Re: Earth's shadow

[SSHS KPHOX <kphox@MAIL.CCSD.K12.CO.US>]

PHYS-L@lists.nau.edu writes:
> "The moon's shadow tapers almost to a point at the earth's surface,
> evidence that the taper of the moon's shadow at this distance is one moon
> diameter. So during a lunar eclipse the earth's shadow, covering the same
> distance, must also taper one moon diameter."

This is unclear but I think that what he is saying is something like this:

If the diameter of the earth's shadow were measured at the position of the
moon during a lunar eclipse, it would be smaller than the diameter of the
earth by a distance equal to one moon diameter. Thus the size of the
earth's shadow at the moon's position will cover the entire moon.

Having said that I need to say that Hewitt's language is very unclear. I
don't have that edition to see the page around it or the context.

Anyone else?

Ken Fox

This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.