Before it was a website, Ask A Mathematician / Ask A Physicist was two guys sitting in the desert at Burning Man, presuming to answer (almost) any question that happened to occur to whomever happened to appear at our stand.
We’ll be at burning man, and out of contact for the next week or so, so if it takes an especially long time for us to answer emails, it’s nothing personal.
There! Aug 31 and Sep 1, from 1:00pm-4:00pm.
We’ll be setting up a stand on August 31st and September 1st, from 1:00pm-4:00pm. So, if you’re going to be around, and you’d like to meet two people who actually write an honest-to-god web blog, then stop on by.
Here is the official description from the Burning Man events guide:
“Questions about the nature of reality, pi, infinity, primes, imaginary numbers, love, quantum theory, relativity, black holes, calculus etc? Come by! AAMAAP is about having access to a couple friendly people with math and physics backgrounds to answer questions that have been bothering you, or just a chance to soak in the vibe. The universe is a weird place. But not so weird that there aren’t any good answers to things! Location: 6:00 and walk a hundred yards toward the Man.”
If light could be emitted into a container with perfectly reflective surfaces, would it continue to be lit even after the source is turned off?
Yup!
How would you go about checking that?
With a perfectly reflective camera.
Also, nothing is perfectly reflective, so this is all just a thought experiment.
Also, “How would you go about checking that?” is the 1,000th comment! I can’t think of a more scientific comment!
How would a perfectly reflective camera work? Wouldn’t it have to absorb some of the light in order detect its existence? Or would it somehow keep track of how much light it absorbed and re-emit “that much” light using energy from outside the box?
That was sarcasm.
Like you say; a perfectly reflective camera wouldn’t work!
Wouldn’t the original light beam be both dead and alive until you looked in the box?
Well, I assume if you have access to a perfectly reflective container, you would also have access to an incredibly accurate scale. You could then weigh the container and find that it weighs very slightly more than an unlit container.
But Jason, I thought light has no mass so how would the “scale” be able to detect the light?
The perfectly reflective camera is simply a mathematical calculation, if it has a slightly absorbent surface to be able to measure, a feedback system could be set up to return that energy back into the container.
You could also add energy that is equal to the energy absorbed prior to measurement and then reduce it while measuring to determine if the loss is greater than the absorbed energy
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