Just focusing on what exists now seems a bit exclusive. And if we include everything that has ever existed as part of the universe, why not include t… - John Barrow

The physicist's concept of nothing—the vacuum... began as empty space—the void... turned into a stagnant ether through which all the motions of the Universe swam, vanished in Einstein's hands, then re-emerged in the twentieth-century quantum picture of how Nature works.

Continual miniaturisation allows resources to be conserved, efficiency to be increased, pollution to be reduced, and the remarkable flexibilities of the quantum world to be tapped. Very advanced civilizations elsewhere in the universe may have been forced to follow the same technological path. Their nano-scale space probes, their atomic-scale machines and nano-computers, would be imperceptible to our coarse-grained surveys of the universe. ...This may be the low-impact evolutionary path you need to follow in order to survive into the far, far future.

The secret of how galaxies came into being may well be fathomed by the study of the most elementary particles of matter in particle detectors buried deep underground; the identity of those elementary particles may be revealed by observations of distant starlight. ...by the coming together of the largest and the smallest aspects of the physical world our appreciation of the unity of the universe becomes more impressive and complete.