Gaia

Chapter 3 of Eternity by Greg Bear is set on Gaia, the alternative Earth that Patricia/Patrikia had accessed near the end of Eon. I feel that, at this point, the hard sf of Eon became fantasy. The element that I find fantastic is not the existence of alternative Earths but the means of finding and entering them.

While inside the infinite artificial corridor called "the Way," which  physically is out there somewhere in interstellar space, projected from one end of a spacecraft, Patricia was one of a number of people who had a knack like water-dousing. Each of them wielded a device that enabled them to locate a particular point on the inner surface of the Way, namely a point at which it would then be possible, using the same device, to open an entryway to a particular alternative Earth at a particular moment of its history.

Patricia sought a history in which there had not been a recent nuclear war, therefore in which her parents and fiancee had not died in such a war, but in which she herself had nevertheless died in some accident so that the Patricia arriving from the Way would be able to replace the Patricia who had died in the accident. She walks around inside the Way holding the device called the "clavicle," somehow sensing the presence of alternative Earths, receiving an impression of their contents, even information about them, and homing in on the one that she wants. It seems that she does not read the data on dials or a screen on the clavicle but rather inwardly senses them with the help of the clavicle?

So an analogy might be an astronomer seeking stars with habitable planets who points a telescope at the sky, moves it around and is guided by the telescope to focus on a particular part of the sky and eventually on a single star? This does not sound like a scientific process. In fact, to complete the analogy, he would be able to specify and locate a planet not merely habitable but Earth-like in every detail although uninhabited?

When she begins "...the gate dilation," the clavicle whistles painfully, she sees "...a circle of whirling possibilities at her feet..." (Eon, London, 2002, p. 470) and the circle becomes a gateway to a point on the Earth's surface, although she gets the wrong Earth. But I find it difficult to accept that she can get to any Earth by such a means.