“What the probe had found was a star with reasonable possibilities for encouraging life; a belt of debris, including particles, planetoids, irregular chunks somewhat under planet size with interesting implications for systemic formation, and a planetary companion with its own system of debris and moons…A planet desolate, baked, forbidding. It was no Eden, no second Earth, no better than what existed in the sun’s own system, and it was a far journey to have gone to find that out. The press grappled with questions it could not easily grasp itself, sought after something to give the viewers, lost interest quickly. If anything, there were questions raised about cost, vague and desperate comparisons offered to Columbus, and the press hared off quickly onto a political crisis in the Mediterranean, much more comprehensible and far bloodier.”

"By Jove!" in View from a Height (1963); often misquoted as "Jupiter plus debris".
General sources

Letter to a Friend (circa 1656)

Beyond the Veil
Context: The reason which placed the stars, the sense of proportion which we recognize in the planetary system, finds its correspondence in this brain of ours. We question every feature of what we see, think, and feel. We try every link of the chain and find it sound if we ourselves are sound. This power of remotest question and assent is not of to-day nor yesterday.
It transcends all bounds of time and space. It weighs the sun, explores the pathway of the stars, and writes, having first carefully read, the history of earth and heaven. It moves in company with the immortals. How much of it is mortal? Only so much as a small strip of earth can cover. These remains are laid away with reverence, having served their time. But what has become of the wonderful power which made them alive? It belongs to that in nature which cannot die.

As quoted in The Discovery of Nature (1965), by Albert W. Bettex
Context: There are countless suns and countless earths all rotating round their suns in exactly the same way as the seven planets of our system. We see only the suns because they are the largest bodies and are luminous, but their planets remain invisible to us because they are smaller and non-luminous. The countless worlds in the universe are no worse and no less inhabited than our earth. For it is utterly unreasonable to suppose that those teeming worlds which are as magnificent as our own, perhaps more so, and which enjoy the fructifying rays of a sun just as we do, should be uninhabited and should not bear similar or even more perfect inhabitants than our earth. The unnumbered worlds in the universe are all similar in form and rank and subject to the same forces and the same laws. Impart to us the knowledge of the universality of terrestrial laws throughout all worlds and of the similarity of all substances in the cosmos! Destroy the theories that the earth is the center of the universe! Crush the supernatural powers said to animate the world, along with the so-called crystalline spheres! Open the door through which we can look out into the limitless, unified firmament composed of similar elements and show us that the other worlds float in an ethereal ocean like our own! Make it plain to us that the motions of all the worlds proceed from inner forces and teach us in the light of such attitudes to go forward with surer tread in the investigation and discovery of nature! Take comfort, the time will come when all men will see as I do.

Descriptio Globi Intellectualis (1653, written ca. 1612) Ch. 6, as quoted in "Description of the Intellectual Globe," The Works of Francis Bacon (1889) pp. 517-518, https://books.google.com/books?id=lsILAAAAIAAJ&pg=PA517 Vol. 4, ed. James Spedding, Robert Leslie Ellis, Douglas Denon Heath.

Heaven and Earth (2009)

Source: Culture series, Matter (2008), Chapter 10 “A Certain Lack” (p. 167)

Source: Flying saucers, the process of matter and energy, science, the revolutionary and working-class struggle and the socialist future of mankind (26 June 1968)

Source: The Seth Material (1970), p. 312