"The whole episode of human presence on this earth is a mere speck in the history of the universe." This reflection on time is from Stephen Jay Gould, the palaeontologist. When he makes his comment (in response to a remark overstating the importance of man for the future of our planet) the accompanying shrug of his shoulders puts the activities of man in a different perspective. However, is it the proper perspective? You might say with equal right that the history and the future of the universe do not concern us, and that the proper perspective for humans is the history of humanity, man's individual life span in particular, and last but not least mankind's immediate and distant future. We have a rational idea of cosmological time, and it has no connection with time as experienced in human life: the cosmos is simply too large to arouse a sense of space or time in proportion to its size. When we talk about the origin of the universe or the life-cycle of stars, we shrink our time-scale. We enlarge it when we discuss a quantum experiment on elementary particles. We stretch and compress time until the duration fits the capacity of our imagination. Personally I feel comfortable with the view that time has no beginning and no end but can be episodically stretched and compressed (J.S.Stamps 1979). This has for consequence that in my spatial perception there is room for the infinitely small as well as for the infinitely large, thanks to relativity and the elasticity of time. While some parts of the universe disappear into nothingness, others are recreated and begin a new existence. Time is stretched along with the expanding space: when objects in space become unimaginably large and distant, they move at speeds that are equally beyond our powers of imagination. Events in an environment of cosmic size can be taken in by our imagination, but only if we drastically reduce the spatial dimensions as well as the time-scale. The light year as a unit of distance is a reduction device, that helps us to handle the unimaginable. The Planetarium, an auditorium-sized model of the universe, is helpful and so is the book and video by Boeke/Morrison/Eames: 'Powers of Ten; the world in twenty steps'. Even more helpful is a piece of the magic mushroom, like the one which is nibbled by Alice in Wonderland whenever she wants to fit into a new environment. By stretching and shrinking space and time we obtain access to the micro- and mega-worlds. Micro-telescopy has enabled us to see similarities that would otherwise have escaped our attention. As we let our thoughts fly through space and time, we constantly change frames. In the world of molecules and atoms, we help our imagination by multiplying the dimensions and stretching the time. Looking over the shoulder of Dr J.P.Tollenaere, professor in computational chemistry, I see how he simulates a chemical reaction: the screen of the computer shows a macro-molecule the size of a football, slowly changing its configuration. Bonds between atoms are rearranged under the influence of electrical and Van der Waals forces when a receptor site on the molecule is approached by a molecule with properties of affinity. The events on the screen are the result of calculations of the intra molecular forces of attraction and how they affect each other. We see in seconds what in the real chemical reaction occurs in nanoseconds.