In article <7qp33o$d1d$1 at iceman.tac.net>,
falk at arc.ab.ca (Alfred Falk) wrote:
>> Robert Clark <rgclark at my-deja.com> wrote in message
> news:7pu61e$u7t$1 at nnrp1.deja.com...> >
> > Plants indoors will lean toward the Sun because the sunlight streams
> > in from that location in the room. But suppose you have a plant or tree
> > on the outside. Presumably it couldn't follow the Sun across the sky,
> > so do they try to lean toward the Sun outdoors? I was thinking that in
> > high latitudes such as the artic the Sun is low on the horizon even at
> > noon. So would plants lean over at an angle to point to that position
> > in the sky?
>> Need an astronomy lesson here. It is true that the as you go higher in
> latitude, the sun appears lower in the sky. However, it also makes a
> wider arc around the horizon in summer and shorter in winter. (As not
> much growth takes place in winter, we only need to consider summer.)
> The extreme point is that at the pole the sun rises at spring equinox
> and sets at autumn equinox (assuming idealized point sun and no
> atmospheric effects). The sun then appears to move all the way around
> the sky in one day. As you drop in latitude below the arctic circle,
> the sun increasing dips below the horizon on the north side.
>> Anyhow, if a plant were to lean toward the sun it would have to lean in
> different directions through the day, and so the effect generally
> cancels. On the other hand, I find that many plants close to my house
> or fence tend to lean away from the house because the sun necessarily
> comes from that direction, being shaded by the house or fence.
> A L B E R T A Alfred Falk falk at arc.ab.ca> R E S E A R C H Information Systems Dept (780)450-5185
> C O U N C I L 250 Karl Clark Road
> Edmonton, Alberta, Canada
>http://www.arc.ab.ca/ T6N 1E4
Thanks for the info. I had forgotten that at the North Pole daylight can
last 6 months of the year. And at lower artic latitudes the Sun can stay
visible for several "days" straight ("day" here meaning a 24 hour period.)
This means that the Sun is moving across the sky much more slowly at such
high latitudes and it is conceivable that a plant simply leaning over at
angle (not necessarily moving horizontally) can increase the amount of
sunlight it receives.
"In order for a scientific revolution to occur,
most scientists have to be wrong"
-- Bob Clark
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