Excerpt of Summer Sanctuary by Laurie Gray

From Summer Sanctuary by Laurie Gray

Chapter 8, pp. 48-52

©2010 by Socratic Parenting LLC. All rights reserved.

"What are you studying?" Dinah asked as she sat down at the table across from me.

"Time dilation and the speed of light," I said propping my head up in my hands.

"What for?" asked Dinah, examining the book closest to her.

"I have this theory that I'm hoping to prove, but it's turning out to be way more complicated than I thought." I flipped the book in front of me shut and sighed. "Did you know that a light year is a measure of distance, not time?"

Dinah shrugged. "So what's your theory?"

"I started reading Einstein's theory of relativity and how the only constant speed we know of is the speed of light." Dinah raised her eyebrows and opened her eyes wide, trying to take it all in. "It's like this," I explained. "Suppose I throw a ball to you at 50 miles per hour. The ball's traveling at 50 miles per hour, right?"

"Okay," agreed Dinah.

"Now suppose we're riding on a train that’s traveling 50 miles per hour. I'm holding the ball, so you and me and the ball are all traveling at 50 miles per hour on the train, right?" I checked to make sure she was still with me.

"Right," Dinah said.

"Okay, now suppose I throw the ball to you at 50 miles per hour. You and I are still traveling at 50 miles per hour, but the ball is traveling at 100 miles per hour, right?" I was nodding, but Dinah wasn't convinced.

"Which way are you facing?" Dinah asked.

"What do you mean which way am I facing?" I thought she was just messing with me.

"I mean are you throwing the ball in the same direction the train's moving or do you have your back to the front of the train, throwing it back to me?" Dinah asked. She was serious, and suddenly it dawned on me what she meant.

"Let's say I'm facing the front of the train and throwing the ball in the same direction that the train's moving," I said.

"Okay, then I can see that the ball would be traveling 100 miles per hour," Dinah conceded.

"So how fast something is traveling is relative to how fast the things around it are traveling. And that's true for everything except light. Light always travels at 300,000 kilometers per second. If the train was traveling at 100,000 kilometers per second and had a light on the front of it, the light would still only travel at 300,000 kilometers per second. If you were on another train traveling toward the light at 100,000 kilometers per second and the train with the light wasn't moving, the light would still travel toward you at 300,000 kilometers per second."

"Well, that seems a little weird," Dinah said. "So what's time dilation?"

"Time dilation is how time slows down the faster you move. So if you were in a rocket zooming by earth, you wouldn't age as fast as I would here on earth," I explained.

"And that's what you're trying to prove?" Dinah asked, looking at me like my hair suddenly poofed up like Einstein’s.

"No, Einstein already proved all that. I'm trying to prove that the Bible told us this way before Einstein figured it out," I said. My palms were getting sweaty. I suddenly wondered if quoting Bible verses to Dinah was such a great idea.

"You mean like Einstein's theory of relativity is written in the Bible?" Dinah asked.

"Not all spelled out exactly, but when I was reading all the stuff Einstein proved, I kept thinking of two things I'd read in the Bible- -that God is light, and that 1,000 years on earth is like a single day to God. So I want to do the math to see if the time dilation traveling at the speed of light would be like one day equals 1,000 years."

"So is that like algebra or geometry or what?" Dinah wanted to know.

"That's what I'm trying to figure out. I thought that I just needed to look up how long a light year is and then compare the number of seconds in a thousand light years to the number of seconds in a single day on earth. Only a light year is how far light travels in a year. Distance, not time. Now I'm stuck."