Foundation and Earth

''The fifth novel in Asimov's popular Foundation series opens with second thoughts. Councilman Golan Trevize is wondering if he was right to choose a collective mind as the best possible future for humanity over the anarchy of contentious individuals, nations and planets. To test his conclusion, he decides he must know the past and goes in search of legendary Earth, all references to which have been erased from galactic libraries. The societies encountered along the way become arguing points in a book-long colloquy about man's fate, conducted by Trevize and traveling companion Bliss, who is part of the first world/mind, Gaia.''

About the Book
Foundation and Earth is a science fiction novel by Isaac Asimov published in 1986. It was the fifth novel of the Foundation series.

The book was nominated to the Locus Award for Best Science Fiction Novel in 1987.

History
Several centuries after the events of Second Foundation, two citizens of the Foundation seek to find Earth, the legendary planet where humans are said to have originated. Even less is known about Earth than was the case in Foundation, when scholars still seem to know the location of 'Sol'. The story follows on from Foundation's Edge, but can be read as a complete work in itself. (It does, however, give away most of the mysteries that Foundation's Edge is built around.)

Gaia
[1] Golan Trevize decides to search the Earth to find the answer to the question "Why did I do It?", referring to his decision to embrace the all-encompassing supermind of Galaxia. He decides to go even if he must go alone. [2] Janov Pelorat decides to help his friend to find Earth. Bliss informs she would go to representing Gaia. [3] Looking for information about Earth, Trevize finds out there are not documents related to it in Gaia. [4] Gaia´s memory functionality is explained by Bliss. It´s said that Gaia don´t have any information about Earth, although it has last for about fifteen thousand years.
 * The Search Begins
 * Toward Comporellon

COMPORELLON
First, they journey to Comporellon, which claims to be the oldest currently-inhabited planet in the galaxy. Although many other planets make that claim, Comporellon has a very long history with which to back it up. Upon arrival, they are imprisoned, but negotiate their way out. While there, they find the coordinates of three Spacer planets. Since the Spacers were the first colonists from Earth back in the ancient days of space travel, it is surmised that their planets would be fairly close to Earth.

AURORA
The first Spacer planet they visit is Aurora, where Trevize is nearly killed by a pack of wild dogs, presumed to be the descendants of household pets long since reverted to wolf-like savagery. They escape when Bliss manipulates the dogs' emotions to psychologically compel a retreat, while Trevize uses his neuronic whip on them.

SOLARIA
Next, they go to Solaria, where they find that the Solarians — who have survived the Spacer-Settler conflicts by clever retreat detailed in Asimov's novel Robots and Empire — have engineered themselves into self-reproducing hermaphrodite beings, who have remained generally intolerant of human physical presence or contact. They have also given themselves a natural ability to mentally channel ("transduce") great amounts of energy, and utilize this as their sole source of power. The Solarians intentionally avoid ever having to interact with each other, except by holographic apparatus ("viewing"), and reproduce only when necessary to replace someone who has died. Bliss, Pelorat , and Trevize are nearly killed by a Solarian named Sarton Bander. Bliss, however, deflects the transducer brain-lobes at the moment Bander tries to use them to kill. Bliss intends to knock out Bander, but has not had sufficient time to learn the full workings of the transducer and accidentally kills it instead. While escaping, they find what they assume to be Bander's immature child, Fallom, in a state of panic because its robotic nursemaid, like all other robots on the estate, has stopped functioning. The child Fallom cannot inherit the Bander estate, as would normally be the Solarian custom, because it is too immature to be able to use its transducer lobes. There being no other place for the child on Solaria, the decision of the robots who immediately arrive to investigate the loss of power is that Fallom is to be destroyed. Upon learning this, Bliss insists that they take Fallom with them.

MELPOEMIA
They next go to Melpomenia, the third and final Spacer coordinate they have. They find that the atmosphere has become depressurized to a few thousandths of normal atmospheric pressure. Wearing space suits, they enter a library, and find a statue, as well as writings with the coordinates of all of the Spacer worlds. While departing Melpomenia, they notice a carbon-dioxide-feeding moss has begun feeding off insignificant leakages in their space suits. Barely recognizing this before stepping on their fully pressurized ship — which would have likely been disastrous — they set their blasters to minimum power to fry it off, and then set the ship to heavy UV-illumination before stepping on board. This disinfection procedure kills any trace of the moss, preventing it from spreading to other worlds. As well as giving them another 47 Spacer worlds that they could visit, they now have a vital clue to where Earth may be found. Since the Spacer worlds were settled from Earth, they form a rough sphere with Earth at the centre. Two stars seem to match. One is a binary star, and also on the charts as an inhabited world, though with a question mark where its status should be indicated. The other is uncharted and much more likely to be Earth's star, especially since legends do not mention Earth being part of a binary system. They decide however to go first to the binary system, because it may give them clues about what to expect on Earth itself.

ALPHA
They next journey to the enigmatic charted system, which turns out to be Alpha Centauri. They find a remnant of the inhabitants of Earth, who many millennia ago were resettled there. There is a reference back to the events of Asimov's novel Pebble in the Sky : we learn that the restoration of Earth's soil was indeed attempted but was abandoned. Later, with Earth becoming uninhabitable, there was a grand project to terraform 'Alpha '. This too was not completed; the only dry land is an island 250 kilometers long and 65 kilometers wide. It is left open whether or not the entire population of the dying Earth was sent to Alpha. The natives, who call their home New Earth, are quite friendly, and Bliss , Trevize , Pelorat , and Fallom decide to enjoy some rest and relaxation. It turns out that the natives secretly intend to kill them, so as to prevent them from ever informing the rest of the galaxy of "New Earth" (the natives are paranoid of being taken by another "Empire" of any kind). They are warned by a native woman, who becomes sympathetic upon hearing Fallom playing the flute with its transducer brain-lobes, and make their escape in the middle of the night. Now certain that Alpha Centauri is not Earth but is near Earth, they head towards the uncharted system. They do notice and are puzzled by the very strong similarities between this star and the larger sun of the Alpha Centauri system. Asimov here is drawing attention to an astronomical curio: the nearest star system to Sol contains a star that has the same spectral type, G2 V, though Alpha Centauri A is a little larger and brighter.

EARTH
Entering the solar system of the uncharted star, they notice that it fits legends about Earth's solar system. The sixth planet has very prominent rings, much more so than any known gas giant. Also the third planet, the one fit for life, possesses an abnormally large moon for any planet other than a gas giant. Obviously this is Earth and its solar system. On the approach to Earth, they detect that it is highly radioactive, and not capable of supporting life, but, while trying to use the ship's computer to locate Solaria , Fallom calls Trevize's attention upon the moon, which is big enough to serve as a hideout for the forces that lived on Earth. They land on there and find R. Daneel Olivaw, who explains that he has been paternalistically manipulating humanity for many millennia, and indeed, since Elijah Baley 's time, which was long before the Galactic Empire or Foundation. He caused the settlement of Alpha Centauri, the creation of Gaia, and the creation of psychohistory (detailed in Prelude to Foundation and Forward the Foundation). He also manipulated Trevize into making his decision at the end of Foundation's Edge (although he did not manipulate the decision itself). Trevize confirms that decision, as the numerous narrow escapes have convinced him that the creation of Galaxia is the correct choice. Also, Daneel's positronic brain is deteriorating. He explains that he is unable to design a new brain, as it would require extreme miniaturization, to the point where the brain would deteriorate immediately. Thus, he tells his visitors that he wishes to merge Fallom's brain with his own, as Fallom's life span is the exceptionally long one of a Spacer. This will buy him time to oversee Galaxia's creation. Daneel continues to explain that since the dawn of civilization, man has been divided. This was the reason for his causing the creation of Psychohistory and Gaia. Another reason this was important was because of the likelihood of advanced life beyond the galaxy eventually attacking humanity. This danger is part of the conclusion to Asimov's book The End of Eternity, in which "Project Eternity" (which manipulated human history to maintain human comfort) had to be destroyed to undo that same extraterrestrial disaster -— extraterrestrials giving humanity no hope of expansion, at which point the birth rate fell, and humanity became extinct.