He should have felt those inky stares on his back when he was like this, staring into the apartment, his back to the night. But now those eyes had disappeared, assimilated into the darkness.
Just what was it that was watching him? Kaoru had never thrown this question out at his father. He doubted even his father would be able to give him an answer.
Now he felt a chill, in spite of the heat. He no longer felt like being on the balcony.
Kaoru went back into the living room and peeked into the kitchen at his mother. She’d finished washing the dishes and was now wiping the edge of the sink with a dishcloth. Her back was to him, and she was humming. He stared at her thin, elegant shoulders, willing her to notice his gaze. But she just kept humming, unmoved.
Kaoru came up behind her and spoke.
“Hey, Mom, when’s Dad getting home?”
He hadn’t intended to startle her, but there was no denying that his approach had been a little too silent, and his voice when he spoke a little too loud. Machiko jumped, her arms jerked, and she knocked over a dish that she’d placed at the edge of the sink.
“Hey, don’t scare me like that!”
She caught her breath and turned around, hands to her breast.
“Sorry,” Kaoru said. He often accidentally took his mother unawares like this.
“How long have you been standing there, Kaoru?”
“Just a few seconds.”
“You know Mom’s jumpy. You shouldn’t startle me like that,” she scolded.
“I’m sorry. I didn’t mean to do it.”
“Really? Well, you did it all the same.”
“Didn’t you notice? I was staring at your back, just for a few seconds.”
“Now, why should I notice that? I don’t have eyes in the back of my head, you know.”
“I know, but, I …” He trailed off. What he wanted to say was, People can feel someone staring at them even if they don’t turn around. But he knew that would scare his mother even more.
So he went back to his original question. “When’s Dad getting home?” Of course, he knew it was pointless to ask: not once had his mother ever known when his father was coming home.
“He’ll probably be late again today, I imagine.” She gave her usual vague answer, glancing at the clock in the living room.
“Late again?”
Kaoru sounded disappointed, and Machiko said, “You know your dad’s really busy at work these days. He’s just getting started on a new project, remember?” She tried to take his side. He got home late every night, but never did she betray the slightest hint of discontent.
“Maybe I’ll wait up for him.”
After she’d finished putting away the dishes, Machiko went over to her son, wiping her hands with the dishcloth.
“Do you have something you want to ask him again?”
“Yeah.”
“About his work?”
“Unh-uh.”
“How about I ask him for you?”
“Huh?” Kaoru couldn’t stop himself from laughing.
“Knock that off! You know, I’m not as dumb as you think I am. I did go to grad school, you know.”
“I know that. But … you studied English lit, right?”
Machiko had indeed belonged to a department of English language and literature at the university, but to be exact her focus had been on American culture, rather than English literature. She’d been particularly knowledgeable about Native American traditions; even now she kept up on it, reading in her free time.
“Never mind that, just tell me. I want to hear what you have to say.”
Still holding the dishcloth, Machiko ushered her son into the living room. Kaoru thought it was a little odd: why should she suddenly take an interest tonight, of all nights? Why was she reacting differently?
“Wait a minute, then.” Kaoru went to his bedroom and came back with two pieces of paper. He sat down on the sofa next to his mother.
As she glanced at the pages in Kaoru’s hand, Machiko said, “What’s this? I hope these aren’t full of difficult figures again!” When it came to mathematical questions, she knew it was time for her to admit defeat.
“It’s nothing hard like that this time.”
He handed her the two pages, face up, and she looked at them in turn. A map of the world was printed on each one.
“Well, this is a change. You’re studying geography now?”
Geography was one of her strong suits, particularly North American. She was confident that in this field, at least, she knew more than her son.
“Nope. Gravitational anomalies.”
“What?” It looked like she’d be out of her league after all. A faint look of despair crept into her eyes.
Kaoru leaned forward and began to explain how these maps showed in one glance the earth’s gravitational anomalies.
“Okay, there’s a small difference between the values you get from the gravity equation and those you get by correcting gravitation acceleration for the surface of the geoid. Here we have those differences written on maps in terms of positive or negative numbers.”
The pages were numbered, “1” and “2”. On the first map were drawn what seemed like an endless series of contour lines representing gravitational anomalies, and each line was labeled with a number accompanied by a plus sign or a minus sign. The contour lines looked just like the ones found in any normal atlas, where positive numbers equaled heights above sea level and negative numbers depths below sea level.
But in this case, the lines showed the distribution of gravitational anomalies. In this case, the greater the positive number, the stronger the gravitational force, and the greater the negative number, the weaker the gravitational force at that particular location. The unit was the milligal (mgal). The map was shaded, too: the whiter areas corresponded to positive gravitational anomalies, while the darker areas corresponded to negative ones. It was set up so that everything could be understood at a glance.
Machiko stared long and hard at the gravitational anomaly distribution map she held in her hands, and then looked up and said, “Alright, I give up. What is a gravitational anomaly?” She’d long since given up trying to fake knowledge in front of her son.
“Mom, surely you don’t think that the earth’s gravity is the same everywhere, do you?”
“I haven’t thought about it once since the day I was born, to be honest.”
“Well, it’s not. It varies from place to place.”
“So what you’re saying is that on this map, the bigger the positive number, the stronger the force of gravity, and the bigger the negative number, the weaker, right?”
“Uh-huh, that’s right. See, the matter that makes up the earth’s interior doesn’t have a uniform mass. Think of it like this: if a place has a negative gravitational anomaly, it means that the geological material below it has less mass. In general, the higher the latitude, the stronger the force of gravity.”
“And what’s that piece of paper?”
Machiko