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Tag Archives: distance

distance to the Moon [try it]

How far is the Moon? You don’t have to look up the answer in a book. You can measure it yourself, and quite easily at that. You will need an accomplice however. For this, you will need some way to record the precise location of the Moon in the sky relative to the stars in […]

parallax [try it]

How do we know how far anything is? For nearby objects, we can pace off the distance, of course, but what about places we can’t walk to? How does your brain know that that door is 10 feet away without marking it off on a ruler? Suppose you are standing at point A (see figure) […]

the 4th dimension [Q&A]

Gautham of Poornaprajna College asks, what is the definition of time in 4-dimensional space? Typically, when people speak of the 4th dimension, they are talking of a spatial dimension. Any point in the 3-D space we are used to can be represented by 3 coordinates, say (x,y,z), with unit vectors all perpendicular to each other. […]