This is the first time I'm writing something that jumps from one period of time to another in a short story:
The field was vast and empty, like a green abandoned planet. Icaro and Maru were lying on the middle of it, sharing a joint, and gazing at the ocean of stars above them. Occasionally, a breeze would come through creating gentle waves in the grass.
Maru took a long drag on the joint and passed it to him. "You know, sometimes I wonder why we have to die. Why can't we last forever, like a crystal?"
Icaro glanced at her, then turned back his eyes to the sky. An airplane was passing over them, high in the sky. It almost seemed to merge with the stars.
"I have a theory," he said, in a neutral voice. "Our lives are temporary because we just serve as disposable machines for something that is within us."
She sat up and narrowed her eyes at him. "Something like a soul or a little alien?"
"More like a crystal," he corrected her. She kept silent for a moment, waiting for him to continue.
"They built us to transport themselves, compete with each other, find other crystals, and build new machines so they can continue living on them," he said.
"What's the point of doing that?" she asked after giving it a thought.
"There's neither a point nor a purpose. They just do it because that's what they are supposed to do. In fact, they are not even conscious of it."
Maru looked up at the stars for a while, trying to digest what Icaro had just said. The airplane was nowhere to be seen.
"So according to your theory, our lives don't actually have a meaning. We are just cargo ships delivering supplies and goods to other cargo ships," she said.
He glanced at her, took another drag on the joint, and blew the smoke up into the air. "I know, it's not a very comforting theory."
They remained quiet for a few minutes, lost in their thoughts, feeling as if the conversation had transported them into a foreign land.
"Well," Maru finally said. "Even if your theory tells us that life doesn't have a meaning, it's still a cheerful thought."
Icaro turned his head and stared at her. "How is that?"
"If we happen to have these crystals, even if our bodies turn into dust one day, part of us will never die."
He looked at her with a smile on his lips, and looked back to the stars.
Hundreds of years had passed, but the field looked the same as before. It was early in the morning and the sun had just risen. The sky was clear except for a few clouds on the horizon. A young boy and a girl were walking through the field. There was a soft wind coming from somewhere, blowing their hair slightly.
"I think this is a nice spot," he said and sat in the grass. She followed his action, settling herself beside him.
They remained silent for a moment, listening to the sound of the wind.
"So your grandmother is not in good health?" the little girl asked, turning her head towards him.
He nodded without looking at her. She felt as if she had just said something inappropriate.
"You know, sometimes I wonder why life is so short," he said after a moment.
She gazed up into the sky and looked at an airplane that was flying near by.
"I got a theory," she said.
I am doing this effectively? If not, how to improve it?