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Greetings, my fellow port swillers!

This week Youngest Gel started evening swim practices in anticipation of her high school team getting under way in about a month or so.  (This will be her third year on the varsity, he mentioned gratuitously.)

As we drove home after I picked her up, she began talking about how lovely the moon was up in the sky in front of us.  This led to a discussion about sunlight and starlight, and eventually about how light travels.  (What was it Douglas Adams said? It travels so fast that it takes most civilizations thousands of years to realize that it travels at all?)

Eventually, I got round to reeling off what I remember of the speed of light: 12 million miles a minute; it takes about six minutes or so to travel from the Sun to Earth; measuring distances in space by light-years; etc.

“What is a light-year, anyway?” the Gel asked.

“Well,” I said, “It’s the distance light travels in one year.  Remember how I said 12 million miles a minute?  So multiply that by sixty to get miles per hour, then multiply that by twenty-four to get miles per day, and multiply that by three hundred sixty-five to get an approximation of the distance of a light year.  I don’t know the exact number, but I do know it’s awfully big.”

Out of the corner of my eye, I could see her lips moving as she did a quick and dirty calculation in her head, her eyes steadily widening.

“Well, okay.  How far away are the stars, then?” she asked.

“That varies, of course, ” I replied.  “Alpha Centauri is our nearest neighbor at about two light-years’ distance.  On the other hand, Betelgeuse, the left shoulder of the constellation of Orion, is 500 light years off.  Others are at different distances, some very much farther than that.”

“Five hundred!” she exclaimed.  “Are you telling me that the light I see on Orion’s shoulder left it 500 years ago? Like when Columbus had just arrived in the Americas?”

“Yippers,” I said. “And for all we know, it could have gone supernova or even disappeared altogether any time between then and now and we wouldn’t even know it until the effects got here.”

The Gel huddled herself together, an awe-struck look on her face.

“This is seriously freaking me out,” she said.

Ol’ Robbo, for one, is glad that the Gel had this reaction.  Not only am I pleased at her grasp of the physical concepts (and math) involved, I also believe it demonstrates a proper sense of humility.

It’s also one that I happen to share.  When looking about God’s Creation, I can’t think of anything more humbling than contemplating interstellar distances (unless it’s geological time, another of my favorite things to noodle).

Oh, and obligatory (not because I like the movie – I don’t much – but because I often sing it in the shower and it’s also my chief reference for quick and dirty facts of this sort):

 

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