"Well, I see only stars - ordinary stars, that is. Aurora has a sun. We are close enough to Aurora, I imagine, to make the star that is its sun considerably brighter than the others."
"Entirely too bright, Partner Elijah. It is blanked out or you might suffer retinal damage."
"Then where is the planet Aurora?"
"Do you see the constellation of Orion?'
"Yes, I do. - Do you mean we still see the constellations, as we see them in Earth's sky, as in the City planetarium?"
"Just about. As stellar distances go, we are not far from Earth and the Solar System of which it is part, so that they have the starview in common. Aurora's sun is known as Tau Ceti on Earth and is only 3.67 parsecs from there. - Now if you'll imagine a line from Betelgeuse to the middle star of Orion's belt and continue it for an equal length and, a bit more, the middling-bright star you see is actually the planet Aurora. It will become increasingly unmistakable over the next few days, as we approach it rapidly."
Baley regarded it gravely. It was just a bright star-like object. There was no luminous arrow, going on - and off, pointing to it. There was no carefully lettered inscription arced over it.
He said, "Where's the sun? Earth's star, I mean."
"It's in the constellation Virgo, as seen from Aurora. It is a second magnitude star. Unfortunately, the astrosimulator we have is not property computerized and it would not be easy to point it out to you. It would, in any case, just appear to be a star, quite an ordinary one."
"Never mind," said Baley. "I am going to turn off this thing now. If I have trouble - help out."
He didn't have trouble. It flicked off just as he thought of doing so and he sat blinking in the suddenly harsh light of the room.
It was only then, when he had returned to his normal senses, that it occurred to him that for forty minutes he had seemed to himself to have been out in space, without a protecting wall of any kind, and yet his Earthly agoraphobia had not been activated. He had been perfectly comfortable, once he had, accepted his own nonexistence.
The thought puzzled him and distracted him from his bookfilm viewing for a while.
Periodically, he returned to the astrosimulator and took another look at space as seen from a vantage point just outside the spaceship, with himself nowhere present (apparently). Sometimes it was just for a moment, to reassure himself that he was still not made uneasy by the infinite void. Sometimes he found himself lost in the pattern of the stars and he began lazily counting them or forming geometrical figures, rather luxuriating in the ability to do something which, on Earth, he would never have been able to do because the mounting agoraphobic uneasiness, would quickly have overwhelmed everything else.
Eventually, it grew quite obvious that Aurora was brightening. It soon became easy to detect among the other dots of light, then unmistakable, and finally unavoidable. It began as a tiny sliver of light and, thereafter, it enlarged rapidly and began to show phases.
It was almost precisely a half-circle of light when Baley became aware of the existence of phases.
Baley inquired and Daneel said, "We are approaching from outside the orbital plane, Partner Elijah. Aurora's South Pole is more or less in the center of its disk, somewhat into the lighted half, It is spring in the Southern Hemisphere."
Baley said, "According to the material I have been reading, Aurora's axis is tipped, sixteen degrees." He had glanced over the physical description of the planet with insufficient attention in his anxiety to get to the Aurorans, but he remembered that.
"Yes, Partner Elijah. Eventually, we will move into orbit about Aurora and the phases will then change rapidly. Aurora revolves more rapidly than Earth does - "
"It has a 22-hour day. Yes."
"A day of 22.3 traditional hours. The Auroran day is divided into 10 Auroran hours, with each hour divided into 100 Auroran minutes, which are, in turn, divided into 100 Auroran seconds. An Auroran second is thus roughly equal to 0.8 Earth seconds."
"Is that what the books mean when they refer to metric hours, metric minutes, and so on?"
"Yes. It was difficult to persuade the Aurorans, at first, to abandon the time units to which they were accustomed and both systems - the standard and the metric - were in use. Eventually, of course, the metric won out. At present we speak only of hours, minutes, and seconds, but the decimalized versions are invariably meant. The same system has been adopted throughout the Spacer worlds, even though, on the other worlds, it does not tie in with the natural rotation of the planet. Each planet also uses a local system, of course."
"As Earth does."
"Yes, Partner Elijah, but Earth uses only the original standard time units. That inconveniences the Spacer worlds where trade is concerned, but they allow Earth to go its way in this."
"Not out of friendliness, I imagine. I suspect they wish to emphasize Earth's difference. How does decimalization fit in with the year? After all, Aurora must have a natural period of revolution about its sun that controls the cycle of its seasons. How is that measured?"
Daneel said, "Aurora revolves about its sun in 373.5 Auroran days or in about 0.95 Earth years. That is not considered a vital matter in chronology. Aurora accepts 30 of its days as equaling a month and 10 months as equaling a metric year. The metric year is equal to about 0.8 seasonal years or about three-quarters of an Earth year. The relationship is different on each world, of course. Ten days is usually referred to as a decimonth. All the Spacer worlds use this system."
"Surely, there must be some convenient way of following the cycle of the seasons?"