Launch Pad, Day Two: Mike Brotherton on the Electromagnetic Spectrum, Light, Instruments, Telescopes

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Ian Randal Strock was curious about how far away we'd have to be from the sun before it started to appear to be a point rather than a disk. To answer the question, first we have to look at how humans see distant objects: The angular size of an object is proportional to its physical size divided by its distance from us. So if you double the size of an object, it's going to cover an angle twice the size. If you move the object twice as far a...