gravity Archives - Lousy Canuck

Okay, a bit of a misleading title, but I like it nonetheless.

I just had a minor bit of unpleasant SIWOTI, only in meatspace instead of On The Internet. I don’t think I handled it entirely appropriately but that’s mostly because as a nerd, these things do matter to me. But interacting with other people also matters to me.

Caribou Coffee is a local answer to Starbucks that falls about halfway between Tim Horton’s and Starbucks on the scale of fancy-fancy frou-frou (which is a scalar value, obviously). They have a trivia question on a chalkboard next to their menu every day, and getting it right will knock ten cents off your order. It’s not a big deal, but it’s a fun little thing. Today’s question was: “What is Mars’ gravitational pull (relative to Earth’s)?”
Continue reading “The specific gravity of cold-press coffee” →

So, one among the dozens of ridiculous claims made by Ed Kohout in this thread was that the claim famously posited by Carl Sagan in Demon Haunted World, that the obstetrician in the room imparts more gravitational force on a newborn baby than does Pluto, is a strawman. Edit: To clarify, he referred to gravitational and tidal forces as proof that the planets have an effect on human lives (which we, of course, understand and can measure!), and handwaved away the Sagan quote preemptively as though it was a strawman caricature of the actual astrological arguments about gravity (which he didn’t, by the way, expand on). This strikes me as a bit of a Courtier’s Reply, and the fact is, the argument about gravity actually knocks gravity out as a potential vehicle for whatever influences are claimed about the planets’ influences — especially given that these influences are purportedly equally strong/subtle for any of the planets. The Sagan quote about Pluto’s gravity being less than the obstetrician’s is a sound-bite form of a knockout argument for one of the four fundamental forces.

Well, Ed said Jupiter instead, but I’m willing to crunch some numbers to see how right he is. For these calculations, since I’m no math genius, I’m using this Newtonian gravity equation calculator. Yeah, yeah, Newtonian physics have been superceded by relativity, but I’m not about to try to calculate this out using relativity, that would be ridiculous. Newtonian physics hold in this case anyway.

I’ve expanded out all the numbers from scientific notation to straight digits. Average baby weight is 3.4kg, so let’s go with that. As some commenters helpfully point out, this assumes the force from the center of a spherical mass, so assume a spherical baby and a spherical obstetrician. Because gravitational calculations are wibbly with oddly-shaped objects.

Jupiter at closest approach to Earth, weight rounded up:

object 1 mass (m1) = 3.4 kilogram
object 2 mass (m2) = 1900000000000000000000000000 kilogram
distance between objects (r) = 628743036 kilometer

Solution:
gravitational force (F) = 0.000001090388427237 newton

Continue reading “Astrology’s “obstetrician strawman” is no strawman” →