From Spektrum, July 2, 2018: Woher stammen die Sterne der Milchstraße? Eine Himmelskartierung stößt auf eine Reihe von Besuchern – Sternströme aus fremden Galaxien.

From Science News, June 19, 2018: Fermilab physicist Dan Hooper proposes that, to offset a future cosmic energy shortage caused by the accelerating expansion of the universe, a super-advanced civilization could pluck stars from other galaxies and bring them home. It’s a far-out idea, tackling a dilemma in a future so distant that human beings can hardly fathom it: 100 billion years from now, each neighborhood of the universe will be marooned as if on a cosmic island, with resources from the rest of the universe inaccessible.