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Posts Tagged ‘General Theory of Relativity

“If it was so, it might be; and if it were so, it would be; but as it isn’t, it ain’t. That’s logic.”*…


Your correspondent is headed into the chilly wilds for the Thanksgiving holiday, so this will be the last post until after the passing of the tryptophan haze.  By way of keeping readers amused in the meantime, the puzzle above…

Find a step-by-step guide to its answer at “How to Solve the Hardest Logic Puzzle Ever.”

* Tweedledee, in Lewis Caroll’s Through the Looking-Glass, and What Alice Found There


As we muddle in the excluded middle, we might recall that it was on this date in 1915 that Albert Einstein presented the Einstein Field Equations to the Prussian Academy of Sciences.  Einstein developed what was elaborated into a set of 10 equations to account for gravitation in the curved spacetime described in his General Theory of Relativity; they are used to determine spacetime geometry.

(German mathematician David Hilbert reached the same conclusion, and actually published the equation before Einstein– though Hilbert, who was a correspondent of Einstein’s, never suggested that Einstein’s credit was inappropriate.)

On the right side of the equal sign, the distribution of matter and energy in space; on the left, the geometry of the space, the so-called metric, a prescription for how to compute the distance between two points.



Written by LW

November 25, 2015 at 1:01 am

The miracle(s) of life…

The Barnados Threadsnake (Leptotyphlops carlae)

In the last issue of The New Yorker, Elizabeth Kolbert’s “The Sixth Extinction?” sounds an alarm.  Observing that of the many species that have existed on earth, more than ninety-nine per cent have disappeared, and that these extinctions have tended to come in waves– five of which were especially broad– she ponders the possibility that we are at the lip of the sixth great wave of species disappearance.

While there’s every reason to worry that Kolbert is right, one notes that new species are uncovered every year– even in periods of relative decline in diversity.  Indeed, Wired provides a nifty catalogue of “10 Strange Species Discovered Last Year.”

The forces of life and variety fight back!

As we celebrate the creative impulse (in all of it forms and products), we might recall that it was on this date in 1919 that Arthur Eddington confirmed Einstein’s light-bending prediction– a part of The Theory of General Relativity– using photos of a solar eclipse.  Eddington’s paper the following year was the “debut” of Einstein’s theoretical work in most of the English-speaking world (and occasioned an urban legend: when a reporter supposedly suggested that “only three people understand relativity,”  Eddington was supposed to have jokingly replied “Oh, who’s the third?”)

One of Eddington’s photos of the 1919 solar eclipse

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