I found this in You-Know-Who's latest cache of papers. I'm inclined to believe that it's from one of his not-so-parallel iterations, given that the thing appears to be dated to the 1930s. Still, I'm sure our friends would stump up something for it if they were to be persuaded of its provenance.
—Marshall

Item designation number: #45393BE-048
Warning: Phenomenon presently encloses and has been determined to present an existential risk to the Earth. Its appearance on 1903/03/01 has caused an irretrievable breach of secrecy for the Foundation and the Overseers have directed that the Foundation is to lend all assistance, including the utilisation of any and all objects under its control, to the governments of the United Kingdom of Great Britain and Ireland, Third French Republic, German Empire, United States of Austria, Kingdom of Italy,  Russian Empire and their allies in the preservation of the world.
Description of item:
Initially reported as a cloud or nebula enclosing the Earth, it has been determined that the phenomenon actually comprises the interior of a cube approximately 66,580 miles wide. This volume has been determined to be inhabited by an inconsistent number of humanoid entities some 25.5 million times larger than homo sapiens. These entities have been observed to enter and leave the space surrounding the Earth, suggesting that the extent of the phenomena may be much greater than previously suspected.
The difficulty currently experienced in imaging these entities and the interior of the cube is a product of the anomalous qualities of light incident of Earth from this volume—experiments indicate light quanta emanating from the phenomenon are scaled identically to the humanoid entities. Once refracted from non-anomalous matter the light behaves normally—however, it has been calculated that to properly resolve images from the phenomenon, a lens 126 miles across would be needed.
The fate of the cosmos beyond the phenomena has not yet been established. It is entirely possible that the Earth and its near-space environment has been removed to a new location rather than the phenomenon manifesting in Earth's original environs; in which case the phenomena may comprise the immediate universe. Extreme tidal anomalies since the appearance of the phenomenon indicate that traditional heavenly bodies are no longer present, or that their gravitational effect is entirely masked by the phenomenon.
The humanoid entities have demonstrated an unprecedented ability to alter both the physical and temporal characteristics of the Earth. By physically manipulating the barrier between the Earth and the phenomenon they are able to cause an event currently designated #45393BE-048-01. During a #45393BE-048-01 event the extent of the phenomenon narrows sharply before disappearing for a brief instant. In this instant all matter on Earth, as far as can be established, is returned to the position it held at 0530 on 1903/03/01. Although 19 years have passed chronologically since the phenomenon initially appeared, the population of Earth has experienced 32 subjective years over the course of eight #45393BE-048-01 events.
Detail of current containment:
The phenomenon is currently uncontained and, at our current level of technology, uncontainable. Heroic efforts are being made by the surviving Great Powers to prevent at all costs another #45393BE-048-01 event—present theories of science indicate individuals conceived after the last such event (some 160 million individuals) are infinitesimally unlikely to survive the next event. We have furthermore seen the recovery of individuals in infancy or in utero in 1903 who were thought permanently broken by repeated regression—another #45393BE-048-01 event is highly likely to render these individuals' sanity unrecoverable.
The current disposition of the phenomenon is asymmetrical, such that a significant portion of the eastern hemisphere, the Southern Cone and the western half of the North American continent is left in total darkness, whilst the remainder enjoys a constant, dim light equivalent to about 900 footcandles. The effect has been the displacement of approximately one billion people and the deaths of some hundred million. Only the authorised use of items #02837RU-006, #07843NY-038 and #78394MI-124 has prevented further casualties due to overpopulation and famine. As much as 30% of all terrestrial species are believed to have passed into extinction since the last iteration of 1903/03/01. Particular matter from #45393BE-048 incident on the Earth has been observed to emit Curie waves and has proved a danger when it impacts in populated areas or in dense forest, causing uncontrollable fires.
Sectors 5 through 11 and 15 have been permanently compromised by the #45393BE-048 phenomenon, necessitating the evacuation of Sites 15, 17, and 19 through 36. As a consequence the Foundation has lost control of items including #09712NJ-008, #56439AR-017 and #87631MN-060. The eastern seaboard of the United States, as far north as the 49th parallel, has been designated Zone-001 and is subject to indefinite quarantine. All British and American naval assets have been requisitioned for this task, and the remaining armed forces of the United States and the Dominion of Canada have been deployed in a fortified defensive line at the northern border of Zone-001.
Containment procedures update 1917/06/19: Defensive line 'Yankee' has been overwhelmed. Forces fell back to defensive line 'Esquimaux' at the 51st parallel. All of North America subsequently designated part of Zone-001. Sectors 22 and 23 are considered lost. Anomalous elements are currently being held at the southern border of Zone-001 at the Panama canal works, which have been converted into a fortified position.
Containment procedures update 1919/06/19: The islands of Ireland and Great Britain have been overrun by #09712NJ-008 elements. Firebombing with Curie devices was approved on 1919/09/10 and sterilisation appears to be successful as of 1919/12/25. The islands have been designated Zone-002. His Majesty Edward VII has been successfully evacuated to the Cape Colony. Proposals for the sterilisation of Zone-001 are under consideration.
Report: On 1920/04/30 expeditionary forces retrieved #67463CN-144 from the area formerly known as Tibet. Item has been turned over to the authority of the United States of Austria. On 1920/08/06 a complement of space-vessels powered by particular matter from #45393BE-048 has been launched using #67463CN-144 with the intent of seizing control of the immediate area of the phenomenon and eliminate the threat caused by two #45393BE-048 entities who had been observed to approach the barrier over the course of the past week. Communication with the fleet ceased when it reached 62 miles above the surface of the Earth and all assets were presumed lost; it was later realised that the fleet had become subject to time dilation similar to that which governs #45393BE-048 entities, preventing useful radiotelegraphic communication. Elements of the fleet re-entered Earth's atmosphere in 1934/03/20 to report a partial success; further assets have since been committed to prevent another #45393BE-048-01 event. The United States of Austria and the German empire report that a further 10,000 Curie weapons have been manufactured and further programmes have been implemented to construct elements harmful to #45393BE-048 entities, including the use of #87364CA-047.
Addendum: The Foundation has been enervated, but endures. Its heart has been torn out, but it continues to beat—from the Cape, from the Rock of Gibraltar, from Rhode Island and the island of Cuba. From Berlin and Vienna, in places once closed to us, a new Foundation emerges; a Foundation not arrogant in its isolation but subject to the Great Powers in servitude to the human race. We can no longer shoulder the burden alone—all men must share the knowledge that the earth beneath their feet was never firm and that the universe never obeyed laws comprehensible to man. To the end of time, we will cling on—we will defend whatever is left to us with a burning fire in our eyes and hearts. All our struggle, all our efforts, have led up to this; to contain and tame that which offends rationality. To feed the poor, to heal the sick, to hurl the vessels of our allies to the heavens to fight the gods who have so wounded the earth. Thus we speak: Survive. Conquer. Punish.
—H Keter