Tess and Harry on the Dock
“Will the stars always be moving away from us?” asked Tess, feeling the cold wood of the dock against her back as she gazed up into infinity.
“Always is a big word,” said Harry. “But as far as you and I are concerned, their motion will stay the same.”
“Why?” It was Tess’s favorite question because Harry loved answering it.
“Newton’s first law.”
“Stars have to obey the law?”
“Everything in the universe has to obey the laws of science.”
“Who made the laws?”
“A very good question, Tess. When you find out the answer, I hope you’ll tell me.”
“What’s Newton’s first law?”
“Isaac Newton was a scientist who reasoned that three laws govern all motion in the universe. The first law states that an object in motion will remain in motion—at the same speed and in the same direction—unless it is acted on by an external force. It’s called inertia.”
“Inertia,” repeated Tess, rolling the word around in her mouth. “Marie uses that word when I won’t get out of bed.”
“Because inertia also says that an object at rest will remain at rest.”
“Marie doesn’t let me remain at rest.”
“And in that example, your mother is the external force that acts on you and changes your state from being at rest to being in motion.”
“And inertia says that whatever direction an object is moving…”
“It will keep moving in that direction.”
“So, wherever I’m headed in life—I’m going to keep moving in that direction?”
“Not at all, Tess.”
“Why not?”
“Because you are your own external force.”