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Sometimes, you just get these serendipitous moments. Yesterday, in the parking lot of the grocery store, there was a U-haul rental truck sporting a remarkably sophisticated graphic that explains the Manson impact structure in Iowa. When I got home, I went to the U-haul website, and discovered that they have a clear and beautifully self-contained tutorial on giant impacts. The site even explains the terms in the ballistic range equation, which gives the distance from impact that a piece of ejecta lands, given the radius and gravitational acceleration of the Earth, along with the ejection angle and the ejection velocity. And for those wanting more details, U-haul points to Jay Melosh’s Impact Cratering: A Geologic Process (one of the Oxford Monographs on Geology and Geophysics).

Inside the grocery store, at the checkout counter, I noticed that this week’s issue of The Sun is carrying a rather startling astronomically themed story:

Which brings me to the serendipity. Tomorrow afternoon, I’ll be engaging in a joint presentation/discussion with Chris McKay of NASA’s Ames Research Center on the topic of “Real Doomsdays: How Life Could End on Earth”. We’ll be discussing not just the long-term fate of life on Earth, but also the fate of the Earth itself. And indeed, a black hole plunge is one of a handful of fates that Earth might suffer in the ultra-distant future. If our planet isn’t engulfed by the red giant Sun, then it’ll eventually either be ejected into the utter isolation of the exponentially expanding intergalactic medium to slowly evaporate via nucleon decay, or it’ll wind up in the Milky Way-Andromeda central black hole. Presumably, that’s the eventuality that the editors of this week’s Sun are referring to.

Anyway, here are the details. The event is free, and is organized by Tucker Hiatt and the Bay Area Wonderfest organization:

WHO: UC Santa Cruz astrophysicist Greg Laughlin and NASA planetologist Chris McKay

WHAT: “Real Doomsdays: How Life Could End on Earth”

WHERE: Roxie Theater, 3117 – 16th Street, San Francisco

WHEN: 1:00-2:30 PM, Sunday, August 28, 2011