’s Magnetic Biosphere
In this lecture, Dr. Kirschvink will illustrate with several examples how the science of magnetism is leading to fundamentally new and fun discoveries about the origin and evolution of life on Earth. Some of these include: (1) Magnetic data first demonstrated that meteorites ejected from Mars can travel to Earth on low-temperature, low-shock trajectories that would not harm microbes traveling with them, thereby implying that our biosphere might have evolved first on Mars nearly 4 billion years ago, and traveled through space to Earth in them. (2) Recent genetic studies on the magnetotactic bacteria demonstrate that they evolved very early in Earth History (during Archean time), and show that the geomagnetic field also is very ancient, thereby protecting our atmosphere and oceans from the solar wind. (3) A record of Earth’s magnetic field is trapped in many rocks as they form, allowing us to record the position of continents throughout most of Earth history, and can be used to test ideas like ‘Snowball Earth’ and True Polar Wander events, such as that which occurred during the Cambrian Explosion. Finally, (4) He will mention exciting new developments in the study of how animals detect and use the geomagnetic field with tiny magnets similar to those which evolved in the magnetotactic bacteria so many years ago.
6:00 Hors d’oeuvres and cash bar
8:30 Questions and discussion
Parking available in the SB Club lot or on the street