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Why are there only 3 time zones between NY & LA and 5 between NY & London?
LA and London are approximately the same distance apart from New York, so why is there a difference in the number of time zones? There are about 70° of longitude between London and New York, and about 50° between New York and Los Angeles. The Earth rotates through 360° of longitude each day, so that an ideal time zone is 15° of longitude wide. That makes a bit less than 5 time zones between NY and London (70¸15) and a bit more than 3 time zones between NY and LA (50¸15). However, since time zones are political as well as geographic, it turns out that we round up for London and down for LA. Because New York is 10° of latitude south of London, and Los Angeles only about 5° south of New York - and the distance represented by a longitude degree shrinks as you go north from the Equator - it may well be that New York is about the same distance in miles from LA as from London. But it's longitude that matters for time zones. Unfortunately the maps many of us are used to are not distance-realistic (or area-realistic) projections. Here's a site dedicated to the Peters Equal-Area Projection, which explains how it differs from the more common Mercator Projection.
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