Susie Ghahremani

Q: I’ve noticed that sunsets last a long time in northern latitudes, like Canada, and are much shorter in equatorial regions. Is this because the earth’s rotation is faster at the equator than at the poles?

A: How long a sunset lasts depends on the angle at which the sun approaches the horizon. In equatorial regions, the sun sets nearly perpendicular to the horizon. At higher latitudes, both northern and southern, the sun’s approach angle is sharper. So, the further away from the equator, the more the setting sun moves along the horizon, taking it longer to move fully out of sight.

Q: How do spiders manage to get their webs to extend horizontally between two distant objects? I’ve heard they cast out a strand to the winds and wait for it to attach somewhere, and then when it does, they spin their web around that. But that seems way too haphazard for these methodical creatures.

A: When a spider lets out an initial thread, even the slightest air current can pull it, allowing the spider to let out as much as is needed. Often it’s only a matter of seconds before the thread latches on to a remote anchor. Once it sticks, the spider tightens the initial thread to make a "bridge line." The methodical part comes when a spider "decides" which strategy—a horizontal or a vertical web—is best, based on which direction its insect prey are coming from.

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