Before considering the question I'm about to ask, first go have a beer or a sip or two of good bourbon. At the very least, clear your mind of all extraneous thoughts, sit cross-legged and stare blankly at the sky for a few minutes.
Are you ready?
OK then.
Is a shadow SOMETHING or is it just the LACK OF SUNLIGHT?
I ponder this question just about every year at this time.
"Well, that's understandable," you are probably saying. "After a long Canadian winter you are probably getting a bit daft!"
That is always a possibility, I suppose.
The question at first seems as simple as it gets. A shadow is just where the light is blocked. It is where there is a LACK OF SUNLIGHT. It isn't something in itself.
I could easily believe that premise any time of year except now. You see the daylight is quite long now, almost 12 hours, in fact. And there is a lot of warmth in it too.
Something funny happens to footprints made in the snow right about now. They grow!
For a fact, a footprint made today will be quite a bit larger tomorrow and will be even larger the next and this will continue until the snow is either gone or there is a new snowfall that fills the footprint in again. That's what happened to our dog Sam's tracks in the second photo. The tracks on the left were made today. The much larger one was made by him two days ago.
What could cause this?
Well, the shadow caused by the depth of the footprint is darker than the rest of the snow and this darkness absorbs more sunlight -- and therefore heat -- than its surroundings and the footprint melts faster.
If you think the footprint might melt faster because the snow is compressed you would be dead wrong. Compressed snow is more dense and is considerably slower to melt. In fact, the footprints made in the snow last winter, then filled in by subsequent snowfalls, stand like little stalagmites in the spring. They don't melt as easily as does the rest of the snow.
No, it is the SHADOW of the recent footprint that accelerates the melting of the snow. How can the LACK OF SUNLIGHT create a reaction from the sunlight? I don't think it can.
Therefore, a shadow is SOMETHING.
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1 comment:
Like everything in the universe, shadows are something. Newtons law explains this. keep the blog coming, I look forward to them every day
Joe O.
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