Essay in 2004

Fluid dynamics: Ludwig Prandtl's ideas brought hydraulics and hydrodynamics together to found a new field.

Greenhouse effect: Fourier's concept of planetary energy balance is still relevant today.

Ion transport: the division between active transporters and passive channels is beginning to blur

Proprioception: is the sensory system that supports body posture and movement also the root of our understanding of physical laws?

Co-evolution: Earth history involves tightly entwined transitions of information and the environment, but where is this process heading?

Language evolution: evolutionary vestiges may provide clues to the ultimate origins of human language.

Time: how much of the cosmological timescale do we control and use?

Carcinogenesis and tissue repair: how might chronic tissue injury lead to the development of cancer?

Redfield ratios: the uniformity of elemental ratios in the oceans and the life they contain underpins our understanding of marine biogeochemistry.

Reversible computation: how feasible is a computer that is both logically and physically reversible?

Heterogeneous catalysis: just as for enzymes, flexibility and mobility are emerging as key features of catalytically active metal surfaces.

Planetary science: both the deductive skills of geologists and the mathematical approach of astrophysicists are needed to study planets.

Red blood cell vasodilation: nitric oxide and haemoglobin help to match blood flow to metabolic demand.

Dream consciousness: our understanding of the neurobiology of sleep offers insight into abnormalities in the waking brain.

Attachment: the nature of the bonds between humans are becoming accessible to scientific investigation.

Niche construction: do the changes that organisms make to their habitats transform evolution and influence natural selection?

Electroweak-symmetry breaking: solving the riddle of how symmetry is broken may determine the future direction of particle physics.

Scale and proportion: do the mechanisms of planar polarity also help determine the shape and size of animals?

Dark matter and dark energy: they might be more abundant than the stuff we are made of, but are they any more interesting?

Anatomy: displays of bodies are no longer sufficient to explain the richness of modern anatomy to students or to the public.